Wilson Journal of Ornithology Volume 123, Number 1, March 2011 Ewell Sale Stewart Library 2011 Published by the Wilson Ornithological Society f THE WILSON ORNITHOLOGICAL SOCIETY FOUNDED 3 DECEMBER 1888 Named after ALEXANDER WILSON, the first American ornithologist. I President — E. Dale Kennedy, Biology Department, Albion College, Albion, MI 49224, USA; e-mail: dkennedy@albion.edu First Vice-President — Robert C. Beason, P. O. Box 737, Sandusky, OH 44871, USA; e-mail: Robert. C .Beason@gmail .com Second Vice-President — Robert L. Curry, Department of Biology, Villanova University, 800 Lancaster Avenue, Villanova, PA 19085, USA; e-mail: robert.curry@villanova.edu Editor — Clait E. Braun, 5572 North Ventana Vista Road, Tucson, AZ 85750, USA; e-mail: TWILSONJO@ comcast.net Secretary — John A. Smallwood, Department of Biology and Molecular Biology, Montclair State University, Montclair, NJ 07043, USA; e-mail: smallwoodj@montclair.edu Treasurer — MelindaM. 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THE WILSON JOURNAL OF ORNITHOLOGY (formerly The Wilson Bulletin ) THE WILSON JOURNAL OF ORNITHOLOGY (ISSN 1559-4491) is published quarterly in March, June, September, and December by the Wilson Ornithological Society, 8 10 . East 10th Street, Lawrence, KS 66044-8897. The subscription price, both in the United States and elsewhere, is $40.00 per year. Periodicals postage paid at Lawrence KS. POSTMASTER: Send address changes to OSNA, 5400 Bosque Boulevard, Suite 680, Waco, TX 767 1 0. All articles and communications for publication should be addressed to the Editor. Exchanges should be addressed to The Josselyn Van Tyne Memorial Library, Museum of Zoology, Ann Arbor, MI 48109, USA. Subscriptions, changes of address, and claims for undelivered copies should be sent to OSNA sunn Boulevard. Suite 680. Waco, TX 76710, USA. Phone: (254) 399-9636; e-mail: business@osnabirds org Back issues or single copies are available for $12.00 each. Most back issues of the journal are available and may be ordered from OSNA Special prices will be quoted for quantity orders. All issues of the journal published before 1117, 0 2 web site a, the University of New Mexico library (http://elibrary.u,Ledu/L^ reproductions of all papers (including illustrations) are available as either PDF or DjVu files ^ hable> and fiiH-text © Copyright 201 I by the Wilson Ornithological Society Printed by Allen Press Inc., Lawrence, KS 66044, USA COVER: Wilson’s Snipe ( Gallinago delicaia). Illustration by Scott Rashid © This paper meets the requirements of ANSI/NISO Z39.48-1992 (Permanence of Paper). ssp poecilinotus duidcie ssp lepidonotus ssp griseiventris ssp nigrigula FRONTISPIECE. Taxa in the revised Scale-backed Antbird ( Vtllisorms poecilinotus) complex. Upper five figures are Common Scale-backed Antbird (W. poecilinotus ); bottom three are Xingu Scale-backed Antbird (W. vidua). Art reproduced with permission from Plate 67, Volume 8 of Handbook of the Birds of the World (J. del Hoyo, A. Elliott, and D. A. Christie 2003), Lynx Edicions, Barcelona, Spain. Paintings by Hilary urn. The Wilson Journal of Ornithology Published by the Wilson Ornithological Society VOL. 123, NO. 1 March 2011 PAGES 1-198 The Wilson Journal of Ornithology 123(1): 1-14, 2011 SPECIES LIMITS IN ANTBIRDS (THAMNOPHILIDAE): THE SCALE-BACKED ANTBIRD ( WILLISORNIS POECILINOTUS) COMPLEX MORTON L. ISLER1 3 AND BRET M. WHITNEY1 2 ABSTRACT. — The geographic range of the Scale-backed Antbird (Willisornis poecilinotus) encompasses Amazonia. Seven currently defined subspecies are distinguished from one another by diagnostic plumage characters except for one pair. Six pairs of subspecies are apparently parapatric and lack a known barrier to intergradation in at least a portion of their contact zone; yet confirmed hybrids are known only for one pair in one location. An analysis of >350 recordings, however, found vocal differences among them insufficient to recommend elevating subspecies to the species level with one exception. Populations in southeastern Amazonia should be considered a distinct species, Willisornis vidua (Hellmayr), Xingu Scale-backed Antbird, on the basis of their distinct loudsongs, raspy call series, and contact calls. Within the widespread Willisornis poecilinotus , Common Scale-backed Antbird, the remaining instances of parapatry without extensive intergradation provide a focus for future fieldwork to define interrelationships in contact zones and mechanisms of species recognition that may be sustaining them on independent evolutionary paths. Received 75 May 2010. Accepted 9 September 2010. The Scale-backed Antbird ( Willisornis poecili¬ notus) (Cabanis 1847), a widespread Amazonian complex, occupies a unique place in thamnophilid antbird evolution. Scale-backed Antbirds, as described in detail by Willis (1982), primarily forage over or near army ant swarms, but their morphology directed early taxonomists (Ridgway 1911, Cory and Hellmayr 1924) to place them in the genus Hylophylax with species that were not obligate ant-followers. Willis (1982) and other observers (e.g., Zimmer and Isler 2003) noted that Scale-backed Antbirds did not look or behave like 1 Department of Vertebrate Zoology, MRC-1 16, National Museum of Natural History, Smithsonian Institution, P. O. Box 37012, Washington, D.C. 20013, USA. 2 Museum of Natural Science, 1 19 Foster Hall, Louisiana State University, Baton Rouge, LA 70803, USA. ^Corresponding author; e-mail: antbird@cox.net other Hylophylax species, but it remained for a molecular study (Brumfield et al. 2007) to demonstrate that Scale-backed Antbirds evolved in the clade of army ant-following birds distant from Hylophylax species in the phylogenetic tree. The genus Dichropogon had been erected earlier (Chubb 1918) for the complex, but Agne and Pacheco (2007) found the name Dichropogon was preoccupied by a genus of asilid flies and proposed the new generic name of Willisornis in honor of Edwin O'Neill Willis, who had contrib¬ uted so much to the understanding of the complex as well as other thamnophilid species. Seven subspecies have been recognized (Peters 1951, Zimmer and Isler 2003). Almost all are readily distinguished by plumage features, pri¬ marily in females. Substantial differences in female plumage led Hellmayr (1929) to include the complex in his seminal study of geographic 1 2 THE WILSON JOURNAL OF ORNITHOLOGY • Vol. 123, No. 1, March 2011 forms that present more well-marked characters in females than in males, variation which he termed heterogynism. In temporal order, the seven subspecies are W. p. poecilinotus (Cabanis 1847), W. p. griseiventris (von Pelzeln 1869), W. p. lepidonotus (Sclater and Salvin 1880), W. p. vidua (Hellmayr 1905), W. p. nigrigula (Snethlage 1914), W. p. duidae (Chapman 1923), and W. p. gutturalis (Todd 1927). Together they populate the Amazonian lowlands (Fig. 1). In the years since these subspecies were described, ornithological surveys in Amazonia have expanded our knowledge of their distribution and have produced a large number of vocal recordings from throughout their range. Vocal characters afford a relevant “yardstick” ( sensu Mayr and Ashlock 199!) for estimating repro¬ ductive isolation and species status of sympatric and allopatric populations of suboscine passerines (Isler et al. 1998, Johnson et al. 1999, Baptista and Kroodsma 2001, Helbig et al. 2002, Remsen 2005). Recently obtained data provide an oppor¬ tunity to reevaluate the taxonomic status of Willisornis populations based on geographic relationships among plumage-defined subspecies, and on the extent to which vocal differences among these subspecies support species status. METHODS Populations were based on geographic ranges of currently defined subspecies with two further subdivisions. Vocalizations of lepidonotus were divided into recordings obtained below and above 800 m elevation based on preliminary molecular analysis of J. M. Bates (pers. comm.). Vocaliza¬ tions of griseiventris were allocated to popula¬ tions east and west of the Rio Madeira because the Rio Madeira is a major barrier to gene flow in understory birds (Isler et al. 2007a, b; Burney and Brumfield 2009). Specimens were examined at the Louisiana State University Museum of Natural Science (LSUMZ), the Museo Paraense Emilio Goeldi (MPEG), the Museo de Zoologia, Universidade de Sao Paulo (MZUSP), and the National Museum of Natural History, Smithsonian Institution (USNM) with additional data provided by staffs of the American Museum of Natural History (AMNH), the Carnegie Museum of Natural History (CM), the Coleccion Ornitologica Phelps (COP), and the Field Museum of Natural History (FMNH). Measurements of bill width, depth, and length (at nares) and tarsus, tail, and wing chord were taken with MAX-CAL electronic digital calipers, which were also used to measure the length of the white interscapular patch at the center of the back. Colors were recorded by comparison with Mun- sell Soil Color Charts (Kollmorgan Instruments Corp., New Windsor, NY, USA), and English color names used in verbal plumage descriptions were adapted from these charts. We developed a locality-based map (Fig. 1) of the geographic distribution of each subspecies based on sites listed in museum inventories, sites referenced in the literature, and sites of vocal recordings. Tape and digital recordings of vocalizations were compiled from our own inventories, from unarchived contributions of other individuals, and from the Macaulay Library (ML, Cornell Labo¬ ratory of Ornithology, Ithaca, NY, USA). We examined 358 recordings (Appendix). We re¬ viewed the documentation of recordings to identify the number and gender of individuals vocalizing. RAVEN, Version 1.3 (Bioacoustics Research Program, Cornell Laboratory of Orni¬ thology, Ithaca, NY, USA) was used to make a spectrogram of every vocalization type delivered by each individual on every recording. All clearly delineated spectrograms were examined visually for characters (e.g., note shape) that might distinguish a population. Spectrograms shown in figures were selected to express typical measure¬ ments (e.g., the mean number of notes in loudsongs) and were made by exporting RAVEN files into CANVAS, Version 9.0.4 (ACD systems, Victoria, BC, Canada). Vocal characteristics obtained for loudsongs were: (1) number of notes, (2) duration, (3) pace, (4) change of pace, (5) note shape, (6) change in note shape, (7) note length, (8) change in note length, (9) interval length, (10) change in interval length, (11) frequency (nadir, peak, and max), and (12) change in frequency. The nadir is the lowest point in the tracing of a note; peak the highest point; and maximum frequency is measured at the point of highest intensity in the note. Measure¬ ments were taken of the initial, central (in time), and terminal notes and their associated intervals. Characteristics obtained for calls were fewer as they contained fewer notes. We required pairs of measurements expressing diagnostic characters to have correlation coefficients <0.80 given the possibility that some characters might be linked by common ancestry. Quantitative measures were obtained from spectrograms projected on a 43-cm screen using Isler and Whitney • SPECIES LIMITS IN AN ANTBIRD COMPLEX 3 FIG. 1. Geographic ranges of Willisornis populations. Symbols represent the occurrence of taxa within small geographic sectors (Isler 1997). Open square = poecilinotus', solid triangle = duidae; open circle = lepidonotus\ solid square = gutturalis ; open diamond = gutturalis', solid circle = nigrigula', open triangle = vidua ; star = two subspecies occur in sector; U surrounded by a circle = subspecies not identified. Type localities and locations are as mentioned in text. (1) “British Guiana” (exact locality unknown; type locality of poecilinotus). (2) Borba, Amazonas, Brazil (04° 24' S, 59 35' W; type locality of griseiventris). (3) Sarayacu, Pastaza, Ecuador (01° 44' S, IT 29' W; type locality of lepidonotus ). (4) Igarape Agu, Para, Brazil (01° 07' S, 47° 37' W; type locality of vidua). (5) Boim, Para, Brazil (03° 00' S, 55 27' W; type locality of nigrigula). (6) Cerro Duida, Amazonas, Venezuela (03 25' N, 65° 40' W; type locality of duidae). (7) Sao Paulo de Olivenca. Amazonas, Brazil (03' 27' S, 68 48' W; type locality of gutturalis). (8) Cano Usate, Amazonas, Venezuela (04c 25' N, 67° 48' W). (9) Campamento Manaka, Amazonas, Venezuela (03° 57' N, 67° 05' W). (10) Rio Putaco, Amazonas, Venezuela (02c 50' N, 64° 25' W). (11) Ocamo, Amazonas, Venezuela (02° 48' N, 65 14' W). (12) Demini Camp, Rio Demini, Amazonas, Brazil (00 02' S, 62° 48' W). (13) Sierra de Chiribiquete, Caqueta, Colombia (00° 56' N, 72° 42' W). (14) Tonantins, Amazonas, Brazil (02° 47' S, 67° 47' W). (15) Divisor; Loreto, Peru (07° 12' S, 73" 53' W). (16) Kiteni, Cuzco Peru (12" 20' S, 72° 50' W). (17) Cordillera de Pantiacolla, Madre de Dios, Peru (12 40' S, 71 : 13' W). (18) Santa Cruz, Rio Eiru, Amazonas, Brazil (07° 30' S, 70 49' W). (19) Eirunepe, Amazonas, Brazil (06' 40' S, 69 52' W). (20) Reserva Uakarai, Amazonas, Brazil (05° 26' S, 67° 17' W). (21) Carauarf, Amazonas, Brazil (04° 52' S, 66 54' W). (22) Region of the Rio Canuma, Amazonas, Brazil. (23) Jacareacanga, Amazonas, Brazil (06r 27' S, 57° 54' W). (24) Rio Sucunduri near BR 230, Amazonas, Brazil (06° 46' S, 59° 07' W). (25) Alta Floresta, left bank Rio Teles Pires (09c 50' S, 55" 54' W) and Rio Cristalino, right bank (09° 36' S, 55° 56' W), Mato Grosso, Brazil. (26) Riozinho, Area Indigena Kayapo, Para, Brazil (~ 08° 00' S, 52° 00' W). (27) Bosque de Guaipe, Vichada, Colombia (05c 18' N, 67 57' W). (28) Vicinal Aporui, 12 km north of Caracarai, Roraima, Brazil (01° 59' N, 61° 45' W). 4 THE WILSON JOURNAL OF ORNITHOLOGY • Vol. 123, No. 1, March 2011 default settings of RAVEN 1.3 (Charif et al. 2008), except the display was set to smooth, overlap was adjusted from 50 to 93.7% depending on recording quality, and contrast was adjusted according to recording intensity with care taken to retain all elements of the vocalization. Cursor measurements were typically at scales of 0.07 sec/ cm and 0.6 kHz/cm. A concern that voices of males and females might differ as in some other thamnophilid species (e.g., Isler et al. 2002, 2007a) dictated that the analysis initially distin¬ guished recordings of males and females. Unfor¬ tunately, individuals in the Willisomis complex often vocalize from beneath dense cover, and many recordings did not identify either male or female. Consequently, the analysis proceeded in an iterative fashion, aggregating samples when results did not indicate differences between males and females or between those identified and unidentified to gender. For example, we compared samples of male loudsongs of populations (except gutturalis , whose recording inventory of male vocalizations was insufficient) before adding samples of recordings of females and those unidentified to gender. Sample sizes cited reflect number of individuals, not number of vocaliza¬ tions measured. Diagnostic differences had to be discrete, non¬ overlapping character states that have the poten¬ tial for unambiguous signal recognition (Isler et al. 1998, 1999). Ranges of samples of continuous variables could not overlap, and the likelihood that ranges would not overlap with larger sample sizes was estimated by requiring the means (x) and standard deviations (SD) of the population with the smaller set of measurements (a) and the population with the larger set of measurements ( b ) to meet the test: ka “I" ^aSDa 2,000 m. There are more proximate locations to the north in intervening terrain of lower elevation cited in the literature with unidentified subspecies. - 10 THE WILSON JOURNAL OF ORNITHOLOGY • Vol. 123, No. 1, March 2011 Contact Between W. p. gutturalis and W. p. griseiventris. — Females are distinguished by brown underparts in gutturalis (gray in griseiven¬ tris) and white “scales” on the lower back of gutturalis (absent in griseiventris). Females of gutturalis also typically have crown redder than back (concolor in other populations). Males of gutturalis have black throat patches (absent in griseiventris). The geographic range of gutturalis is the smallest of any subspecies, restricted in Peru and Brazil to the region immediately south of the Amazon and east of the lower Rio Ucayali (Fig. 1). The extent of its range to the east and south is unclear. The likelihood that the Rio J urua provides a barrier in a section of their contact zone is supported by specimens of female gutturalis from Eirunepe (formerly Joao Pessoa) on the left bank of the Jurua and by male griseiventris from Santa Cruz on the Rio Eiru, a right bank tributary (Pinto 1942, 1978; specimens examined at MZUSP). However, sight records from both banks of the Rio Jurua at the Reserva Uakarai were identified as griseiventris (Andrew Whittaker, pers. comm.). To the southwest, in the Jurua-Ucayali interfluvium, griseiventris has been found at Divisor, Loreto, Peru, and at two other locations west of the Sierra del Divisor (Vriesendorp et al. 2006:195). Consequently, known ranges of gutturalis and griseiventris are separated by ~280 km of probably suitable habitat in this region with no river barriers. Contact Between W. p. griseiventris and W. p. nigrigula. — The extension of the gray of the underpails to the sides of the head (ear coverts and lores) distinguishes female nigrigula from grisei¬ ventris. Males of nigrigula have a black throat, while throats of male griseiventris are plain gray. The Rio Canuma and, continuing further up¬ stream, the Rio Sucunduri, separates their ranges (regions of locations 22 and 24; Fig. 1). However, the range of griseiventris passes the headwaters of the Rio Sucunduri to reach the Rio Tapajos above Jacareacanga, where it overlaps nigrigula and may hybridize with it locally (BMW observations and recordings of both taxa). Beyond this point, to the south, only griseiventris has been found on the left (west) bank of the Rio Tapajos and its major tributary, the Rio Teles Pires, whereas nigrigula occurs on the right (east) bank of these rivers. Contact Between W. p. nigrigula and W. p. vidua. — Males of nigrigula have discreet black throat patches which are absent in vidua , the throat of which tends to be more whitish than its gray underparts. Females of vidua differ from nigrigula by having flanks suffused reddish- yellow-brown (slightly tinged in nigrigula) and wing edgings grayish-brown (reddish-yellow- brown in nigrigula). Interscapular patches are larger in nigrigula (15-20 mm) than in vidua (0- 10 mm). The known geographic ranges of nigrigula and vidua with one exception are separated by a wide geographic gap west of the Rio Xingu (Fig. 1), although much of the region between the known ranges of these populations is unexplored ornithologically. The only known convergence of nigrigula and vidua is based on sight records by BMW in September 1994 of males within ~1 km of each other at Riozinho, Area Indigena Kayapo, Para; it cannot be considered definitive, but does serve to suggest the possibility of parapatry of these forms in this poorly studied region. DISCUSSION Diagnostic differences in loudsongs, raspy series, and contact calls were documented be¬ tween two groups of taxa that were also distinct in plumage: nigrigula and vidua of southeast Ama¬ zonia, and the remaining populations. However, compared to other widespread Amazonian tham- nophilid complexes studied by the authors (e.g., Isler et al. 2007a, b), relatively few vocal differences meeting our guidelines for species status were found among other populations in the Willisornis complex. Consequently, we recom¬ mend the complex be considered to consist of two species and seven subspecies: Willisornis poecilinotus (Cabanis) — Common Scale-backed Antbird W. p. poecilinotus (Cabanis) W. p. duidae (Chapman) W. p. lepidonotus (Sclater and Salvin) W. p. griseiventris (von Pelzeln) W. p. gutturalis (Todd) Willisornis vidua (Hellmayr) — Xingu Scale- backed Antbird W. v. nigrigula (Snethlage) W. v. vidua (Hellmayr) The proposed English name of W. vidua is taken from the major river that flows through the center of its geographic range. Within each of these two groups, differences in Isler and Whitney • SPECIES LIMITS IN AN ANTBIRD COMPLEX 11 plumage characters, such as the presence/absence of a black throat patch, served to distinguish almost all subspecies at the 100% level. The single exception was duidae and lepidonotus , whose differences in coloration (redder female, paler male in duidae ) may or may not prove to be clinal when additional specimens are obtained in Colombia. The clear differences in plumage characters led us to concentrate our analysis on the biogeographic relationships between members of pairs of parapatric populations. Considering duidae and lepidonotus as a single taxon (lepido¬ notus has priority), locality data indicated that geographic ranges of five pairs of taxa (poecili - notus/lepidonotiis , lepidonotus/ grisei ventris, gut- tu ra l is/grisei ventris, griseiventris/nigrigula , and nigrigula/vidua) were not separated, or only partially separated, by wide river barriers. Large geographic gaps in our knowledge of the taxa occupying these potential contact zones currently prevents us from ascertaining whether: (1) some or all of these plumage-defined populations are evolving independently and deserve species status under the BSC; (2) there is widespread intergra¬ dation between neighbors; or (3) secondary contact of populations is only incipient, and the evolutionary dynamic in regions of overlap is yet to unfold. Consequently, we reserve judgment on the possible species status of the taxa listed as subspecies. Field work in potential contact zones is needed not only to obtain morphological data and material for genetic analysis, but also to record vocalizations. Differences in vocal charac¬ ters between these populations did not meet our conservative requirements to be diagnosable, but recordings from contact zones may provide a different perspective. Geographically fine-grained recording of loudsongs can provide a test of whether vocalizations converge or diverge in contact zones, and it is possible that calls rarely recorded for the complex may differ diagnosably. Collections of specimens and vocal recordings are needed from the Andean foothills (>800 m) population of lepidonotus given the suggestion in vocalizations and preliminary molecular studies that it may be distinct from lowland populations. The two available examples of the contact call of lepidonotus >800 m were short in duration and therefore similar to that of griseiventris. Genetic analysis now underway at FMNH (J. M. Bates, pers. comm.) should provide relevant insights into the phylogenetic relationships of these taxa including whether members of para¬ patric pairs are closest relatives. Early results showed 6.8% divergence in two mitochondrial genes between nigrigula and griseiventris across the Rio Teles Pires near the confluence of the Rio Cristalino; 0.6% divergence of griseiventris between left bank Teles Pires and right bank Rio Jiparana; 0.5% divergence between nigrigula on right bank Teles Pires and two sites (Serra dos Carajas and 52 km S Altamira) of vidua (Bates et al. 2004). In addition, a study of speciation in the region of the upper Rio Negro in northwestern Brazil found 10.8% genetic divergence between poecilinotus and duidae (Naka 2010). Differences in duration of contact call notes of Willisornis populations north and south of the Amazon suggest an early divergence that should be relevant to evolutionary studies as well as systematics. Current knowledge provides only the “tip of the iceberg,” and valuable insights relevant to systematics, conservation, and broader studies of evolution await further investigation of the Will- isomis complex. ACKNOWLEDGMENTS We are deeply grateful to P. R. Isler for preparing the figures of spectrograms and for helpful comments, to J. V. Remsen Jr. for his careful review of an earlier version of the manuscript, and to L. F. Silveira and Fabio Schunck of MZUSP for excellent fieldwork and collection of speci¬ mens. Two anonymous reviewers and C. E. Braun provided helpful comments. L. M. Martinez supplied distributional data from COP. G. F. Budney and M. D. Medler provided recordings and distributional data from the Macaulay Library. We appreciate the efforts of Paul Sweet and Thomas Trombone in providing a large series of detailed photographs of specimens collected on Mt. Duida, Vene¬ zuela, housed in the AMNH. L. N. Naka contributed important location data and molecular results from northern Brazil. J. M. Bates provided descriptions of FMNH specimens and shared early results of his ongoing molecular study. G. A. Bravo confirmed the identification of specimens housed in the Instituto de Investigation de Recursos Biologicos Alexander von Humboldt. Finally, we thank the recordists credited in the Appendix, especially K. J. Zimmer, for providing recordings essential to this study. LITERATURE CITED Agne, C. E. Q. and J. F. Pacheco. 2007. A homonymy in Thamnophilidae: Dichropogon Chubb. Revista Brasi- leira de Omitologia 15:484-485. Baptista, L. F. and D. E. Kroodsma. 2001. Avian bioacoustics. Pages 1 1-52 in Handbook of the birds of the world. Volume 6. Mousebirds to hombills (J. del Hoyo, A. Elliott, and J. Sargatal, Editors). Lynx Edicions, Barcelona, Spain. 12 THE WILSON JOURNAL OF ORNITHOLOGY • Vol 123, No. 1, March 2011 Bates, J. M., J. Haffer, and E. Grismer. 2004. Avian mitochondrial DNA sequence divergence across a headwater stream of the Rio Tapajos, a major Amazonian river. Journal of Omithologie 145:199- 205. Brumfield, R. T., J. G. Tello, Z. A. Cheviron, M. D. Carling, N. 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Remsen Jr., and C. Cicero. 1999. Resolution of the debate over species concepts in ornithology: a new comprehensive biological species concept. Proceedings of the International Ornitholog¬ ical Congress 22:1470-1482. Mayr, E. and P. D. Ashlock. 1991. Principles of systematic zoology. McGraw-Hill, New York, USA. Meyer de Schauensee, R. 1964. The birds of Colombia and adjacent areas of South and Central America. Livingston Publishing Company, Narberth, Pennsyl¬ vania, USA. Naka, L. N. 2010. The role of physical and ecological barriers in the diversification process of birds in the Guiana Shield, northern Amazonia. Dissertation. Louisiana State University, Baton Rouge, USA. Peters, J. L. 1951. Check-list of birds of the world. Volume 7. Museum of Comparative Zoology, Cam¬ bridge, Massachusetts, USA. Pinto, O. M. de O. 1942. Sobre uma nova forma heteroginica de Hylophylax poecilinota (Cabanis). Proceedings of the Eighth American Scientific Con¬ gress 3:481-485. Pinto, O. M. de O. 1978. Novo catalogo das aves do Brasil. Primeira parte; Aves nao Passeriformes e Passeri¬ formes nao Oscines, com exclusao da famiilia Tyrannidae. Emprea Grafica do Revista dos Tribunais, S. A., Sao Paulo, Brazil. Remsen Jr., J. V. 2005. Pattern, process, and rigor meet classification. Auk 122:403-413. Ridgely, R. S. and G. Tudor. 1994. The birds of South America. Volume 2. The suboscine passerines. University of Texas Press, Austin, USA. Ridgway, R. 1911. The birds of North and Middle America. Part 5. Bulletin of the U.S. National Museum 50:1-859. SCLATER, P. L. AND O. S alvin. 1880. On new birds collected by Mr. C. Buckley in eastern Ecuador. Proceedings of the Zoological Society of London 1880:155-161. Snethlage, E. 1914. Neue vogelarten aus amazonian. Omithologische Monatsberichte 22:39^14. Stiles, F. G., J. L. Telleri'a, and M. Diaz. 1995. Observaciones sobre la composicion, ecologfa, y zoogeografia de la avifauna de la Sierra de Chiribi- quete, Caqueta, Colombia. Caldasia 17:481-500. Todd, W. E. C. 1927. New gnateaters and antbirds from tropical America, with a revision of the genus Myrmeciza and its allies. Proceedings of the Biological Society of Washington 40:149-178. von Pelzeln, A. 1 869 ( 1 868). Zur Omithologie Brasiliens, Resultate von Johann Natterers Reisen in den Jahren 1817 bis 1835. Abth. 2. A. Pichler’s Witwe & Sohn, Wien, Germany. Isler and Whitney • SPECIES LIMITS IN AN ANTBIRD COMPLEX 13 Vriesendorp, C., T. S. Schulenberg, W. S. Alverson, D. K. Moscovits, and J.-I. Rojas Moscoso. 2006. Peru: Sierra del Divisor. Rapid Biological Inventory Report 17. The Field Museum, Chicago, Illinois, USA. Willis, E. O. 1982. The behavior of Scale-backed Antbirds. Wilson Bulletin 94:447—462. Zimmer, J. T. 1934. Studies of Peruvian birds. XII. Notes on Hylophylax , Myrmothera, and Grallaria. American Museum Novitates 703:1-21. Zimmer, K. J. and M. L. Isler. 2003. Family Thamnophi- lidae (typical antbirds). Pages 448-681 in Handbook of the birds of the world. Volume 8. Broadbills to tapaculos (J. del Hoyo, A. Elliott, and D. A. Christie, Editors). Lynx Edicions, Barcelona, Spain. APPENDIX Recordings Examined. — The following list identifies recordings used in the study by taxon, country, state or department, recording location, and recordist. Numbers following the recordist name identify the number of cuts per recordist per location. Acronyms for recording archives: BSA = Banco de Sonidos Animates, Instituto de Investigation de Recursos Biologicos Alexander von Humboldt, Bogota. FSM = Florida State Museum Sound Archive. ML = Macaulay Library, Cornell Laboratory of Ornithology, Ithaca; ISL = recordings not yet archived in an institutional collection but that have been copied into the inventory maintained by Morton and Phyllis Isler. Many of these unarchived recordings either are in the process of being archived or will eventually be archived by the recordists. Nomen¬ clature reflects recommended taxonomic position. Willisornis p. poecilinotus : (53 recordings; 24 locations). Brazil: Amapa: Porto Grande (Zimmer 3 ISL); Amazonas: Rio Apuau (Cohn-Haft 1 ISL), 60-90 km N Manaus (Bierregaard 1 ML, Stouffer 1 ML, Whitney 1 ISL, Whittaker 1 ISL), Reserva Ducke (Whitney 1 ISL). Guyana: Acarai Moun¬ tains (Robbins 1 ML), Baramita (Brumfield 1 ISL), Iwokrama Forest Reserve (Whitney 5 ISL), Kaieteur Fall (Milensky 1 ISL), Kako River (Robbins 2 ML), Kopinang (O'Shea 1 ML), Kuyuwini River (Finch 2 ML), Marshall Falls (Finch 1 ML), Nappi Village (Parker 1 ML), Sipu River (Milensky 1 ISL), Waruma River (O’Shea 1 ML). Suriname: Brownsberg Nature Reserve (Davis 2 ML, Whitney 2 ISL), Kraka-Zenderij Road (Whitney 1 ISL), Raleigh Vallen (Whitney 1 ISL), Voltzberg (Davis 1 ML, M. Isler 1 ML, Whitney 1 ISL). Venezuela: Amazonas: Jungla- ven Camp (Zimmer 1 ISL); Bolivar: El Palmar (Parker 2 ML, Schwartz 3 ML), La Escalera (Behrstock 1 ISL, M. Isler 1 ML, Macaulay 1 ML, Schwartz 1 ML, Whitney 1 ISL, Zimmer 2 ISL), 20-30 km SE Maripa (Stejskal 1 ISL, Whitney 2 ISL), Sierra de Lema (Behrstock 1 ISL, Zimmer 1 ISL). Willisornis p. duidae : (29 recordings; 9 loca¬ tions). Brazil: Amazonas: P. N. do Jaii (Pacheco 1 ISL, Whitney 1 ISL, Whittaker 1 ISL), Manaca- puru (Whitney 1 ISL), Sao Gabriel da Cachoeira, island in Rio Negro (Whitney 2 ISL), Sao Gabriel da Cachoeira. L bank Rio Negro (Whittaker 1 ISL, Whitney 3 ISL, Zimmer 2 ISL), Sao Gabriel da Cachoeira. R bank Rio Negro (Cohn-Haft 1 ISL, Whitney 1 ISL, Zimmer 1 ISL). Colombia: P. N. N. Chiribiquete (M. Alvarez 10 BSA), Vaupes: Mitu (Hilty 2 ISL). Venezuela: Amazonas: Frente Isla Cigarron (Schwartz 1 ML), Picua (Coons 1 ISL). Willisornis p. duidae or lepidonotus: (4 record¬ ings; 1 location). Colombia: Amazonas: Parque Nacional Natural Amaca-yacu (P. Isler 1 ISL, Whitney 3 ISL). Willisornis p. lepidonotus below 800 m: (37 recordings; 18 locations). Ecuador: Morona-San- tiago: Miazal (Whitney 1 ISL), Santiago (Robbins 1 ISL); Napo: La Selva Lodge (Behrstock 1 ISL, Coopmans 2 ML, Donahue 1 ML, Wolf 2 ISL), km 37 Maxus Road (Krabbe 3 ISL), Tiputini Biodiversity Station (Behrstock 1 ISL, Zimmer 2 ISL); Pastaza: Kapawi Lodge (Whitney 1 ISL, Wolf 1 ISL); Sucumbtos: Cuyubeno (Whitney 1 ML). Peru: Loreto: Colon i a Angamos (Lane 1 ISL), 79 km WNW Contamana (Lane 3 ISL), El Dorado (Whitney 3 ISL), El Tigre (J, Alvarez 3 ISL), Explorama Lodge (Whitney 1 ISL), Intuto (Whitney 1 ISL), Quebrada Oran (Whitney 2 ISL), Quebrada Sucusari (P. Isler 1 ML), Sachacocha (J. Alvarez 1 ISL), Yanamono (Budney 2 ML, Whitney 1 ISL); San Martin: Tarapoto- Yurimaguas Road (Lane 1 ISL). Willisornis p. lepidonotus above 800 m: (16 recordings; 8 locations). Ecuador: Napo: 15 to 80 km W of Loreto by road (J. Rowlett 1 ISL, R. Rowlett 1 ISL, Whitney 2 ISL, 1 ML, Wolf 1 ISL), Volcan Sumaco (R. Rowlett 1 ISL); Zamora-Chinchipe: Parque Nacional Podacaipus (Wolf 1 ISL). Peru: Cajamarca: Cordillera del Condor, (Schulenberg 1 ISL), Puesta Vigilancia (Schulenberg 1 ML); Loreto: 77 km WNW Contamana (Lane 3 ISL), -90 km SE Juanjui (Lane 2 ISL); San Martin: Jirillo, 15 km NE (Schulenberg 1 ML). Willisornis p. gutturalis : (12 recordings; 3 locations). Brazil: Amazonas: Benjamin Constant (Whitney 4 ISL), R. N. Palmarf (Whitney 5 ISL, 14 THE WILSON JOURNAL OF ORNITHOLOGY • Vol. 123, No. 1, March 2011 Zimmer 1 ISL). Peru: Loreto: Tahuayo Lodge (Hornbuckle 2 ISL). Willisomis p. griseiventris : W of Madeira: (40 recordings; 23 locations). Bolivia: La Paz: Campamento Nuano (Tello 1 ISL), Chalalan (Whitney 1 ISL), Cadena Pilon (Parker 1 ISL), Puerto Linares (Wiedenfeld 1 ML), Serrania Tequeje (Hennessey 1 ML); Pando: Rio Abuna, (Parker 1 ISL), Camino Mucden (Parker 3 ML), 12-20 km SW Cobija (Parker 1 ISL), San Juan de Nuevo Mundo (Parker 1 ISL). Brazil: Acre: Boca de Tejo (Whittaker 2 ISL); Amazonas: Amazon Lodge (Zimmer 2 ISL), Humaita (Whitney 3 ISL), Labrea (Whitney 1 ISL, Zimmer 1 ISL), Igarape Santa Maria (Whitney 1 ISL), Tefe (Pacheco 1 ISL), Fazenda Toshiba (Marantz 1 ML), Tupana Lodge (Zimmer 4 ISL), Uara (Whittaker 1 ISL). Peru: Madre de Dios: Cuzco Amazonica Lodge (Marantz 1 ML), Explorer’s Inn (Donahue 1 ML, M. Isler 1 ML, Kibler 3 ML, Parker 2 ML), Cordillera del Pantiacolla (Fitzpatrick 2 ML); Puno: Campamento Topo Tres (Schulenberg 1 ISL); Ucayali: Cerro Tahuayo (Meyer 1 ISL). Willisomis p. griseiventris : E of Madeira: (74 recordings; 25 locations). Bolivia: Santa Cruz: Flor de Oro (Whitney 1 ISL), Los Fierros (Whitney 2 ISL), Perseverancia (Fisher 1 ISL, Parker 1 ISL, l ML). Brazil: Amazonas: Rio Atininga (Whitney 1 ISL), Rio Bararati (Whitney 5 ISL), Barra de Sao Manuel (Whitney 4 ISL), Borba (Whitney 1 ISL, Whittaker 1 ISL), Nova Olinda (Rio Aripuana) (Whitney 1 ISL), Rio Ipixuna (Whitney 1 ISL), Puxurizal (Marantz 1 ML, Whitney 1 ISL), mouth of Rio Palomitas (Whitney 4 ISL), Pousada Jurume (Whitney 2 ISL), Pousada Rio Roosevelt (Whittaker 2 ISL, Zimmer 1 ISL), Prainha Nova (Whitney 1 ISL), L bank Rio Sucunduri near BR 230 (Whitney 5 ISL); Mato Grosso: Alta Floresta (M. Isler 2 ISL, P. Isler 1 ISL, Parker 2 ISL, Whitney 3 ISL, Zimmer 5 ISL), R bank Rio Juruena opposite mouth Rio Bararati (Whitney 1 ISL), mouth of Rio Sao Benedito (Whittaker 1 ISL), mouth of Rio Sao Tome (Whitney 2 ISL); Rondonia: Rio Caracol (Whitney 1 ISL), R bank Rio Jiparana opposite Palmeiras (Whitney 3 ISL), Serra dos Pacaas Novo s (Whittaker 3 ISL), Palmeiras (Whitney 4 ISL), Porto Velho (Whitney 6 ISL), Fazenda Rancho Grande (Zimmer 3 ISL). Willisomis vidua nigrigula: (47 recordings; 15 locations). Brazil: Amazonas: Igarape Pedral (Whitney 4 ISL), Igarape do Seringal (Whitney 2 ISL), 52 km W Jacareacanga (Whitney 1 ISL), R bank Rio Sucunduri near BR 230 (Whitney 3 ISL); Mato Grosso: Rio Cristalino (Michael 1 ML, Whitney 2 ISL, Zimmer 8 ISL); Para: Parque Nacional de Amazonia (Whittaker 5 ISL), Aveiro (Whitney 3 ISL), Boim (Whitney 1 ISL), Cachimbo (Whittaker 1 ISL), Capelinha Trail (Parker l ML), km 209 S of Itaituba (Whitney 3 ISL), Jacareacanga (Whitney 3 ISL), Miritituba (Whitney 3 ISL, Willis 3 FSM), Porto do Meio (Whitney 1 ISL), Riosinho (Whitney 1 ISL), Ruropolis (P. Isler 1 ML). Willisomis v. vidua: (39 recordings; 6 loca¬ tions). Brazil: Para: Serra dos Carajas (Whitney 3 ISL, Zimmer 2 ISL), Caxiuana (Marantz 1 ML, Whitney 6 ISL, Whittaker 1 ISL, Zimmer 13 ISL), Reserva Indigena Kayapo (Whitney 1 ISL), Paragominas (Whitney 5 ISL), Fazenda Rio Capim (Zimmer 6 ISL); Tocantins: Babagulandia (Pacheco 1 ISL). The Wilson Journal of Ornithology 123(1): 15-23, 2011 HIGH APPARENT ANNUAL SURVIVAL AND STABLE TERRITORY DYNAMICS OL CHESTNUT-BACKED ANTBIRD (. MYRMECIZA EXSUL ) IN A LARGE COSTA RICAN RAIN FOREST PRESERVE STEFAN WOLTMANN1-2 AND THOMAS W. SHERRY1 ABSTRACT. — Antbirds (Thamnophilidae) are a diverse component of neotropical forest avifaunas, and are particularly vulnerable to population declines and extirpations in fragmented landscapes. We lack estimates of apparent survival and dispersal for the majority of species, despite their value in effectively managing populations of understory birds. We studied a population of Chestnut-backed Antbird ( Myrmeciza exsul ) from 2004 to 2009 in a large rain forest preserve in northern Costa Rica to generate estimates of apparent annual survival (tp). and breeding dispersal (i.e., movement from one breeding territory to another) in continuous forest. Estimates of

1,100 ha of old-growth tropical wet forest. La Selva is currently surrounded on three sides by a largely agricultural matrix. Annual rainfall is nearly 4,000 mm with a predictable dry season from Individuals are paired and maintain territones year-round, and are highly sedentary, at least at short (<1 year) time scales (Marcotullio and Gill 1985, Stutchbury et al. 2005, Losada-Prado 2009). Moore et al. (2008) provided evidence of poor dispersal by this species by demonstrating its inability to sustain flight for 100 m over water, although how this limitation applies to dispersal in more typical terrestrial settings is unknown. Field Procedures. — We selected a 300-ha focal study area (200 ha from 2004 to 2005; 300 ha from 2006 to 2009) dominated by old-growth forest (two territories included in survival analy¬ ses were outside the focal plot, but in similar habitat). Forty of 41 territories monitored were in forest at least 40 years of age with a well developed canopy and understory; the other territory was in older second-growth with a canopy height of ~3 m. Birds were lured into mist nets using conspecific playback, uniquely banded with a numbered aluminum band and three colored plastic leg bands, and released. Bird capture and marking began in December 2004, and annual dry-season surveys were conducted February-March 2005-2009 (and into Apr 2009). Chestnut-backed Antbirds in post-juvenal plumages are readily identified as male or female based on underpart coloration (Wolfe et al. 2009). Incomplete knowledge of the timing of definitive prebasic molt and observations of breeding activity nearly year-round at La Selva indicate that Hatch-Year (HY) and After-Hatch- Year (AHY) terminology is inappropriate at this site. We classified birds as “adult” (fully ossified skull and definitive plumage) or “juvenile” (skull <90% ossified or formative plumage; Howell et al. 2003), and note we occasionally captured “juvenile” birds in breeding condition (cloacal protuberance and/or brood patch). We attempted to relocate all previously marked birds during each annual survey, and to capture any unbanded individuals. Territories were thor¬ oughly searched during morning hours with good weather (when birds are most active and vocal), and vocalization playback was used to find and identify individuals. We considered a territory unoccupied if no bird was found after two separate searches (minimum 45 min each) at least Woltmann and Sherry • SURVIVAL AND TERRITORY DYNAMICS OF ANTBIRDS 17 TABLE 1. Models of apparent survival ((p) and detection probability (p ) of Chestnut-backed Antbirds at La Selva, Costa Rica. “# Par” is the number of parameters included in each model; “a2” indicates a 2-age class system (juveniles and adults). Model AICc AAICc AICc weights Model likelihood # Par Deviance {^Pa2 Psexl 275.306 0.000 0.554 1.000 4 91.277 {2 km apart) suggest that we could have detected greater movements than the mean distance of <400 m. Four occupied territories became vacant over Woltmann and Sherry • SURVIVAL AND TERRITORY DYNAMICS OF ANTBIRDS 19 TABLE 2. Number (sample size) of territory-years (T-Y), observed disappearances and switches, and adjusted disappearance rates for Chestnut-backed Antbirds in Costa Rica. D0 bs = observed disappearance rate; Am>r — false disappearance rate, calculated for 2005-2008, and Adjusted = Abs — Arror* which was used in place of Abs *n turnover calculations (Table 3). T-Y Obs. (#) disappeared Obs. (#) switched Dobs Denor ^adjusted Male Adult 100 26 4 0.260 0.014 0.246 Juvenile 15 6 1 0.400 0.083 0.317 All 115 32 5 0.278 0.024 0.255 Female Adult 36 16 3 0.444 0.185 0.259 Juvenile 9 4 1 0.444 0.125 0.319 All 45 20 4 0.444 0.171 0.273 the course of our study, but four previously unoccupied territories became occupied (one gain resulted from a territory splitting). Between three and six once-occupied territories were empty in any given year, and density was relatively stable at 9.3-10.0 pairs/ 100 ha from 2006 to 2009. Territory locations and boundaries appeared stable regardless of the owner, suggesting territory locations are intrinsic to the environment, or become constrained by traditional boundaries. We identified seven males and one female (the female was not captured) on the 300-ha focal plot that appeared to be floaters. These were generally (6 of 8) unpaired individuals that responded TABLE 3. Annual turnover and territory switching of Chestnut-backed Antbirds compared to ecologically similar species. Numbers in columns represent males and females respectively, where available; a single value represents males and females combined. Turnover Switch rate Species Male Female Male Female Source Chestnut-backed Antbird Adult 0.29 0.34 0.04 0.08 This study Juvenile 0.39 0.43 0.07 0.11 All 0.30 0.36 0.04 0.09 Spotted Antbird 0.27 0.32 0.09 0.12 Willis 1974 ( Hylophylax naevioides ) Bicolored Antbird 0.39 0.53 0.12 0.18 Willis 1974 ( Gymnopithys leucaspis ) Ocellated Antbird 0.26 0.49 0.04 0.12 Willis 1974 ( Phaenostictus mcleannani) Checker-throated Antwren ( Epinecrophylla fulviventris ) Dusky Antbird 0.23 0.25 -0.33 0.27a Greenberg and Gradwohl 1997 Morton et al. 2000 ( Cercomacra tyrannina) White-bellied Antbird 0.36 0.36 0.25 0.19 Fedy and Stutchbury ( Myrmeciza longipes ) Buff-breasted Wren ( Cantorchilus leucotis) 0.07 0.1 5b 2004 Gill and Stutchbury 2006 d Estimated separately for a subset of contiguous territories (E. S. Morton, pers. comm.). Averaged over 3 years, derived from Gill and Stutchbury (2006: Table 1). 20 THE WILSON JOURNAL OF ORNITHOLOGY • Vol. 123, No. 1, March 201 1 aggressively to playback, but were not associated with a known territory. Three (2 juveniles) of the floater males (4 juveniles, 3 adults) were seen again elsewhere on the plot in subsequent years with females on known territories. One juvenile male traveled through the focal plot with an unbanded female in 2006 and attempted to establish a territory in the center of the study area, but both birds disappeared within 1 week. This “territory” had not been previously occu¬ pied, and was not occupied thereafter. DISCUSSION Chestnut-backed Antbirds, once on a territory, exhibit restricted movement. The few individuals that switched territories typically moved to an adjacent territory, and all movements observed were <850 m. Mean life span of adult Chestnut- backed Antbirds at La Selva is —4.24 years (mean life span = l/-ln(s), where 5 = annual survival; Brownie et al. 1985). Thus, breeding dispersal, even over the course of a lifetime, may be insufficient to maintain direct demographic or genetic connectivity between populations separat¬ ed by more than a few kilometers, especially if barriers (e.g., large rivers, habitat discontinuities) are present. Apparent Annual Survival and Detection Prob¬ ability. — Our estimates of (p for adult Chestnut- backed Antbirds are at the high end of the range of estimates for other thamnophilids summarized by Blake and Loiselle (2008) (range = 0.45-0.87). We found no evidence for differential apparent survival between adult males and females, and high detection probabilities suggest that our estimates of (p are close to true survival, at least for adult males (Jones et al. 2004, Ruiz-Gutierrez et al. 2008). Apparent survival of all juveniles was poorly estimated largely due to small sample size, as juveniles by definition only contribute to a single capture period, and afterwards contribute to adult survival estimates. However, p for juvenile males was relatively high, and the large confi¬ dence intervals around estimates of juvenile male cp can be interpreted as evidence of greater variability in apparent survival. Detection probabilities (p ) of males and fe¬ males were strikingly different with females having lower and more variable values. The unequal detection rates of age and male or female classes highlight ecologically important differenc¬ es in the behavior of individuals (e.g., Crespin et al. 2008), and also have methodological implica¬ tions. For example, in sexually monomorphic species, or those with delayed male plumage maturation (e.g., some Pipridae; DuVal 2005), important differences in apparent survival among groups may go undetected, and lead to high variance of parameter estimates. Turnover Rate and Territory Switching.— Over¬ all rate of turnover (disappearing + switching) by Chestnut-backed Antbirds at La Selva was comparable to other antbird species. Turnover was higher for females, and turnover among female Chestnut-backed Antbirds was the highest reported for any species (Table 3). Territory switching by Chestnut-backed Antbirds was markedly less common than for several other species studied (e.g.. White-bellied [Myrmeciza longipes] and Dusky [Cercomacra tyrannina ] antbirds). The few territory switches of Chest- nut-backed Antbirds observed generally were on the scale of 1-2 territory- widths, and all switches involved distances of <1 km, consistent with patterns in other small tropical understory resident insectivores (Greenberg and Gradwohl 1997, Morton et al. 2000, Robinson 2000, Gill and Stutchbury 2010). Low switching rates and short breeding dispersal distances have been reported in a wide variety of bird species, both tropical and temperate, and may be a general characteristic of monogamous species with year-round, multipur¬ pose territories (e.g., Woolfenden and Fitzpatrick 1989, Bried and Jouventin 1998, Komdeur and Edelaar 2001, Thorstrom et al. 2001, VanderWerf 2004, Gill and Stutchbury 2006, Eikenaar et al. 2008, Gill and Stutchbury 2010). The abundance of floaters ( sensu Winker 1998) is difficult to quantify, especially for females. Most territorial vacancies (male and female) were filled from year to year, mainly by unbanded birds, and both adults and juveniles were represented among the replacements. However, not all vacancies were filled, and some territories remained vacant at the end of our study. How floaters may affect long-term population trends or estimates of dispersal patterns is not clear, but should be considered in future studies (Zack and Stutchbury 1992, Winker 1998). CONSERVATION IMPLICATIONS Our findings have important implications for conservation of tropical understory forest birds in fragmented landscapes. Rare and small-scale lifetime breeding dispersal by Chestnut-backed Antbirds in a contiguous forest setting agrees with Woltmann and Sherry • SURVIVAL AND TERRITORY DYNAMICS OF ANTBIRDS 21 other studies documenting breeding dispersal patterns in tropical birds (Greenberg and Grad- wohl 1997, Morton et al. 2000, Fedy and Stutch- bury 2004). Short movements through continuous and favorable rain forest habitat (Losada-Prado 2009, this study), coupled with inability to fly long distances (Moore et al. 2008) makes breeding dispersal between forest fragments separated by kilometers of unsuitable habitat unlikely in this and perhaps other ecologically similar species (Woltmann 2010). Knowledge of genetic and demographic con¬ nectivity is needed to understand why some species persist in highly fragmented landscapes and others do not. Chestnut-backed Antbird nests are difficult to find, and breeding activity by this species occurs nearly year-round at La Selva, necessitating intense (essentially year-round) field effort to find and monitor sufficient nests. Moreover, clutch size is low in this and many other tropical understory species (Skutch 1985), nest failure rate is high (Robinson et al. 2000), and post-fledging parental care is often extensive (Russell et al. 2004), all of which increase the amount of effort required to track fledglings or otherwise measure natal dispersal. These technical and logistic difficulties suggest that alternate methods (e.g., molecular genetic approaches) are needed to compliment field-based approaches to understanding demographic and genetic connec¬ tivity in complex landscapes. ACKNOWLEDGMENTS Funding for this study came from Sigma Xi, Organization for Tropical Studies, Stone Center for Latin American Studies and Gunning Fund (Tulane University), Cooper Ornitholog¬ ical Society, American Ornithologists' Union, American Museum of Natural History, a National Science Foundation (NSF) grant to TWS, and the Louisiana Experimental Program to Stimulate Competitive Research (EPSCoR) funded by NSF and the Board of Regents Support Fund. We are grateful for the logistic support provided by Deedra McClearn and personnel at the La Selva Biological Reserve. We thank MINAE for permission to conduct this work in Costa Rica. This work was conducted under Tulane IACUC protocol # 0298R-UT-C. This manuscript benefited from helpful comments by M. F. Cashner, the Sherry Laboratory, J. D. Brawn and an anonymous reviewer. A dedicated field crew made this study possible: M. L. Brady, M. F. Cashner, R. S. Terrill, and J. M. Wielfaert. LITERATURE CITED Blake, J. G. and B. A. 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Princeton University Press, Princeton, New Jersey, USA. Zack, S. and B. J. M. Stutchbury. 1992. Delayed breeding in avian social systems: the role of territory quality and “floater” tactics. Behaviour 123:194- 219. ■ The Wilson Journal of Ornithology 1 23( 1 ):24 — 32, 2011 ORNITHOLOGICAL RECORDS FROM A CAMPINA/CAMPINARANA ENCLAVE ON THE UPPER JURUA RIVER, ACRE, BRAZIL EDSON GUILHERME' 24 AND SERGIO H. BORGES1,4 ABSTRACT. — We inventoried the bird fauna of an isolated enclave of white-sand vegetation, known locally as a campina/campinarana, in the western extreme of the Brazilian State of Acre between 22 and 31 January 2007 (wet season). A total of 1 14 bird species was registered in 1,425 net-hrs of mist-netting and 8 hrs of recordings of vocalizations. This included six species known to be associated with campinas and campinaranas in western Amazonia. A number of important records were made of species endemic to the southwestern Amazon Basin, but poorly-known in Brazil. Despite the relatively small size of the campina/campinarana enclave, these records indicate the area is extremely important for conservation of local biodiversity, and reinforces the need for further studies of both the avifauna and other groups of animals. Received 4 March 2010. Accepted 6 August 2010. Campina and campinarana refer to a complex mosaic of non- forest vegetation growing on nutrient-poor sandy soils at a number of different locations throughout the Amazon Basin (Ander¬ son 1981, Daly and Mitchell 2000, Alonso and Whitney 2003, Vicentini 2004). These two types of habitat are most common in the basin of the Rio Negro, which is a major northern (left bank) tributary of the Amazon/Solimoes River (Macedo and Prance 1978, Hess et al. 1998). Local residents in Brazil use campina to refer to “islands” or enclaves of bushy herbaceous vegetation on white-sand soils, which form patches of open grassland in the middle of the forest. Residents refer to this habitat as campinar¬ ana, which means “false campina”, when the vegetation of these enclaves is characterized by relatively high densities of trees of reduced stature and girth, but lacks emergents, lianas, or epiphytes (Anderson 1981). Campinas and campinaranas are found only in the western extreme of the State of Acre in the River Jurua Basin (Acre 2000, IBGE 2005). The species richness of the flora of the campinaranas is relatively low in comparison with other forested ecosystems in the Amazon, but 1 Universidade Federal do Acre, Centro de Ciencias Biologicas e da Natureza, Laboratorio de Pesquisas Paleontologicas, Campus Universitario. Rodovia BR 364, Km 04, n 6637 - Distrito Industrial. CEP: 69915-900, Rio Branco- Acre. Brasil. Pos Gradua^ao em Zoologia, Universidade Federal do Para/Museu Paraense Emilio Goeldi, Caixa Postal 399, CEP: 66040-170, Belum, PA, Brasil. * Funda9ao Vitoria Amazonica, Rua Estrela d’Alva n°07, Conjunto Morada do Sol, CEP: 69080-510, Manaus,’ Amazonas, Brasil. Corresponding author; e-mail: guilherme@ufac.br or sergio @ fva.org. br botanical research in these enclaves has revealed a relatively large number of endemic species (Anderson 1981, Daly and Mitchell 2000, Vice¬ ntini 2004). A similar pattern of high levels of endemism has been recorded in studies of invertebrate (Hofer et al. 1996, Marini-Filho 1999, Barbosa et al. 2002, Ricetti and Bonaldo 2008) and vertebrate (e.g., birds: Oren 1981, Alonso 2002, Alonso and Whitney 2003, Borges 2004, Poletto and Aleixo 2005) faunas of campina and campinarana enclaves. Species richness and abundance are markedly lower than those of the adjacent forest ecosystems. Birds are the best-studied vertebrate group from the white-sand enclaves of the Amazon. Surveys at a number of sites have revealed new species (Whitney and Alonso 1998, Alonso and Whitney 2001, Isler et al. 2002) and expanded the known geographic ranges of a number of taxa (Borges and Almeida 2001, Alonso and Whitney 2003, Poletto and Aleixo 2005). Borges (2004) argued that comparisons between bird communities from different Amazonian campinas are hindered by a lack of inventories for most sites. We provide the first discussion and annotated list of the bird fauna of a campina/campinarana enclave on the upper Rio Jurua in the Brazilian State of Acre. This enclave is isolated from all others in southwestern Amazonia. METHODS Study Area. — The campina/campinarana en¬ clave studied is in the municipality of Porto Walter, on the right bank of the stream Cruzeiro do Vale (08° 20' 35.7" S, 72° 36' 19.7" W, Fig. 1). The enclave has a total area of 103 km1 2 and is 193 m above sea level. It is bordered by both varzea (flooded whitewater habitat) and terra 24 Guilherme and Borges • BIRDS OF THE UPPER JURUA RIVER, ACRE, BRAZIL 25 74WW 73WW 72°0'0"W 71°0'0"W firme forest. The survey of the bird fauna occurred between 22 and 31 January 2007. Edge habitats bordering the surrounding varzea and terra firme forests were also sampled. A base camp was established at the Colonia Dois Portos community on the bank of the Cruzeiro do Vale stream, ~2 km from the campina enclave. The commu¬ nity was inhabited by 20 people in four families. The area surrounding the base camp included a small pasture for cattle and a tract of secondary forest (regenerating from subsistence agriculture), where additional observations of birds were conducted. Species Inventory. — The local bird fauna was inventoried using two procedures: (1) quantitative sampling through captures with 20, 12 X 2-m mist nets (36 mm mesh), and (2) collection of complementary records based on field observa¬ tions with 8 X 42 binoculars and recordings of vocalizations using a Sony TCM 5,000 recorder. Mist nets were set in linear transects of 10 nets each within the campina and campinarana, and in the adjacent forest edge. Nets were set at dawn (0530 hrs) and remained open until 1500 hrs to maximize the number of specimens captured. Voucher specimens were collected for laboratory analysis. All specimens were prepared using standard taxidermy techniques and deposited in the Ornithology Laboratory of the Goeldi Muse¬ um (Museu Paraense Emilio Goeldi-MPEG) in Belem. Specimen collection was authorized by the Brazilian Environment Institute (IBAMA), through license number 044/2006-COFAN. Sci¬ entific nomenclature followed that recommended by the IOC (Gill and Donsker 2010). RESULTS AND DISCUSSION The 10 days of data collection resulted in 1,425 net/hrs of captures using mist nets, and 8 hrs of recordings resulting in identification of 114 species of birds (Table 1). Six (4.4%) are known to be associated with campinas and campinaranas of the western Amazon (Stotz et al. 1996, Alonso 2002). Only two, Zimmer’s Tody-Tyrant ( Hemi - triccus minimus ) and Black Manakin (Xenopipo atronitens) are included in Stotz et al.’s (1996) list of birds associated with the white-sand habitats of the southern Amazon Basin. We also report important records of species endemic to south¬ western Amazonia but which are little known in Brazil (Guilherme and Borges 2008). Brown-banded Puffbird ( Notharchus ordii). This species is often associated with habitats on white sandy soils in northeastern Peru (Alonso 26 THE WILSON JOURNAL OF ORNITHOLOGY • Vol. 123, No. 1, March 2011 TABLE 1. Avian families and species recorded in campina and campinarana habitats in western Acre. Habitat: CA - Campina; CN = Campinarana; RF = riparian forest; OF = Open rain forest with palms; FE = forest edge; SF = secondary forest. Records: S = specimen collected and deposited at the Goeldi Museum; O = observation; V = vocalization recorded and recognized. Family (number of species) Species Habitat Record Tinamidae (3) Tinamus guttatus CN, OF S Crypturellus undulatus CN, OF s, V C. strigulosus * CN V Ardeidae (1) Butorides striata RF S, 0 Accipitridae (2) Elanoides forficatus FE o Harpagus bidentatus OF s Psophiidae (1) Psophia leucoptera OF S, 0 Rallidae (1) Ar amides cajanea RF S, 0 Eurypygidae (1) Eurypyga helias OF s, o Columbidae (5) Columbina talpacoti CA S, 0 Patagioenas plumbea OF s Leptotila verreauxi CA, OF s L. rufaxilla OF, SF s Geotrygon montana OF s Psittacidae (1) Aratinga weddellii FE, RF s, o Cuculidae (2) Crotophaga ani CA, FE S, 0 C. major RF s, o Strigidae (1) Megascops watsonii OF, SF s, V Apodidae (1) Tachornis squamata CA, RF o Trochilidae (4) Phaethornis philippii CA, CN s Topaza pyra CA s Chrysuronia oenone FE, RF S, 0 Heliomaster longirostris CA, CN s Trogonidae (3) Trogon viridis CN, OF s T. rufus OF, FE S, 0 T. melanurus OF, FE s, o,v Momotidae (1) Momotus momota OF s Galbulidae (1) Galbula cyanicollis OF S, 0 Bucconidae (5) Notharchus ordiia CN, FE S, 0 Bucco macrodactylus CN, FE s Nystalus striolatus CN, FE, SF s Nonnula sclateri OF s Monasa nigrifrons OF, FE, RF s, 0, V Ramphastidae (2) A ulacorhynchus atrogularis OF, FE s Pteroglossus mariae OF; SF o Picidae (6) Melanerpes cruentatus OF; FE o, V Colaptes punctigula FE, SF, RF s, O, V Piculus chrysochloros CN s Celeus elegans OF s C. grammicus CN s Campephilus melanoleucos OF, FE, SF s Thamnophilidae (13) Taraba major SF, RF s, V Thamnophilus aethiops OF, SF s T. murinus OF, SF S, V T. doliatus BF S, V, o S, V Thamnomanes ardesiacus CN, OF, SF Myrmotherula axillaris OF, SF S, V M. iheringi CN, SF s Cercomacra nigrescens CN, SF s Myrmoborus myotherinus CN, OF, SF S V Hypocnemis peruviana CN, OF, SF s, V s Myrmeciza spp. M. atrothorax OF SF Willisornis poecilinotus OF, SF o s, V Guilherme and Borges • BIRDS OF THE UPPER JURUA RIVER, ACRE, BRAZIL 27 TABLE 1. Continued. Family (number of species) Species Habitat Record Conopophagidae (1) Conopophaga aurita CN S Dendrocolaptidae (6) Dendrocincla merula OF s, V Glyphorynchus spi rurus OF, SF S Dendrexe tastes rufigula CN S Dendrocolaptes certhia OF s, v Xiphorhynchus guttatus OF, SF s, v X. elegans OF s Furnariidae (4) Furnarius leucopus RF S, 0, V Berlepschia rikeri CA V Xenops minutus OF, SF s Philydor erythropterum CN, OF s Tyrannidae (14) Mionectes oleagineus OF, SF s Leptopogun amaurocephalus OF, SF s Hemitricctis minimus “ CN s H. griseipectus CN s Cnemotriccus fiuscatus duidae “ CN s Myiopagis gaimardii SF, FE s, V Cnipodectes subbrunneus CN s Contopus virens SF, FE s Pitangus sulphuratus CN, FE o, V Megarhynchus pitangua FE 0, V Myiozetetes granadensis SF, FE s Ramphotrigon ruficauda CN s Tyrannulus elatus CN s A tti la ci trin i ventrisa CN s Pipridae (6) Machaeropterus striolatus CN s M. pyrocephalus OF, SF s Dixi ph ia rubrocapilla OF s D. pipra CN, 0 F s Manacus manacus CN s Xenopipo atronitenf CN s Tityridae (4) Schijfornis turdina CN s Laniocera hypopyrra OF s Iodopleura isabellae FE s Pachyramphus polychopterus OF, SF s Vireonidae (1) Vireo flavoviridis SF, FE s Corvidae (1) Cyanocorax violaceus OF, RF s, 0, V Troglodytidae (1) Pheugopedius genibarbis SF, FE S, V Turdidae (4) Catharus ustulatus SF s Turdus ignobilis CA, FE s, v T. lawrencii OF, SF V T. hauxwelli OF, SF S, V Thraupidae (10) Ramphocelus nigrogularis SF, FE, RF S, 0 R.xarbo SF, FE, RF S, 0 Thraupis episcopus CA, FE, SF o, V T. palmarum CA, FE, SF s, 0, V Cissopis leverianus RF, FE o Tangara chilensis FE, SF S, 0 T. nigrocincta FE, SF S, 0 T. velia FE, SF s Cyanerpes nitidus FE, SF s C. caeruleus FE, SF s Cardinalidae (2) Saltator tnaximus SF, FE s, 0, V S. coerulescens SF, FE s, 0, V 28 THE WILSON JOURNAL OF ORNITHOLOGY • Vol. 123, No. 1, March 2011 TABLE 1. Continued. Family (number of species) Species Habitat Record Icteridae (6) Psarocolius bifasciatus RF, FE, SF s, O, V P. viridis RF, FE, SF S, 0 Clypicterus oseryi RF, FE s Cacicus cela RF, FE, SF s, O, V C. solitarius RF, FE s Icterus cayanensis CA s a Species closely associated with campina and campinarana habitats of southwestern Amazonia (Stotz et al. 1996, Alonso 2002). and Whitney 2003), southwestern Venezuela, and the upper Rio Negro region of northern Brazil (Zimmer and Hilty 1997). The first record of this species in Acre was from Serra da Jaquirana, in dense submontane rain forest, in Serra do Divisor National Park. Two specimens were collected and deposited in the Goeldi Museum collection (Alonso and Whitney 2003: MPEG 52726, 52727). The female we collected (MPEG 62025) in terra finne forest at the edge of the campinar¬ ana on 26 January 2007, represents the second record of this species for Acre. Fiery Topaz ( Topaza pyra). This species is widely distributed in the western Amazon Basin, including Brazil, Peru, and Ecuador (Hu et al. 2000), but is known from Acre only from three specimens collected by D. C. Oren and co¬ workers in Serra do Divisor National Park (MPEG 52719, 52720, 52721). We collected a male (MPEG 62008) on 24 January 2007 in a mist net in open campina habitat. This record repre¬ sents the southernmost limit of the distribution of the species in the Amazon biome. Our record does not support the hypothesis that distribution of Fiery Topaz in southwestern Amazonia is related to blackwater river basins, as suggested by Hu et al. (2000). The drainage of our study area is exclusively whitewater, characterized by high concentrations of suspended sediments (Toivonen et al. 2007) in contrast with the region of Cruzeiro do Sul (where the first Acre records of Fiery Topaz were collected) which, near Serra do Moa, is dominated by blackwater streams (EG, pers. obs.). The Fiery Topaz has been recorded frequently in campinarana habitats, including Jau National Park (Borges et al. 2001) and" the municipality of Guajara in Amazonas State (A. Aleixo, unpubl. data). We believe the distribution of Fiery Topaz, in contrast with that of its congener Crimzon Topaz (T. pella ), is more closely related to campina and campinarana habitats than blackwater river basins. Golden-tailed Sapphire ( Chrysuronia oenone). The first published record of this species from Brazil was provided by Ruschi (1957) based on two specimens collected in the vicinity of Benjamin Constant, in the State of Amazonas. There are only two additional Brazilian records, both from the upper Rio Jurua in Acre. One record is from the Alto Jurua Extractive Reserve (Whit¬ taker et al. 2002), and the other is from Serra do Divisor National Park (B. M. Whitney, unpubl. data; Guilherme 2009). The species appears to be common in the varzea habitats of the Jurua Basin. The species was observed on a daily basis at our study site, feeding on Inga spp. inflorescences in the varzea forest adjacent to the campinarana. A male (MPEG 62006) was collected on 31 January 2007 in the varzea forest outside a school next to our base camp. This is the first specimen from Acre. Antbird ( Myrmeciza spp.). We collected a male (MPEG 62088) on 24 January 2007 belonging to the Southern Chestnut-tailed Antbird (M. hemi- melaena) species complex, in terra firme forest at the edge of the campinarana. EG compared the specimen with 35 others in Museu Goeldi’s ornithological collection, collected at a variety of localities in Acre (Guilherme 2009), and noted the pileum was distinctly blackish in contrast with the gray ol those ot other specimens of Chestnut¬ tailed Antbird. This pattern was also observed in a male (MPEG 57134) collected in Tefe, Amazo¬ nas, a region with abundant campinarana habitat. The black pileum in these two specimens appears to agree with Zimmer’s (1932) description of a male Zimmer s Antbird (M. hemimelaena casta- nea) from Loreto, northwestern Peru. Isler et al. (2002) recently elevated this form to full species status, based on an analysis of morphological Guilherme and Borges • BIRDS OF THE UPPER JURUA RIVER, ACRE, BRAZIL 29 traits and vocalization patterns. We decided against classifying the MPEG 62088 specimen as Zimmer’s Antbird (M. castanea) because we believe a more thorough investigation of the Goeldi Museum specimens collected in campinar- anas of the southwestern Amazon Basin is necessary. A more detailed field study of the ecology and vocalizations of individuals with these morphological traits is also necessary. This would permit more reliable comparisons with the characteristics of the Peruvian Zimmer’s Antbird (Isler et al. 2002), and a more dependable identification of the specimen collected in the present study. Amazonian Barred Woodcreeper (Dendroco- laptes certhia polyzonus). The most common form of this taxon in Acre is D. c. juruanus , which has been recorded throughout practically the entire state (Pinto and Camargo 1954, Novaes 1957, Guilherme 2009). We netted four Amazonian Barred Woodcreepers between 23 and 27 January 2007 in the campinarana, three of which were collected-one female (MPEG 62042) and two males (MPEG 62043-62044). EG concluded, upon analyzing specimens in the Museu Goeldi’ s ornithological collection, that these individuals have more striking coloration, including well- defined black striping of the pileum, mantle, and throat, which is conspicuously different when compared with the other specimens of D. c. juruanus collected in Acre. The plumage traits of the specimens collected in the campinarana during the present study appear to coincide with those observed in D. c. polyzonus from the southwestern edge of Amazonia, Bolivia and Peru (Marantz et al. 2003; R. Batista and A. Aleixo, unpubl. data). This record of D. c. polyzonus from Acre is the first for Brazil. Citron-bellied Attila ( Attila citriniventris). This species is uncommonly documented in southwest¬ ern Amazonia with the majority of specimen records from northern Peru (Robbins et al. 1991, Schulenberg et al. 2007). The Citron-bellied Attila has been recorded in forested habitats in Acre on the upper Jurua by Whittaker et al. (2002), and A. Aleixo and F. Poletto (unpubl. data). We collected two specimens on 22 and 23 January 2007, a female (MPEG 62124) and a male (MPEG 62125), in the campinarana. This species can also be found in terra firme forest (Robbins et al. 1991), but we believe it is more closely associated with campinarana habitats than rain forest (Alonso 2002, Schulenberg et al. 2007), as observed at our study site, and in Jau National Park north of the Rio Solimoes (Borges et al. 2001). Zimmer’s Tody-Tyrant ( Hemitriccus minimus). This species is patchily distributed in the Amazon Basin (Fitzpatrick et al. 2004). It occurs in igapo forests in the Rio Negro Basin (Novaes 1994, Borges et al. 2001) and in terra firme forest in Mato Grosso (Zimmer et al. 1997), but this species appears in many areas to be closely associated with campinarana habitats (Stotz et al. 1996, Borges et al. 2001, Alonso 2002, Alonso and Whitney 2003, Fitzpatrick et al. 2004). We collected a male (MPEG 621 17) in the campinar¬ ana on 23 January 2007. Zimmer’s Tody-Tyrant has also been recorded in a campina/campinarana enclave in the municipality of Guajara, Amazo¬ nas, close to the city of Cruzeiro do Sul in Acre (A. Aleixo, unpubl. data) and in a bamboo (Guadua spp.) forest in eastern Acre (Guilherme and Santos 2009). Fuscous Flycatcher (Cnemotriccus fuscatus duidae). This taxon has only been recorded in western Acre (Guilherme 2009). We collected a male and a female C. f duidae (MPEG 62119 and 62175, respectively) in the campinarana on 22 and 24 January 2007. We believe C.f duidae in Acre is a facultative inhabitant of the campina and campinarana formations, given that it has also been recorded in other habitats, including sub¬ montane forests of Serra do Divisor National Park, in the western extreme of the state (B. M. Whitney, unpubl. data; MPEG 52797). Alonso (2002) suggests C. f duidae is better treated as a distinct species (Cnemotriccus duidae) given differences in plumage, vocalizations, and habitat preferences compared to those of other taxa in the complex. He noted that a taxonomic revision of the C. fuscatus complex is in preparation by B. M. Whitney and collaborators. Black Manakin ( Xenopipo atronitens). This species is an Amazonian white-sand habitat specialist (Oren 1981, Stotz et al. 1996, Borges 2004, Poletto and Aleixo 2005, Schulenberg et al. 2007). The recorded localities closest to Acre are “Pampas del Heath’’ on the Bolivian border in southeastern Peru (Graham et al. 1980), and a campinarana enclave in the municipality of Guajara in southwestern Amazonas on the border with Acre (Poletto and Aleixo 2005). Thirteen individuals were captured in mist nets set in the campinarana between 22 and 31 January. Six were collected (MPEG 62141-62146; 4 males, 2 I - 30 THE WILSON JOURNAL OF ORNITHOLOGY • Vol. 123, No. 1, March 2011 females). These are the first records and speci¬ mens of the species from the State of Acre. The Black Manakin is relatively well-known from the central and eastern Amazon Basin, ranging from eastern Colombia to the Brazilian State of Para (Snow 2004). However, the species is only known from a few scattered and isolated localities in western Amazonia (Snow 2004, Poletto and Aleixo 2005, Schulenberg et al. 2007). Our record of Black Manakin expands its Brazilian range and reinforces the hypothesis that the species is an obligate resident of campinarana habitats in western Amazonia (Poletto and Aleixo 2005). Yellow-green Vireo (Vireo flavoviridis ). This is a Neartic-neotropical migrant rarely observed in Brazil (Whitney and Pacheco 2001). All Brazilian records of this species with the exception of the specimens collected by J. Hidasi on the Rio Javari in Amazonas State (Whitney and Pacheco 2001), are from Acre (Whittaker and Oren 1999, Guilherme 2009). We collected one bird (MPEG 62172) on 27 January 2007 in secondary forest adjacent to the campinarana. This is the first specimen of this taxon collected in Acre, and only the fourth from Brazil. EG subsequently, on 17 November 2007, collected another specimen of Yellow-green Vireo in varzea forest on the left bank of the Rio Envira in central Acre. These records indicate the species can be found throughout the State of Acre, at least during the North temperate winter, between November and March. Casqued Oropendola (Clyp icterus oseryi). This species was recorded in Brazil first by Whittaker and Oren (1999) in the Junta Basin (Amazonas and Acre). There are now a number of records of this species from Acre (Guilherme 2009), includ¬ ing some from the eastern extreme of the state (A. Aleixo and E. Guilherme, unpubl. data). We collected two specimens (MPEG 62208, 62209) on 30 January 2007 in varzea forest on the left bank of the Cruzeiro do Vale stream, adjacent to our base camp. The campinarana enclave surveyed in the present study is relatively small. However, it supports habitat specialists which are widely- dispersed and patchily distributed in southwestern Amazonia. In addition, a number of bird species that are poorly-known in Brazil are found in the forests adjacent to this enclave. We emphasize the need for further studies in this region, including not only birds, but also other taxonomic groups, to demonstrate the need for establishment of a permanently protected area by local authorities within the near future. ACKNOWLEDGMENTS The authors are grateful to Conservation International (CI-Belem) for financial support of the expedition to the campinaranas of western Acre through the project "Bird Fauna of the State of Acre: Composition, Geographic Distribution, and Conservation”. We thank Alexandre Aleixo, curator of the ornithological collection of the Goeldi Museum, for technical and field support and for comments on identification of specimens in the laboratory. We are also grateful to Sr. Damiao Gonsalves for permission to work in the Dois Portos colony, and to Sr. Leoncio for field assistance. We thank the renowned taxidermist Sr. Manoel Santa Bngida for dedicated and skillful preparation of specimens in the field. 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Elliott, and J. Sargatal, Editors). Lynx Edicions, Barcelona, Spain. Marini-Filho, O. J. 1999. Distribution, composition and dispersal of ant gardens and tending ants in three kinds of central Amazonian habitats. Tropical Zoology 12:289-296. NovAES, F. C. 1957. Contribuigao a ornitologia do noroeste do Acre. Boletim do Museu Paraense Emilio Goeldi, Nova Serie Zoologia 9:1-30. Novaes, F. C. 1994. Aves da floresta de igapo, Rio Negro (Estado do Amazonas), Brasil. Boletim do Museu Paraense Emilio Goeldi, Serie Zoologia 10:155-167. Oren, D. C. 1981. Zoogeographic analysis of the white sand campina avifauna of Amazonia. Thesis. Harvard University, Cambridge, Massachusetts, USA. Pinto, O. and E. A. Camargo. 1954. Resultados omitologicos de uma expedigao ao territorio do Acre pelo Departamento de Zoologia. Papeis Avulsos do Departamento de Zoologia XI(23):3 1 7—4 1 8. Poletto, F. and A. Aleixo. 2005. Implicates biogeo- graficas de novos registros omitologicos em um enclave de vegetagao de campina no sudoeste da Amazonia brasileira. Re vista Brasileira de Zoologia 22:1196-1200. Ricetti, J. and A. B. Bonaldo. 2008. Diversidade e estimativas de riqueza de aranhas em quatro fitofisio- nomias na Serra do Cachimbo, Para, Brasil. Iheringia, Serie Zoologia 98:88-99. Robbins, M. B., A. P. Capparella, R. S. Ridgely, and S. W. Cardiff. 1991. Avifauna of the Rio Maniti and Quebrada Vainilla, Peru. Proceedings of the Academy of Natural Sciences of Philadelphia 143:145-159. Ruschi, A. 1957. A Trochilifauna da foz do rio Javari e rio Amazonas em Benjamin Constant. Boletim do Museu de Biologia Mello Leitao 20:1-8. Schulenberg, T. S., D. F. Stotz, D. F. Lane, J. P. O’Neill, and T. A. Parker III. 2007. Birds of Peru. Princeton University Press, Princeton, New Jersey, USA. Snow, D. W. 2004. Family Pipridae (Manakins). Pages 110-169 in Handbook of the birds of the world. Volume 9. Cotingas to pipits and wagtails (J. del Hoyo, A. Elliott, and D. Christie, Editors). Lynx Edicions, Barcelona, Spain. Stotz, D. F., J. W. Fitzpatrick, T. A. Parker III, and D. K. Moskovits. 1996. Neotropical birds: ecology and conservation. University of Chicago Press, Chicago, Illinois, USA. Toivonen, T., S. Maki, and R. Kalliola. 2007. The riverscape of western Amazonia-a quantitative ap¬ proach to the fluvial biogeography of the region. Journal of Biogeography 34:1374-1387. Vicentini, A. 2004. A vegetagao ao longo de um gradiente edafico no Parque Nacional do Jau. Pages 105-131 in Janelas para a biodiversidade no Parque Nacional do Jau: uma estrategia para o estudo da biodiversidade na Amazonia (S. H. Borges, S. Iwanaga, C. C. Durigan, and M. R. Pinheiro, Editors). Fundagao Vitoria Amazonica, WWF-Brasil, USAID, Manaus-Amazo- nas, Brasil. Whitney, B. and J. A. Alonso. 1998. A new Herpsiloch- mus antwren (Aves: Thamnophilidae) from northern Amazon Peru and adjacent Ecuador: the role of 32 THE WILSON JOURNAL OF ORNITHOLOGY • Vol 123, No. 1, March 2011 edaphic heterogeneity of terra firme forest. Auk 115:559-576. Whitney, B. M. and J. F. Pacheco. 2001. Evidencia material para a presensa de Vireo flavoviridis (Cassin, 1851) no Brasil. Nattereria 2:36-37. Whittaker, A. and D. C. Oren. 1999. Important ornitho¬ logical records from the Rio Jurua, western Amazonia, including twelve additions to the Brazilian avifauna. Bulletin of the British Ornithological Club 119:235-260. Whittaker, A., D. C. Oren, J. F. Pacheco, R. Parrini, and J. Minns. 2002. Aves registradas na Reserva extrati vista do alto Jurua. Pages 81-99 in Enciclopedia da Floresta: O alto Jurua: praticas e conhecimentos das populates (M. C. Cunha and M. B. Almeida, Editors). Editora Companhia das Letras, Sao Paulo, SP, Brasil. Zimmer, J. T. 1932. Studies of Peruvian birds. VI. The formicarian genera Myrmohorus and Myrmeciza in Peru. American Museum Novitates 545:1-24. Zimmer, K. J. and S. L. Hilty. 1997. Avifauna of a locality in the upper Orinoco drainage of Amazonas, Vene¬ zuela. Ornithological Monographs 48:865-885. Zimmer, K. J., T. A. Parker, M. L. Isler, and P. R. Isler. 1997. Survey of a southern Amazonian avifauna: the Alta Floresta region, Mato Grosso, Brazil. Ornitho¬ logical Monographs 48:887-918. The Wilson Journal of Ornithology 1 23( 1 ):33— 47, 2011 STABLE NITROGEN AND CARBON ISOTOPES MAY NOT BE GOOD INDICATORS OF ALTITUDINAL DISTRIBUTIONS OF MONTANE PASSERINES YUAN-MOU CHANG,1 KENT A. HATCH,2 HSIN-LIN WEI,1 HSIAO- WEI YUAN,3 CHENG-FENG YOU,4 DENNIS EGGETT,5 YI-HSUAN TU,6 YA-LING LIN,7 AND HAU-JIE SHIU1-8 ABSTRACT. — We examined 5I5N and 8I3C values of feathers from nine species, belonging to three feeding guilds (herbivores, omnivores, and insectivores), of wild passerines at eight sites along an altitudinal gradient (339-2,876 m asl) within Taroko National Park, Taiwan. We examined: (1) if altitudinal patterns in feather §15N and 5I3C are consistent with previously published values for plants and soils, (2) if feather 515N and 813C differ among sites, and (3) if there are year-to- year and/or month-to-month fluctuations in feather 8I5N and 5I3C of the same birds. We found no simple relationship between feather isotope values and altitude. Feather 8I5N values decreased significantly with increasing altitude for insectivores, but not for herbivores and omnivores. Feather SI3C values increased significantly with increasing altitude for herbivores and omnivores, but not for insectivores. Altitudinal trends in feather 5I5N and 8I3C values exhibit even more inconsistent patterns when data were analyzed by species; feather 8,5N and 5I3C values for some species increased significantly with increasing altitude, others decreased significantly with increasing altitude, and still others exhibited no significant relationship between isotopic values and altitude. The R2 for the relationship between feather 8I5N, 813C values and altitude was generally low regardless of whether the analysis was by feeding guilds or species. This indicates much of the variation cannot be explained by altitude. There were either no significant differences between sites, or significant differences between some but not all sites when investigating 815N or 8I3C, whether by feeding guilds or by species. Our study suggests that carbon and nitrogen isotopes may be not useful markers to track altitudinal migration of montane passerines. Received 16 April 2010. Accepted 15 September 2010. Stable isotope analysis in animals is a powerful tool in reconstruction of diets (Hobson and Clark 1992), trophic levels (Kelly 2000), feeding habitats (Hobson and Sealy 1991, Cherel et al. 2000), and in understanding migration patterns (Hobson 1999b, Webster et al. 2002, Rubenstein and Hobson 2004, Hobson 2005). Feathers are particularly appealing material for use in stable isotope studies of the migratory ecology of birds 1 Department of Ecoscience and Ecotechnology, National University of Tainan, 33 Su-Lin Street, Section 2, Tainan 70101, Taiwan. 2 Biology Department, C.W. Post Campus of Long Island University, 720 Northern Boulevard, Brookville, NY 11548, USA. 3 School of Forestry and Resource Conservation, National Taiwan University, Number 1, Section 4, Roosevelt Road, Taipei 106, Taiwan. 4 Department of Earth Science, National Cheng Kung University, Number 1, University Road, Tainan 70101, Taiwan. ^Department of Statistics, Brigham Young University, 230 TMCB, Provo, UT, 84602, USA. 6 Department of Statistics, National Cheng Kung Univer¬ sity, Number 1, University Road, Tainan 70101, Taiwan. 7 Department of Life Sciences, National Cheng Kung University, Number 1, University Road, Tainan 70101, Taiwan. 8 Corresponding author; e-mail: shiuhj@mail.nutn.edu. tw because they are metabolically inert after synthe¬ sis. Isotopic signatures of both temporal and, if the animal is moving, spatial scales are, therefore, permanently recorded in the feathers (Chamber- lain et al. 1997, Hobson and Wassenaar 1997, Hobson 1999a, Kelly 2000, Wassenaar and Hobson 2000, Kelly et al. 2002, Rubenstein et al. 2002, Dalerum and Angerbjorn 2005). Despite the wide application of stable isotopes to ques¬ tions of animal migration, the potential value for examining altitudinal migration has been little studied (Graves et al. 2002, Hobson et al. 2003, Yi and Yang 2006, Mannel et al. 2007). Studying altitudinal migration using stable isotopes relies on variation in isotopic signatures over an altitudinal gradient. In plants, 5I3C values typically increase with increasing altitude which is related to plant physiological adaptation to changes in CO2 partial pressure, soil moisture, ambient humidity, and air pressure with altitude (Komer et al. 1988, 1991; Marshall and Zhang 1994; Sparks and Ehleringer 1997). In contrast, 515N values in plants and soil decrease with increasing altitude due to the influence of lower temperatures, lower pH, and higher precipitation at higher altitude (Mariotti et al. 1980, Schuur and Matson 2001, Amundson et al. 2003). The isotope patterns at the base of the food chain can be 33 34 THE WILSON JOURNAL OF ORNITHOLOGY • Vol. 123, No. 1, March 2011 FIG. 1. Banding sites in Taroko National Park, Taiwan. Longitude, latitude, and altitude of sampling sites are in Table 1. passed on to the organisms at higher trophic levels, and animals should reflect the altitudinal trends of the plants and soils in their local habitats (Mannel et al. 2007). However, not all animals exhibit altitudinal trends of 5I3C and 6I5N similar to those observed in plants and soils. Previous studies on altitudinal patterns of isotopic signatures in animals have focused on either one species (Graves et al. 2002, Yi and Yang 2006) or several species within a single feeding guild (e.g., nectarivores or herbi¬ vores) (Hobson et al. 2003, Mannel et al. 2007). In each case they were primary consumers. The 8I3C values of animals in some cases become more positive with increasing altitude (Graves et al. 2002, Mannel et al. 2007), while others show no altitudinal trends (Graves et al. 2002). Two studies show 515N values increase with increasing altitude (Hobson et al. 2003, Yi and Yang 2006), one study shows no altitudinal trend (Graves et al. 2002), and the other shows 5I5N values decreasing with increasing altitude (Mannel et al. 2007). More studies should be conducted in other ecosystems with animals in a variety of trophic levels to expand our understanding of the effect of altitude on 8*'C and 5I5N of animals. We discuss altitudinal patterns of feather 513C and 515N values of nine wild passerine species, belonging to three feeding guilds (Chen and Chou 1999, Lin et al. 2003) collected along a large altitudinal gradient of ~2,500 m in Taroko National Park, Taiwan (Fig. 1, Table 1): Herbivores: Japanese White-eye (Zosterops japonicus ), Taiwan Yuhina ( Yuhina brunnei- ceps); Omnivores: Grey-cheeked Fulvetta (Alcippe morrisonia ), Steere’s Liocichla ( Liocichla steerii), Grey-hooded Fulvetta (A. cinereiceps)', and Insectivores: Collared Bush Robin ( Tarsiger johnstoniae ), Green-backed Tit ( Parus monti- colus ), Rufous-capped Babbler ( Stachyris rufi- ceps ), White-browed Bush Robin (T. indicus). Our first objective was to ascertain if 813C values in feathers increased, while 5I5N values in feathers decreased with increasing altitude for each guild and each species. Our second objective was to examine year-to-year and/or month-to- month fluctuations of 513C and 515N in feathers of birds. This would naturally reflect altitude and diet inferences. The presence or absence of Chang et al. • ALTITUDINAL CHANGES OF 815N AND S13C IN MONTANE BIRDS 35 TABLE 1 . Longitude, latitude, altitude, and code for each feather collection site, Taroko National Park, Taiwan. Site Code Longitude Latitude Altitude (m) Bulouwan BL 121° 57' 31" E 24° 16' 95" N 339 Sibao SI 121° 49' 00" E 24° 20' 52" N 956 Loshao LO 121° 45' 04" E 24° 20' 78" N 1,179 Bilyu Sacred Tree BS 121° 40' 03" E 24° 18' 06" N 2,231 Guanyuan GY 121° 33' 98" E 24° 18' 76" N 2,415 Dayuling DY 121° 31' 36" E 24° 17' 96" N 2,500 Hehuan Farm HF 121° 30' 71" E 24° 17' 03" N 2,740 Siafongkou SF 121° 29' 73" E 24° 17' 20" N 2,876 significantly different stable isotope values in feathers collected from the same bird but grown in different years would indicate if the bird exhibited year-to-year molting site fidelity. Similarly, fluctuations in stable isotope values between feathers grown at different times within a single year would indicate altitudinal movements of the bird during the period of feather growth. Third, we explored if nitrogen and carbon isotopes can be used as tracers to study altitudinal migration of montane birds in Taiwan. If feather nitrogen and carbon isotopic profiles are distinguishable among sites along an altitudinal gradient, these two isotopes would provide an opportunity to sample individuals at other times of the year to identify their origins. METHODS Study Sites. — We mist-netted birds at eight banding sites at different altitudes (100-3,000+ m) in Taiwan’s Taroko National Park (Fig. 1, Table 1) from July 2007 to January 2008. Taroko is in the northern section of the Central Mountain Range of Taiwan, and includes high mountains and steep gorges. Climate and vegetation changes, along with altitude, in this area create vegetation zones that can be generally classified as broadleaved forests (< 1 ,500 m asl), mixed broadleaved and coniferous forests (between 1,500 and 3,000 m asl), and subalpine coniferous forests (>3,000 m asl) (Xu and Lin 1984). Most banding sites were in natural forests, but some areas within Sibao, Loshao, and Hehuan Farm have been used as vegetable plantations for many decades. The major vegeta¬ bles cultivated on these farmlands are cabbages, peas, spinach, and tomatoes. The overall latitudinal and longitudinal spreads of these eight banding sites are less than 1°. Feather Collections. — We collected feathers from each mist-netted bird for stable isotope analysis, but we also banded, classified as male or female (if possible), and recorded morphological and plumage characteristics for these birds prior to release. We collected the first primary feather from each wing of each bird mist-netted. Feathers which had a glossy color, no nicks in the outer webs, a visible terminal end of the rachis beyond the wing margin, and no abrasions were identified as new feathers grown in 2007. We assumed bleached and worn feathers were grown in 2006. We collected an old primary feather adjacent to the currently growing or newly grown feathers from each wing from those birds still in the process of molting, therefore having two gener¬ ations of feathers. Some birds were captured more than once, and the feathers replacing the first primary feathers we had pulled previously were again sampled. We selected primary feathers because they are molted shortly after breeding and re-grown prior to migration in most passer¬ ines (Pyle et al. 1997), making them the most likely plumage to represent the isotopic values of molting locations. All collected feathers were sealed in labeled, small paper envelopes and stored in a dry location prior to shipment to the United States for stable isotope analysis. All feathers were heated at 60° C for 30 min before shipping to meet the import requirements of the United States. Feather Cleaning and Preparation. — We ran¬ domly selected one of the two collected feathers, including old feathers grown in 2006 and new feathers grown in 2007, from each bird for analysis. Feathers were sonicated in distilled water for 30 min in preparation for isotopic analysis, followed by sonication in petroleum ether for an additional 30 min to remove contaminants from the feather surface. Feathers were then air-dried in a fume hood for 24 hrs. We cut sections weighing between 0.7 and 0.8 mg after feathers were cleaned and air-dried. We used most of the feather between the tip and the middle 36 THE WILSON JOURNAL OF ORNITHOLOGY • Vol. 123, No. 1, March 2011 of the feather for 8I3C and 5I5N analysis because the feathers were small, wrapping each in a separate tin capsule. There is a concern regarding isotopic variations within a feather (Wassenaar and Hobson 2006, Chang et al. 2008), and we did not attempt to examine different portions within a feather because it was necessary to use a large portion of the feather. Isotopic Analysis. — We analyzed 8,3C and 8I5N of the feather samples using an elemental analyzer (Costech ECS 4010, Valencia, CA, USA) coupled to a Delta V mass spectrometer (Finnigan, Bre¬ men, Germany) at Brigham Young University. We used UCLA Carrera (a working standard from Ian Kaplan’s laboratory, UCLA, 813C = 2.52%o) and LSVEC (NIST, 8,3C = — 46.5%o) as external standards for carbon, and USGS 25 (NIST, S,5N = -30.4%) and USGS 26 (NIST, 815N = 53.5%o) as external standards for nitrogen. Instru¬ ment precision for the measurements was ±0.2%o for 813C and 515N. All stable isotope ratios of the samples are reported in per mil (%o) using the “delta” (5) analysis of variance (MANOVA) with Wilks' Lambda as the test statistic to identify feather isotopic differences among sites for each guild and each species. Bonferroni’s method was used to examine differences in isotope values between sites for post hoc tests of MANOVA. We used repeated-measure ANOVAs to examine year-to- year and within year fluctuations of feather 513C and 8I5N values sampled from the same individ¬ uals. We only used 8,3C and 8,5N values of the first primary feather collected the first time the bird was captured in 2007 compared to 8,3C and 8,:>N values of an older primary feather collected from the same bird at the same time for year-to- year comparisons. We also examined the statisti¬ cal power of non-significant results of the year-to- year and within year repeated-measure ANOVAs. All statistical analysis were calculated with SAS statistical software (SAS 2003). notation. §sample [(Rsample/Rstandard) 1] X 1,000, where the 5sarnple is the isotope ratio of the sample relative to the standard, and Rsampie and R.standard are the fractions of heavy to light isotopes (13C /,2C and l5N/14N) in the sample and standard, respectively. Delta values for carbon and nitrogen are expressed relative to PDB (Craig 1957) and atmospheric nitrogen (Mariotti 1983), respectively. Data Analysis. — We limited our investigation of altitudinal trends and differences among sites for 8,3C and SI5N values to first primary feathers grown in 2007 collected from birds at time of first capture. The relationships between values of 5I3C, ^'5N, and altitude for each guild and each species were analyzed using linear regression. Feather isotopic differences among sites for each guild and each species were measured using a one-way ANOVA tor data with normal distribution (tested by Shapiro-Wilk normality test) or a Kruskal- Wallis test if data were not normally distributed. Tukey’s post hoc tests were used to identify differences in isotope values between sites for data with normal distribution, and Bonferroni’s post hoc tests were used to identify differences in isotope values between sites for data without normal distribution. Combined analysis of multi¬ ple isotopes should increase the power of site identification (Webster et al. 2002). We used both eather 8 C and 515N values in a multivariate RESULTS Altitudinal Pattern and Site Comparison of S,5N Values. — Feather 815N values exhibited varying relationships to altitude among guilds and among species (Figs. 2-4). Insectivores were the only group which had a significant decrease in feather 8I5N values with increasing altitude (Fig. 4A). Feather 815N values for other two guilds had no significant relationship to altitude (i.e., P > 0.05) (Figs. 2A and 3A). When analyzed by species, the Rufous-capped Babbler (Fig. 4D) was the only species which had significant decreases in feather 815N values with increasing altitude. White-browed Bush Robins, however, had a significant increase in feather 815N values with increasing altitude (Fig. 4E). The R 2 of Rufous-capped Babblers and White-browed Bush Robins were 0.27 and 0.37, respectively. Feather SI5N values for the other seven species had no significant relationship to altitude (i.e., P > 0.05) (Figs. 2B, C; 3B, C, D; 4B, C). Feather 8I5N values were significantly different between some, but not all, sites for omnivores (Fig. 3 A) and insectivores (Fig. 4A). Herbivores did not have significant differences across sites (Fig. 2A). When analyzed by species, feather 815N values were significantly different between some, but not all, sites for Grey-cheeked Fulvettas (Fig. 3B), Grey-hooded Fulvettas (Fig. 3D), Ru¬ fous-capped Babblers (Fig. 4D), and White- browed Bush Robins (Fig. 4E). The other five species did not have significant differences across sites (Figs. 2B, C; 3C; 4B, C). Chang et al. • ALTITUDINAL CHANGES OF 515N AND 8,3C IN MONTANE BIRDS 37 12 10 8 6 4 2 0 h h- h < L 1 1 re S13C = 0.14 x Alt + 6.98 ( R 2 = 0.01 , P = 0 GLM; F6 ,9 = 0.69, P = 0.66 .78) 813C = 0.65 x Alt - 24.76 (R2 = 0.43, P < 0.001 ) 0.5 1.5 2.5 0.5 1.5 2.5 12 10 8 6 4 2 0 Japanese White-eye (B) -20 (E) Kfl "o -22 o' o -24‘ CO To -26 (2) (4) W S15N = -3.39 x Alt + 9.84 (R2 = 0.30, P = 0.10) 513C = 0.49 x Alt - 24.60 (R2 = 0.1 5, P = 0.27) Kruskal-Wallis test; H2 = 3.68, P = 0.16 -28 Kruskal-Wallis test; H2 = 2.46, P = 0.29 0.5 1.5 2.5 0.5 1.5 2.5 Taiwan Yuhina FIG. 2. Change in 5I5N and 8I3C values of feathers of herbivorous birds with altitude in Taroko National Park, Taiwan. Results of all species combined are shown in A and D. Results of individual species are shown in B, C, E and F. Stable isotope values of all individuals of each species collected at the same sites are expressed as means ± SE. Numbers of feathers used for isotope analyses for each species at different sites are in parentheses. Numbers of feathers used for isotope analyses for all species combined correspond to those of each species at different sites. One-way ANOVA results are also presented. Asterisks indicate significant differences (P < 0.05) between sites. Altitudinal Pattern and Site Comparison in SI3C Values . — Feather 8I3C values exhibited varying relationships to altitude among guilds and among species (Figs. 2-4). These values for both herbivores (Fig. 2D) and omnivores (Fig. 3E) decreased significantly with increasing altitude. Feather 5I3C values for insectivores had no significant relationship to altitude (Fig. 4F). When analyzed by species, Grey-cheeked Fulvet- tas (Fig. 3F), Rufous-capped Babblers (Fig. 41), and White-browed Bush Robins (Fig. 4J) had significant increases in feather 513C values with increasing altitude. However, Grey-hooded Ful- vettas (Fig. 3H) had significant decreases in feather 813C values with increasing altitude. The R 2 of the four species varied between 0.14 and 0.35. The relationship for the other five species between feather 8I3C values and altitude did not reach significance (P > 0.05) (Figs. 2E, F; 3G; 4G, H). Feather 813C values were significantly different between some, but not all, sites for all three guilds (Figs. 2D, 3E, 4F). When analyzed by species, 8l3C values were significantly different between some, but not all, sites for Grey-cheeked Fulvettas (Fig. 3F), Steere’s Liocichla (Fig. 3G), Grey- hooded Fulvettas (Fig. 3H), Rufous-capped Bab¬ blers (Fig. 41), and White-browed Bush Robins 38 THE WILSON JOURNAL OF ORNITHOLOGY • Vol. 123, No. 1, March 2011 12 10 8 6 4 2 0 (A) All species combined for omnivores 815N = -0.23 x Alt + 6.31 ( R 2 = 0.01, P = 0.13) Kruskal-Wallis test; H7= 31.83, P< 0.001 0.5 1.5 2.5 Grey-cheeked Fu Ivetta Steere's Liocichla Results of aU^soedes'coTnh' ""h 0fAfeat^rSD0f °™ivorous birds with altitude in Taroko National Park, Taiwan. Results of all spec es combined are shown in A and E. Results of individual species are shown in B-D F-H Stable isotope SSSSSSfiSS SP"'Th " "* ~ «*— - means ± SE ZiL J SS S Seta eoStadlSsSS ,h , n “ ” '’""““'“a Numben, of femhees used f„, iso.ope analyses for all species combined correspond to those of each species at different sites. One-way ANOVA results are also presented Asterisks indicate significant differences (P < 0.05) between sites. presented. (Fig. 4J). The other four species had similar 5I3C values across sites (Figs. 2E, F; 4G, H). Combined Analysis of 8,3C and SI5N Values Among Sites. — M ANOVA of 5I3C and 8,5N values of feathers from different sites revealed significant differences between some, but not all, sites for all three guilds (Figs. 5A, D; 6A: Appendices 1, 2). When analyzed by species, significant differences between some, but not all, sites were apparent for Grey-cheeked Fulvettas Chang et al. • ALTITUDINAL CHANGES OF 515N AND 513C IN MONTANE BIRDS 39 All species combined for insectivores Green-backed Tit (C) Green-backed Tit -20 (H) Green-backed Tit _ -22 o o cT -24 O (2)axP(3) (17) $2 -26 S13C = -1 .58 x Alt - 20.26 (R2 = 0.03, P = 0.42) 815N = -3.93 x Alt + 14.81 (R2 = 0.04, P = 0.39) CO Kruskal-Wallis test; H2 = 0.94, P = 0.63 -28 Kruskal-Wallis test; H2 = 3.36, P = 0.19 0.5 1 1.5 2 2.5 3 0.5 1 1.5 2 2.5 3 Rufous-capped Babbler 12 FIG. 4. Change in 8,5N and 5,3C values of feathers of insectivorous birds with altitude in Taroko National Park, Taiwan. Results of all species combined are shown in A and D. Results of individual species are shown in B, C, E and F. Stable isotope values of all individuals of each species collected at the same sites are expressed as means ± SE. Numbers of feathers used for isotope analyses for each species at different sites are in parentheses. Numbers of feathers used for isotope analyses for all species combined correspond to those of each species at different sites. One-way ANOVA results are also presented. Asterisks indicate significant differences (P < 0.05) between sites. 40 THE WILSON JOURNAL OF ORNITHOLOGY • Vol. 123, No. 1, March 2011 (D) All species combined for omnivores (32) r(43) Wilk's X = 0.59 F 14 . 326 -7.16 P < 0.001 *-< ^(18) (5) (22) • Bulowan (339 m) O Siboa (956 m) A Loshao (1179 m) A Bilyu Sacred Tree (2231 m) T Guanyuan (2415 m) V Dayuling (2500 m) ■ Hehuan Farm (2740 m) □ Siafongkou (2876 m) (E) Grey-cheeked Fu Ivetta Wilk's X = 0.64 F 8.128 = 4.01 P< 0.001 IT*] Joz) jl (9)hD^(20) 1 1 T (5) *h X 1(4) (F) Steere's Liocichla Wilk's X = 0.77 F 6,120 ~ 2 78 P = 0.02 (30) (16)t ^ X t(7) (12) | ^ i_* j 10 - 8 (G) Grey-hooded Fulvetta r * 1 Wilk's X = 0.20 F 6.64 = 13.49 P< 0.001 i i r 1 1 1 ii 1<7> r Y •k * r (114- '(10) 1 i — ^ — i - * -i 1 ‘ l! |-jH 0) -26 -24 -22 -2 513C (°/00) shown in A^D M T* ^ ^ Results of aU s?ecies combined a colirte^aUh“saSe2es^ spec,“-e shown in B, C. and E-G. Stable isotope values of all individua in parentheses. Asterisks indicate si^nificMt^ferences'r'p'To osThT ^ ‘Sp°Pe 3nalyses at different sitesa Appendix 1. 0.05) between sites. Post hoc test results of D are Chang et al. • ALTITUDINAL CHANGES OF 515N AND 513C IN MONTANE BIRDS 41 (A) All species combined for insectivores (6)t T l— I (8) -4— -< Wilk's X = 0.50 (18) F 14,226 = 6.59 V ’fy. p< 0.001 I <41) (5) / x/4g\ (20) • Bulowan (339 m) O Siboa (956 m) A Loshao (1179 m) A Bilyu Sacred Tree (2231 m) ▼ Guanyuan (2415 m) V Dayuling (2500 m) ■ Hehuan Farm (2740 m) □ Siafongkou (2876 m) (D) Rufous-capped Babbler r Wilk's X = 0.21 | F 8,58 = 8-66 P=< 0.001 (4) I - * - , / (7)h§h (3) (8) / li*Jl _ * _ J( II II (E) White-browed Bush Robin Wilk's X = 0.37 f4.34 = 5.54 P = 0.002 r * “1 1 1 5(10) (3) ^ (8) 1-5-H -26 -24 -22 -20 S13C (°/00) FIG. 6. MANOVA comparisons of sites of insectivorous birds. Results of all species combined are shown in A. Results of individual species are shown in B-E. Stable isotope values of all individuals collected at the same sites are expressed as means ± SE. Numbers of feathers used for isotope analyses at different sites are in parentheses. Asterisks indicate significant differences ( P < 0.05) between sites. Results of post hoc test of A are in Appendix 2. (Fig. 5E), Steere’s Liocichla (Fig. 5F), Grey- hooded Fulvettas (Fig. 5G), Rufous-capped Bab¬ blers (Fig. 6D), and White-browed Bush Robins (Fig. 6E). The other four species did not differ across sites (Figs. 5B, C; 6B, C). Year-to-year and Within-year Comparisons. — Seven species had sufficient data for between- year (Fig. 7, Table 2) and six species for within- year (Fig. 7, Table 3) comparisons. Feathers for all species from the same individuals did not have significant between-year and within-year varia¬ tions in 8I3C. The power of the tests varied between 0.05 and 0.45. Feathers from the same individuals for 8,5N values had no significant between-year and within-year variations in isoto¬ pic values for all species except Taiwan Yuhinas {F 1,9 = 13.1, P = 0.006), and Steere’s Liocichlas (F 1,13 = 4.9, P = 0.045). The 515N values for - 42 THE WILSON JOURNAL OF ORNITHOLOGY • Vol. 123, No. 1, March 2011 Steere's Liocichla Gray-cheeked Fulvetta □ 2006 o 1st 2007 A 2nd 2007 Taiwan Yuhina Japenese White-eye 8 10 12 14 16 -28 -26 -24 51SN (‘ I 813c cl HF - m o - E O ffl o ED 0 & DY - 0 o 0 O mo (27 9 10 O 0 BD 00 SO CEU so Q]4 GY iD CHi & O a O A O A O A O A O A D4 0)4 BS O A AO 4[g\ - 4QJA mo 0 o 0 o - O 0 04 - 04 Q8 - so GY 0 o - so E o - ED - iS - AO - a o - 0 O - A) - A O BS 60 - 6fO - Q]9 - 9 ED - O - A O - mo - . 0O . - Qi - m o - Q2 - cm - cdi - 0 O - m o - 0 o - oai - a cm LO SO - O 0 - no - O0 - ca - C0 - O 0 - O 0 - Di - Q]i - 4) - OA - mo - 80 - 0 o - 50 - ED - E O .M . Q . - EEO - 4) - . A . SI ED - m o E O - m o - O A - © - m o - 0 o HF 50 EO - mo 8ED E O - O E - 0 o - - 0 o . E. O - 0 o BS E O - .51 O . E O - 50 LO SI O 0 - iGD - - b - ' - t — — r ^ i - t - 1 - \- — i — *9 , — , — -22 -20 -18 takTfrom the^e indW-- 2006 a"d - well as those grown at different times in 2007 but used for isotope analyses, i.e., 3. The code for each site < . ^ ’ Ui5 vvwii ao uiuac glUV ;. !?ll ldUa'S'. number in each s<5uare represents the number of the primary feather grown in 2006 corr “ If ^epref"ts the seventh primary feather. Statistical results are in Tables 2 and corresponds to Fig. 1 and Table 1 . Chang et al. • ALTITUDINAL CHANGES OF 815N AND S13C IN MONTANE BIRDS 43 Rufous-capped Babbler GY SO 40 n o no m o . - © o Q4 C35 © o 70 L0 . 4D' ' iD 04 fflCA HD si . ca . 3(0 . CA . 3Q . BL . 4 tO . SO 04 a O OS 04 Green-backed Tit o OQ _ § A> - £ Collared Bush Robin sf o a OA . ■ O A . CA . "ffl . O - Qi O <1 - AD HF O A - O A O A - O A . 0 . O . - m o GY - © Grey-hooded Fulvetta O ffl AH " mo Amo A . - . & . - 4(D DY O . - . A . . OH - ca GY Q3 - 03 _ Q2 _ _ . _ . _ — 2 4 6 8 10 12 14 16 -28 -26 -24 -22 -20 -18 S15N (0/„o) 513c (°/J FIG. 7. Continued. these two species in feathers grown in 2007 were significantly higher than those grown in 2006 (Fig. 7, Table 2). The power of these tests varied between 0.05 and 0.43. DISCUSSION Altitudinal Trends in Feather S,5N and S13C Values. — A major finding was that there is no simple relationship between feather isotope values and altitude. Feather 815N values decreased significantly with increasing altitude for insecti- vores, but not for herbivores and omnivores. Feather 813C values increased significantly with increasing altitude for herbivores and omnivores, but not for insectivores. Altitudinal trends in feather 815N and 8,3C values exhibited more inconsistent patterns when analyzed by species; feather 815N and 813C values for some species increased significantly with increasing altitude, others decreased significantly with increasing altitude, and still others exhibited no significant relationship between isotopic values and altitude. In addition, these patterns do not reflect those typically reported for plants and soils (Mariotti et al. 1980; Korner et al. 1988, 1991; Marshall and Zhang 1994; Sparks and Ehleringer 1997; Schuur and Matson 2001; Amundson et al. 2003), i.e., 513C values increasing (—1.1 %o/km) (Korner et al. 1991), and 8I5N values decreasing (—1.6 %o / km) (Mariotti et al. 1980; Handley et al. 1999; Jacot et al. 2000a, b; Schuur and Matson 2001; Amundson et al. 2003; Mannel et al. 2007) with increasing altitude. The mechanisms responsible for altitudinal patterns in feather 8I3C and 8I3N values are still not understood, but the altitudinal patterns of feather 8I3C and 815N values could be interpreted by several interrelated hypotheses involving nutrition. First, 8I3C and 8I5N values of plants (Mariotti et al. 1980; Handley et al. 1999; Jacot et al. 2000a, b; Amundson et al. 2003; Mannel et al. 2007) and arthropods (Markow et al. 2000, Herrera et al. 2002, Hood-Nowotny and Knols 2007) exhibit interspecific differences. Previous studies conducted in Taroko show that plant (Xu and Lin 1984, Chen 1994) and insect (Xu 2006, 2007) species change with altitude. Assuming these birds stay locally at their molting sites, perhaps the lack of altitudinal patterns in feather SI3C and 8I5N values in many of the species we 44 THE WILSON JOURNAL OF ORNITHOLOGY • Vol. 123, No. 1, March 2011 TABLE 2. Repeated-measures ANOVA for isotopic values of the feathers grown in 2006 and 2007 from the same individuals. Significant differences (P < 0.05) are in bold italics. Degrees of freedom are indicated in parentheses (df for numerator, df for denominator). Results (1-/?) of the power analysis are presented (a = 0.05). Sample sizes of each species are indicated in parentheses by the common name of each species. 8I5N 8I3C Species F P i-p F P i -P Herbivores Japanese White-eye (2) Taiwan Yuhina (9) 12.25 (1, 1) 13.1 (1, 9) 0.18 0.006a 0.05 13.44 (1, 1) 0.44 (1, 9) 0.17 0.52 0.05 Omnivores Gray-cheeked Fulvetta (25) 2.97 (1, 23) 0.10 0.36 3.75 (1, 23) 0.07 0.45 Steere’s Liocichla (13) 4.9 (1, 13) 0.045* 0.00 (1, 13) 0.96 0.05 Grey-hooded Fulvetta (6) 0.47 (1, 5) 0.52 0.07 0.05 (1,5) 0.83 0.10 Insectivores Collared Bush Robin (2) 26.56 (1, 1) 0.12 0.06 0.66 (1, 1) 0.57 0.05 Rufous-capped Babbler (12) 4.06 (1, 11) 0.07 0.43 0.37 (1, 11) 0.55 0.09 a Feathers grown in 2007 were significantly higher than those grown in 2006 (Fig. 7). sampled may be attributed to individuals of these species consuming a variety of insects and/or plant matter during the time of molt which, when combined, cancel the effect of altitude. Similarly, increase/decrease of feather 513C and 8I5N values with increasing altitude for some species may also be due to the combination of foods they choose to eat, rather than to any effect of altitude. Detailed surveys of the isotopic ratios of foods and knowledge of diet-tissue fractionation (Gannes et al. 1997) of these birds are both necessary for testing these hypotheses. Second, different indi¬ viduals of the same species may move freely during feather growth between different resource patches along a wide range of altitudes to obtain their daily food requirements. Foraging over a wide altitudinal range may lead to feather 5I3C and 5I5N values that do not to reflect expected altitudinal trends. Year-to-year arid Within-year Comparison — One can examine changes in diet or in feeding locations over time by repeatedly comparing isotopic values of tissue samples at different time intervals, but from the same source (Dalerum and Angerbjorn 2005). Feathers are ideal for a temporal analysis of feeding locations (Mizutani et al. 1990, Hobson and Clark 1992, Thompson and Furness 1995) because they can be collected continually from the same individual (Ainley et al. 2003, Dalerum and Angerbjorn 2005). Our results show within-individual variation of feather 5I5N and 5I3C values is low both between- and TABLE 3. Repeated measures ANOVA for isotopic values of the feathers grown at different times in 2007 from the same individuals. Degrees of freedom are in indicated parentheses (df for numerator, df for denominator) Results (1-fl) of the power analysis are presented (a = 0.05). Sample sizes of each species are indicated in parentheses by the common name 8I5N 8,3C — Species F P i-p F P i-P Omnivores Gray-cheeked Fulvetta (6) Steere’s Liocichla (7) Grey-hooded Fulvetta (3) 2.26 (2, 6) 5.37 (1, 6) 0.02 (2, 2) 0.19 0.06 0.98 0.07 0.45 0.05 1.20 (2, 6) 4-29 (1,6) 0.05 (2, 2) 0.36 0.08 0.95 0.20 0.37 0.05 Insectivores Collared Bush Robin (7) Green-backed Tit (2) Rufous-capped Babbler (2) 4.44 (1, 5) 0.66 (1, 1) 0.24 (1, 1) 0.09 0.56 0.71 0.33 0.05 0.05 4.08 (1, 5) 0-12 (1, 1) 0.13 (1, 1) 0.10 0.79 0.78 0.30 0.05 0.05 Chang et al. • ALTITUDINAL CHANGES OF 515N AND 513C IN MONTANE BIRDS 45 within-year for most of the species examined. This suggests these birds feed on similar diets and at similar feeding locations/altitudes when molt¬ ing flight feathers both within a single season and from year to year. Also, these birds may exhibit strong feeding site fidelity during molt periods. However, the scale of what constitutes a feeding site as indicated by isotopic analysis of feathers is still unclear, and may not correspond to the exact locations where the birds were captured. Taiwan Yuhinas and Steere’s Liocichlas had significant yearly variations in 5,5N values in this study. Thus, the differences in 5,5N values of the feathers of these species suggest that, from 1 year to the next, these birds either fed at different altitudes or remained at the same location but changed the composition of their diet, or remained at the same location and did not change the composition of their diet, but 8I5N values of the diet varied (Dalerum and Angerbjorn 2005). Our attempt to separate individuals from different altitudes and to establish a sound isotope profile along the altitudinal gradient using feather carbon and nitrogen isotope was unsuccessful. Thus, these two isotopes do not appear to be suitable for the study of altitudinal migration of montane passerines in Taroko. First, we found either no significant differences between sites, or significant differences between some, but not all sites when investigating 8l5N, and 5I3C separately or together regardless of whether the data are analyzed at the guild level or species level. Second, feathers reflect isotopic values at the time and location of molt (Chamberlain et al. 1997, Hobson and Wassenaar 1997, Wassenaar and Hobson 1998, Hobson 1999b, Wassenaar and Hobson 2000) and the application of stable isotopes to study bird migration relies on sound information of isotopic values across their altitu¬ dinal range. However, not only did we find instances where there were weak relationships between feather 5I5N, 513C, and altitude, but even where there was a significant relationship, the amount of variation explained by the relationships (R2) was quite low. This is also the case in previous studies (Graves et al. 2002, Hobson et al. 2003, Mannel et al. 2007), although these studies suggested that 5I5N and 5I3C might be useful for studying the altitudinal movements of animals. While these studies found significant relationships between feather 513C or feather 5I5N and altitude, they did not indicate the R2 value or discuss the predictive strength of the relationship. In contrast, our study suggests that carbon and nitrogen isotopes are not adequate to serve as regional markers of individuals or populations inhabiting different altitudes. While feather carbon and nitrogen isotopes exhibit a significant altitudinal trend for some guilds or species; it is not strongly predictive and does not appear to be useful for tracking altitudinal movement of montane passer¬ ines. ACKNOWLEDGMENTS We greatly appreciate B. V. Chu, Jian Hong Chen, Jia Hong Chen, and H. Y. Lin for help with fieldwork, and Talita Alencar, A. M. Johnson, and Jenilyn Weston for feather cleaning and sample preparation. We thank David Tingey for assistance with the isotope analyses. We are grateful to Ellen Paul for help and support with feather shipments. We thank Taroko National Park of Taiwan for financial and logistic support. This study was also supported by grants NSC 96-2621 -B-024-001 from the National Science Council of Taiwan to HJS. LITERATURE CITED Ainley, D. G., G. Ballard, K. J. Barton, B. J. Karl, G. H. Rau, C. A. Ribic, and P. R. Wilson. 2003. Spatial and temporal variation of diet within a presumed metapopulation of Adelie Penguins. Condor 105:95— 106. Amundson, R., A. T. Austin, E. A. G. Schuur, K. Yoo, V. Matzek, C. Kendall, A. Uebersax, D. Brenner, and W. T. Baisden. 2003. Global patterns of the isotopic composition of soil and plant nitrogen. Global Biogeochemical Cycles 17:1-10. Chamberlain, C. P., J. D. Blum, R. T. Holmes, X. H. Feng, T. W. Sherry, and G. R. Graves. 1997. 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Trends in Ecology and Evolution 17:76-83. Xu, G. S. and Z. T. Lin. 1984. The survey of flora and their ecology in Taroko National Park. Taroko National Park, Hualian, Taiwan. Xu, Y. F. 2006. The community and function of insects in Taroko National Park (1). Taroko National Park, Hualian, Taiwan. Xu, Y. F. 2007. The community and function of insects in Taroko National Park (2). Taroko National Park, Hualian, Taiwan. Yi, X. F. and Y. Q. Yang. 2006. Enrichment of stable carbon and nitrogen isotopes of plant populations and plateau pikas along altitudes. Journal of Animal and Feed Sciences 15:661-667. APPENDIX 1 . Post hoc t- test of MANOVA for feather isotopic values (%o) from sites of omnivorous birds. Asterisks and plus signs indicate significant ( P < 0.05) and no ( P > 0.05) differences between sites, respectively. The code for each site corresponds to Fig. 1 and Table 1. BL (339 m) SI (956 m) LO (1,179 m) BS (2,231 m) GY (2,415 m) DY (2,500 m) HF (2,740 m) SF (2,876 m) BL (339 m) SI (956 m) + LO (1,179 m) + + BS (2,231 m) + + + GY (2,415 m) * + * * DY (2,500 m) + + * * * HF (2,740 m) * + * * + * SF (2,876m) + + * * * + * APPENDIX 2. Post hoc t- test of MANOVA for feather isotopic values (%o) from sites of insectivorous birds. Asterisks and plus signs indicate significant (P < 0.05) and no (P > 0.05) differences between sites, respectively. The code for each site corresponds to Fig. 1 and Table 1. BL (339 m) SI (956 m) LO (1,179 m) BS (2,231 m) GY (2,415 m) DY (2,500 m) HF (2,740 m) SF (2,876 m) BL (339 m) SI (956 m) + LO (1,179 m) * * BS (2,231 m) * + * GY (2,415 m) * + * + DY (2,500 m) * * * + + HF (2,740 m) * * * + + + SF (2,876 m) * + * + + + + p ' The Wilson Journal of Ornithology 1 23(1):48— 58, 2011 SEASONAL FECUNDITY AND SOURCE-SINK STATUS OF SHRUB-NESTING BIRDS IN A SOUTHWESTERN RIPARIAN CORRIDOR L. ARRIANA BRAND13-4 AND BARRY R. NOON1 2 ABSTRACT. — Saltcedar ( Tamarix spp.) has increasingly dominated riparian floodplains relative to native forests in the southwestern U.S., but little is known about its impacts on avian productivity or population status. We monitored 86 Arizona Bell’s Vireo ( Vireo bellii arizonae ), 147 Abert’s Towhee ( Melozone aberti), and 154 Yellow-breasted Chat ( Icteria virens ) nests to assess reproductive parameters in cottonwood-willow ( Populus-Salix ), saltcedar, and mesquite ( Prosopis spp.) stands along the San Pedro River, Arizona during 1999-2001. We also assessed source-sink status for each species in each vegetation type using field data combined with data from the literature. There were no significant differences in reproductive parameters between vegetation types for Abert’s Towhee or Yellow-breasted Chat, although seasonal fecundity was quite low across vegetation types for the latter (0.75 ± 0.14; mean ± SE). Bell’s Vireo had extremely low seasonal fecundity in saltcedar (0.10 ± 0.09) and significantly fewer fledglings per nest in saltcedar (0.09 ± 0.09) compared with cottonwood (1.07 ± 0.32). Point estimates of X were substantially <1 for all three focal species in all habitats indicating the entire study area may be performing as a sink; 90% Cl of X included 1 only for Abert's Towhee across vegetation types and Bell’s Vireo in cottonwood vegetation. These results are surprising given the San Pedro is considered to be one of the best remaining occurrences of lowland native riparian vegetation in the southwestern United States. Received 15 April 2010. Accepted 8 October 2010. The proportion of lowland riparian corridors covered by exotic saltcedar ( Tamarix spp.) relative to native broadleaf forests and shrublands has increased dramatically in the Southwest over the past 50 years (Hunter et al. 1987, Sher et al. 2000, Morisette et al. 2006, Stromberg et al. 2007). Avian density responses to these vegeta¬ tion types have been documented in numerous studies across river systems, yet few studies have assessed measures of productivity for southwest¬ ern riparian birds. In particular, little is known about the impacts of exotic vegetation on avian productivity or population status in the region (Sogge et al. 2008). Many canopy-nesting bird species have highest densities in tall, gallery cottonwood-willow ( Po¬ pulus-Salix) forests compared with saltcedar, although saltcedar has maintained high abundance of some shrub-nesting species (Hunter et al. 1987, 1988; Ellis 1995; Brand et al. 2008, 2010). Exotic vegetation is one circumstance in which patterns of abundance and productivity may diverge (Van 1 Department of Hydrology and Water Resources, University of Arizona, Sustainability of Semi-Arid Hydrol¬ ogy and Riparian Areas (SAHRA) Center, P. O. Box 210158-B, Tucson, AZ 85721, USA. Department of Fish, Wildlife, and Conservation Biol¬ ogy, Colorado State University, Fort Collins, CO 80523 USA. Current address: U.S. Geological Survey, Western Ecological Research Center, San Francisco Bay Estuary Field Station, 505 Azuar Drive, Vallejo, CA 94592, USA. Corresponding author; e-mail: arriana_brand@usgs.gov Home 1983, Battin 2004, Bock and Jones 2004); thus, it is important to assess productivity and population status for shrub-nesting birds in different habitat types comprised of native and exotic vegetation. Brand et al. (2010) documented nest survivorship of common shrub-nesting birds on the San Pedro River and found a tendency for Arizona Bell’s Vireo (Vireo bellii arizonae) to have higher nest survivorship in cottonwood versus mesquite (Prosopis spp.) and saltcedar. but no difference in nest survivorship between vegetation types for Yellow-breasted Chat (Icteria virens) and Abert’s Towhee (Melozone aberti). Nest survival is only one component of avian fecundity, and further work is needed to document productivity and population status for these species. Source-sink models have been applied extensively to assess habitat quality of fragmented versus contiguous habitats across the Midwest and other regions in the U.S. (e.g., Pulliam 1988, Donovan et al. 1995, Fauth 2000, Yackel Adams et al. 2007), but little is known about productivity or source-sink status of shrub-nesting birds in southwestern riparian habitats. Our primary research objectives were to assess repi oductive parameters (e.g., clutch size, young per nest, seasonal fecundity) and source-sink status of three relatively common shrub-nesting bird species on the San Pedro River in southeast¬ ern Arizona among vegetation types. This study supplements and provides greater context for previous nest survivorship estimates (Brand et al. 2010) for this population with additional 48 Brand and Noon • SHRUB-NESTING BIRDS IN A RIPARIAN CORRIDOR 49 productivity measures and draws information from the literature to assess source-sink status. The San Pedro River is generally considered one of the best remaining examples of lowland riparian cottonwood-willow woodland and forests in the region. We hypothesized that native cottonwood-willow and mesquite riparian forests would maintain higher productivity and serve as population sources, and saltcedar would serve as a sink. METHODS We used estimates from field data collection supplemented with information from the literature to assess reproductive parameters and source-sink status for three shrub-nesting species with ade¬ quate data: Yellow-breasted Chat, Abert’s Tow- hee, and Arizona Bell's Vireo. We collected field data at 23 sites on the San Pedro River during the 1999-2001 field seasons. Study sites included 16 areas within the San Pedro Riparian National Conservation Area (SPRNCA) managed by the Bureau of Land Management (BLM) and seven sites on privately-owned land north of the SPRNCA (Fig. 1). Cottonwood-willow forests are the predominant woody vegetation type along the San Pedro River floodplain with saltcedar occurring in the drier stretches. A second zone of riparian vegetation occurs beyond the flood- plain — river terraces on the San Pedro are vegetated mainly by mesquite forests. We searched for and monitored nests in cottonwood, saltcedar, and mesquite stands every 2-5 days during the avian breeding season (10 May to 20 Jul) at each site following BBIRD protocol (Martin et al. 1997, Brand et al. 2010). We recorded egg or nestling age, adult behavior, and nest status at each nest check. Ages were based on observed laying dates, hatch dates, and nestling size and development. We estimated clutch size by counting the number of host eggs following onset of incubation. We considered nests failed if they showed clear signs of failure (e.g., torn or fallen nest, broken eggs, dead nestlings) or if the nest was intact but eggs or nestlings disappeared >2 days before the expect¬ ed fledging date. We estimated the number of young fledged per nest by counting the number of nestlings observed within 2 days of the expected fledge date, and where there was direct observa¬ tion of fledging or indirect evidence such as flattened nest rim and fecal material on the rim or below the nest. The finite rate of population increase ( X ) is a key parameter used to assess population status and, in particular, whether a population is functioning as a population source or sink (Pull¬ iam 1988, Battin 2004). We used the finite rate of population increase (X) in the absence of immi¬ gration or emigration to assess the status of each species within each vegetation type and across vegetation types. We calculated X = Sa +S/-p by vegetation type where Sa is annual survival of adults, Sj is annual survival of juveniles, and (3 is seasonal fecundity, or the number of females produced per breeding female (Pulliam 1988). We estimated seasonal fecundity by vegetation type as (3 = nsf-a, where ns = % nest survival by vege¬ tation type,/= the mean number of female young produced per successful nest by vegetation type, and a = average number of nesting attempts per season (Pulliam 1988, Fauth 2000, Grzybowski and Pease 2005). We used estimates of ns for each species in each vegetation type, and across all vegetation types, from a companion study of the same populations (Brand et al. 2010; Table 1). That study used the method of Stanley (2000) to assess daily nest survival probability ( p ) and then calculated nest survival as the percentage of clutches that resulted in >1 fledged offspring equal to TOO, where dj and d2 = average days in the incubation and nestling periods, respectively (Jehle et al. 2004). We estimated / from field data as the total number of fledglings per successful nest divided by two, assuming an equal sex ratio at hatching. We considered species- and vegetation-specific estimates of nest survival and number of female young fledged per successful nest to represent 3-year breeding- season averages since nests were monitored throughout the breeding season and we combined data across years. We did not measure the average number of nesting attempts by species per season on the San Pedro. Instead, we adopted estimates for each species from previous studies that followed all nesting attempts by a cohort of females though a breeding season. Based on previous studies, we assumed that Yellow-breasted Chat and Abert’s Towhee adult females nested 1.4 ± 0.1 (mean ± SE) and 3.9 ± 0.5 times on average per season, respectively (Thompson and Nolan 1973, Finch 1984). Budnik et al. (2001) reported average number of nesting attempts separately for para¬ sitized versus non-parasitized pairs in recognition that birds parasitized by Brown-headed Cowbirds w 50 THE WILSON JOURNAL OF ORNITHOLOGY • Vo/. 123, No. 1. March 2011 □ SPRNCA - San Pedro River — Interstate highway = Highway - Local roads Cities (population size) o <10,000 © 10000 - 40000 O >40,000 Upper San Pedro Watershed Kilometers K. Benedict 10/07 ' kj fan River showing bird sites' highways, cities, boundary between upper and lower basins, and San Pedr Riparian National Conservation Area (SPRNCA). United States Mexico A Bird sites — Boundary between upper and lower basins Brand and Noon • SHRUB-NESTING BIRDS IN A RIPARIAN CORRIDOR 51 TABLE 1. Reproductive parameters (mean ± SEd) for Abert’s Towhee, Yellow-breasted Chat, and Bell’s Vireo in saltcedar (SC), cottonwood (CW), mesquite (MQ), and across all vegetation types. Species Habitat n a % nest survival w Clutch size d Fledglings per nest d Fledglings per successful nest d Seasonal fecundity cd Abert’s SC 36 30 9 2.80 ± 0.11 1.03 ± 0.22 2.13 0.22 1.23 ± 0.43 Towhee CW 45 29 8 2.79 -t- 0.09 1.19 ± 0.20 2.43 + 0.13 1.32 ± 0.40 MQ 66 30 6 2.81 0.09 1.07 ± 0.17 2.50 0.15 1.43 ± 0.36 ALL 147 30 4 2.80 0.05 1.09 ± 0.11 2.38 0.09 1.34 ± 0.27 Yellow SC 25 39 + 11 3.31 0.18 1.13 ± 0.25 2.17 0.21 0.60 ± 0.18 -breasted CW 71 43 7 3.17 0.08 1.16 ± 0.20 2.64 ± 0.22 0.81 ± 0.16 Chat MQ 58 41 + 7 3.56 0.09 1.31 ± 0.21 2.62 0.20 0.77 ± 0.16 ALL 154 42 4 3.36 + 0.06 1.20 ± 0.13 2.54 ■± 0.29 0.75 ± 0.14 Bell’s SC 11 9 8 2.86 + 0.31 0.09 ± 0.09 1.00 ± 0.00c 0.10 ± 0.09 Vireo CW 15 34 13 3.10 0.18 1.07 ± 0.32 2.29 0.18 0.66 ± 0.27 MQ 60 12 4 3.13 0.13 0.47 ± 0.14 2.33 ± 0.28 0.28 ± 0.10 ALL 86 14 ± 3 3.09 + 0.10 0.54 ± 0.11 2.14 ± 0.19 0.31 ± 0.09 d n = total nest sample size. b From Brand et al. 2010. c Seasonal fecundity = mean number of female offspring (number of fledglings divided by 2) successfully fledged per adult female per year. d 90% Cl = mean ± 1.645 x SE. e SE = 0 as only one of 1 1 Bell’s Vireo nests found in saltcedar was successful. (Molothrus ater) may nest more frequently. We used average nesting attempts weighted by the proportion of nests parasitized by vegetation type from Brand et al. (2010) to account for this variation, and assumed that Bell’s Vireos nested 1.7 ± 0.2, 2.0 ± 0.1, 2.2 ± 0.2, and 2.0 ± 0.2 times (mean ± SE) in cottonwood, mesquite, saltcedar, and across all vegetation types, respec¬ tively (Budnik et al. 2001). We used estimates of annual adult survival from the literature specific to the Southwest. The estimates were Sa = 0.574 ± 0.072 for Bell’s Vireo (mean ± SE), Sa = 0.518 ± 0.028 for Yellow-breasted Chat, and Sa = 0.486 ± 0.126 for Abert’s Towhee obtained from 6, 18, and 5 Monitoring of Avian Productivity and Survivor¬ ship (MAPS) stations in the southwestern U.S., respectively (DeSante and Kaschube 2006, Mich¬ el et al. 2006). Juvenile survival estimates are lacking for these species, and we assumed that annual survival of juveniles was half that of adults (Temple and Carey 1988, Donovan et al. 1995, Budnik et al. 2000). Use of the same adult and juvenile survivorship estimates for the different vegetation types will tend to underestimate differences in X between them. We estimated the standard error of |3 and X using the delta method (Armstrong et al. 2002, Powell 2007). We assumed covariances = 0 since S^, ns, and a were estimated with different data. Only one successful Bell’s Vireo nest was observed in saltcedar (thus SE = 0), and we substituted the estimated standard error of the number of fledglings per successful nests ob¬ served in mesquite (SE = 0.28) to represent maximum observed variability in the system for that species for the delta method estimation of SE(P) and SE(?Q. We set a = 0.10 to minimize the probability of a Type II error and interpreted meaningful differences in reproductive parame¬ ters among vegetation types in terms of non- overlapping 90% confidence intervals. The population for X> 1 was considered to be a potential source of emigrants and the population for X=\ was considered stable (Pulliam 1988). The population for X,<1 was considered to demonstrate characteristics of a population sink (Pulliam 1988, Battin 2004). We set a = 0.10 to minimize the probability of a Type II error and interpreted results with 90% confidence intervals (Cl) around We also separately estimated adult survivorship, seasonal fecundity, and the average number of nesting attempts required to obtain a stable population (X = 1 ) with other vital rates held constant. We used this approach to assess whether estimated rates were within 90% confi¬ dence intervals of what was observed or assumed, and to provide insight into what survivorship levels would be needed to conceivably maintain a stable population on the San Pedro. We conducted a sensitivity analysis to assess what levels of parameters drawn from the literature — adult 52 THE WILSON JOURNAL OF ORNITHOLOGY • Vol. 123, No. 1, March 2011 ■ Saltcedar EDMesquite DCottonwood □ All habitats Bell's Vireo Yellow-breasted Chat Abert's Towhee FIG. 2. Finite rate of population increase (X) ±90% confidence intervals (Cl) for Bell’s Vireo, Yellow-breasted Chat, and Abert’s Towhee by vegetation type. Data to estimate X was drawn from field studies conducted on 23 sites along the San Pedro River 1999-2001 and from the literature. survivorship and average number of nesting attempts — would be required to attain X = 1 at observed levels of population-specific vital rates from the San Pedro — nest survival and number of young per successful nest — within each vegeta¬ tion type. RESULTS We monitored 86, 147, and 154 Bell’s Vireo, Abert’s Towhee, and Yellow-breasted Chat nests, respectively, during a 72-day interval during the avian breeding season across 3 years. Clutch sizes were similar among vegetation types for all three species (Table 1 ). Estimated young per nest, young per successful nest, and seasonal fecundity were similar among vegetation types for Abert’s Towhee and Yellow-breasted Chat although seasonal fe¬ cundity estimates for Yellow-breasted Chat were quite low (Table 1). Bell’s Vireo had extremely low seasonal fecundity, particularly in saltcedar, and had significantly fewer fledglings per nest in saltcedar compared with cottonwood based on non¬ overlapping confidence intervals (Table 1). Point estimates of X were substantially < 1 for Bell’s Vireo, Yellow-breasted Chat, and Abert’s Towhee in all vegetation types (Fig. 2). Bell’s Vireo had the greatest variation in X across vegetation types of the three species with 27 and 17% higher estimates in cottonwood compared with saltcedar and mesquite, respectively. The upper 90% confidence limit for X was <1 for Bell s Vireo and Yellow-breasted Chat in all habitat types with the exception of Bell’s Vireo in cottonwood where the upper confidence limit barely exceeded 1. Cls (90%) for Abert’s Towhee surrounding X were large and included 1 for all vegetation types. Annual adult survivorship required to maintain X = 1, at observed levels of seasonal fecundity, was 0.60 across vegetation types for Abert’s Towhee with little variation between vegetation types; estimates were within 90% Cl of assumed survivorship (Fig. 3). Annual adult survivorship required to maintain X = 1 , at observed levels of seasonal fecundity, were 0.77, 0.72, 0.71, and 0.73 for Yellow-breasted Chat and 0.95, 0.87, 0.75, and 0.87 for Bell’s Vireo in saltcedar, mesquite. cottonwood, and across vegetation types, respec¬ tively; these estimates were higher than the upper 90% Cl of assumed survivorship estimates. Seasonal fecundity estimates needed to main¬ tain a stable population (^=1), given assumed annual survivorship, were higher than observed for all species in all vegetation types and not within the 90% Cls of our estimates (Fig. 3). Seasonal fecundity needed for Bell’s Vireo to maintain a stable population was — 15, five, two. and live times higher than observed in saltcedar. mesquite, cottonwood, and across vegetation types, respectively. Seasonal fecundity to main¬ tain a stable population needed to be about two and three times higher than observed across vegetation types for Abert’s Towhee and Yel¬ low-breasted Chat (Fig. 3). There was a strong trade-off between adult survivorship and average number of nesting Brand and Noon • SHRUB-NESTING BIRDS IN A RIPARIAN CORRIDOR 53 ■ Saltcedar I Mesquite I Cottonwood □ All habitats ^ Survivorship if A=1 u X® 1.2 1 o 05 -b 0.8 a ‘J3 0.6 -- >-< o > > 0.4 -- L- 3 C/3 0.2 ' Bell's Vireo Yellow-breasted Chat Abert's Towhee ■ Saltcedar ■ Mesquite ■ Cottonwood □ All habitats Fecundity if A. = 1 FIG. 3. Observed estimates of (A) adult survivorship and (B) seasonal fecundity ±90% confidence intervals (Cl) for Bell’s Vireo, Yellow-breasted Chat, and Abert’s Towhee by vegetation type drawn from 23 sites along the San Pedro River 1999-2001 or the literature in solid colors. Fecundity or survivorship required to obtain A = 1 with other vital rates held constant in pattern color. attempts needed to maintain a stable population in the absence of immigration at observed levels of nest productivity on the San Pedro (Fig. 4). Adult survivorship and/or the average number of nesting attempts required to maintain a stable population was high for Bell’s Vireo, and higher in mesquite and saltcedar than cottonwood, given observed nest survivorship and young per successful nest in the different vegetation types (Fig. 4). Levels of adult survivorship and average nesting attempts required to maintain a stable population were lower for Abert’s Towhee and Yellow-brested Chat than Bell’s Vireo and varied little by vegetation type (Fig. 4). DISCUSSION Possible population sources (based on 90% Cl of A that included 1) only occurred for Abert’s Towhee across vegetation types and Bell’s Vireo in cottonwood vegetation using nest survival and productivity estimates from local populations and survivorship estimates from the literature. Our point estimates of A were all substantially <1 indicating the entire study area may be operating as a population sink. These results are surprising given the San Pedro is considered to be one of the best remaining occurrences of lowland native riparian vegetation in North America (Noss et al. 1995). We calculated annual survivorship required to maintain a stable population given observed fecundity levels to compare with what could conceivably occur. Annual survivorship required to maintain a stable population across vegetation types was within the 90% Cl of our estimate for Abert’s Towhee (0.60), although we know of no 54 THE WILSON JOURNAL OF ORNITHOLOGY • Vol. 123, No. 1, March 2011 — cw -S-MQ —♦—ALL • CW — IS— MQ —♦—ALL Average number of nesting attempts FIG. 4. Sensitivity analysis of different levels of adult survivorship by average number of nesting attempts at a stable population (X = 1) when holding nest survivorship and number of female young per successful nest at observed levels from 23 sites along the San Pedro River 1999-2001 for Bell’s Vireo, Yellow-breasted Chat, and Abert’s Towhee in saltcedar (SC), cotton wood- willow (CW), mesquite (MQ), and across all vegetation types. other estimates from the literature. Estimated annual survivorship for Yellow-breasted Chat needed to maintain X = 1 across vegetation types on the San Pedro (0.73) was higher than estimates from the Southeast (0.35 ± 0.04; mean ± SE) and Midwest (0.610 ± 0.067) (DeSante et al. 2001, DeSante and Kaschube 2006, Michel et al. 2006). Estimated annual survivorship for Bell’s Vireo needed to maintain X = 1 across vegetation types (0.87) was well above estimates from the south- central region (0.56 ± 0.04; mean ± SE) and Midwest (0.61 ± 0.04) (Budnik et al. 2000, DeSante and Kaschube 2006, Michel et al. 2006); it was more similar to that of a long-lived raptor species such as California Condor ( Gytnnogyps californianus) (Meretsky et al. 1999). Estimates of annual survivorship required to maintain a stable population for Yellow-breasted Chat and Bell’s Vireo were higher than generally found for small passerine species (0.40-0.62; Martin 1995, DeSante and Kaschube 2006). Thus, at observed levels of fecundity and within the range of possible survivorship, it appears unlikely that Bell’s Vireo or Yellow-breasted Chat populations could maintain stable populations in the absence of immigration on the San Pedro over the study period. Local estimates of adult and juvenile survivor¬ ship are needed to draw strong conclusions about population status. Population-specific estimates of adult and juvenile survivorship are lacking for the species we examined, and our results must be interpreted with caution. The estimates we used were drawn from the southwestern region (De¬ Sante and Kaschube 2006, Michel et al. 2006), although we can only assume these estimates represent the specific location and vegetation types of interest. We used the common assump¬ tion of juvenile survivorship equal to half of adult survivorship. Data are lacking to assess the quality of this assumption, but the few studies that have directly estimated juvenile survivorship suggest this estimate may be slightly high and thus conservative (Gardali et al. 2003, Yackel Adams et al. 2007). The survival estimates we used were based on mark-recapture models that did not distinguish between mortality and emigration; they may underestimate true survivorship (McCoy et al. 1999). One approach that has been used is to add 0.1 to published estimates of adult survival to account for birds that dispersed (McCoy et al. 1999, Yackel Adams et al. 2007). When adult survivorship estimates are raised by 0.1, point estimates of X across vegetation types become 0.98 for Abert’s Towhee but still well below 1 (0.85 and 0.78) for Yellow-breasted Chat and Bell’s Vireo, respectively. Observed fecundity was low on the San Pedro, particularly for Yellow-breasted Chat and Bell s Vireo. High nest-predation rates can profoundly decrease nest survival. Nest-predation rates for Bell s Vireo on the San Pedro varied by vegetation type with 55, 51, and 33% of nests preyed upon in saltcedar, mesquite, and cotton¬ wood, respectively (Brand et al. 2010). These nest-predation rates were generally higher than those on the Bill Williams River 06-31%; Averill-Murray et al. 1999). Nest-predation rates Brand and Noon • SHRUB-NESTING BIRDS IN A RIPARIAN CORRIDOR 55 were also quite high for Yellow-breasted Chat (37-46%) and Abert’s Towhee (43-50%) on the San Pedro across vegetation types (Brand et al. 2010). Nest parasitism by Brown-headed Cowbirds can reduce both nest survival and young fledged per successful nest. Nest survival rates observed for Bell’s Vireos on the San Pedro were low, particularly in saltcedar and mesquite, and similar to those recorded along the Bill Williams River (Averill-Murray et al. 1999). Parasitism rate decreased on the Bill Williams River and Bell’s Vireo nest survival increased by over 400% in the breeding season following initiation of cowbird control and cessation of adjacent ranching oper¬ ations (Averill-Murray et al. 1999). Cowbird parasitism rates for Arizona Bell’s Vireos on the San Pedro were substantially higher in saltcedar (73%) and mesquite (60%) compared with cottonwood (33%; Brand et al. 2010). These rates in saltcedar and mesquite were lower than those observed on the Bill Williams River, but higher than most of those observed for federally listed Least Bell’s Vireo (Vireo bellii pusillus) and Southwestern Willow Flycatcher ( Empidonax traillii extimus) across the region (Averill-Murray et al. 1999, Finch and Stoleson 2000, Kus and Whitfield 2005, Kus et al. 2010). In contrast, Abert’s Towhee parasitism rates were low on the San Pedro across vegetation types (11-17%) compared with those on the Lower Colorado River (Finch 1983, Brand et al. 2010). There were also substantially fewer fledglings for parasitized versus unparasitized nests on the Lower Colorado (Finch 1983). Parasitism rates were intermediate for Yellow-breasted Chat on the San Pedro (42, 41, and 23% in saltcedar, mesquite, and cotton¬ wood, respectively; Brand et al. 2010). In comparison, no chat nests were parasitized by Brown-headed Cowbirds in a study in central Kentucky (Ricketts and Ritchison 2000). The average number of nesting attempts per breeding season has a strong effect on annual fecundity (Schmidt and Whelan 1999, Grzybow- ski and Pease 2005). This parameter is difficult to measure because it requires birds to be color banded and followed throughout a breeding season. Renesting can be influenced by cowbird parasitism and we were able to incorporate different average nesting attempts by vegetation type for Bell’s Vireo (Budnik et al. 2001). Our estimate of the average number of nesting attempts for Abert’s Towhee came from a population with about twice the rate of parasitism compared with the San Pedro (Finch 1984, Brand et al. 2010); thus, the estimate may have been high for the San Pedro population. Of the three species, average number of nesting attempts was most likely underestimated for Yellow-breasted Chat, since estimated nesting attempts came from a population with apparently lower parasitism rates (Thompson and Nolan 1973). The average number of nesting attempts per season required to maintain a stable population based on our sensitivity analysis was 6.0 for Abert’s Towhee and 3.5 for Yellow-breasted Chat with little variation between vegetation types. Abert’s Towhee is a resident species with a long nesting season, but an average of six attempts per season is beyond the 90% Cl of what was observed for 10 pairs; only two (20%) females attempted to nest > five times in a season (Finch 1984). The Yellow-breasted Chat is a neotropical migrant with a much shorter nesting season, and 3.5 nests per season is beyond the 90% Cl of what was observed for 24 pairs; only two (8%) females attempted to nest > two times in a season (Thompson and Nolan 1973). We estimated that 10 average nesting attempts per season would be required for a stable Bell’s Vireo population on the San Pedro across all vegetation types (33, 1 1, and 4 in saltcedar, mesquite, and cottonwood, respectively) when holding other vital rates at assumed or observed levels. Kus et al. (2010) reported a maximum of seven nesting attempts for individual Bell’s Vireos across all studies with population averages similar to those used in this study; >10 average nesting attempts per season to maintain a stable population in all vegetation types except cottonwood would almost certainly be beyond the physiological capabilities of Bell’s Vireos. Year-to-year variation in fecundity rates can be substantial for some species (Eckerle and Thomp¬ son 2001) and it is important to evaluate if our fecundity estimates are representative. Average annual precipitation can strongly influence bird populations in semi-arid regions. For example, Abert’s Towhee density and productivity de¬ creased in years with lower precipitation (Mar¬ shall 1960, Meents et al. 1981). The years of data collection in this study occurred over one of three major statewide droughts during the 20th century (Jacobs et al. 2005) and the subsequent 7 years of combined precipitation (2003-2010) in southeast¬ ern Arizona averaged 85% of normal (1971- 56 THE WILSON JOURNAL OF ORNITHOLOGY • Vol. 123, No. 1, March 2011 2000) levels (U.S. Department of Commerce 2010). Our estimates likely represent drought conditions that have continued to be representa¬ tive and may endure with projected climatic conditions (Dixon et al. 2009). We are not aware of other source-sink or population status results from the region to compare for these species. Yellow-breasted Chat and Abert’s Towhee had stable trends in Arizona over the last 10- and 40-year periods based on Breeding Bird Survey (BBS) data (Sauer et al. 2007). However, BBS population trends for these species were highly variable in Arizona over the period of the study (Sauer et al. 2007), which may indicate variability in population status among riparian systems. Further documentation of pop¬ ulation status, habitat selection, and habitat quality among watersheds over a similar time period is needed to gain landscape and regional perspectives of population dynamics for these species. Bell’s Vireos in Arizona, also based on Breeding Bird Survey (BBS) trends, had a non¬ significant decline over the past 40-years (-2.3% per year, P = 0.38) but declined significantly over the past 10-years ( — 3.7% per year, P = 0.0001; Sauer et al. 2007). The low nest survival rates on the Bill Williams River (Averill-Murray et al. 1999) and low seasonal fecundity and X estimates in this study for the San Pedro are surprising since these rivers should represent some of the best habitat within the limited range of Arizona Bell’s Vireos (Kus et al. 2010). There is increasing evidence that additional conservation focus is needed for Bell’s Vireos in Arizona. The status of these species depends on their fecundity and survivorship, and we believe the future research effort needed to obtain this information from local populations is warranted. ACKNOWLEDGMENTS We appreciate the work of the field crew that assisted with data collection on the San Pedro River: Mark Faherty, Janine McCabe, Brian Acord, Carey Hill, Devin Biggs, Chris Putnam, Brynne Langan, and Dolly Crawford. The Bureau of Land Management, San Pedro Project Office, provided access to the San Pedro National Conservation Area as well as housing for the three summers of data collection effort. We are also grateful for permission to work on lands granted by numerous private landowners. We thank Steve Beissinger for discussions that contributed to this research. We also thank Julie Stromberg, James Diffendorfer, Clait Braun, and two anonymous reviewers for their helpful comments on this manuscript. Karl Benedict kindly provided the map of the study area. Data collection for this research was funded by the Strategic Environment Research and Development (SERDP) project CS-1100. Analysis and writing portions for LAB were supported by SAHRA (Sustainability of Semi-Arid Hydrol¬ ogy and Riparian Areas) under the STC Program of the National Science Foundation, Agreement #EAR-9876800. and the U.S. Environmental Protection Agency “Integrated Modeling and Ecological Valuation” EPA STAR GRANT Program #2003-STAR-G2. LITERATURE CITED Armstrong, D. P., E. H. Raeburn, R. G. Powlesland, M. Howard, B. Christensen, and J. G. Ewen. 2002. Obtaining meaningful comparisons of nest success: data from New Zealand Robin ( Petroica australis) populations. New Zealand Journal of Ecology 26:1- 13. Averill-Murray, A., S. Lynn, and M. L. Morrison. 1999. Cowbird parasitism of Arizona Bell’s Vireos (Vireo bellii arizonae ) in a desert riparian landscape: implications for cowbird management and riparian restoration. Studies in Avian Biology 18:109-120. Battin, J. 2004. When good animals love bad habitats: ecological traps and the conservation of animal populations. 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Mowing is a common maintenance practice to control woody plants and noxious weeds in herbaceous buffers. Buffers enrolled in Maryland’s Conservation Reserve Enhancement Program (CREP) cannot be mowed during the primary bird nesting season between 15 April and 15 August. Most mowing of buffers in Maryland occurs in late summer or fall, leaving the vegetation short until the following spring. We studied the response of wintering birds to fall mowing ot buffers. We mowed one section to 10-15 cm in 13 buffers and kept another section unmowed. Ninety-two percent of birds detected in buffers were grassland or scrub-shrub species, and 98% of all birds detected were in unmowed buffers. Total bird abundance, species richness, and total avian conservation value were significantly greater in unmowed buffers, and Savannah Sparrows (Passerculus sandwichensis), Song Sparrows ( Melospiza melodia), and White-throated Sparrows ( Zonotrichia albicollis ) were significantly more abundant in unmowed buffers. Wintering bird use of mowed buffers was less than in unmowed buffers. Leaving herbaceous buffers unmowed through winter will likely provide better habitat for wintering birds. Received 21 December 2009. Accepted 23 August 2010. Herbaceous buffers are strips of herbaceous vegetation planted between working agricultural land and streams or wetlands. They are designed to manage environmental concerns such as water quality and can provide habitat for a variety of wildlife species (Clark and Reeder 2005). The U.S. Department of Agriculture's (USDA) Con¬ servation Reserve Program (CRP) offers several types of herbaceous buffer practices to agricul¬ tural producers, and Maryland’s Conservation Reserve Enhancement Program (CREP) offers additional financial incentives for landowner enrollment. Over 15,000 ha of herbaceous buffers are established in Maryland through the CRP (USDA 2010), most of which are enrolled in Maryland’s CREP. Herbaceous buffers in Mary¬ land are usually planted either to native warm- season grasses or cool -season grasses with the addition of native wildflowers or introduced legumes (USDA 2009b). Maintenance is required to keep CREP plant¬ ings in Maryland in good condition and function¬ ing properly (USDA 2009b). Mowing is a common maintenance practice to control woody 1 Marine-Estuarine-Environmental Sciences Program, University of Maryland, College Park, MD 20742, USA. -Department of Entomology, University of Maryland, College Park, MD 20742, USA. 'Current address: USGS, Patuxent Wildlife Research Center, 12100 Beech Forest Road, Laurel, MD 20708, USA. 4 Current address: Eastern Shore Land Conservancy Southern Office, 601 Locust Street, Suite 302, Cambridge, MD 21613, USA. '’Corresponding author; e-mail: blankpj@gmail.com plants and noxious weeds in herbaceous plantings. Mowing is generally not allowed on CRP or CREP land during the primary nesting and brood rearing seasons for wildlife (dates vary from state to state), but is allowed during the rest of the year. Maryland’s CREP land may not be mowed between 15 April and 15 August (USDA 2009b). Most mowing of buffers in Maryland occurs in late summer or fall (hereafter, fall mowing) and often within a few days of 15 August (P. V. Barry, pers. comm.; J. E. Gerber, pers. comm.). Fall mowing is also a common practice in herbaceous CRP plantings in other states, including Virginia (G. I. Hall, pers. comm.), Ohio (M. D. DeBrock, pers. comm.), and Tennessee (M. E. Zeman, pers. comm.). Fall mowing leaves the vegetation short until growth begins the following spring. Farm managers often choose to mow in fall instead of late winter or spring because they believe shorter grass looks better, the ground may be too wet in spring for mowing, or fall is when they have the most time available (S. V. Strano, pers. comm.). It is recommended that buffers be mowed no more than once every 2 to 3 years with no more than half of the area mowed in any 1 year (USDA 2009b). A common recommendation is to mow a third of each buffer every year on a 3-year rotation (USDA 2009b). However, some farm managers mow entire buffers each year (PJB, pers. obs.). Buffers often represent the only uncultivated herbaceous areas on farmland in Maryland and may be important habitat for early-successional birds. Many studies have evaluated the response by breeding birds to mowing of early-successional 59 60 THE WILSON JOURNAL OF ORNITHOLOGY • Vol 123, No. 1, March 2011 habitats (e.g., Swanson et al. 1999, Warren and Anderson 2005, Zuckerberg and Vickery 2006), but few studies have evaluated the effects of mowing on wintering bird communities. We studied the response of wintering birds to fall mowing of herbaceous buffers. We hypothesized that wintering bird abundances, species richness, and total avian conservation value would be less in mowed than in unmowed buffers. We focus on the response of grassland and scrub-shrub birds because they are experiencing substantial popula¬ tion declines (Sauer et al. 2008) and are of high conservation concern (Hunter et al. 2001, Askins et al. 2007). METHODS Study Area— The Eastern Shore of Maryland (east of Chesapeake Bay) has —46% of land- cover in farms (US DA 2009a) and 77% of the CREP buffers in the state (USDA 2007). Filter strips (USDA Practice CP21) are the most common type of herbaceous buffers in Maryland (USDA 2010). We conducted an experiment in 13 filter strips (hereafter, buffers) among two coun¬ ties (Queen Anne’s and Talbot) on Maryland’s Eastern Shore. All buffers selected were installed between 1997 and 2004, and were >3 years of age at the time of the study. Each buffer was between a rowcrop field and a forested wetland, which is a common location of buffers in Maryland. The adjacent rowcrops had been planted to either com or soybeans in the previous growing season, and most were planted to winter wheat after fall harvest. Nine buffers were planted with cool-season grasses and four were planted with warm-season grasses. Common warm-season grasses were big bluestem ( Andropogon gerardii ), little bluestem ( Schizachyrium scoparium ), indiangrass ( Sor - g hast rum nutans ), and broomsedge bluestem (A. virginicus). The most common cool-season grass in buffers was orchardgrass (Dactylis glomerata), but other cool-season grasses including red ( Festuca rubra ) and sheep (F. ovina) fescue were also planted. We established two treatments in each buffer: (1) a section (experimental treatment) mowed in late summer or fall (Aug-Dec) to 10-15 cm in height, and (2) an unmowed section. Mowed and unmowed treatments were randomly located along the length of the buffer and spanned the entire width of the buffer. We established one study site in each treatment. Each study site spanned the width of the buffer, was >50 m from the ends of the buffer and from the interface with the other treatment, and > 1 00 m from the other study site in the same buffer. Mowed and unmowed study sites among all buffers were similar (x ± SD) in length (mowed: 176.0 ± 50.0 m; unmowed: 176.6 ± 50.3 m). We defined the width of each buffer as the distance from the crop edge to the wooded edge and calculated width by averaging measurements taken every 50 m over the length of the buffer. Buffers ranged in width from 11 to 91 m, and average buffer width was 40.9 ± 35.7 m. We measured the length of each study site in a Geographic Information System (GIS) and calcu¬ lated the area of each site by multiplying site width by site length. Vegetation Surveys. — We conducted vegetation surveys once at each study site in winter 2007. We established one transect line through the center of the site in buffers <45 m wide, and two transect lines spaced evenly across the width of the site in buffers >45 m wide. We measured vegetation structure characteristics within 1-m2 sampling plots at random distances perpendicular to five points spaced evenly apart along each transect line. Thus, we surveyed vegetation at five plots in buffers <45 m wide and 10 plots in buffers >45 m wide. We visually estimated the percent cover (non-overlapping) of grasses, forbs, trees, bare ground, and litter in each plot. We also measured vertical vegetation density (Robel et al. 1970), litter depth, and maximum vegetation height. Bird Surveys. — We conducted three bird sur¬ veys at each study site between 19 January and 10 March 2007. All surveys were between 1 hr after sunrise and 1 hr before sunset. We did not conduct surveys in precipitation, fog, or wind >16 km/hr. Bird surveys in the two study sites in the same buffer were subsequent to one another and in random order. Individual birds observed in one study site were not observed to move to any other study sites, and study sites were considered independent. We surveyed birds across the entire area of each study site. All surveys were conducted simultaneously by P. J. Blank and J. R. Parks. We walked parallel to the wooded edge of the buffer <20 m apart. The distance between us varied depending on width of the buffer. Nine buffers were <40 m wide and required only one pass. Four buffers were >80 m wide and required Blank et al. • WINTERING BIRD RESPONSE TO FALL MOWING 61 three passes. We communicated regularly and watched for birds moving within study sites so that individual birds were not counted twice. By using these methods, at least one observer walked within 10 m of all points in the study sites. Diefenbach et al. (2003) reported nearly 100% detection of breeding grassland birds within 25 m of observers, and Roberts and Schnell (2006) recommended that observers walk within 10 m of all points in fixed areas when calculating density of wintering grassland birds. Thus, we assumed 100% detection during our surveys. One obser¬ vation of an American Kestrel ( Falco sparverius) observed foraging above a study site during a survey was included in the counts. Statistical Analyses. — We used three bird community metrics to compare bird use of mowed and unmowed buffers: total abundance, species richness, and total avian conservation value (TACV). The latter is an index used to assess the relative conservation value of different sites that incorporates the biological vulnerability and the regional importance of each species (Nuttle et al. 2003). We calculated TACV by multiplying each species’ abundance by its Partners in Flight conservation priority rank (Carter et al. 2000, Nuttle et al. 2003) for the Mid- Atlantic Bird Conservation Region (Partners in Flight 2008), and then summing the species-specific TACV scores within a site (Conover et al. 2007, 2009). We categorized each bird species as either a grassland or scrub-shrub species based on litera¬ ture of species assemblages (Askins 1993, Vick¬ ery et al. 1999, Hunter et al. 2001, Sauer et al. 2008, Schlossberg and King 2008, Poole 2010). We calculated the mean of each bird commu¬ nity metric and species’ abundance across the three rounds of bird surveys, and used the means as response variables in statistical analyses. Bird and vegetation metrics were not normally distrib¬ uted within treatments, and we used generalized linear mixed models (GLMM) in Proc GLIMMIX (SAS Institute, Cary, NC, USA) to compare responses in mowed and unmowed treatments. We specified a Poisson distribution for models of bird metrics and either a log-normal or a Poisson distribution for models of vegetation metrics. We treated management type (mowed or unmowed) as a fixed factor, buffer as a random block (to account for the paired study sites), and grass type (cool- or warm-season) as a random factor. We included study site area as an offset in all bird models because study sites differed in area, and TABLE 1. Vegetation characteristics (mean ± SE) in mowed and unmowed buffers on the Eastern Shore of Maryland, winter 2007. Management type Vegetation - - characteristic Mowed Unmowed F P Vertical density 5.5 + 0.9 21.9 2.7 115.4 <0.001 Maximum height, cm 3.2 + 0.1 4.6 0.1 158.3 <0.001 Litter depth, cm 4.7 + 0.7 4.4 0.7 0.1 0.72 Percent cover Grass 3.2 H- 0.2 3.6 -i- 0.2 5.1 0.045 Forbs 4.1 + 2.1 5.7 3.0 8.2 0.016 Trees 0.1 0.1 0.6 0.3 4.0 0.070 Litter 3.9 0.4 3.5 -4- 0.4 3.7 0.078 Bare ground 5.1 ± 1.4 2.9 2.6 3.5 0.086 included width as a covariate because buffer width influences bird communities (Best 2000, Clark and Reeder 2005, Blank et al. 2011). We only analyzed the species-specific responses of Savannah Sparrow ( Passerculus sandwichensis). Song Sparrow ( Melospiza melodia ), and White- throated Sparrow ( Zonotrichia albicollis) because we could not fit appropriate models to the distribution of other species due to a lack of detections in most study sites. We considered a test result statistically significant at P < 0.05. RESULTS Vertical vegetation density, maximum height, percent cover of grass, and percent cover of forbs were significantly greater in unmowed than in mowed buffers (Table 1). We detected 412 birds in buffers, of which 98% were in unmowed buffers. We observed five species in mowed buffers and 14 species in unmowed buffers. Eight species were grassland or scrub-shrub birds (Table 2) and constituted 92% of all detections. The Song Sparrow was the most abundant species (45% of detections), followed by Field Sparrow ( Spizella pusilla ; 19%), and Savannah Sparrow (10%). Savannah Sparrow (FltI2 = 6.36, P = 0.027), Song Sparrow {F\^2 = 16.54, P = 0.001), and White-throated Sparrow (FU2 = 5.68, P = 0.035) were all more abundant in unmowed than in mowed buffers. Total abundance, species richness, and TACV were all greater in unmowed than in mowed buffers (Table 3). DISCUSSION Wintering bird use of mowed buffers was less than in unmowed buffers. All bird community 62 THE WILSON JOURNAL OF ORNITHOLOGY • Vol. 123, No. 1, March 2011 TABLE 2. Mean density (birds/ 10 ha ± SD) of grassland and unmowed buffers on the Eastern Shore of Maryland, winter 2007. scrub-shrub bird species detected in mowed and Management type Common name Scientific name Mowed Unmowed American Kestrel Falco sparverius 0.0 ± 0.0 0.1 ± 0.5 Eastern Bluebird Sialia sialis 0.0 ± 0.0 0.1 ± 0.4 Field Sparrow Spizella pusilla 0.0 ± 0.0 11.3 ± 34.7 Savannah Sparrow Passerculus sandwichensis 0.6 ± 2.1 7.2 ± 16.2 Song Sparrow Melospiza melodia 2.1 ± 5.3 70.1 ± 60.1 Swamp Sparrow M. georgiana 0.0 ± 0.0 5.5 ± 13.3 White-throated Sparrow Zonotrichia albicollis 1.6 ± 5.7 15.9 ± 51.0 Dark-eyed Junco Junco hyemalis 0.7 ± 2.4 3.4 ± 12.2 metrics and species’ abundances tested were significantly greater in unmowed than in mowed buffers, and 98% of all bird detections were in unmowed buffers. Wintering birds use herbaceous habitats for foraging, roosting, and escape cover (Watts 1990, Marcus et al. 2000, Smith et al. 2005, Conover et al. 2007) and fall mowing removes valuable habitat that wintering birds could otherwise exploit (Harper 2007). These results are especially important because most birds detected in unmowed buffers were grassland or scrub-shrub species, two guilds experiencing substantial population declines (Hunter et al. 2001, Askins et al. 2007, Sauer et al. 2008). Three species detected in buffers (Field Sparrow, Savannah Sparrow, and Dark-eyed Junco [Junco hy emails]) are listed as species of greatest conservation need in Maryland (Maryland Department of Natural Resources 2004). Thus, reducing the practice of fall mowing could provide additional habitat for several birds of conservation concern. Our findings agree with other studies of wintering bird use in mowed and unmowed herbaceous habitats. Saab and Petit (1992) reported relative bird abundance and species richness were lower on grazed pastures main¬ tained by mowing compared to abandoned pastures in Belize. Marcus et al. (2000) found greater sparrow abundance in herbaceous field borders than in mowed field edges in North Carolina. However, compared to studies of breeding birds, there have been few studies on the response of wintering birds to mowing of herbaceous habitats. This study focused on the response of wintering birds to fall mowing but did not examine bird response to mowing at other times of year. Late winter or early spring mowing instead of fall mowing could provide additional habitat for wintering birds (Harper 2007). For example, mowing a buffer on 15 March instead of 15 August could provide 7 months of additional unmowed habitat. There are practical reasons why fall mowing may be preferred, including wet weather or lack of time to mow in late winter or early spring, that should be considered prior to altering mowing schedules. Late winter or early spring mowing may also remove habitat for wintering birds that may have become dependent on unmowed buffers for food or cover. When mowing is necessary, leaving nearby herbaceous areas unmowed will provide habitat that may be a refuge for some bird species (Bryan and Best 1991). Following the recommended guideline of mowing one-third of the area per year will provide more habitat for wintering birds than completely mowing buffers. interim?3' ^ COmmunity raetrics (mean * SE) in mowed and unmowed buffers on the Eastern Shore of Maryland. Management type — Bird community metric Mowed Unmowed F p Total abundance Species richness Total avian conservation value 0.3 ± 0.2 0.5 ± 0.3 0.4 ± 0.2 11.0 ± 3.1 3.3 ± 0.8 19.9 ± 5.8 48.8 11.0 94.4 <0.001 0.006 <0.001 Blank et al • WINTERING BIRD RESPONSE TO FALL MOWING 63 Mowing should not be the sole form of management in herbaceous plantings to maintain early successional habitat (McCoy et al. 2001, Harper 2007). Mowing can accelerate grass succession and litter accumulation which creates unfavorable conditions for wildlife (McCoy et al. 2001). Burning, discing, and targeted herbicide applications may be more effective than mowing for maintaining optimal early successional habitat for wildlife (Harper 2007). CONSERVATION IMPLICATIONS Our results clearly indicate the negative impacts of fall mowing of herbaceous buffers on wintering bird communities in Maryland. This study has implications for the mowing schedules of many types of herbaceous habitats, including lawns, meadows, grasslands, and powerline rights-of-ways, and has particular relevance to management of herbaceous CRP or CREP plant¬ ings. When possible, leaving these herbaceous areas unmowed through winter will likely provide better habitat for wintering birds. ACKNOWLEDGMENTS We thank D. E. Gill, L. W. Adams, P. P. Marra, and G. L. Brewer for help with study design. We thank the many farm owners that allowed us to work on their properties. The Natural Resources Conservation Service (NRCS) and the Farm Service Agency staff in Queen Anne's and Talbot counties helped with locating CREP buffers and with technical information. J. E. Gerber and the staff at Chesapeake Wildlife Heritage provided technical informa¬ tion and advice. P. J. Barbour, C. A. Rewa, and S. V. Strano provided comments on earlier versions of the manuscript. 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B. Best. 1991. Bird abundance and species richness in grassed waterways in Iowa rowcrop fields. American Midland Naturalist 126:90- 102. Carter, M. F., W. C. Hunter, D. N. Pashley, and K. V. Rosenberg. 2000. Setting conservation priorities for landbirds in the United States: the Partners in Flight approach. Auk 117:541-548. Clark, W. R. and K. F. Reeder. 2005. Continuous Conservation Reserve Program: factors influencing the value of agricultural buffers to wildlife conservation. Pages 93-113 in Fish and wildlife benefits of Farm Bill conservation programs: 2000-2005 update (J. B. Haufler, Editor). Technical Review 05-2. The Wildlife Society, Bethesda, Maryland, USA. Conover, R. R.. L. W. Burger Jr., and E. T. Linder. 2007. Winter avian community and sparrow response to field border width. Journal of Wildlife Management 71:1917-1923. Conover, R. R., L. W. Burger Jr., and E. T. Linder. 2009. Breeding bird response to field border presence and width. 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Effects of conservation practice, mowing, and temporal changes on vegetation structure on CRP fields in northern Missouri. Wildlife Society Bulletin 29:979-987. Nuttle, T., A. Leidolf, and L. W. Burger Jr. 2003. Assessing conservation value of bird communities with Partners In Flight-based ranks. Auk 120:541-549. Partners in Flight. 2008. Species assessment database. Rocky Mountain Bird Observatory, Fort Collins, Colorado, USA. Poole, A. (Editor). 2010. The birds of North America online. Cornell Laboratory of Ornithology, Ithaca, New York, USA. http://bna.birds.cornell.edu/BNA/. Robel, R. J., J. N. Briggs, A. D. Dayton, and L. C. Hulbert. 1970. Relationships between visual obstruc- 64 THE WILSON JOURNAL OF ORNITHOLOGY • Vol. 123, No. 1, March 2011 tion measurements and weight of grassland vegetation. Journal of Range Management 23:295-297. Roberts, J. P. and G. D. Schnell. 2006. Comparison of survey methods for wintering grassland birds. Journal of Field Ornithology 77:46-60. Saab, V. A. and D. R. Petit. 1992. Impact of pasture development on winter bird communities in Belize, Central America. Condor 94:66-71. Sauer, J. R., J. E. Hines, and J. Fallon. 2008. The North American Breeding Bird Survey, results and analysis 1966-2007. Version 5.15.2008. USGS, Patuxent Wildlife Research Center, Laurel, Maryland, USA. http://www.mbr-pwrc.usgs.gov/bbs/bbs.html. Schlossberg, S. AND D. I. King. 2008. Are shrubland birds edge specialists? Ecological Applications 18:1325-1330. Smith, M. D., P. J. Barbour, L. W. Burger Jr., and S. J. Dinsmore. 2005. Density and diversity of overwinter¬ ing birds in managed field borders in Mississippi. Wilson Bulletin 1 17:258-269. Swanson, D. A., D. P. Scott, and D. L. Risley. 1999. Wildlife benefits of the Conservation Reserve Program in Ohio. Journal of Soil and Water Conservation 54:390-394. U.S. Department of Agriculture (USDA). 2007. Mary¬ land CREP report. Natural Resources Conservation Service, Annapolis, Maryland, USA. U.S. Department of Agriculture (USDA). 2009a. 2007 Census of agriculture, United States summary and state data. Volume 1. Geographic Area Series, Part 51. National Agricultural Statistics Service, Washington, D.C., USA. U.S. Department of Agriculture (USDA). 2009b. Maryland CREP technical handbook. Natural Resourc¬ es Conservation Service, Annapolis, Maryland, USA. U.S. Department of Agriculture (USDA). 2010. Con¬ servation Reserve Program. Monthly Summary, April. Farm Service Agency, Washington. D.C., USA. Vickery, P. D., P. L. Tubaro, J. M. Cardosa da Silva. B. G. Peterjohn, F. R. Herkert, and R. B. Caval CANTi. 1999. Conservation of grassland birds in the western hemisphere. Studies in Avian Biology 19:2- 26. Warren, K. A. and J. T. Anderson. 2005. Grassland songbird nest-site selection and response to mowing in West Virginia. Wildlife Society Bulletin 33:285-292. Watts, B. D. 1990. Cover use and predator-related mortality in Song and Savannah sparrows. Auk 107:775-778. Zuckerberg, B. and P. D. Vickery. 2006. Effects of mowing and burning on shrubland and grassland birds on Nantucket Island, Massachusetts. Wilson Journal of Ornithology 118:353-363. The Wilson Journal of Ornithology 1 23( 1 ):65— 75, 2011 INTERSPECIFIC VARIATION IN HABITAT PREFERENCES OF GRASSLAND BIRDS WINTERING IN SOUTHERN PINE SAVANNAS MATTHEW E. BROOKS1'2 AND PHILIP C STOUFFER1 ABSTRACT. — We studied wintering grassland bird communities in De Soto National Forest in southern Mississippi, USA to assess differences in bird communities and vegetation structure among different stand types. We also examined which vegetation structure and plant species predicted occurrence of Bachman’s Sparrow ( Peucaea aestivalis ), Henslow’s Sparrow (Ammodramus henslowii ), and Sedge Wren ( Cistothorus platensis). Bachman’s Sparrows occurred only in uplands (x. = 0.5 birds/ha) and stands managed for Red-cockaded Woodpeckers ( Picoides borealis ; x = 0.9 birds/ha), Henslow’s Sparrows occurred only in bogs (x = 3.8 birds/ha) and stands managed for Red-cockaded Woodpeckers (x = 2.1 birds/ha), while Sedge Wrens occurred in all stand types (x = 0.1 -0.3 birds/ha). There were no significant differences among stand types in total bird densities for all three species combined. Dense, spatially uniform herbaceous cover and cover of Scleria muhlenbergii , a preferred food item in bogs, best predicted Henslow’s Sparrow occurrence (39% s2 explained). Increased woody understory vegetation and decreased tree density best predicted Sedge Wren occurrence (17% s2 explained). Management for Henslow’s Sparrows should focus on small-scale herbaceous ground-layer restoration in bogs. Bachman’s Sparrows will respond more to thinning dense upland stands. Sedge Wrens and Bachman’s Sparrows benefit from Red- cockaded Woodpecker management, whereas Henslow’s Sparrow use of woodpecker stands is ephemeral. Received 6 March 2010. Accepted 9 September 2010. Virtually all remaining longleaf pine ( Pinus palustris) savannas are subject to management for habitat improvement and sensitive species. Man¬ agement, such as that for Red-cockaded Wood¬ peckers ( Picoides borealis ; hereafter RCW), may alter portions of forest stands in ways that create distinct patches. Natural variation in local topog¬ raphy in pine savannas, combined with forest management, leads to a variety of localized habitat types that differ in plant species compo¬ sition and structure (Kirkman et al. 2001, Drewa et al. 2002a). These differences may also be reflected in grassland bird habitat preferences. Understanding these preferences is crucial for developing efficient species-specific conservation plans. The majority of pine savanna habitats in De Soto National Forest (DSNF) can be divided into three distinct types: (1) upland pine stands (“uplands”), (2) upland pine stands managed for RCWs (“RCW”), and (3) hillside seepage pitcher plant ( Sarracenia spp.) bogs (“bogs”). RCW clusters are an artificially designated stand type, whereas uplands and bogs are naturally occurring and well documented in the literature (Clewell 1986, Olson and Platt 1995). Concern over the impact of ecosystem man¬ agement on non-target species has sparked 1 School of Renewable Natural Resources, 227 RNR Building, Louisiana State University and LSU Agriculture Center, Baton Rouge, LA 70803, USA. 2 Corresponding author; e-mail: mattebrooks@gmail.com interest in the effects of RCW management on other organisms (Hunter et al. 1994, Brennan et al. 1995, Provencher et al. 2002). Several studies have shown stands managed for RCWs contain different bird communities than unmanaged stands and have higher densities of Bachman’s Sparrows (Peucaea aestivalis) (Conner et al. 2002, Provencher et al. 2002, Wood et al. 2004). No published studies have documented RCW cluster use by Henslow’s Sparrow ( Ammodramus henslowii) or Sedge Wren ( Cistothorus platensis), common wintering grassland birds in pine savan¬ nas. Few studies have examined grassland bird preferences among habitat types in pine savannas. Some studies suggest Henslow’s Sparrows may prefer bogs over uplands (Plentovich et al. 1999, Tucker and Robinson 2003), while others have found birds in upland stands (Carrie et al. 2002, Johnson 2006, Palasz et al. 2010). Henslow’s Sparrows generally use both upland longleaf pine savannas and bogs, but may prefer bogs when both habitat types are in close proximity. Bach¬ man’s Sparrow habitat preferences across differ¬ ent stand types have rarely been studied in winter. Allen et al. (2006) found breeding Bachman’s Sparrows were more common in upland habitats compared to wetter pocosins, a type of bog, in North Carolina longleaf pine savannas. Bach¬ man’s Sparrows, as is also the case for Henslow’s Sparrows (Bechtoldt and Stouffer 2005), prefer to winter in grasslands that were burned in the previous growing season (Cox and Jones 2009). 65 66 THE WILSON JOURNAL OF ORNITHOLOGY • Vol. 123, No. 1. March 2011 Our focal species were three wintering grass¬ land birds that frequent pine savannas along the Gulf Coast: Bachman’s Sparrow, Henslow’s Sparrow, and Sedge Wren. Numerous studies over the last decade have examined wintering Henslow’s Sparrow ecology, but few have reported habitat preferences among a mosaic of localized habitat types. Bachman’s Sparrow and Sedge Wren rarely have been studied in winter, and most reports of Bachman’s Sparrows using RCW clusters are from the breeding season. We do not know of published studies on Sedge Wren habitat preferences in southern pine savannas (Herkert et al. 2001). Our objectives were to: (1) assess differences in wintering grassland bird communities and vegetation structure among upland, RCW, and bog stands, and (2) ascertain which vegetation structures and plant species predict occurrence within a stand by Henslow’s Sparrows and Sedge Wrens. METHODS Study Area. — De Soto National Forest (153,780 ha) in southern Mississippi, USA is mostly managed for longleaf and slash pine ( Pinas elliottii). The majority of pine savanna habitats in DSNF are upland stands, and many of these areas have severe shrub {Ilex spp., Gaylussacia spp.) encroachment due to past fire suppression (Brooks 2010). The pine savanna ecotypes in DSNF are described as xeric sand barrens and uplands, subxeric sandy uplands, and seeps (Peet 2006). We selected 27 study sites to sample grass¬ land birds. Ten sites were classified as upland stands, 10 as bog stands, six were managed RCW clusters, and one was classified as other. Our selection criteria were that each site needed >50% herbaceous cover and <50% shrub cover. Sites with >50% shrub cover were considered a priori to be unsuitable for grass¬ land birds. We established 100^00 m of 20-m wide transects in upland, bog, and other stands, depending on stand size (from <1 to >10 ha). We established tour-sided plots in RCW clusters. These plots were 0.2 to 1.0 ha encompassing the majority of the managed cluster. Canopy closure within and among stand types varied from 0 to >70%. Bird Surveys. — We sampled grassland birds using flush net surveys. Surveys were conducted on fixed-width transects between 28 November and 28 February in 2007-2008 and 2008-2009. We sampled 16 sites the first winter and 11 different sites the second year. Each site was sampled three times per winter except for three that were burned before the third round of sampling. All sites sampled the same year were >500 m apart. Our flush netting protocol was modified from Shackleford et al. (2001) and Carrie et al. (2002) as described by Brooks (2010). When a bird was flushed, it was identified to species if possible. If identification was uncertain, we would attempt to capture the bird for identification following the capture technique described in Bechtoldt and Stouffer (2005). We used the same sampling method in RCW stands, but made multiple systematic, non-overlapping passes through plots until they were completely sampled. Grassland birds that could not be identified to species were excluded from spe¬ cies-specific analyses but were included in analysis of total grassland bird density. Vegetation Sampling. — We sampled vegetation structure and plant species composition at each site. Each 20-m wide transect in sites with transects was partitioned into 20-m intervals for vegetation sampling plots. We measured canopy closure in each plot using a spherical densitometer (Lemmon 1956), and basal area with a 10-factor prism (Avery 1967) and Biltmore stick (Jackson 191 1). We measured herbaceous and woody plant density using a randomly placed 3-cm diameter pole (Wiens 1974), and modal herbaceous and woody heights within 30-cm of the pole were visually estimated to the nearest decimeter. We used a randomly placed 1-m2 frame to estimate percent cover of herbaceous and woody ground vegetation, and species composition. We estimat¬ ed the number of woody stems at ground level inside each 1-trr frame. We later grouped plant species into 15 guilds by combinations of life form (graminoid, forb, or woody) and U.S. Fish and Wildlife Service Wetland Indicator Status (W1S) (USDI 1988) to reduce the number of variables. We collected the same vegetation data for RCW clusters using 5—10 randomly placed sampling plots per cluster. Two 1-m2 frame and four pole measurements were taken in each sampling plot lor all stand types. Many of our study sites had patchy distributions of herbaceous cover and shrubs. We used the coefficient of variation (CV) to measure patchiness for herba¬ ceous cover, woody cover, and herbaceous density among points in each transect (Wiens 1974). The CV was calculated using each individual mea- Brooks and Stouffer • GRASSLAND BIRDS IN PINE SAVANNAS 67 surement within a site and represents heterogene¬ ity, or patchiness, within a study site. Statistical Analyses— Individual stands were treated as the sample unit for all analyses. We calculated the number of birds Hushed per hectare in each survey and averaged these densities from all surveys at each site. Vegetation sampling plots also were averaged over each site. We omitted one site classified as “other” and four sites that were >2 growing seasons since fire for analyses comparing bird densities and vegetation variables among stand types. Omitting these samples removed variation introduced by differences in time since fire among sites. Nineteen of the remaining 22 sites were one growing season since fire and three (1 /stand type) were two growing seasons since fire. Six of these sites were upland stands, six were RCW stands, and 10 were bogs. All analyses were performed with SAS Version 9.2 (SAS Institute 2006). We used log-linear generalized models to test for differences in densities of each species and total grassland birds among stand types. Hen- slow’s Sparrows did not occur in one stand type, and Bachman’s Sparrows did not occur in another; we tested for differences in densities only between stand types in which these species occurred. We specified a Poisson distribution for Sedge Wren and a negative binomial distribution for Bachman's Sparrow, Henslow’s Sparrow, and total bird densities, both of which are appropriate for zero-rich data. Appropriate distributions were selected by estimating an overdispersion factor (c = Pearson x2/df) and choosing the distribution with c closest to 1 .0. All models had c < 1.02 and were not overdispersed (Burnham and Anderson 2002). We used a significance level of 0.05 for all tests. We conducted principal components analyses (PC A) to reduce the number of correlated vegetation structure variables and plant species composition guilds to fewer, uncorrelated princi¬ pal components (PCs). We performed one PC A of vegetation structure variables using the n = 22 data set and two other PC As with the complete data set ( n = 27), one on vegetation structure, and another on plant species guilds. We used varimax rotations to aid in interpretation of the PCs and retained all PCs with Eigenvalues >1. We used the n = 22 PCs to examine vegetation structure differences among stand types; the n = 27 PCs were used to model bird occurrence. We used MANOVA to test for differences in vegetation structure PC scores among stand types ( n = 22). Pairwise differences between means were tested using Tukey-Kramer tests. Residuals were tested for normality using Shapiro-Wilks’ tests. We used logistic regression to model the probability of Henslow’s Sparrow and Sedge Wren occurrence based on vegetation variables. We used the entire data set ( n = 27) and its corresponding PCs for these analyses. We used the vegetation structure and plant guild PCs as independent predictor variables in an information- theoretic model selection approach (Burnham and Anderson 2002). The third plant PC was highly correlated with a vegetation structure PC and was not used when constructing candidate models. Henslow’s Sparrow and Sedge Wren global models were assessed for overdispersion (c = 1.40 and 1.13, respectively). Models were ranked using Akaike’s Information second-order Criteri¬ on (AICc) for small sample size (Burnham and Anderson 2002). Models with AAICc < 2 were considered the best models (Burnham and Ander¬ son 2002). We also calculated an r General Information Criterion (rG\c) for each model (Wright 2001). This is a pseudo r calculated from any one of the common information criteria and represents the relative proportional variance explained by a model. RESULTS Henslow’s Sparrows occurred at 11 of 27 study sites, Sedge Wrens at nine, and Bachman’s Sparrows at five sites. Henslow’s Sparrow densities were highest across all sites, followed by Bachman’s Sparrow and Sedge Wren. Densi¬ ties of each species, considering only the sites where they occurred, were; Henslow’s Sparrow = 0.52-13.33, Sedge Wren = 0.42-3.03, and Bach¬ man’s Sparrow = 0.42-2.22 birds/ha. The highest densities of Henslow’s Sparrows occurred on a 0.2-ha transect in a small (< 1 ha) bog. Grassland birds that could not be identified to species (e.g., Ammodramus spp. or other emberizids) accounted for 6% (5 birds) of the total bird density across all stand types combined. We did not model Bach¬ man's Sparrow occurrence because this species was detected at so few sites. Bird Differences Among Stand Types. — Grass¬ land bird densities in upland, RCW, and bog stands varied among species (Fig. 1). Bachman’s Sparrows were not detected in bog stands, and densities did not differ between upland and RCW stands (Fj l0 = 0.33, P = 0.58). Henslow’s 68 THE WILSON JOURNAL OF ORNITHOLOGY • Vol. 123, No. 1. March 2011 c 4 ■ Bachman's Sparrow ■ Henslow's Sparrow □ Sedge Wren ■ All species Upland (n - 6) RCW (n = 6) Stand type Bog (n = 10) DeSoto NatiOTa^nFores^M^sissippi.(b'rdS^a^ ^ ^ °f win,ering grass,and birds and all species combined r Sparrows were not detected in upland stand' and densities did not differ between bog an RCW stands (FU4 = 0.91, P = 0.36). Sedg Wren densities did not differ among stan, types (F2,|9 — 0.38, P = 0.69). There were m differences in total grassland bird density amoni stand types (F2,19 = 3.12, P = 0.068), but densib was highest in bogs (Fig. 1). PCA of Vegetation Structure.— PCA of the vegetation structure variables with the n = 22 dal- resuhed in three PCs with Eigenvalues >T representing 84% of the variance (Table 1 ) The first PC represented woody understory structure and was mostly correlated with all woody understory structure variables and herbaceous eight. The second PC represented herbaceous structure and was mostly correlated with the remaining herbaceous structure variables and wood, cover CV. The third PC represented ,ree density and was mainly correlated with canopy closure and tree basal area. py f, Pf/\°||lhe nation structure variables with with F I'6' (n = 27) reSulted in plrce PCs Eigenvalues >1, representing 82% of the ..nance (TaWe 2). PCs followed the pare,™* the n - 22 analysis (Table 1). The first PC represented woody understory structure the second represented herbaceous structure, and he t ird represented tree density. PCA of the plant species composition guilds resulted in five Pci with Eigenvalues >1, representing 70% of the variance (Table 3). 5 or the Vegetation Structure Difference c A e Types.— MANOVA revealed 8 structure PC value differences amn ” Veg?tatlon (Wilks’ X = 023 F. - ,aTgDStand types ^6, 34 - 6.18, P < 0.001) Herbaceous structure was higher in bogs than in upland ( P < 0.001) and RCW stands (P < 0.001: Fig. 2); thus, bog stands had more continuous herbaceous cover and patchier woody cover There were no significant differences in means for the woody structure PC, but RCW stands had a lower mean value. The tree density PC was not significantly different among stand types. Henslow's Sparrow Models. — Henslow’s Spar¬ row occurrence was best predicted by decreasing herbaceous density CV and increasing cover of the sedge Scleria muhlenbergii (Table 4). The best model was the only one with AAICc < 2 and explained 39% of the relative proportional variation. The null model had AAICc = 13.50. Parameter estimates for both variables in the best model had 95% confidence intervals that con¬ tained zero, indicating that, although there was an effect, the extent of the effect could not be quantified. Abnormally large parameter estimates resulting from logistic regression may occur due to small sample sizes (Nemes et al. 2009). The parameter estimate and standard error for Scleria muhlenbergii cover was /? = 10.75 ± 6.67 (95% ~ ~3.0-24.51). The estimate for the herba¬ ceous density CV was p = -0 10 ± 0.05 (95% Cl = -0.21-0.02). Sedge Wren Models.— Sedge Wren occurrence was best predicted by decreasing tree basal area an increasing woody understory vegetation structure PC values (Table 5). No other models ^ AICc < 2. The null model had AAICc = ’ ^nC- dlC ^est hi 0 del explained only 17% of the relative proportional variation. The parameter estimate and standard error for the woody understory PC was p = 1.22 ± 0.63 (95% Cl = Brooks and Stouffer • GRASSLAND BIRDS IN PINE SAVANNAS 69 TABLE 1. Rotated principal components pattern from a PC A of 12 vegetation structure variables ( n = 22) used to compare vegetation among three stand types. Values are the correlations of the raw variables with each PC. Highest correlations are in bold. CV = coefficient of variation. Variable Woody PC Herb PC Tree PC Woody cover 0.896 -0.268 0.270 Woody density 0.885 -0.279 -0.154 Number stems 0.857 -0.305 0.024 Woody height 0.738 -0.570 0.157 Herb height 0.651 -0.222 0.115 Herb density -0.191 0.935 -0.125 Herb cover -0.386 0.835 -0.035 Woody cover CV -0.571 0.632 -0.068 Herb cover CV 0.613 -0.693 0.276 Herb density CV 0.550 -0.737 0.072 Canopy closure 0.136 0.091 0.948 Tree basal area 0.009 -0.378 0.869 Proportion s2 explained 61% 14% 9% —0.08-2.51). The estimate for basal area was Bachman’s Sparrows occurred in upland and -6.99 ± 3.25 (95% Cl = — 13.71— — 0.28). RCW stands but not in bog stands in our winter study. These results support the breeding season DISCUSSION observations of Allen et al. (2006), who reported Most upland stands supported low numbers of grassland birds (< 1 bird/ha), but the presence of Henslow’s Sparrows in RCW and bog stands led to densities >3 birds/ha. This type of information is important because it provides baseline knowl¬ edge of which habitat types may be most important for birds. Species-specific preferences should be considered, however, as two of our three study species did not occur in all three stand types. Our small sample sizes may have limited revealing significant differences between birds and vegetation among stand types. Bachman’s Sparrows to be more common in upland habitats compared to wetter pocosins in North Carolina. Haggerty (1998) suggested breed¬ ing Bachman’s Sparrows may prefer patchy herbaceous ground cover because this facilitates prey capture by foraging birds. Cox and Jones (2009) reported Bachman’s Sparrow winter abun¬ dances at sites in Georgia were positively correlated with bare ground and negatively correlated with increased grass structure and shrubs <1 m in height. Upland stands in DSNF have patchy herbaceous cover, and Bachman’s TABLE 2. Rotated principal components pattern from a PCA of 12 vegetation structure variables ( n = 27) used to model Henslow’s Sparrow and Sedge Wren occurrence. Values are the correlations of the raw variables with each PC. Highest correlations are in bold. CV = coefficient of variation. Variable Woody PC Herb PC Tree PC Woody density 0.902 -0.166 0.037 Woody cover 0.884 -0.155 0.383 Number of stems 0.819 -0.313 0.055 Woody height 0.815 -0.319 0.256 Herb cover CV 0.693 -0.553 0.379 Herb height 0.580 -0.236 -0.025 Woody cover CV -0.693 0.468 -0.158 Herb density -0.163 0.943 -0.096 Herb cover -0.480 0.773 -0.166 Herb density CV 0.529 -0.755 0.151 Canopy closure 0.122 -0.031 0.922 Tree basal area 0.118 -0.230 0.888 Proportion s2 explained 60% 13% 9% 70 THE WILSON JOURNAL OF ORNITHOLOGY • Vol. 123, No. 1, March 2011 TABLE 3. Rotated principal components pattern from a PCA of 15 plant species composition guilds ( n = 27) used to model Henslow’s Sparrow and Sedge Wren occurrence. Values are the correlations of the raw variables with each PC Highest correlations are in bold. Gram is graminoid. Uppercase abbreviations refer to USFWS Wetland Indicator Status (USDI 1988). OBL = obligate wetland, FACW = facultative wetland, FAC = facultative, FACU = facultative upland, and UPL = upland. Variable PC I PC II PC III PC IV PCV Gram FAC Gram FACU Woody FACU Gram UPL Gram FACW Woody OBL Forb FACW Woody FACW Woody FAC Forb OBL Forb UPL Woody UPL Forb FACU Forb FAC Gram OBL Proportion s2 explained 0.813 0.804 0.549 -0.746 -0.751 -0.129 -0.155 -0.061 0.073 -0.582 -0.062 0.169 0.175 0.024 -0.235 28% -0.267 -0.048 -0.049 0.028 -0.323 0.095 -0.152 -0.114 -0.090 0.152 0.204 -0.347 -0.266 0.174 -0.200 -0.117 0.133 -0.31 1 -0.222 0.000 0.927 0.068 -0.042 -0.053 0.871 -0.117 -0.033 0.022 -0.139 0.862 -0.058 0.240 0.139 0.744 0.186 -0.353 0.052 -0.640 -0.034 -0.021 0.084 0.055 0.808 -0.013 -0.097 -0.041 0.684 -0.293 -0.149 0.140 0.491 0.353 -0.071 0.069 -0.050 0.850 0.352 -0.371 -0.082 0.512 12% 11% 10% 9% Sparrows were at least tolerant of this cover typ during both breeding and nonbreeding season* although an adequate level of graminoid cover i important for stand occupancy (Brooks am Stoufler 2010). Bachman’s Sparrows are oftei associated with areas of dense herbaceous cove and low shrub cover (Plentovich et al 1998b Tucker et al. 2004), but they may be flexible it their habitat preferences. Haggerty (2000) con ducted a region-wide study across five states anc found Bachman’s Sparrow preferences for fort cover, vegetation height, and tree density varieo widely across regions. We found Bachman’s Sparrows used two of the FIG. 2. SS6 amon® six clusters managed for RCWs (Dunning and Watts 1990, Wilson et al. 1995). Plentovich et al. (1998b) also found that not all RCW clusters surveyed at sites in Florida were suitable for Bachman’s Sparrows. One explanation is the relatively small size of many RCW clusters. The mean breeding season home-range size of Bach¬ man s Sparrow is between 1.5 and 4.8 ha, and varies with time since fire, timber age, and vegetation structure (Haggerty 1998, Stober and Krementz 2006, Cox and Jones 2007). Many, but not all, RCW clusters in DSNF are probably too small (< 0.5 ha) to be of value to Bachman's Sparrows, particularly if the surrounding habitat is inadequate. Winter home range size, however, has not been well studied. There may be several reasons why Bachman’s Sparrows avoided bogs. Bogs often contain standing water (Folkerts 1982), and some species of giound-d welling birds may prefer drier habi¬ tats. Another reason is that most bogs in DSNF have either few trees or a closed canopy of pine. tands with high tree densities are generally ^QQsded by Bachrnan’s Sparrows (Haggerty , 2000), and open bog stands may luck adequate singing perches, which are important habitat features (Dunning and Watts 1990, Gobris 992, Brooks and Stouffer 2010). Perches may indicate appropriate habitat, even in winter, if Brooks and Stouffer • GRASSLAND BIRDS IN PINE SAVANNAS 71 TABLE 4. Candidate models used to model Henslow’s Sparrow occurrence. Plantl-Plant5 are principal components of the plant species guilds. Gram = graminoid, Herb = herbaceous structure. Wood = woody understory structure, Tree = tree density, CV = coefficient of variation, SCMU8 = Scleria muhlenbergii , OBL = obligate wetland indicator status, and FACW = facultative wetland indicator status. Model AICc AAICc Wi P GIC Herb density CV + SCMU8 25.76 0.00 0.06 0.39 Herb density CV + Plant 1 + Plant5 31.74 5.99 0.04 0.24 Herb density CV + Plant 1 + Herb density CV*Plantl 31.85 6.09 0.04 0.24 Herb density CV + Plant 1 32.44 6.68 0.04 0.22 Herb density CV + Plant5 32.60 6.84 0.04 0.22 Herb density CV 33.54 7.78 0.04 0.19 Herb PC + Plant4 + Herb PC*Plant4 33.81 8.05 0.04 0.18 Herb cover 34.49 8.73 0.04 0.16 Herb density CV + Plant 1 4- Plant4 35.17 9.41 0.04 0.14 Herb density CV + Gram OBL 35.61 9.85 0.04 0.13 Herb density CV + Gram FACW 35.79 10.03 0.04 0.12 Herb density CV + Plant4 Herb PC + Plant 1 + Plant4 + Herb PC*Plantl + 36.00 10.24 0.04 0.11 Herb PC*Plant4 36.87 11.11 0.03 0.08 Herb PC 37.48 11.72 0.03 0.06 Wood PC + Herb PC 37.76 12.00 0.03 0.05 Herb PC + Plant 1 37.89 12.13 0.03 0.05 Herb density 38.87 13.12 0.03 0.01 Null 39.26 13.50 0.03 0.00 Wood PC 39.73 13.97 0.03 -0.02 Herb PC + Plant4 39.89 14.14 0.03 -0.02 Herb PC + Tree PC 39.92 14.16 0.03 -0.02 Herb PC + Plant 1 + Herb PC*Plantl 40.20 14.44 0.03 -0.04 Herb PC + Plant 1 + Plant4 40.43 14.67 0.03 -0.04 Wood PC + Herb PC + Tree PC 40.46 14.70 0.03 -0.05 Wood PC + Plant 1 + Plant2 40.61 14.85 0.03 -0.05 Tree PC 41.51 15.75 0.03 -0.09 Wood PC + Plant2 41.89 16.14 0.03 -0.10 Wood PC + Tree PC 42.19 16.43 0.03 -0.11 Global 46.52 20.76 0.02 -0.31 birds maintain territories throughout the year (Cox and Jones 2009). Damage from Hurricane Katrina in 2005 disproportionately affected mature upland stands in DSNF, possibly improving upland stand habitat quality for Bachman’s Sparrows. The hurricane thinned canopies, simultaneously pro¬ ducing downed tree crowns and upturned root balls. Bachman’s Sparrows sing from downed crowns and may use root balls for escape; absence of these features reduces breeding season occu¬ pancy by Bachman’s Sparrows (Brooks and Stouffer 2010) and could affect winter habitat use. Henslow’s Sparrows were detected only in bog and RCW stands. These sparrows, in the Gulf Coastal Plain, seem to prefer some grassland habitats over others. Plentovich et al. (1999), working in pitcher plant bogs and upland pine stands in Alabama, only found Henslow’s Spar¬ rows in bogs and transition zones between bog and upland pine habitats. Tucker and Robinson (2003) also found Henslow’s Sparrows using small bogs in upland pine habitat in winter along the Gulf Coast. Other studies, however, have found high densities of Henslow’s Sparrows in upland longleaf pine habitats (Carrie et al. 2002, Johnson 2006, Palasz et al. 2010), but many of these sites were well-managed with fire and not adjacent to bogs. The primary reason Henslow’s SpaiTOws avoided upland habitats in DSNF is probably the lack of a dense, continuous herba¬ ceous layer, reflected by inclusion of the herba¬ ceous density CV in the best habitat model, even in stands regularly managed with fire. The majority of the upland stands we sampled had experienced only one growing season since fire, a condition that should favor Henslow’s Sparrows (Carrie et al. 2002, Bechtoldt and Stouffer 2005). These stands had an herbaceous layer, but it was 72 THE WILSON JOURNAL OF ORNITHOLOGY • Vol. 123, No. 1, March 2011 TABLE 5. Candidate models used to model Sedge Wren occurrence. Plantl-Plant5 are principal components of the plant species guilds. Herb = herbaceous structure. Wood = woody understory structure, and Tree = tree density. Model AICc AAICc ' 1 GIC Wood PC + Basal area Basal area Wood PC + Canopy closure Herb PC + Tree PC Canopy closure Wood PC + Herb PC + Tree PC Wood PC Null Plant5 Herb PC + Plant4 Plant2 Wood PC + Herb PC Herb PC Plant 1 Wood PC + Plant4 + Wood PC*Plant4 Plant 1 + Plant5 Plant2 + Plant4 Plant 1 + Plant4 Plant 1 + Plant2 Plant 1 + Plant2 + Plant4 + Plant5 Global 28.08 0.00 0.07 0.17 30.49 2.41 0.06 0.09 30.59 2.52 0.06 0.09 30.93 2.86 0.06 0.08 31.00 2.93 0.06 0.07 31.24 3.17 0.06 0.07 32.73 4.65 0.05 0.01 33.06 4.99 0.05 0.00 33.56 5.48 0.05 -0.02 34.59 6.51 0.05 -0.06 35.10 7.03 0.05 -0.08 35.16 7.09 0.05 -0.08 35.30 7.22 0.05 -0.09 35.39 7.31 0.05 -0.09 35.95 7.87 0.04 -0.11 36.09 8.01 0.04 -0.12 36.77 8.69 0.04 -0.15 37.04 8.97 0.04 -0.16 37.63 9.55 0.04 -0.18 40.69 12.61 0.04 -0.33 46.86 18.78 0.03 -0.67 too patchy to provide suitable habitat. The; results demonstrate that fire history alone may n predict sparrow occurrence in pine savanna Henslow’s Sparrows will use both upland longle, pine savannas and bogs in some areas, bi apparently prefer bogs when surrounding uplar habitat is of marginal quality, as is the case i DSNF. Small-scale bog restoration may fc important for Henslow's Sparrows in these area Henslow s Sparrow stand occurrence in DSN was best predicted by increasing continuou: spatially homogenous herbaceous density, whic is also reflected by their avoidance of uplan stands Qur results support those of Rotenberr and Wiens (1980) who found abundance o tallgrass praine birds, including breeding Hen Slow s Sparrows, was negatively correlated will ground cover heterogeneity. Patchy herbaceou structure can have negative effects on grasslan, buds in multiple ways (Shriver 1996, Perkins an. Vickery 2001, Thatcher et al. 2006) Cover of the sedge Scleria muhlenbergi increased the probability of Henslow’s Sparrov stand occurrence. This sedge can reach >50<2 cover in some bogs in DSNF but does not occur ir upland stands. All bogs that had high densities 01 Henslow s Spmrows also had high cover of 5 muhlenbergu. Scleria is an annual that senesces achenes in autumn (W. J. Platt, pers. comm.), and the seeds are available to ground-foraging birds in early winter. Species of Scleria have been found to be important in Henslow’s Sparrow diets in Mississippi and Louisiana (Fuller 2004, DiMiceli 2006). Schleria muhlenbergii could be important for identifying high-quality habitat if Henslow’s Sparrows use habitat cues to select wintering areas upon fall arrival. Scleria muhlenbergu responds strongly to fire and is most abundant the first growing season after fire, but decreases substantially by the following season in the absence of fire (W. J. Platt, pers. comm.). Henslow’s Sparrow use of RCW stands was ephemeral. Mean Henslow’s Sparrow density in RCW stands declined from 3.5 birds/ha in late November to 0.6 in early January (Brooks 2010). Henslow’s Sparrows are site faithful during the core months of winter (Dec-Feb) (Plentovich et ah 1998a, Thatcher et al. 2006, Johnson et al. 009 ). Oui results suggest temporary use of RCW stands by transient birds that had not settled on winter territories, a result that corresponds to movements described in Louisiana (Johnson et al. 2009). RCW stands in DSNF had lower herba¬ ceous structure than bog stands, indicating the habitat was of lower quality than bogs, where densities did not significantly decline during the Brooks and Stouffer • GRASSLAND BIRDS IN PINE SAVANNAS 73 year of sampling (Brooks 2010). Patch size could be one reason why birds did not remain in RCW stands. Henslow’s Sparrows occupy small habitat patches in high-quality bogs but could be more area sensitive in lower-quality habitats. Sedge Wrens occurred in all stand types, and densities did not differ among stand types. We found only one Sedge Wren in one RCW stand; this species was not detected in two other studies of winter bird communities in RCW clusters (Conner et al. 2002, Provencher et al. 2002). Our modeling of stand occurrence based on vegetation variables weakly suggests Sedge Wrens in DSNF may prefer woody understory vegetation. Woody understory vegetation is abundant in all stand types in DSNF but is lowest in RCW clusters. Our results do not show statistically fewer Sedge Wrens and lower woody structure in RCW clusters, perhaps because of our small sample size, but we suspect that further sampling may reveal differences. Sedge Wren site occurrence was best predicted by decreasing tree basal area and increasing woody understory vegetation structure. The many habitat types used by Sedge Wrens across the Southeast show they are habitat generalists in wintering areas (Lowery 1974, Imhof 1976, Baldwin et al. 2007). Thus, it is not surprising the best model explained only 17% of the relative proportional variation. Our finding of Sedge Wren preference for woody understory contrasts with Baldwin et al. (2007), the only other quantitative study of Sedge Wren winter habitat preference. Site occupancy and abundance in their study were not associated with shrub densities but with dense herbaceous vegetation. However, they worked in Texas costal prairies, an entirely different ecosys¬ tem than pine savannas. Sedge Wrens are insectivorous (Herkert et al. 2001), and insect abundance also could be an important driver of habitat selection. Caution must be used when interpreting trends observed during this study because they are based on only two seasons of observations. We believe, however, the conditions in DSNF during the study influenced the observed habitat-type preferences of the study species. These habitats change rapidly between years and after fire; thus, quality of habitat types will be in flux, and specific habitats may appeal to birds differently between years. Our best habitat models were not substantially better than null models, and the parameter estimates had large confidence intervals. These models may not be suitable for prediction, but are suggestive of potentially important associations warranting further research. We did not include weather data in our analyses. We observed a gradual decline in Henslow’s Sparrow and Sedge Wren densities over sampling events in the first sampling year (Brooks 2010). We speculate this was due to lower- than-average precipitation the previous growing season, which could lead to increased predation and fewer seed resources (Pulliam and Parker 1979, Thatcher et al. 2006). Precipitation in DSNF in 2007 was 4- 1 59 mm below average every month from March to November except for October (85 mm above average), while the 2008 growing season received an even mixture of above- and below-average precipitation (USDC 2009). CONSERVATION IMPLICATIONS Many areas that appear suitable for Henslow’s Sparrows, particularly upland longleaf pine sa¬ vannas, are unsuitable because of the patchy distribution of herbaceous vegetation. Restoring the herbaceous component of longleaf pine savannas to a continuous layer should be one of the principal goals for those interested in grass¬ land bird conservation. Upland stands are suitable for Bachman’s Sparrows and Sedge Wrens in DSNF and, if restored, may become suitable for Henslow’s Sparrows. This sparrow occasionally occupies isolated patches of upland habitat, but the general trend in many areas is a preference for bogs. Bogs can be maintained with tree thinning and prescribed fire, but upland stands require reduction in shrub cover, which will not happen with fire alone. It may require a combination of fire, mechanical removal, and herbicide applica¬ tion (Boyer 1992, Olson and Platt 1995, Drewa et al. 2002b). Small-scale bog restoration for Hen¬ slow’s Sparrow is likely the most effective management strategy. Many practices currently used in DSNF benefit grassland birds via ecosystem restoration (e.g., prescribed fire, a shift towards more growing-season fires, and slash pine removal in bogs). Increasing the size and number of RCW clusters also will increase the area of potentially suitable habitats for all three grassland bird species. ACKNOWLEDGMENTS We thank the USDI, Fish and Wildlife Service for funding and the USDA, Forest Service for support, particularly M. E. Moody for providing field housing, C. 74 THE WILSON JOURNAL OF ORNITHOLOGY • Vol. 123, No. 1, March 2011 J. Boykin for fire information, and D. L. Tyron and Keith Coursey for biological and historical information. We also thank M. D. Kaller and W. J. Platt at LSU for assistance with the original thesis manuscript from which this paper is derived. We especially thank L. M. Palasz, E. I. Johnson, D. M. Fox, F. L. Owens, J. L. Anderson, J. H. Carpenter, Adam Walz, M. G. Hunter, R. S. Babin, and K. A. Hackman and Madison Central High School in Madison, Mississippi. We thank the LSU RNR community, partic¬ ularly the graduate students. We also thank two anonymous reviewers whose comments greatly improved this manu¬ script. Most of all we thank the numerous volunteers who helped with field work. This manuscript was approved for publication by the Director of the Louisiana Agricultural Experiment Station as manuscript number 2010-241-5139. LITERATURE CITED Allen, J. C., S. M. Krieger, J. R. Walters, and J. A. Collazo. 2006. 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Managing mid-rotation pine plantations to enhance Bachman's Sparrow habitat. Wildlife Society Bulletin 26:342-348. Tucker, J. W., W. D. Robinson, and J. B. Grand. 2004. Influence of fire on Bachman’s Sparrow, an endemic North American songbird. Journal of Wildlife Man¬ agement 68: 1 1 14-1 123. U. S. Department of Commerce (USDC). 2009. NOAA Satellite and Information Services. Saucier Forest Experiment Station, Saucier, Mississippi. National Climatic Data Center, Asheville, North Carolina, USA. U.S. Department of the Interior (USDI). 1988. National list of vascular plant species that occur in wetlands. Biological Report 88 (26.9). USDI, Fish and Wildlife Service, Washington, D.C., USA. Wiens, J. A. 1974. Habitat heterogeneity and avian community structure in North American grasslands. American Midland Naturalist 91:195-213. Wilson, C. W., R. E. Masters, and G. A. Bukenhofer. 1995. Breeding bird response to pine-grassland community restoration for Red-cockaded Woodpeck¬ ers. Journal of Wildlife Management 59:56-67. Wood, D. R., L. W. Burger, J. L. Bowman, and C. L. Hardy. 2004. Avian community response to pine- grassland restoration. Wildlife Society Bulletin 32:819-828. Wright, S. P. 2001. Statistics, data analysis, and modeling: multivariate analysis using the MIXED procedure. Pages 1-5 in Proceedings of the Twenty-Sixth Annual SAS Users Group International Conference. SAS Institute Inc., Cary, North Carolina, USA. The Wilson Journal of Ornithology 1 23( 1 ):76 — 84, 2011 GEOGRAPHIC SONG VARIATION IN THE NON-OSCINE CUBAN TODY ( TOD US MULTICOLOR) ENEIDER E. PEREZ MENA'-3 AND EMANUEL C. MORA2 ABSTRACT. — We studied sound emission in the non-oscine Cuban Tody ( Todus multicolor) to quantify its acoustic repertoire and to document geographic variation in its songs across the Cuban archipelago. Cuban Todies emitted three types of sounds. The characteristic song of the species was recorded from 98% of 1 16 individuals. The characteristic song of the species and a variant form recorded from two individuals consisted of trains of multi-harmonic short, downward frequency modulated notes emitted at peak frequencies below 4 kHz. A third type of sound in the limited repertoire of the species recorded from two birds is presumably produced with the wings and appears in the spectrograms as a train of short clicks with frequencies also below 4 kHz. Evidence of geographic variation was found in the characteristic song. Birds from Isla de la Juventud and Pinar del Rio emitted more notes per train spaced at longer intervals than birds from the rest of the provinces. The peak frequency of the notes had lower values in birds from Isla de la Juventud. A discriminant function analysis grouped todies from different provinces into two main clusters corresponding to western Cuba and eastern Cuba. This geographic song variation may indicate genetic differences in this sedentary forest bird, and the existence of two incipient species of todies in Cuba. Isolation may have been caused by discontinuities in the mainland of Cuba that occurred between the Pleistocene and Holocene or by deforestation occurring in Cuba for the last five centuries. Received 5 January 2010. Accepted 19 October 2010. Geographical variation should be considered when analyzing vocal repertoires of birds, as species distributed across wide areas may vary in their songs. Geographic variations have been reported mostly from oscines (Mundinger 1982, Martens 1996), but also from non-oscine (Gold¬ stein 1978, Saunders 1983, Bretagnolle 1989, Wright 1996) and suboscine taxa (Isler et al. 1998, Lindell 1998, Isler et al. 1999). Several theories have been proposed to explain the geographic variation in vocalizations observed in different species. Geographic variations may result lrom adaptation to local conditions, such as social or structural environments (Lemon 1975, Payne 1980), but also from non-adaptive process¬ es such as the accumulation of genetic or cultural mutations in a population due to isolation or founder events (Tack et al. 2005), or some combination of genetic variation and learning (Kroodsma 1996). Geographic variation in vocal¬ izations is expected to be reinforced by limited intermixing between the species’ populations due to geographic isolation. Thus, geographic son* variation may reflect structure among populations of a species. The Cuban Tody ( Todus multicolor) belongs to 'Institute for Ecology and Systematic, Carretera de Varona Km 3I/2, Capdevila, Boyeros, CP 10800, Ciudad de La Habana, Cuba. Faculty of Biology, Havana University, Calle 25, No 455 entre J e I. Vedado, Plaza de La Revolution, CP 10400 Ciudad de La Habana, Cuba. Corresponding author; e-mail: jrrubio@infomed.sld.cu a genus of charismatic small and colorful non- oscine birds endemic to the Caribbean, represent¬ ed by two species in Hispaniola, one in Jamaica, one in Puerto Rico, and one in Cuba (Raffaele et al. 1998). The Cuban Tody is well distributed in Cuba and is common in semi-deciduous meso- phytic forest and coastal vegetation (Garrido and Kirkconnell 2000), swamp vegetation complex (Gonzalez et al. 1997), and secondary vegetation (Gonzalez et al. 2001). This species perches for long periods, often bobbing its head up and down while locating the small adult and larval insects, and spiders upon which it feeds. The sedentary behavior, forest use, and short distance flight of this species suggest easier isolation of populations by deforestation, a phenomenon that has occurred in Cuba during the last five centuries (Fig. 1)- ft may be advantageous to study the song repertoire of the Cuban Tody since, among many non- oscines, songs are not learned from other individuals (Konishi and Nottebohm 1969, Kroodsma 1989), and vocal behavior may be used as an unambiguous genetic marker for an individual. Cuba, the largest archipelago of the Greater Antilles, is <150 km wide but extends east-west lor >1,000 km. We tested the hypothesis that the song of the Cuban Tody exhibits geographic variation across the length of Cuba by character¬ izing the acoustic repertoire of the species from individuals recorded in seven provinces represen¬ tative of the island. We specifically predicted that song similarity should be inversely related to 76 Perez Mena and Mora • GEOGRAPHIC SONG VARIATION IN THE CUBAN TODY 77 Current vegetation cover | Forest Original vegetation cover jUjij Grassland fl Forest Cayo Sabinal (3) Cayo Coco (9) 100 Kilometers Cupeyal (19) Ojitode Agua (11) (3) Pico Turquino (8) Baitiquirf (17) FIG. 1. Original vegetation (Del Risco 1989) and current forest cover on the island of Cuba. The seven provinces and the recording sites involved in this study are identified. The number of birds recorded in each site is in parentheses. distance between individuals. There are no acoustic studies of the Cuban Tody. Thus, to test this prediction, we recorded the song of the species across Cuba, characterized it quantitative¬ ly, and examined geographic variation in songs by using a discriminant function analysis. METHODS Field Recordings.— Acoustic recordings of the Cuban Tody were obtained between 2001 and 2006 at 15 sites in seven provinces of Cuba: Isla de la Juventud (1 site), Pinar del Rio (3), Matanzas (4), Ciego de Avila (1), Camagiiey (1), Santiago de Cuba (1), and Guantanamo (4) (Fig- 1). Recordings were made from February to August to include most of the reproductive period of the species (Garrido and Kirkconnell 2000). We recorded songs from 1 16 solitary adults perching in the forest up to 10 m from the microphone. Adults are easily recognized because they combine the ventral pale gray color with a brilliant red throat patch that is absent in young, which are entirely pale gray below (Garrido and Kirkconnell 2000). We could not test for vocal differences between males and females as they can not be identified by plumage (Raffaele et al. 1998, Garrido and Kirkconnell 2000). Recordings were made using a Marantz PMD 222 tape recorder and Sennheiser ME66/K6 microphone. Care was taken to avoid signal saturations and to maximize signal-to-noise ratio. Acoustic Analysis. — A data base of 1,371 songs (11.67 ± 4.52 songs/bird) including 8,885 notes was analyzed. Songs were digitized to examine the quality of the recordings with 16 bit accuracy and a sampling rate of 44,100 Hz using BatSound, Version 2.1 (Petterson Elektronic AB, Uppsala, Sweden). A note was defined as a continuous tracing on a spectrogram following Nelson et al. (1996), while a song was defined following Baptista (1974) and Staicer (1989) as an arrange¬ ment of notes forming a coherent unit. Songs were analyzed with Avisoft-SAS Lab Pro 4.3 (Avisoft Bioacoustics, Berlin, Germany). Spectrograms were made using consecutive Fast Fourier Transforms (FFT’s) and Hamming win¬ dows with a 92% overlap. A 512 points FFT was chosen to attain a frequency resolution of 86 Hz and a time resolution of 0.18 msec. We used an automatic two-threshold algorithm for note separation with the additional start/end threshold set at — 20 dB. This algorithm minimiz¬ es the effect that different note amplitudes may have on the measurements. The following param¬ eters were automatically measured: (1) note duration (time between start and end of a note measured in msec in the spectrogram), (2) peak frequency (frequency in kHz corresponding with the maximal intensity in the power spectrum), (3) initial and (4) final frequency (values of frequency measured, respectively, at the beginning and at end of the note), (5) bandwidth (calculated as the difference between the lower and higher values of frequency measured at 20 dB below peak intensity in the power spectrum), and (6) entropy (used as an estimate of the tonal-noisy structure of the note: zero for pure-tone signals and 1 for random noise). We counted the number of notes in each song and calculated the interval between notes and songs. All values of the acoustic parameters are given as means ± SD. 78 THE WILSON JOURNAL OF ORNITHOLOGY • Vol. 123, No. 1, March 2011 III! till W - llll Illl II FIG. 2. A. Oscillogram (above) and spectrogram (below) of a sequence of the characteristic song of the Cuban Tody. B. Detailed spectrogram (left) and power spectra (right) of the song marked in A with an asterisk. Statistical Analysis. — Statistical analysis was performed using Statistica Version 7.0 (StatSoft Inc. 2004). The data sets were normally distrib¬ uted (Kolmogorov-Smimov test, P > 0.05) and we used parametric statistics (one-way ANOVA). Statistical differences between several mean values were analyzed with a Newman-Keuls post-hoc test (identical letters indicate no statis¬ tically significant difference between means). All analyses were conducted using mean values per individual and the level of significance was a = 0.05. A multivariate discriminant function analysis (DFA) was performed using SPSS Version 16.0 (SPSS, Chicago, IL, USA) with individuals as cases and number of notes, note duration, interval between notes, initial frequency, peak frequency, final frequency, and interval between songs as parameters. We used DFA to generate linear combinations of variables for assigning cases to their pre-determined groups (Quinn and Keough 2002). RESULTS Sounds Emitted. — The characteristic song ( tot- tot-tot ) of the Cuban Tody was present in >98% of the recordings in each province studied. It was emitted by single birds in most cases that alternated singing with feeding behavior. The song was repeated at time intervals of 0.04- 15.62 sec and included 3—23 notes. Each note was downward frequency-modulated and often had a Perez Mena and Mora • GEOGRAPHIC SONG VARIATION IN THE CUBAN TODY 79 harmonic (Fig. 2). The initial frequency of the fundamental harmonic varied from 3.89 to 3.49 kHz and the final frequency from 1.50 to 2.49 kHz. The acoustic parameters that character¬ ized this song in each province varied (Table 1). A variant form of the characteristic song of the Cuban Tody was detected in two individuals, one in Pinar del Rio and one in Santiago de Cuba. Each time, the song accompanied conspecific aggressive behavior and chasing, and sounded like a trmrrrrrr- trrrrrrrrrr. This song variant in the spectrogram resembles the characteristic song in that it is also a train of downward frequency- modulated notes (Fig. 3). This variant, compared to the characteristic song of the species, had a higher note repetition rate (average interval between notes of 23.53 ± 0.72 msec; n = 2 birds; 15 songs) and a lower frequency content of the fundamental harmonic (initial frequency: 2.72 - 0.01 kHz; final frequency: 1.69 ± 0.03 kHz). The notes typically showed two harmonics. Another sound emitted by the Cuban Tody was presumably produced with the wings and is responsible for the species popular name in Cuba “Pedorrera”, a Spanish onomatopoeic rendering of this sound (Garrido and Kirkconnell 2000). Perceived as a prrr-prrr, it was frequently emitted by birds interacting with conspecifics or hetero- specifics invading their territory. The average sound (n = 2 birds) appears in the spectrogram like a train of more than four short clicks (click duration of 6.83 ± 1.22 msec) covering a frequency band between 3.34 ± 0.43 to 2.59 ± 0.18 kHz (Fig. 4). Variation in the Characteristic Song. — Most acoustic parameters used to describe the charac¬ teristic song of the Cuban Tody had statistical differences among provinces. Birds from Isla de la Juventud and Pinar del Rio emitted more notes per train spaced at longer intervals than birds from the rest of the provinces. The peak frequency of the notes had lower values in birds from Isla de la Juventud. These differences, however, did not show monotonic changes along the island of tuba, which was taken as evidence for absence of continuous variation (Table 1). We applied a discriminant function analysis (DFA) to 1 16 individuals from seven provinces of tuba to assess the presence of geographic song variation in the Cuban Tody. Individuals of Isla de *a Juventud and Guantanamo were correctly 183.3%) classified to their provinces (Table 2). Correct classification in the rest of the provinces u o £ g? S o o 13 % ° S3 2 _C rs O) 0) ■s g ° 2 Q a- <*> •_ +1 § 'K £ £ w S <- o ^ c/3 c .£ 2 > - M M N M M M iq iq o- — - m oa — I>5 73 IQ IQ sD OJ ~0 CO ■— *— — - CO +1 +1 +1 +1 +1 +1 +1 CO CO CO CO CO CO CO £ iq £ JO £ £ £ in ir vs if on it q —■co — • • — • d c-i oi +1 +1 +1 +1 +1 +1 +1 cn r-4 q os o it o o i io — * r-~ co cn r~" d _ it co o o t-~ oo oo £ £ £ .o IQ IQ IQ IQ £ IQ it it co o m +1 +1 +1 +1 +1 +1 +1 q oq q q — ; uo d d d d d so IQ IQ £ £ £ £ iq h (N q M en it co oi oi co — +1 +1 +1 +1 +1 +1 +1 q M m o T, p — : oo d d d if represent the results of a Newman-Keuls post-hoc test; a differs statistically from b, and b from c. 80 THE WILSON JOURNAL OF ORNITHOLOGY • Vol. 123, No. 1, March 2011 N I o c 0 3 O' 0 i- II N I > O c 0 3 O’ 0 Li. H 1 ; h ' 1 h 1 1 1 , f | i ! 1 i U 1 ' H M ; : i 1 1 ! 1 1 1 1 iiiiijmtfMt ! f 1 1 1 i i I < i 1 1 j i nmtrmfGf mttnmmt [ f i ' 1 * 1 1 | 1 I 1 f » * I I I 0 1 2 3 4 Time (sec) B Time (msec) Amplitude (dB) Toril/GR3'n A: °sclll°gram (above) and spectrogram (below) of a variant form of the characteristic song of the Cuban y- . e ailed spectrogram (left) and power spectra (right) of the central notes of the song marked in A with an asterisk. ranged between 0.0 to 38.5%. Individuals from Pinai del Rio were statistically reassigned to Isla de la Juventud, while individuals from Matanzas and more eastern provinces were statistically teassigned to Guantanamo. Two individuals from Matanzas were reassigned to Pinar del Rio and one from Ciego de Avila was reassigned to Isla de la Juventud (Table 2; Fig. 5). A MANOVA showed the model was significant (Wilks’ X = 0.099, X2 = 243.3, df = 42, P = 0.000) and that 94.3% of the variation was explained by the two discriminant fiinctions (Fig. 5). The proportion of correctly classified vocalizations by cross-corre¬ lation was 61.2%. The first discriminant function which explained 86% of the variation, was more influenced by interval between notes and number of notes, while the second function was influenced by interval between songs and peak frequency (Table 3). DISCUSSION Vocal Repertoire of the Cuban Tody. — The 1 16 birds studied across the Island of Cuba emitted only three different types of calls. Two of these sounds, the characteristic song of the species and the sound presumably produced with the wings, have been previously described onomatopoeically (Raffaele et al. 1998, Garrido and Kirkconnell 2000). The variant form of the characteristic song had not been previously reported. Its similarities to the characteristic song could have been sufficient to consider both as the same by Perez Mena and Mora • GEOGRAPHIC SONG VARIATION IN THE CUBAN TODY 81 Time (msec) Amplitude (dB) FIG. 4. A. Oscillogram (above) and spectrogram (below) of the sound produced with the wings by the Cuban Tody. B. Detailed spectrogram (left) and power spectra (right) of the train marked in A with an asterisk. researchers undertaking qualitative descriptions. The species repertoire size is comparable to other non-oscines such as Percnostola saturata (Braun et al. 2005), but smaller than that of Todus mexicanus, which exhibits six different song types ln its repertoire (Kepler 1977). Geographic Variation in the Characteristic Son8 of the Cuban Tody. — Our prediction of an averse relation between song similarity and ^stance between individuals was partially sup¬ ported by our findings. The characteristic song of the Cuban Tody exhibits two main forms on the archipelago of Cuba (Fig. 5), one corresponding to Western Cuba (Isla de la Juventud and Pinar del Rio) and the other to Eastern Cuba (from Guantanamo to Matanzas). Song variation can reflect historical barriers (Baril and Barlow 2000, Tack et al. 2005), and we see two possible explanations for the geographic variation that we observed in the Cuban Tody songs: one ancient and the other more recent. The Cuban area alternated between being one continuous island in the Pleistocene, which could propitiate a constant gene flow among the Cuban Tody populations, to several islands during periods of high sea level that might act as a physical barrier to this flow. Kepler (1977) used the fossil evidence presented by Olson (1976) to hypothesize that Paleotodus dispersed from the Yucatan Peninsula to Cuba during the Pleistocene or earlier and thereafter evolved into the Cuban species (Cuban Tody). Overton and Rhoads (2004), in agreement 82 THE WILSON JOURNAL OF ORNITHOLOGY • Vol. 123, No. 1, March 2011 Factor I (85.5%) + Guantanamo FIG. 5. Discriminant function analysis examining geographic song variation in the characteristic song of the Cuban Tody throughout the island of Cuba. Each point represents an individual. The ellipses represent the 95% confidence area for the individuals from Isla de la Juventud and Guantanamo, the two provinces with the highest correct classification percentages. The percentage of cumulative variance is shown between parentheses. A: sonogram of a typical song from Guantanamo. B: sonogram of a typical song from Isla de la Juventud. with Kepler (1977), suggested the Todus group is monophyletic and developed prior to the Pleisto¬ cene. Thus, the opportunity existed for Pleistocene sea-level changes to have created the conditions needed for the variation in vocalizations that we observed. We cannot dismiss the possibility that more recent habitat fragmentation is the cause of the TABLE 2. Discriminant function analysis, using a cross validated method, testing for geographic variation in the characteristic song of the Cuban Tody. IJ: Isla de la Juventud; PR: Pinar del Rio; Mt: Matanzas; CA: Ciego de Avila; Cm: Camagiiey; SC: Santiago de Cuba; Gt: Guantanamo. Classified as u IJ 20 PR 3 Mt 1 CA o Cm 0 SC o Gt 0 Total n 24 % correct identification 83.3 PR Mt CA 5 0 1 5 2 0 2 0 0 0 3 0 0 0 0 0 0 o 1 4 8 13 9 9 38.5 0.0 0.0 Cm SC Gt ooo 0 0 2 0 o 1 0 0 1 0 0 0 0 1 1 3 7 45 3 8 50 0.0 12.5 90.0 Perez Mena and Mora • GEOGRAPHIC SONG VARIATION IN THE CUBAN TODY TABLE 3. Standardized canonical discriminant function coefficients for Cuban Tody songs. Function Parameter I II Interval between notes 0.801 0.314 Note duration 0.100 0.039 Number of notes 0.561 -0.930 Peak frequency -0.098 0.557 Interval between songs 0.248 0.643 Initial frequency 0.065 0.377 Final frequency -0.204 -0.018 observed variation in the Cuban Tody songs, as proposed for the Rufous-collared Sparrow (Zono- trichia capensis) by Tubaro et al. (1993). Pleistocene glaciation is believed to have influ¬ enced the present distribution of many Antillean taxa, but the paucity of information regarding the differentiation of these taxa has left uncertain how much these ancient climatic fluctuations contrib¬ uted to the speciation process (Pregill and Olson 1981). Further, for the last 8,000 years, after the early Holocene subsidence of seas levels (Itur- ralde-Vinent 2004), Cuba has been a single continuous island through which todies could potentially move with relative ease. The potential lor genetic flow was interrupted again in the last l've centuries through ongoing deforestation (Fig. 1). Distinguishing between the impacts of ancient a,id recent isolation of tody populations requires turther research. Regardless of the cause of vocal differentiation, we suggest that more detailed studies are needed to explore the extent to which ttle todys’ two vocally-distinct populations repre- SLnl incipient species” on Cuba. We believe that 11 would be important to investigate the functions °t song in Cuban Todies: whether singing is entirely for mate attraction or serves both for mate attraction and territorial defense (Payne 1979; Gibson 1989; Westcott 1992, 1997), or even Aether the song serves as a contact communica- tl()n in mixed-species flocks (Catchpole and Slater 5), in which we have also observed singing by L1btm Todies. We believe studies of additional Species of birds, looking for consistent geographic Patterns in vocal differentiation, will also have a ro e in helping us understand the evolution of tody Realizations, and more generally in understand- ln£ the evolutionary history of the Cuban avifauna. ACKNOWLEDGMENTS We are indebted to our students (Jovany Rojas, Anay Serrano, and Yanairis Medina) for help during the field trips. We thank Patricia Rodriguez, Hiram Rodriguez, and Daysi Rodriguez for comments on early versions of the manuscript and especially Wesley Hochachka for his constructive comments. We thank our colleagues: Eduardo Inigo, Greg Budney. and John Fitzpatrick from the Cornell Laboratory of Ornithology for inspiring our work on bird bioacoustics. This research was supported by Projects “Salvando un area de vida silvestre unica en el Caribe" and “Estudio para la conservation de poblaciones de aves amenazadas de Cuba”. LITERATURE CITED BAPTISTA, L. F. 1974. 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RODRIGUEZ,2 OSWALDO JADAN,3 AND ELISA BONACCORSO2 ABSTRACT.— The Royal Sunangel ( Heliangelus regalis ) is endemic to sandstone ridges in southeast Ecuador and northeast Peru. This hummingbird is currently considered endangered, although little has been published on its nature history, distribution, and conservation. We found H. regalis in three habitat types, but abundance was higher in stunted shrubland, at ridgetops. It was observed to feed on seven plant species, mostly following regular feeding routes, etween and 2.5 m above ground. We describe six different vocalizations, as well as two flight displays, and observations on socia interactions. We also discuss its current conservation status in Ecuador, where we estimate that —2,500 indivi ua s rnig t persist. Received 5 April 2010. Accepted 8 September 2010. The Royal Sunangel (Heliangelus regalis) occurs in ridgetop and adjacent stunted forests in the Cordillera del Condor, Cordillera de Colan, Cordillera Azul, and other ridges with poor sandy soils in extreme southeastern Ecuador and north¬ eastern Peru (BirdLife International 2009). It was considered endemic to Peru (its southernmost locality being Pauya, Cordillera Azul, Departa- mento San Martin; Schulenberg et al. 2001) until recently (Schulenberg et al. 2007). Krabbe and Ahlman (2009) presented the first documented record for Ecuador from a shrubby forest on a sandstone mountain in the Nangaritza Valley, Zamora Chinchipe Province. Heliangelus regalis is currently ranked as globally Endangered because of its limited distributional range, where selective logging and forest clearing are increasing, and where large- scale mining exploitation represents a major threat. Heliangelus regalis is seemingly rather numerous locally in the Cordillera del Condor, Cordillera de Colan, and Cordillera Azul (Schu- •enberg et al. 2001, 2007). However, its global Population is likely small, confined to unique orests in a limited center of endemism ( Andean 'dgetop Forests; Stattersfield et al. 1998). Little ls known about the ecology, distribution, and conservation status of the Royal Sunangel (Sed- d°n et al. 1996). 'Fundacion Numashir, Casilla Postal 17-12-122, Quito, Ecuador. Muse° de Zooiogfa (QCAZ), Pontificia Universidad 10 'ca del Ecuador, Avenida 12 de Octubre 1076 y Roca, Quito, Ecuador. Lo Hpbario Re'naldo Espinosa, Universidad Nacional de Jru ludad Universitaria La Argelia, Loja, Ecuador, ^responding author; e-mail: jfreileo@yahoo.com We undertook observations on the natural history of H. regalis at two different localities (above Miazi and above Yankuam) during field work for a rapid assessment of two sandstone, flat-top ridgetops (locally called “tepuis’' be¬ cause of resemblance to the Guianan table-top mountains) currently protected by the local com¬ munity of Las Orquideas (04 13' 58.8" S, 78 39' o" W, 900 m asl). We present our field obser¬ vations to briefly assess its habitat preferences, comparing our results with previous habitat descriptions (Fitzpatrick et al. 1979, Seddon et al. 1996), contribute data on its diet, displays, vocalizations, and social interactions, and discuss its current conservation status. OBSERVATIONS Field Identification . — Field identification of ales was straight forward, as H. regalis is the ily hummingbird entirely violet-blue, which oks mostly black in poor light conditions. >males were identified by pale tawny underparts ith some green streaking-spotting in the throat id a plain tawny buff crescent in the chest with a ther long, deep blue forked tail (Schulenberg et 2007). There was no overlap with other eliangelus species and identification of female umage birds is considered accurate (Krabbe and hlman 2009). Habitat. — We observed H. regalis in three ifferent vegetation types (Table 1). On 8 April 309 we observed a single female in the under- on/ of stunted shrubland on a ridgetop above Iiazi (04° 15' 0" S, 78° 37' 1.2" W; Fig. 1). egetation at this site was characterized by low ature, twisted canopy (2-8 m in height), many piphytes and hemiepiphytes, and dense under- 85 86 THE WILSON JOURNAL OF ORNITHOLOGY • Vol 123, No. 1, March 2011 TABLE 1. Habitat types where H. regalis was recorded in two localities in the Nangaritza Valley, Zamora Chinchipe Province, southeast Ecuador. Above Miazi Above Yankuam Elevation (m asl) Terrain Dense foothill forest Dense lower montane forest 1 female/ 1 male 1 female/2 males 1,250/1,300 1,550-1,650 Slopes Slopes Stunted shrubland and paramo-like habitat 1 female 1 female/4 males 1,300 at Miazi, 1,800- 1,850 at Yankuam Ridgetop story. This was the only individual observed despite considerable mist-netting and point-count sampling at this locality. A female was mist-netted at 1,250 m elevation on the slopes of a sandstone mountain above Yankuam Lodge (04° 15' 7.2" S, 78° 40' 1.2" W) on 15 April 2009, and a male was observed feeding at mid-strata in dense foothill forest characterized by 15-25 m canopy height, and dominated by several species of Rubiaceae, Euphorbiaceae, Melastomataceae, Myrsinaceae, Clusiaceae, Meliaceae, and Podocarpaceae with 9537000 9534000 9531000 9528000 9525000 ■ Stunted shrubland Dense lower mountain forest I I Dense foothill mountain forest {and other types of vegetation) — Minor water courses Major water courses - ■ ■ - Tepuis of Nangaritza UTM Zone 1 8 S (WGS84) Mangas Valley afsoutheast "*** “ Freile et al. • NATURAL HiSTORY OF THE ROYAL SUNANGEL 87 scattered Dictiocaryum lamarckianum , Iriartea spp., and Wettinia spp. palms. Two separate males and a single female were observed on 17 April 2009 in dense lower montane forest above Yankuam (Table 1). This forest type was characterized by a fairly discon¬ tinuous canopy with an average height of 10 m (max = 12 m) with lower vegetation where limestone was exposed. Dominant families were Euphorbiaceae, Clusiaceae, Cunoniaceae, Rubia- ceae. Humiriaceae, and Ericaceae. The understory was dense (~ 80% ground cover in some areas) including patches of ground bromeliads with heavy loads of mosses, vine tangles, and epi¬ phytes. Of the observed individuals, one male and one female were in a natural forest gap, while another male was in dense and tangled understory feeding at edges of trails, where vegetation was sparser than in areas away from trails. At least four males and one female were observed feeding at shrubby edges and in tangled interior on the ridgetop of the sandstone mountain above Yankuam (Table 1) on 17 and 19-20 April 2009; three males were observed performing aerial displays near a tall rocky outcrop at the edge of the forest. Two distinctive but intermixed habitats occurred in this area: (1) stunted shrub- land, and (2) an atypical paramo-like vegetation, despite the low altitude for paramos (Sierra 1999). These habitats were characterized by trees and bushes of low stature, a canopy at 2-8 m in height with ‘emergent’ trees barely exceeding 5 m. The understory was dense, reaching 75—80% cover in some areas; the ground cover was also dense with many ground bromeliads, acaulescent rosettes (those having or appearing to have no stem), paramo-like herbs, and terrestrial mosses. The density of epiphytes and mosses was low, but typical paramo families and genera were domi¬ nant, including Macleania and Cavendishici (Eri¬ caceae), Macrocarpaea (Gentianaceae), Meriania and Miconia (Melastomataceae) bushes, ground Asteraceae, and Wienmania (Cunionaceae). Vegetation types described correspond to Previous ecosystem classifications for the Nan- garitza area. Detailed information about general Vegetation types in the Nangaritza Valley is Provided by Foster and Beltran (1997), Palacios 0997), Neill (2007), and Jadan (2010). Feeding Behavior. — A male H. regalis was feeding in dense foothill forest by hovering at an eP!phytic Guzmania (Bromeliaceae) bromeliad "^3 m above ground. At least one other male fed by hovering at several flowers of two ground bromeliads Tillandsia cf asplundii , and one ericad shrub Disterigma alaternoides , both with fairly long (~ 2 cm) corollas, in dense lower montane forest. Feeding heights ranged from 0.30 to 2.5 m. We observed 34 feeding visits of H. regalis to seven different plant species in stunted shrubland and paramo-like habitat above 1,800 m. Plants used for foraging included a small terrestrial yellow-flowered Guzmania gracilior (Bromelia¬ ceae) with six feeding visits; a larger, green-and- pink-flowered epiphytic G. garciaensis (4 feeding visits); the epiphytic, fuchsia-flowered Elleanthus ampliflorus (Orchidaceae) (1 visit); an unidenti¬ fied small epiphytic bromeliad (1 visit); the stunted tree Macrocarpaea harlingii (Gentiana¬ ceae) was visited nine times; an epiphytic Cavendishia spp. and a shrub Macleania spp. (both pink-flowered Ericaceae) were visited six and three times, respectively. Feeding heights ranged from 0 to 2.5 m. H. regalis fed by hovering on most feeding visits (94%, n = 34), but perched on a nearby twig at three of 10 flowers probed during a single visit to a ground-living small bromeliad. It perched on the ground at one of five flowers probed during another visit to a ground bromeliad. A single male was observed to return to the same flowering plants at 8-15 min intervals, following a somewhat similar route. It first visited a 3-m tall Macrocarpaea harlingii where it fed on several individual flowers (but not on the same flowers during consecutive visits), and then moved either to another Macrocarpaea or to an epiphytic Guzmania garciaensis , both ~5 m from the first Macrocarpaea. Subsequently, it visited a cluster of 1 0 ground G. gracilior , and left the area in the same direction from which it arrived. Another individual male was observed making regular visits to a patch of small G. gracilior and a patch of Macleania spp. shrub, returning to a perch of 2 m height. Social Interactions.— Few interactions with other hummingbirds were observed. One male H. regalis was observed displacing, but not directly attacking or chasing, a male Ecuadorian Piedtail ( Phlogophilus hemileucurus) at feeding sites (in ridgetop shrubland above Yankuam), and a male attacked and chased a male Green-fronted Lancebill (Doryfera ludovicae) when it hovered in front of ericaceous flowers in the same site; minutes later a D. ludovicae returned and hovered 88 THE WILSON JOURNAL OF ORNITHOLOGY • Vol. 123, No. 1, March 2011 in front of the same flowers without being displaced. No other aggressive behaviors were reported although other hummingbird species occurred in feeding areas used by H. re galls. No interactions were observed in lower elevation forests above Yankuam (below 1,700 m). Intense disputes were observed among Brown Violetears ( Colibri del- phinae ), Rufous- vented Whitetips ( Urosticte rufi- crissa ), Violet-fronted Brilliants ( Heliodoxa lead- beateri), and Blue-fronted Lancebill (D. johannae) at flowering forest trees and epiphytes, but no H. re galls was observed in those interactions. The only female found above Miazi was observed displacing an unidentified hummingbird and perching upright, with her neck stretched, possi¬ bly in territorial dispute. Vocalizations. — We heard and tape recorded several types of vocalization. A tame and curious male approached one observer (J. F. Freile) and remained perched motionless for 1 min. He uttered a sharp, high-pitched, fast chichup chup! before take off with the last note more emphatic. A female in the same area perched in a natural forest gap uttered a thin, high-pitched tzifp! We failed to record both vocalizations. A feeding male uttered an emphatic tchup or chip! every 3.5-6 sec (deposited at www.xenocanto. org; XC 45910; Fig. 2A1), whereas other feeding calls were uttered at shorter intervals (2-2.5 sec), or in short two- to three-notes descending series tchup- tchup , tch Up -tchup -tchup with the first note higher (XC 459 1 1 ; Fig. 2A2). The duration of each note was -0.1 sec for the feeding call (Fig. 2A2), while frequency ranged from 1.5-1. 8 to 17-19 kHz (call 2A1), and 1.5 to 21 kHz (call 2A2). Two displaying males produced a fast chattered series of very high tEEp or jeet notes lasting 2.5— 4.5 sec (XC 45912; Fig. 2B). This vocalization contained 19 notes of 0.10— sec mean duration (0.07-0. 1 5 sec) with frequencies ranging from l .7 to 16.69 kHz. Two males were observed in stunted shrubland and heard in intense dispute, constantly vocalizing an endless, thin, high- pitched jumble jijijit’ jijit’ jijit’ jijiji. . . , notes uttered at a much faster rate than regular vocalizations. This dispute and chatter was only interrupted when a third male dashed towards them. Our recordings are uploaded to www.xentocanto.org ^XC 45910-45915) as only a single recording of H. regalls is currently deposited in a public audio library (Macaulay Library 18046; N. Krabbe, pers. comm.). Display Flight. — Three males were observed performing display flights in ridgetop stunted shrubland, one above a nectar source ( Macro - carpaea harlingii) and two above a shrub edge and rocky outcrop. In display, one male ascended ~5 m in vertical flight, described one oval, possibly two, at the highest point and descended describing a semicircle to the same perch; the second male followed the first’s display flight constantly vocalizing (Fig. 3A). A somewhat similar display was also observed with a male ascending 10-12 m and then descending in a semicircle, and diving out of sight (Fig. 3B). DISCUSSION Heliangelus regalis is generally regarded as locally fairly common (Seddon et al. 1996; Schulenberg et al. 2001, 2007; Dauphine et al. 2008). Schulenberg et al. (2001) suggested the Cordillera Azul might represent the center of abundance of H. regalis , and that it might be less threatened than currently believed. However, with a global range of only 2,100 km2, its global population has been roughly estimated at 2,500- 9,999 individuals (BirdLife International 2009). Our observations suggest the abundance of H. regalis can vary across different vegetation types. However, in accordance to previous reports (Fitzpatrick et al. 1979, Davis 1986, Seddon et al. 1996, Dauphine et al. 2008), stunted shrubland appears as its preferred habitat, at least judging from relative abundances at the three vegetation types surveyed in this study. Higher numbers in stunted shrubland and paramo-like vegetation suggest these habitats provided plentiful food resources during the study season. Low detection in dense lower montane and foothill forests might also account for lower numbers in these forests (Poulsen et al. 1997). We cannot Rile out seasonal movements along vegetation gradients as previ¬ ously suggested by Seddon et al. (1996). Habitat suitability appears to be higher for stunted shrub- land, but defining optimal habitats solely based on relative abundance has proven to be misleading (van Home 1983, Morris 1987). H. regalis in stunted shrubland likely fed on most available nectar sources. Flowering was limited to a few individual plants of a few species. Our data suggest that H. regalis was not strongly dependent on one food plant species as found in the type locality, where the species was reported as highly dependent on Brachvotum quinquenerve (Melastomataceae) (Fitzpatrick et al. 1979); it Freile et al. • NATURAL HISTORY OF THE ROYAL SUNANGEL 89 (B) FIG- 2. Spectrograms of three vocalization of male Royal Sunangel ( Heliangelus regalis) in ridgetop habitats in the Nangaritza Valley of southeast Ecuador. A1 and A2 = feeding calls; B = aerial displaying calls. Tape-recordings by Paolo Piedrahita and Juan F. Freile filed at www.xenocanto.org, XC 45910-45912; figures by Paolo Piedrahita. should be noted that B. quinquinerve was absent from our study area. Dauphine et al. (2008) also reported few food plants, but failed to identify frem to the species level and provided no lnformation on flowering at their study site. Males and females, as previous authors (Seddon et al. 1996, Dauphine et al. 2008) have suggested, might feed at different elevations or different food plants; a suggestion we failed to prove as we observed few females. 90 THE WILSON JOURNAL OF ORNITHOLOGY • Vol. 123, No. 1, March 2011 A Fanned-tail FIG. 3. Flight displays performed by male Royal Sunangel ( Heliangelus regalis ) at ridgetop shrubland in the Nangantza Valley of southeast Ecuador. 3A has two males in successive flights (illustration by Juan F. Freile); 3B has a single displaying male (illustration by Galo Buitron-Jurado). Fitzpatrick et al. (1979) and Seddon et al. (1996) reported perching to be a more common foraging method than hovering, in contrast to our observations. We suggest these discrepancies indicate local or seasonal differences in feeding strategies, considering that Seddon et al. (1996) performed more prolonged observations (45 observations of males, 44 of females). Observations were limited to 6 hrs in stunted shrubland and ‘paramo’, but we suspect H. regalis followed regular feeding routes in fairly regular time periods within a fixed territory. Two events ol territorial defense were observed which, in accordance to previous observations (Fitzpatrick et al. 1979, Seddon et al. 1996), suggest territoriality (Feinsinger and Colwell 1978). Other Heliangelus species are also reported to be territorial (Ortiz-Crespo 2003). Vocalizations are generally similar to those previously described (Schulenberg et al. 2007), but displaying notes were uttered in fast chattered series, contrary to the high teep note described by Schulenberg et al. (2007). The dispute calls we report are similar to a series of tick notes described by Fitzpatrick et al. (1979) in male- male chases. To our ears, they appear harsher, more metallic, and more chattered than those described by Fitzpatrick et al. (1979). Displays differed from those observed at the type locality (Fitzpatrick et al. 1979) as we did not observe birds repeating the circular flight towards the opposite side of perches in a figure-8 pattern. More detailed observations are needed to eluci¬ date if display flights differ locally. H. regalis is apparently fairly numerous in stunted ridgetop shrubland and paramo-like hab¬ itats at Las Orqufdeas sandstone ridges. At least live different birds were found (one female, four males) in a small sampled area at the ridgetop (~ 0.02 km2; i.e., 500-m linear transect with a 40- m width band), suggesting a healthy population. These observations provide a rough estimate of 250 individuals/km2 in the stunted ridgetop shrubland habitat that H. regalis seemingly preferred during our study. An estimate of the area covered by this forest type (Fig. 1) resulted in 1 0. 1 1 knr of the habitat where H. regalis was most abundant in the Nangaritza Valley. This Freile et al • NATURAL HiSTORY OF THE ROYAL SUNANGEL 91 suggests the total population in the Ecuadorian portion of H. regalis range might total —2,500 individuals. These numbers are crude as better population size estimates and trends are needed. H. regalis is seemingly less numerous in lower elevation montane and foothill forests above Yankuam Lodge. Only three males and one female were observed during 7 days of point- count surveys above Yankuam, in dense foothill and dense lower montane forests, despite a total of 25 10-min point counts. H. regalis was not found in similar habitats above Miazi during 21 10-min point counts, but one female was observed by random sampling on a small ridgetop. We sampled ~2-3 km between both study sites. This might indicate 1-1.5 birds/km in these two forest types, but dense habitat might reduce detection. CONSERVATION IMPLICATIONS Habitat loss is still incipient along the Ecua¬ dorian range of the species, but mining conces¬ sions represent a serious forthcoming threat to the endemic biodiversity of the Cordillera del Condor. There is major interest by the Ecuadorian government to consolidate mining extraction in the Cordillera del Condor region because of apparently large deposits of gold and copper, as well as silver, silica, and other minerals and metals (Lopez et al. 2003, Fontbote et al. 2004, Neill 2007, Drobe et al. 2008; see also www. aurelianecuador.com; www.corriente.com; www. kinross.com). Currently, several areas north of Nangaritza Valley are being prospected by mining companies, and access roads are being rapidly opened and improved. Populations of species confined to these poor-soil growing forests are wiminently threatened as large sandstone ridges will potentially be opened to large-scale mining. Under this scenario, we consider accurate the status of globally Endangered (BirdLife Interna¬ tional 2009) for H. regalis despite current popu¬ lation figures suggesting it is less threatened. Conservation initiatives are underway in the Nangaritza Valley, including private birdwatching tour operators, land protection, and an ongoing Management plan developed by Fundacion Arco Ins of Loja along with local communities. These initiatives benefit from biodiversity surveys that support the biological and hydrological impor¬ tance of the Nangaritza Valley. We encourage others to undertake more specific studies in the region, particularly to assess populations and habitat of globally threatened species including H. regalis. Easy access to the Nangaritza sandstone ridges facilitate biological surveys and bird studies of an avifauna generally regarded as difficult to reach. ACKNOWLEDGMENTS Field work was part of a Rapid Assessment Program by Fundacion Arco Iris of Loja, and supported by Conserva¬ tion International. We especially thank Robert Jimenez for diligent assistance in field work. Oswaldo Jadan thanks Zhofre Aguirre and Bolivar Merino of Herbario LOJA, Jose M. Manzanares, Charlotte Taylor, and Ron Liesner of Missouri Botanical Garden, and Alfonso Garmendia of Universidad Politecnica de Valencia for assistance in plant identification. Niels Krabbe made thorough comments on the manuscript, T. S. Schulenberg provided information from Peru, and Alejandro Solano and Daniel Cadena kindly helped with bibliographic requests. We thank Leonardo Ordonez and Fundacion Arco Iris staff for logistics and issuing plant research permits. This research was conducted under Ministerio del Ambiente research permits Numbers 006-IC-FLO-DBAP-VS-DRLZCH-MA and FAU-001-DNB/VS. Fieldwork by Galo Buitron, Paolo Piedrahita, and Elisa Bonaccorso was supported by Secretarfa Nacional de Ciencia y Tecnologfa (SENACYT) Project PIC-08-470. Comments by three anonymous reviewers greatly improved a previous version of this paper. Juan F. Freile dedicates this paper to the dearly loved memory of Tam i Bueno. LITERATURE CITED BirdLife International. 2009. 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Conservation International RAP Working Papers 7. Washington, D.C., USA. Poulsen, B. O., N. Krabbe, A. Frolander, M. B. Hinojosa, and C. O. Quiroga. 1997. A rapid assessment of Bolivian and Ecuadorian montane avifaunas using 20-species lists: efficiency, biases and data gathered. Bird Conservation International 7: 53-67. Schulenberg, T. S., J. P. O’Neill, D. F. Lane, T. Valqui. and C. Albujar. 2001. Aves. Pages 75-84 in Peru. Biabo-Cordillera Azul (W. S. Alverson, L. 0. Rodriguez, and D. K. Moskovits, Editors). The Field Museum Rapid Biological Inventories 2. Chicago, Illinois, USA. Schulenberg, T. S., D. F. Stotz, D. F. Lane, J. P O’Neill, and T. A. Parker III. 2007. Birds of Peru. Christopher Helm, London, United Kingdom. Seddon, N„ R. Barnes, S. H. M. Butchart, C. W. N. Davies, and M. Fernandez. 1996. Recent observa¬ tions and notes on the ecology of the Royal Sunangel Heliangelus regalis. Bulletin of the British Ornithol¬ ogists Club 116: 46-49. Sierra, R. 1999. Vegetation remanente del Ecuador con¬ tinental, circa 1996. 1:1,000.000. Proyecto INEFAN/ GEF-BIRF and Wildlife Conservation Society, Quito, Ecuador. Stattersfield, A. J., M. J. Crosby, A. J. Long, and D. C, Wege. 1998. Endemic birds areas of the world. Priorities for biodiversity conservation. BirdLife International, Cambridge, United Kingdom. van Horne, B. 1983. Density as a misleading indicator of habitat quality. Journal of Wildlife Management 47: 893-901. The Wilson Journal of Ornithology 123( 1 ):93— 96, 201 1 NESTING BEHAVIOR OF SZECHENYI’S MONAL-PARTRIDGE IN TREELINE HABITATS, PAMULING MOUNTAINS, CHINA KAI ZHANG,1 NAN YANG,1 YU XU,1 JIANGHONG RAN,1-3 HUW LLOYD,3 AND BISONG YUE1 ABSTRACT— We report nesting behavior of Szechenyi’s Monal-Partridge ( Tetraophasis szechenyii) in treeline habitats of the Pamuling Mountains, Sichuan Province, China. Szechenyi’s Monal-Partridge used both ground and tree nests. Ground nests were scrapes in the soil, positioned at the base of a tree or scrub, and occurred in all habitats except Sichuan kobresia ( Kobresia setchwanensis) meadow. Tree nests were cup shaped and placed 1.9-12.0 m above ground level, distributed proportionally in all habitats except scrub hollyleaf-like oak ( Quercus aquifolioides ) and Sichuan kobresia meadow habitats. The proportion of nest types between first and re-nesting attempts did not vary significantly. Only 54% of ground nests and 33% of tree nests survived until hatching with predation being the principal cause ol ground nest failure. Hatching success was 97%. We recorded six re-nesting attempts, four of which were tree nests, but all were unsuccessful. Preserving a mosaic of treeline habitats that include ground vegetation, and fir/oak woodland habitat will be essential for maintaining suitable nesting habitats for Szechenyi’s Monal-Partridge in the Pamuling Mountains. Received 4 March 2010. Accepted 14 August 2010. Most Galliformes are typically ground-nesting species. Two exceptions to this general rule have been discovered among Tragopan and Tetraophasis (Li 1996). Species of Tragopan typically nest above the ground in trees (Johnsgard 1 999, Deng et al. 2005), whereby members of Tetraophasis use two types of nests, either on the ground or at some height in trees (Lu and Lu 1991, Wu et al. 1994). Few data exist regarding many aspects of the breeding ecology of members of the genus Tetra¬ ophasis (Lu and Lu 1991, Potapov 2002, Y ang et al. 2009). This genus is endemic to China and consists of two species: Verreaux’s Monal-Partridge (T. obscurus), which is largely restricted to rhododen¬ dron ( Rhododendron spp.) scrub and alpine mead¬ ows in west central China, and Szechenyi’s Monal- Partridge (T. szechenyii) which occurs in a number of montane habitats in southwestern China, includ- lng hr {Abies spp.) forests, rhododendron scrub, and alpine meadows (MacKinnon and Phillipps 2000). describe the nesting behavior of Szechenyi’s Monal-Partridge in treeline habitats of the Pamuling Mountains, Sichuan Province, China. METHODS Study Area— Our study was conducted over a 4- Year Period in the Pamuling Mountains (30° 06' N, IP E), Yajiang County, Ganzi Tibetan College of Life Sciences, Sichuan University, Chengdu, 6 1 0064, China. World Pheasant Association, Close House Estate, eddon on the Wall, Newcastle upon Tyne, NE15 0HT, UK. Corresponding author; e-mail: rjhong-01@163.com Autonomous Prefecture, Sichuan Province, China. The study area ranges in elevation from 3,900 to 4,200 m and is dominated by a variety of different habitat types. The most dominant habitat type is hollyleaf-like oak ( Quercus aquifolioides) forest (covering ~50% of the study area), distributed along the southern-most slopes of the region. This forest eventually grades into scrub along the western slopes, accounting for 9% of the study area. Flaky fir (Abies squamata) and Masters larch ( Larix mastersiana) coniferous forest (covering 39% of the study area) is the second most widespread habitat. Violet-purple rhododendron ( Rhododendron nitidulum) scrub (covering 1 1% of the study area) is the third most widespread habitat, while Sichuan kobresia ( Kobresia setchwanensis) meadow makes up a smaller proportion (~1%) of the Pamuling Mountains treeline habitats (Xu et al. 2008). Nest Surveys.— We searched for nests from April to June 2006, between March and May in 2007 and 2008, August 2008, and also between March and June 2009. Nests were found by locating nesting birds ( n = 8) previously captured by drop-netting and fitted with radio transmitters (19-g necklace-type, Holohil Systems Ltd., Carp, ON, Canada), and by systematically searching suitable areas of habitats. Each nest was checked regularly at intervals of 1-2 days. Each covey (consisting of a mixed group of I adult breeding pair, up to 3 helpers of either gender and a single brood) from all located nests was observed after incubation to assess chick survival and to monitor any subsequent nesting attempt. Nests discovered either early in the breeding season or in the middle of the season with > three eggs were categorized as 93 94 THE WILSON JOURNAL OF ORNITHOLOGY • Vol. 123, No. 1, March 2011 first nests, whereas those found with < three eggs, or nests found late in the season were categorized as re-nesting attempts (Yang et al. 2009; KZ, unpubl. data). We recorded the following variables for each nest: breeding group composition (breed¬ ing pairs and helpers), nesting attempt, nest type (either ground or tree nest), nest characteristics (structure and material), nest contents, nest tree (scrub) species, and habitat characteristics (habitat type, canopy cover, and scrub cover). Canopy cover and scrub cover were measured within a 10-m diameter plot around each nest. Statistical Analyses. — Analyses were conducted using SPSS Version 13.0 (SPSS Institute 2004). We included only the first nesting attempt by each female in the subsequent analyses to avoid pseudo-replication, and analyzed the few re¬ nesting attempts separately. Chi-square test of independence was used to compare the proportion of nest types between nesting attempts. Data corresponding to re-nesting attempts were exclud¬ ed from the analysis. We also used Chi-square Goodness of Fit tests to examine tree nest site preferences among habitat types. Mann- Whitney U-tests were used to detect differences between ground and tree nests. Statistical tests were two- tailed and P < 0.05 was interpreted as being statistically significant. Mean ± SD values are presented. We combined all egg measurement data from ground and tree nests as they did not differ (Z= - 1.824, P = 0.068; Z = -1.178, P = 0.24, for egg length and width, respectively). RESULTS Nest Surveys. Sixty-eight breeding groups were detected over the four consecutive breeding seasons (18 in 2006, 16 in 2007, 17 in 2008, and 17 in 2009). Szechenyi’s Monal-Partridge in the Pamuling Mountains treeline habitats constructed nests either on the ground or in trees. Fifteen ground nests (all active; 68% of total active nests) and 63 tree nests (56 used and 7 active; 32% of total active nests) were found during the study period. Thirteen ground nests were first nests and two were re-nesting attempts. Three active tree nests were first nests while the remaining four were classified as re-nesting attempts. No third nesting attempts were identified. Tree nests were more common in re-nesting attempts than in first nests (50 and 17%, respectively), but the difference was not significant (Fisher’s exact test, P = 0.40). Nest Characteristics and Nest-site Selection .— Ground nests ( n = 15) were scrapes in the soil and lined with leaves, sticks, and bark, usually positioned at the base of a tree or scrub (Fig. 1A). They occurred in all habitats except Sichuan kobresia meadow, and had lower canopy vegeta¬ tion cover (13 ± 14%, range = 0-40%, n = 13) when compared with tree nest sites (30 ± 17%, range = 20-50%, n = 3); this difference was not significant (Z = — 1 .835, P = 0.066). Tree nests (// = 63) were cup shaped (Fig. IB) and constructed of moss, lichen, and feathers although some nests also contained fragments of man-made cloth. They were positioned 1.9-12.0 m above ground level either at the base of the tree branches and adjacent to the main trunk in coniferous forest and rhododendron scrub, or at the top of trees in oak forest. Tree species used included Abies squamata (61%), Quercus aquifolioides (31%), and Larix potaninii (8%). No tree nests were found within either the scrub holly leaf-like oak habitat or Sichuan kobresia meadow; they were distributed proportionally among the three remaining habitat types (x2 = 0.194, df = 2, P = 0.91, n = 56). Eggs and Nesting Success. — Eggs (n = 46) were pinkish brown with fine, well-dispersed burgundy-colored spots, and measured 53.8 ± 2.6 mm (range = 47-59 mm) X 37.4 ± 1.9 mm (range = 33-42 mm). Only 54% (n = 7) of ground nests survived until hatching, compared with 33% (n = 1) of tree nests. The principal cause of ground nest failure was predation which accounted tor 50% of all failed nests, while severe weather conditions (33%), and human disturbance (17%) accounted for the remaining nest failures. Hatching success was 97% (n = 31 eggs from 8 nests). Twelve chicks (n = 21 from 7 ground nests) survived to fledge, while three chicks from the one tree nest failed to survive. Changes in Nest Location and Nest Type.— We documented re-nesting attempts on six occasions during the 4-year period. There were two occasions where only re-nests were detected: one was a ground nest in 2008, and the other was a tree nest in 2009. We documented the nest location and nest type for both nesting attempts on the other four occasions. On two occasions (once each in 2008 and 2009), females re-nested in the same nest types. One female reused the tree nest after the chicks from first nest failed to survive, the other female changed ground nest location in a i e-nesting attempt following nest predation. Females switched nest locations and nest types from ground to tree nests on the other two occasions (once each in 2007 and 2009) following Zhang et al. • NESTING OF SZECHENYI’S MONAL-PARTRIDGE 95 FIG. 1. (A) Ground nest of Szechenyi’s Monal-Partridge at the base of scrub hollyleaf-like oak, and (B) tree nest in flaky fir. failure of first nests due to extreme weather conditions. One female abandoned a ground nest in violet-purple rhododendron scrub and built a new nest in flaky fir forest, —190 m from the °riginal nest. The other female abandoned a ground nest in hollyleaf-like oak forest and used a tree nest in the same habitat from a previous season, ~300 m from the original nest. Both re¬ nests were also unsuccessful because of predation (either by corvids or mammals). DISCUSSION Elevated nests have been reported for several species of Galliformes, e.g., Green Junglefowl (Gallus varius ), Salvadori’s Pheasant ( Lophura ln°mato), Ring-necked Pheasant ( Phasianus colchi- cus)’ Palawan Peacock-Pheasant ( Polyplectron na- Poleonis), Congo Peacock ( Afropavo con gens is), and Mikado Pheasant ( Syrmaticus mikado ) (Johnsgard 1999). The elevated nest is a variation rather than a distinct shift from the ground nest. Two female Szechenyi’s Monal-Partridges in the Pamuling Mountains changed nest locations and nest types from the ground to tree nests. Similar tree nest observations have been noted with Cabot’s Tragopan ( Tragopan cabotii) but, unlike this species, all arboreal tree nesting by Szechenyi’s Monal-Partridge did not rely on use of pre-existing nest structures for nest construction, such as natural platforms or nests from other species or taxa (Deng et al. 2005), but included collection of new nesting material for the construction of a completely new nest. Most Szechenyi’s Monal-Partridges in the Pa¬ muling Mountains were ground nesting, but some also nested in trees. The tree nest use pattern by Szechenyi’s Monal-Partridge reflected the propor¬ tion of available treeline habitat types in the region. We would expect ground nesting would be more 96 THE WILSON JOURNAL OF ORNITHOLOGY • Vol. 123, No. 1, March 2011 common in low-lying violet-purple rhododendron scrub and scrub hollyleaf-like oak habitat, as few tall trees are available in these habitat types. Tree nests were not as successful as expected in our study, probably due to small sample sizes. Re-nesting attempts and changes in nest locations or habitats between nesting attempts following nest failure have been documented for several species of Galliformes including Willow Ptarmigan ( Lagopus lagopus) (Parker 1981), Wild Turkey ( Meleagris gallopavo ) (Badyaev et al. 1996), Black Grouse ( Lyrurus tetrix) (Marjakan- gas et al. 1997), and Chukar ( Alectoris chukar ) (Lindbloom et al. 2003). Re-nesting in Galli¬ formes was initially thought to be rare (Patterson 1952), but research has shown that re-nesting rates can exceed 40% for some species (e.g., Petersen 1980, Bergerud 1988). Changes in nest locations following nest predation might be a response to avoid revisiting by the predator (O’Reilly and Hannon 1989, Marjakangas et al. 1997). We suspect that unpredictable and severe weather conditions in our study may also be involved. Further systematic nest studies with large sample sizes are needed to identify the relationship between the probability of changing to a different nest location or nest type and causes of previous nest failure. The benefits of switching nest location and nest type for Szechenyi’s Monal- Partridge remain unknown as our sample sizes were too small and all re-nesting attempts also tailed. What is apparent from our observations however is the importance of preserving a mosaic ot treeline habitats that include ground vegetation, and fir/oak woodland habitat to maintain suitable nesting habitats for the Szechenyi’s Monal- Partridge in the Pamuling Mountains. AC KNO WLEDGMENTS We received support from the Forestry Bureau of ajiang County and the Pamuling Monastery throughout the study period. Ying Wang provided radio transmitters and color nng* P. J. Que and P. F. Yu helped collect data in he field, and D. Q. Li, B. B. Du, and Rui Guo assisted with laboratory work. Emily King and J. j. Liang corrected the English writing. Stephen Browne, C. E. Braun, and two anonymous reviewers greatly improved the manuscript. We thank all of these organizations and persons. LITERATURE CITED Badyaev, A. V., T. E. Martin, and W. J. Etges. 1996. Habitat sampling and habitat selection by female Wild Turkeys: ecological correlates and reproductive con¬ sequences. Auk 113:636-646. Bergerud, A. T. 1988. Population ecology of North American grouse. Pages 578-648 in Adaptive strate¬ gies and population ecology of northern grouse (A. T, Bergerud and M. W. Gratson, Editors). University of Minnesota Press, Minneapolis, USA. Deng, W. H., G. M. Zheng, Z. W. Zhang, P. J. Garson. and P. J. K. McGowan. 2005. Providing artificial nest platforms for Cabot’s Tragopan Tragopan caboti (Aves: Galliformes): a useful conservation tool? Oryx 39:1-6, Johnsgard, P. A. 1999. Pheasants of the world: biology and natural history. Second Edition. Smithsonian Institution Press, Washington, D.C., USA. Li, X. T. 1996. The gamebirds of China: their distribution and status. International Academic Publishers. Beijing, China. Lindbloom, A. J., K. P. Reese, and P. Zager. 2003. Nesting and brood-rearing characteristics of Chukars in west central Idaho. Western North American Naturalist 63:429-439. Lu, T. C. AND C. L. Lu. 1991. Pheasant Grouse. Pages 140- 145 in The rare and endangered gamebirds in China (T. C. Lu, Editor). Fujian Science and Technology Press, Fuzhou, China. Mackinnon, J. and K. Phillipps. 2000. A field guide to the birds of China. Oxford University Press, Oxford. United Kingdom. Marjakangas, A., P. Valkeajarvi, and L. Ijas. 1997. Female Black Grouse Tetrao tetrix shift nest site after nest loss. Journal of Ornithology 138:111-116. O’Reilly, P. and S. J. Hannon. 1989. Predation of simulated Willow Ptarmigan nests: the influence of density and cover on spatial and temporal patterns of predation. Canadian Journal of Zoology 67:1263-1267. Parker, H. 1981. Renesting biology of Norwegian Willow Ptarmigan. Journal of Wildlife Management 45:858-864. Patterson, R. L. 1952. The Sage Grouse in Wyoming Sage Books, Denver, Colorado, USA. Petersen, B. E. 1980. Breeding and nesting ecology of female Sage Grouse in North Park, Colorado. Thesis. Colorado State University, Fort Collins, USA. Potapov, R. L. 2002. Distribution, biology and phylogeny of genus Tetraophasis (Elliot, 1872). Russian Journal of Ornithology 11:1051-1066. SPSS Institute. 2004. SPSS for Windows, Version 13.0. SPSS Institute Inc., Chicago, Illinois, USA. Wu, Y., J. T. Peng, and H. Gao. 1994. Study on breeding ecology of the Pheasant Grouse. Acta Ecologica Sinica 14:221-222. Xu, Y., J. H. Ran, X. Zhou, N. Yang, B. S. Yue, and Y. Wang. 2008. The effect of temperature and other factors on roosting times of Szechenyi Monal Partridges Tetraophasis szechenyii during the breeding season. Omis Fennica 85:126-134. Yang, N„ Y . Xu, J. H. Ran, K. Zhang, B. S. Yue, and B. J. Li. 2009. Notes on the breeding habits of the Buff- throated Partridge. Chinese Journal of Zoology 44:48- The Wilson Journal of Ornithology 123(1 ):97 — 1 01, 2011 REPRODUCTIVE STATUS OF SWALLOW-TAILED KITES IN EAST- CENTRAL ARKANSAS SCOTT J. CHIAVACCI,1-3'6 TROY J. BADER,1-4 AMY M. ST. PIERRE.1-5 JAMES C. BEDNARZ,1 AND KAREN L. ROWE2 ABSTRACT. — The Swallow-tailed Kite (Elanoides forficatus) formerly bred in Arkansas, but no nesting attempts were observed in the state for over a century. We initiated a study in 2001 to investigate the species’ reproductive status in east- central Arkansas, USA. We located five nests between 2001 and 2009, all of which failed. Two nests were abandoned (one due to researcher caused disturbance), one failure was likely caused by a Red-shouldered Hawk (Buteo lineatus ) or Barred Owl (Strix varia), one was suspected to be caused by a rat snake ( Elaphe obsolete), and one failed from unknown causes. Nests were built in overcup ( Quercus lyrata) and Nuttall oaks (Q. texana) with a mean (± SD) diameter at breast height of 83.92 ± 7.20 cm, mean tree height of 31.28 ± 4.78 m, and mean projection of 7.15 ± 5.66 m above surrounding trees. Nests were at a mean height of 25.09 ± 4.85 m and positioned 0.30 ± 2.36 m above the surrounding trees. All nests were within a circular area 4 km in diameter. Our discovery of a nest in 2002 represented the first documented case of nesting Swallow-tailed Kites in Arkansas in >100 years and is a considerable (370 km) distance from the closest known nesting site in Louisiana. Received 3 May 2010. Accepted 11 October 2010. The Swallow-tailed Kite ( Elanoides forficatus ) formerly bred in at least 16 states from Florida and the Southeast Coastal Plain west to central Texas and north through the Mississippi and Ohio river drainages to Minnesota (Meyer and Collopy 1995). The population experienced a drastic reduction in numbers around the turn of the I9lh century (Cely 1979) and now breeds in portions of only seven southeastern states (Meyer 2004a). Loss of suitable habitat following destruction of bottomland hardwood forests (Twedt and Loesch 1999), agricultural development, and shooting were likely the primary reasons for the wide¬ spread decline (Cely 1979, Meyer 1995, Meyer and Collopy 1995). Observations of Swallow- tailed Kites increased in former breeding areas in the 1940s (Cely 1979), suggesting small scale ^occupation of historical range (Brown et al. 1997). However, reasons for this kite’s inability to lully reoccupy its former range mostly remain unknown (Meyer and Collopy 1995). Swallow-tailed Kites were considered relatively abundant in Arkansas lowlands at the end of the 19 century, but became rare by 1910 with the last Department of Biological Sciences, P. O. Box 599, Kansas State University, Jonesboro, AR 72401, USA. Arkansas Game and Fish Commission, 31 Hallowell Lane, Humphrey, AR 72073, USA. Current address: Illinois Natural History Survey, 1816 ^ h °ak Street, Champaign, IL 61820, USA. Current address: USDA-ARS, Stuttgart National Aqua- ^hure Research Center, P. O. Box 1050, Stuttgart, AR 721 60, USA. ^Current address: P. O. Box 27, Kelly, WY 83011, USA. Corresponding author; e-mail: schiavacci@gmail.com known nesting attempt occurring in 1890 (Howell 1 9 1 1 ). A sighting of a single kite occurred in north¬ west Arkansas in October 1913 (Smith 1915), and from 1915 to 1986, only two secondhand accounts of kites were reported; one in 1935 and a pair of kites observed on 10 July 1949 (Baerg 1951). A subsequent lack of repoits suggests the species may have been extiipated from Arkansas in the late 1940s (James and Neal 1986). Four sporadic observations of Swallow-tailed Kites during mi¬ gration occurred between 1986 and 1997, but it was not until 1998 that a pair was observed during the breeding season. Observations in 1998 oc¬ curred in the White River National Wildlife Refuge (WRNWR) and, based on these reports, we initiated a study to investigate the breeding status of Swallow-tailed Kites in the refuge. Our objectives were to: (1) document Swallow-tailed Kites present during the breeding season in the White River National Wildlife Refuge and (2) locate, monitor, and record nesting attempts. METHODS Study Area. — The White River National Wild¬ life Refuge, in east-central Arkansas (34° 22' N to 34° 39' N, 90° 59' W to 91° 22' W) comprises —64,700 ha and is one of the largest remnants of contiguous bottomland hardwood forest in the Mississippi Alluvial Valley. It consists primarily of bottomland hardwood forest with small sec¬ tions of upland hardwood forest, scattered fallow and agricultural fields, 356 natural and man-made lakes, >140 km of the White River, and a large number of bayous and sloughs. Dominant tree species include overcup oak ( Quercus lyrata ), 97 98 THE WILSON JOURNAL OF ORNITHOLOGY • Vol. 123, No. 1 , March 2011 TABLE 1. Dates of observation and nest discovery, and nest fates of Swallow-tailed Kites in the White River National Wildlife Refuge, Arkansas, USA. Year Obs" Observedb Nest found Stage Date failedc Stage Failure cause 2002 13 1 May-24 May 24 May Building 27 May Building Abandoned 2003 7 12 May-24 Jun 2004 17 24 Apr- 13 Jul 19 May Building 27 May Incubation Unknown 2005 12 8 May-21 Jul 23 May Nestling 28 May Nestling Raptor 2006 11 17 Apr-3 Jun 17 Apr Building 30 Apr Incubation Possibly ratsnake 2007 9 24 Apr-8 Jun 2008 16 9 Apr-6 Aug 15 Apr Building 26 May Nestling Researcher disturbance 2009 8 15 Apr-30 May a Number of observations involving si kite. Inclusive dates for all kite observations. c Failure date was estimated as the middle of visitation intervals (2008 failure date known by reviewing video). Nuttall oak (Q. texana), sugarberry ( Celtis laevigata), green ash ( Fraxinus pennsylvanica ), bald cypress ( Taxodium distichum ), and hickory (Cary a spp.). Field Procedures. — We searched for kites from early April through mid-July 2001 to 2009. Searches in 2001 and 2002 were based on reported observations and suitable habitat, and were broader than later searches, covering several large areas of the refuge and bordering lands (St. Pierre 2006). Searches in subsequent years focused on areas of previous nests and observa¬ tions. We conducted searches from a helicopter in 2002 and 2007 following repeated observations of a pair of kites in a localized area. We checked status and stages of nests by monitoring them every 3 to 7 days using binoculars and a spotting scope at 50-100 m from the nest tree. Nests were considered occupied if a kite was on the nest during >1 nest check and we estimated nesting stage by monitoring adult behavior. We attached snake excluder devices (SNED) (Neal et al. 1998) to trunks of nest trees (none attached in 2002) >1 week after incubation began. SNEDs consisted of a thin sheet of aluminum flashing 90 cm high, camouflaged with paint, attached using staples or screws, and greased as an added preventive measure. We used a specially-designed infrared video recording system from Fuhrman Diversified Inc. (Fieldcam: Field Television System: LDTLV/Box/Versacam/ IR60, Seabrook, TX, USA) in 2008 near a nest when we estimated nestlings to be 7 days of age. We deployed the camera shortly after sunrise to prevent chicks from being exposed to mid-day temperatures. The camera (dimensions: 30 X 22 X 10 cm) was mounted 3 m from the nest on an adjacent limb within the nest tree and was covered with camouflage fabric. We noted vegetation characteristics from nest and paired random sites following the BBIRD protocol (Martin et al. 1997, St. Pierre 2006). Random plots were within 250 m of nest trees and were generated using a random number table. Our data collection at nest and random sites included: height of all overstory trees within an 11.3-m radius circular plot, emergence of nest or plot center trees above surrounding trees, diameter at breast height (DBH) of nest and plot center trees, and distance to nearest forest edge. Nest and tree height, DBH, and plot distance from edge were measured using a clinometer, diameter tape measure, and Global Positioning System (GPS) unit, respectively. We used paired /-tests (SAS Institute 2003) for all statistical comparisons except for non-normal data which we analyzed using Wilcoxon's signed-ranks test. Means ± SD are reported and we considered results significant if P < 0.05. RESULTS We located five nests of Swallow-tailed Kites in the White River National Wildlife Refuge; one each during 2002, 2004, 2005, 2006, and 2008 (Table 1). All nesting attempts failed. We ob¬ served no Swallow-tailed Kites in 2001. We observed a single kite in 2003 and a pair in both 2007 and 2009, but were unable to locate a nest during these years; we failed to observe any fledglings in years we did not locate nests. We found the 2002 nest during a helicopter search ol an area where we made repeated observations ol kites. Upon locating a nest, the helicopter hovered ^50 m from it for <45 sec before leaving the Chiavacci et al • SWALLOW-TAILED KITES IN ARKANSAS 99 FIG. 1. Swallow-tailed Kite nest sites in the White River National Wildlife Refuge, Arkansas, USA, 2001-2009. area. An adult flew from the nest and we observed the nest was completed, but contained no eggs or nestlings. The nest was rechecked several times on a weekly basis from the ground, no adults were present, and we considered it abandoned. We observed an adult on a nest in incubation position in 2004, 6 days after discovering it, but it was unoccupied during the following three nest visits, indicating failure. Nine days after discovering a nest in 2005, we recovered two dead nestlings weeks of age below the nest tree. Both chicks had wounds on their torsos and wings consistent with the talon spread of a Barred Owl (Strix varia) °r Red-shouldered Hawk ( Buteo lineatus). We believe failure of the 2006 nest may have been the result of rat snake ( Elaphe obsoleta) depredation due to the presence of a long, vertical “track” through grease on the SNED and streaks of grease leading down the trunk onto the ground. We installed a camera in 2008 when we estimated nestlings were 1 week of age. Camera installation took ~2 hrs from the time we arrived below the nest tree to the time we left the nest area. The udult kite remained on the nest until we climbed to within 4 m of it. We checked the nest 2 days later, did not see an adult on it and, after reviewing our video data, discovered the adults did not return following camera installation. We climbed to the nest the following day and recovered two dead nestlings. All nests and most observations were within a 4-km area (Fig. 1). The 2004, 2005, 2006, and 2008 nests were 3.4 km, 1 90 m, 270 m, and 1 .6 km from the 2002 nest, respectively. Nests were in Nuttall ( n = 2) and overcup oaks ( n = 3), placed near the tops of trees at a mean (± SD) height of 25.09 ± 4.85 m, and were positioned 0.30 ± 2.36 m above the surrounding canopy. Nest trees had significantly greater DBHs than random trees (Table 2). Nest tree emergence above the sur¬ rounding canopy was greater than that of random trees, but not significantly so (Table 2). DISCUSSION Our documentation of a Swallow-tailed Kite nest in 2002 represents the first observed nesting attempt in Arkansas in >100 years and is a considerable (370 km) distance from the closest known nesting site in Louisiana (St. Pierre 2006). The individuals we observed were unbanded, but 100 THE WILSON JOURNAL OF ORNITHOLOGY • Vol. 123, No. 1, March 201 1 TABLE 2. Characteristics of Swallow-tailed Kite nest ( n = 5) and paired random sites ( n = 5) in the White River National Wildlife Refuge, Arkansas, USA. Nest site Random site Variable Mean ± SD Mean ± SD t df p Tree height, m 31.28 ± 4.78 27.12 ± 6.40 2.56 4 0.125 Diameter at breast height, DBH (cm) 83.92 ± 7.20 49.33 ± 15.09 6.74 4 0.003 Nest tree emergence, ma 7.15 ± 5.66 0.42 ± 4.74 3.01 3b 0.057 Distance to nearest edge, m 498.1 ± 56.5 451.9 ± 185.8 0.73 4 0.508 Wilcoxon’s signed-ranks test used for analysis. Nest tree emergence data not collected in 2006. the strong nest site fidelity of the species (Meyer 1995) indicates that reuse of a relatively small area (4 km) for nesting in the refuge suggests at least one individual from the nesting pair observed in 2002 may have returned to nest in subsequent years. The repeated use of this area indicates the existence of suitable nesting habitat. The most important characteristics within the Swallow-tailed Kite’s breeding range are exis¬ tence of tall, accessible trees and open areas that facilitate prey capture (Meyer 1995). Many relatively tall trees exist throughout the refuge and, although not quantified in this study, the many bayous, sloughs, lakes, and ponds in the refuge likely provide ample openings for prey acquisition. Similar to our results, kites nesting in South Carolina and Florida placed nests near the tops of trees that projected above the surrounding canopy (Cely and Sorrow 1990. Meyer and Collopy 1995, Meyer 2004a). Kites in Arkansas selected nest trees with significantly greater DBHs than those of random trees, which may all oid kites stronger nest supporting limbs decreasing the likelihood of failure during high winds, a common cause of failure in south Florida (Meyer and Collopy 1995, Meyer 2004a). Cely and Sorrow (1990) noted the variability in tolerance of Swallow-tailed Kites to human disturbances near nests, but indicated most kites appeared unaffected by observer presence early in the nesting cycle. In contrast, the kites we monitored appeared to be sensitive to disturbance near the nest. Helicopters have been used in Florida to search for and monitor kite nests without any negative effects (Meyer and Collopy 1995, Meyer 2004a, b). We cannot discount the possibility that our helicopter search may have caused abandonment in 2002. The pair may have been more prone to disturbance-associated nest abandonment due to the lack of parental invest¬ ment (i.e., no eggs or young), or the relatively late initiation of the nesting attempt. It is also possible the nest may have been constructed and not used (Meyer 1 995) or was depredated during the week following its discovery when no nest checks occurred. We observed no fledglings despite repeated searches throughout the breeding and post¬ breeding periods during years when no nests were located. We installed a camera at the nest in 2008 to record nesting activity and causes of failure, because all previously located nests and presum¬ ably all undocumented nesting attempts failed. We delayed camera installation until 1 week into the nestling stage to reduce the likelihood of abandonment; the only case of camera-related abandonment was reported by Meyer in Coulson et al. (2008) and occurred during incubation. We believe the camera and not necessarily our climbing to the nest was the reason for abandon¬ ment, as we observed two adults flying within 100 m of the nest during camera removal, suggesting they remained in the nest area. We did not monitor the kites’ response to the camera, as we left the area immediately following setup to avoid further disturbing the pair. Had we checked the nest sooner and noticed the kites not returning, we could have removed the system and possibly prevented abandonment. Our experiences, and those reported by Meyer in Coulson et al. (2008) indicate that some nesting Swallow-tailed Kites may be particularly sensitive to disturbances associated with camera systems, especially during incubation and the early nestling stage. Observations of Swallow- tailed Kites have in¬ creased in parts of Arkansas in recent years, which may represent increased visitation by dispersing and migrating kites, or increased effort by observers. Monitoring of kites observed during the breeding season should be undertaken to ascertain if kites are Chiavacci et al. • SWALLOW-TAILED KITES IN ARKANSAS 101 nesting outside of the White River National Wildlife Refuge, as this is the only area in the state surveyed thoroughly for breeding individuals. In addition, we recommend Arkansas develop a survey and moni¬ toring program similar to that developed in Texas (Shackelford and Simons 2000) to ascertain the species’ status throughout Arkansas. ACKNOWLEDGMENTS The Arkansas Game and Fish Commission and U.S. Fish and Wildlife Service, through a State Wildlife Grant, and the Arkansas Audubon Society Trust funded portions of this project. We are grateful for support by R. E. Hines and the WRNWR staff. J. E. Cely, J. O. Coulson, K. D. Meyer, and B. A. Millsap provided valuable information and insight throughout this project. Comments by N. M. Anich, J. O. Coulson, E. T. Macchia. and P. W. Sykes Jr. improved earlier versions of this manuscript. We thank Bradley Bawden, Brian Cannon. N. L. Chiavacci, W. D. Edwards, J. L. Everitts, Brian Gill, Y. R. Mensing-Solick, W. D. Reed, M. A. Reed, Sabine Schaefer, Rebecca Schneider, and J. R. Wynn for field assistance. We also thank persons that reported observations throughout this study. LITERATURE CITED Baerg, W. J. 1951. Birds of Arkansas. Bulletin Number 258. University of Arkansas Agricultural Experiment Station, Fayetteville, USA. Brown, R. e., J. H. Williamson, and D. B. Boone. 1997. Swallow-tailed Kite nesting in Texas: past and present. Southwestern Naturalist 42:103-105. Cely, J. E. 1979. Status of the Swallow-tailed Kite and factors affecting its distribution. Pages 144-150 in Proceedings of the first South Carolina endangered species symposium (D. M. Forsythe and W. B. Ezell E, Editors). South Carolina Wildlife and Marine Resources Department, Columbia, USA. Cely, J. e. and J. A. Sorrow. 1990. The American Swallow-tailed Kite in South Carolina. Nongame and Heritage Trust Section Publication Number 1. South Carolina Wildlife and Marine Resources Department, Columbia, USA. Coulson, j. o., T. d. Coulson, S. A. Defrancesch, and L W. Sherry. 2008. Predators of the Swallow-tailed Kite in southern Louisiana and Mississippi. Journal of Raptor Research 42:1-12. Howell, A. H. 1911. Birds of Arkansas. University of Arkansas Press, Fayetteville, USA. James. D. A. and J. C. Neal. 1986. Arkansas birds. University of Arkansas Press, Fayetteville, USA. Martin, T. E., C. R. Paine, C. J. Conway, W. M. Hochachka, P. Allen, and W. Jenkins. 1997. BBIRD field protocol. Montana Cooperative Wildlife Research Unit, University of Montana, Missoula, USA. Meyer, K. D. 1995. Swallow-tailed Kite (Elanoides forficatus). The birds of North America. Number 138. Meyer, K. D. 2004a. Conservation and management of the Swallow-tailed Kite (Elanoides forficatus). Final Report NG97-024. Florida Fish and Wildlife Conser¬ vation Commission, Tallahassee, USA. Meyer, K. D. 2004b. Demography, dispersal, and migra¬ tion of the Swallow-tailed Kite. Final Report NG97- 025. Florida Fish and Wildlife Conservation Commis¬ sion, Tallahassee, USA. Meyer, K. D. and M. W. Collopy. 1995. Status, distribution, and habitat requirements of the American Swallow-tailed Kite (Elanoides forficatus) in Florida. Project Report GFC-87-025. Florida Game and Fresh Water Fish Commission, Tallahassee, USA. Neal, J. C., W. G. Montague, D. M. Richardson, and J. H. Withgott. 1998. Exclusion of rat snakes from Red-cockaded Woodpecker cavities. Wildlife Society Bulletin 26:851-854. SAS Institute. 2003. Version 9.1. SAS Institute Inc., Cary, North Carolina, USA. Shackelford. C. E. and G. G. Simons. 2000. A two-year report of the Swallow-tailed Kite in Texas: a survey and monitoring project for 1998 and 1999. PWD BK W7000-496. Texas Parks and Wildlife, Austin, USA. Smith, A. P. 1915. Birds of the Boston Mountains, Arkansas. Condor 17:41-51. St. Pierre, A. M. 2006. The breeding ecology of Swallow¬ tailed ( Elanoides foificatus) and Mississippi kites (Ictinia mississippiensis) in southeastern Arkansas. Thesis. Arkansas State University, Jonesboro, USA. Twedt, D. J. and C. R. Loesch. 1999. Forest area and distribution in the Mississippi Alluvial Valley: impli¬ cations for breeding bird conservation. Journal of Biogeography 26:1215-1224. The Wilson Journal of Ornithology 123(1): 102—106, 2011 NESTLING BEHAVIOR AND PARENTAL CARE OF THE COMMON POTOO ( NYCTIBIUS GRISEUS ) IN SOUTHEASTERN BRAZIL CESAR CESTARI,1’2 *-4 * * * ANDRE C. GUARALDO,13 AND CARLOS O. A. GUSSONI12 ABSTRACT. — We recorded and quantified the nocturnal activity and parental care of a brooding Common Potoo ( Nyctibius griseus) using an infrared camera in southeastern Brazil. Parents alternated care of the nestling and decreased their presence as the nestling grew. Nestling feeding on passing insects while sitting on the nest, movements on the nest, wing exercising, preening, and defecating were recorded primarily while it was alone. The frequency of begging calls per hour was higher when the nestling was accompanied by one of the parents. Nocturnal recordings of this species on the nest revealed behaviors that were not cited in past studies, including: feedings bouts on passing flies performed by the nestling and adults, nestling defecation, and nestling plumage maintenance. The well-known plus newly quantified behaviors of the Common Potoo reinforce their value to survival during the long nestling period. Received 24 May 2010. Accepted 14 September 2010. Potoos are members of the Nyctibiidae, which is composed of seven species of a single genus ( Nyctibius ), all geographically restricted to the Neotropics (Cleere 1998, Cohn-Haft 1999, Ho- lyoak 2001). Five species are considered resident in Brazil with the Common Potoo (N. griseus ) being the most widespread (Sick 1993) inhabiting rain-forest areas as well as dry forests, cerrado savannas, mangroves, tall secondary growth forests, and partially disturbed areas (Cleere 1998, Cohn-Haft 1999, Holyoak 2001). Potoos normally assume a motionless posture during the day, perched upright on horizontal branches or on top of a broken branch relying heavily on their cryptic coloration. Shortly before dusk, potoos initiate their nightly activities (Cohn- Haft 1999). Their secretive behavior and cryptic coloration makes them difficult to detect but, once found, detailed observations of their behavior are relatively easy, especially at the nest. Descriptive studies of the nesting behavior of the Common Potoo in neotropical regions have been reported by Goeldi (1896), Muir and Butler (1925), Haverschmidt (1958), Skutch (1970), Tate (1994), Cohn-Haft (1999), Lopes and Anjos (2005), and Corbo and Macarrao (2010). Published data on the nesting behavior of the Common Potoo were opportunistically obtained by observers during the day or rarely during moonlit nights. These studies frequently over¬ 1 Universidade Estadual Paulista (UNESP), Avenida 24A 1515. Bela Vista, Rio Claro, SP, CEP 13506-900, Brazil. - Programa de Pos-Graduagao em Zoologia, Universidade Estadual Paulista (UNESP), Rio Claro, Brazil. Programa de Pos-Graduagao em Biologia Vegetal Universidade Estadual Paulista (UNESP), Rio Claro, Brazil’ Corresponding author; e-mail: cesar_cestari @yahoo.com.br looked a sequence of behaviors during the main peak of activities in the first hours of the night. We describe and quantify the nocturnal activities of a nesting Common Potoo based on continuous observations using an infrared digital camera. METHODS Study Area. — The study was conducted on the edge of the Universidade Estadual Paulista campus (22° 23' 57.7" S, 47° 32' 13.5" W), municipality of Rio Claro, southeastern Brazil. The nest site was in transitional vegetation among a small 0.5-km2 fragment of disturbed scrub native savanna cerrado and a 25-km2 fragment of secondary dry forest mixed with non native Pinus spp. and Eucalyptus spp. trees on the east side. The study site is considered an urban area as the closest populated area is <1 km to the west. Data Collection. — Data were collected on 8, 12. 13, and 16 December 2008. We used an infrared digital Sony DSC H9 camera on a tripod hidden in a small bush ~ 1 m from the fence post where the Common Potoo nested. A wire frame and an additional infrared diode system were installed next to the camera to improve image quality during recordings. Recording sessions were initiated at dusk and continued after 1900 hrs when the potoos started their nocturnal activities (Table 1). The maximum length of recordings was ~3 hrs. We used two batteries on some days with nearly 1.5 hrs ot recording capacity on each. Immediately before the first battery quit, a person quietly approached the nest to change the batteries. Digital recordings were analyzed in the labora¬ tory and the following categories of behavior were recorded while the nestling was alone in the nest 102 Cestari et al. • COMMON POTOO NESTLING BEHAVIOR 103 TABLE 1 . Recording sessions at a Common Potoo nest in southeastern Brazil. Date (sampling day) Estimated nestling age (days) Total recording time (hrs, min) Recording periods (hrs) 8 Dec 14 2, 35 1920-2210 12 Dec 18 2, 57 1832-2138 13 Dec 19 2, 02 1823-2028 16 Dec 22 1, 31 1844-2015 or accompanied by one of the parents: (1) feeding bouts on passing insects, (2) defecations, (3) movements in the nest, (4) wing exercising, (5) plumage maintenance, and (6) calling. Feeding bouts to capture insects were used by the nestling and adults while they were perched on the nest (on the top of the fence post) and attacked flies that were passing. Defecation behavior was perceived when the nestling raised the tail and ejected feces from the nest. Movements on the nest were used by the nestling to move short distances (several centimeters) from border to border of the stump. Wing exercising was used by the nestling apparently to exercise without flying. Plumage maintenance with the beak was used by the nestling and adults. Calls were used in a parental interaction and included begging notes uttered by the nestling and advertisement calls uttered by adults. We quantified the frequency per hour of each of these categories. We verified the amount of time the nestling and each parent remained in alert posture, the frequency and times that each parent left the nest, and the number of times they alternated care and fed the nestling through regurgitation. The alert posture was adopted when nestling or adults raised their beak, compressed the plumage, and kept the neck outstretched (Fig. 1). Common Potoos do not show any sexual dimorphism (Cohn-Haft 1999). However, we noted a difference in the pattern of dark blotches °n the breast of the two adults (hereafter, indicated as individuals A and B) that enabled us to identify shared parental care. RESULTS Description of the Nest , Egg, Nestling, and Parents.— A Common Potoo responded to a Playback of its call by vocalizing during a nocturnal bird survey and perched on a fence post on 4 November 2008. The potoo could be closely approached and another visit to the site was made 2 days later to confirm the existence of a nest. The simple and unlined nest contained a single dull white egg with lilac and brown spots (40.95 X 31.55 mm). It was directly placed on top of a 1.25-m tall abandoned fence post. The top of the post had an irregular surface that measured 5 X 19 cm (Fig. 1). Presence of the nestling with an egg tooth and eggshell fragments in the nest indicated hatching occurred between 22 and 24 November. The nestling was covered by creamy-white down plumage marked with fine gray brown stripes on the first recording day (8 Dec). It was — one-third of the size of an adult at this time and could stay completely hidden among the ventral feathers of the parent (Fig. 1). The nestling was slightly more than half the size of an adult on the last day of recording (16 Dec), and remained almost com¬ pletely exposed even when among the ventral feathers of the adult. Adults had a buff plumage with light gray and black blotches. The same gray-brown stripes of the nestling were also apparent along the adult’s body. A visit to the nesting site on 21 December revealed the nestling had probably been predated and the adults were no longer present. Quantitative Aspect of Categories of Behav¬ ior.— Digital recordings (9 hrs and 6 min) were made when the nestling was — 14 — 16 days until 22-24 days of age (Table 1). Adults stayed with the nestling during nearly 5 hrs and 54 min (64.8% of total recording time) and the time the parents brooded the nestling decreased as it became older (Fig. 2). The adult present gradually relaxed to a less motionless posture and slowly opened its eyes at nightfall. It completely opened its eyes at -1854 to 1908 hrs and initiated nocturnal activities, flying from the nest between 1904 to 1909 hrs. Generally, the nestling became active from the motionless posture similarly to the adult. The nestling engaged in feeding bouts on passing flies and flapped its wings only when alone after the first day of recording. Frequencies of short movements on the nest and plumage maintenance were also higher when the nestling 104 THE WILSON JOURNAL OF ORNITHOLOGY • Vol. 123, No. 1, March 2011 plumaee (on the Hi 5'°mmon Poto° (Nyctibius griseus) with adult (on the left) and nestling covered by creamy-white down n sZg (on , e lem K “ “ P°StUre' L°Wer dght Coraer = frame with the infrared camera showing to nestling (on the left) bemg fed by adult B (on the right) on 12 December. Note the eye and beak of the adult. Estimated age (days) of nestling FIG. 2. Brood, ng (% of time) of the nestling Common Potoo by an adult as a function of age. Cestari et al • COMMON POTOO NESTLING BEHAVIOR 105 TABLE 2. Frequency per hour (total recording time = 9 hrs and 6 min) of behavioral activities by Common Potoo nestling when alone at the nest and when accompanied by an adult. Feeding on passing flies Defecation Brief movements Wing flapping Plumage maintenance Vocalization (calls) Alone 1.87 0.31 6.25 4.06 4.37 4.37 Accompanied 0 0.34 2.38 0 1.70 647.1 was alone. The nestling vocalized much more frequently while accompanied by one of the parents than when alone (Table 2). Adults A and B stayed in the nest for 1 hr and 59 min (17.5% of total recording time), and 4 hrs and 17 min (47.2% of total recording time), respectively. A change-over between adults at the nest was recorded four times: day 1 at 2028 hrs; day 2 at 2135 hrs; and day 3 at 1919, and 2115 hrs. Both adults left the nest six and 13 times during the sampled period: adult A (day 1 at 2030 hrs; day 2 at 1957 and 2056 hrs; day 3 at 1919 and 2115 hrs; and day 4 at 1927 hrs), and adult B (day 1 at 1931, 1935, 2008, and 2209 hrs; day 2 at 1905, 1940, and 2137 hrs; day 3 at 1909, 1919, 1942, and 2131 hrs; and day 4 at 1904 and 1923 hrs). Adults also fed on passing insects while perched in the nest, but only adult B called once. The frequency of food regurgitation to the nestling was similar between adults (Table 3). The nestling, adult A, and adult B adopted the alert posture during nearly 5 min and 24 sec (1.0% of total sampled time), 2 min and 24 sec (0-4%), and 1 hr and 48 min (19.8%) of video recording, respectively. DISCUSSION The infrared recording sessions enabled us to analyze and quantify behaviors of nestling and adult Common Potoos during the darkest nights. Parental attendance at the nest decreased as the nestling grew. Skutch (1970) and Tate (1994) reported that 25 days after hatching, adults were no longer staying with the nestling at the nest. They also reported that until nearly 50 days of age, the fledgling moved frequently with short flights, and the adults fed it in surrounding areas. Some behaviors of Common Potoo recorded in our study were also reported elsewhere, but rarely quantified, including: brief movements of the nestling in the nest (Tate 1994); wing exercising (Skutch 1970); alert posture (Muir and Butler 1925, Skutch 1970, Tate 1994); calling of the nestling and adults at the nest (Muir and Butler 1925, Skutch 1970, Corbo and Macarrao 2010); adults feeding the nestling by regurgitation (Skutch 1970, Corbo and Macarrao 2010); and alternation of adults at the nest (Lopes and Anjos 2005). Other behaviors of the potoos we observed are described for the first time, including: feeding bouts on passing insects by both the nestling and adults while sitting in the nest; defecation, and plumage maintenance by the nestling. Brief movements on the nest by the nestling were performed when it was alone. Tate (1994) also observed nestling movements on a nest in Venezuela. We observed the nestling moved mainly to empty space left by the adult when it flew from the nest. One explanation for brief movements might be the improvement of blood circulation considering the great motionless period of the nestling during the day (Cohn-Haft 1999). The nestling flapped its wings at times for a few seconds after or before moving, probably as a way to exercise its pectoral muscles. This wing exercising started when the nestling was 14 days of age, 2 days earlier than mentioned by Skutch (1970) in Costa Rica. The adults and nestling relied on the motionless alert posture during most of the day and in threatening situations during the night (Skutch 1970). We noted that a noise caused by a person near the nest site immediately modified the relaxed posture to an alert posture. We also observed the adult slowly turning its head to keep the intruder in focus in agreement with Muir and Butler (1925), Skutch (1970), and Tate TABLE 3. Frequency per hour (total recording time = 9 hrs and 6 min) of behavioral activities by adult Common p°toos (A and B) at the nest. Feeding on passing insects Calling _ Feeding of nestling Adult A Adult B 3.77 1.86 8.18 0.70 0 0.93 2.52 2.10 106 THE WILSON JOURNAL OF ORNITHOLOGY • Vol. 123, No. 1, March 2011 (1994). The nestling and adult gradually returned to the relaxed position, if left undisturbed for ~ 10 min. During relaxed situations, and when the nestling was on its own in the nest, it frequently engaged in feeding on passing flies and in maintaining its plumage. We did not perceive if the nestling captured prey during the faster feeding bouts, but this foraging behavior may be important in the early stages of species maturation as it optimizes food intake by the nestling in periods of absence of adults. Preening is also important to get rid of mites and lice (Cohn-Haft 1999). Adults performed the same behaviors when they were sitting in the nest. Feeding bouts of adults while perched are a way to supplement their diet without flying and abandoning its primary defense of inconspicuousness. Defecation was another observed care behavior 2005, Greeney et al. 2008, Corbo and Macarrao 2010), possibly facilitated a predation event. However, several behaviors of the species led to the inconspicuousness during this time, and the long time of parental investment attest to their protective value for survival (Skutch 1970, Cohn- Haft 1999). New methods and technology to precisely study behaviors are needed. The use of infrared cameras in future studies would allow obtaining better insight of the nightly activities at the nest. Identification of the gender of adults would allow better study of how males and females share incubation and brooding duties. ACKNOWLEDGMENTS We are grateful to two anonymous reviewers for their appropriate suggestions about this manuscript. of the nestling. This occurred when the nestling raised its tail and ejected feces 30 to 50 cm from the nest. The absence of feces in and near Common Potoo nests has been reported (Skutch 1970, Sick 1993, Cohn-Haft 1999, and Lopes and Anjos 2005). This behavior should reduce the risk of predation and presence of parasites. The nestling uttered a soft song while alone and on occasions that it was accompanied by one of the adults. This behavior has been reported in the literature prior to the arrival of an adult at the nest (Skutch 1970, Corbo and Macarrao 2010). Stronger calls in our study were also uttered by an adult when it approached the nest, probably to inform the nestling of its presence. The nestling increased the frequency of begging for food calls when an adult arrived at the nest, and when the adult fed it by regurgitation. Adults came to the nest three to 10 times to feed the nestling by regurgitation before midnight, similar to the observations of Skutch (1970) and Lopes and Anjos (2005). One of the parents (adult B) came more frequently to the nest, but we were not able to identify if it was male or female. Cryptic plumage, inconspicuous behavior, and reduced activities around the nest are all adapta¬ tions to reduce attention to nesting potoos (Cohn- Haft 1999). The 51 days of the nestling period of the Common Potoo from hatching to young departure from the nest (Skutch 1970) is consid¬ ered very long among birds (Sick 1993). The lower leight of the nest in our study, in comparison with the interval from 3 to 15 m reported in other studies ( un and Butler 1925, Haverschmidt 1958 Borrero 1970, Skutch 1970, Lopes and Anjos LITERATURE CITED Borrero, H. J. I. 1970. Photographic study of the Potoo in Colombia. Living Bird 9: 257-263. Cleere, N. 1998. Nightjars. A guide to the nightjars, nighthawks, and their relatives. Yale University Press. New Haven, Connecticut, USA. Cohn-Haft, M. 1999. Family Nyctibiidae (Potoos). Pages 288-300 in Handbook of the birds of the world. Volume 5. (Barn-owls to hummingbirds) (J. delHoyo, A. Elliott, and J. Sargatal, Editors). Lynx Editions. Barcelona. Spain. Corbo, M. C. and A. Macarrao. 2010. Parental care in Common Potoo Nyctibius griseus in Brazil. Cotinga 32: 122. Goeldi, E. A. 1 896. On the nesting of Nyctibius jamaicensis and Sclerurus umbretta. Ibis 7: 229-310. Greeney, H. F., J. Simbana, and A. P. Tangila. 2008. Threat display and hatchling of Common Potoo Nyctibius griseus. Cotinga 29: 172-173. Haverschmidt, F. 1958. Notes on Nyctibius griseus in Surinam. Ardea 46: 144-148. Holyoak, D. 2001. Nightjars and their allies. The Caprimulgiformes. Oxford University Press, Oxford. United Kingdom. Lopes, E. V. and L. Anjos. 2005. Observances sobre reprodunao de Nyctibius griseus no campus da Universidade Estadual de Londrina, norte do Parana. Ararajuba 13: 109-112. Muir, A. and A. L. Butler. 1925. The nesting of Nyctibius griseus (Gmel.) in Trinidad with photographs. Ibis 32: 654-659. Sick, H. 1993. Birds in Brazil. A natural history. Princeton University Press, Princeton, New Jersey, USA. Skutch, A. F. 1970. Life history of the Common Potoo. Living Bird 9: 265-280. Tate, D. P. 1994. Observations of nesting behavior of the Common Potoo in Venezuela. Journal of Field Ornithology 65: 447-452. The Wilson Journal of Ornithology 123(1): 107-1 15, 2011 BOTFLY PARASITISM EFFECTS ON NESTLING GROWTH AND MORTALITY OF RED-CRESTED CARDINALS LUCIANO N. SEGURA1'3 AND JUAN C. REBORED A2 ABSTRACT. — We collected observational data in three consecutive breeding seasons to study interactions between the botfly Philornis seguyi and Red-crested Cardinals ( Paroaria coronata) in a temperate zone near the southern limit ol Philomis distribution. We analyzed: (1) seasonal trends in prevalence of parasitism, (2) influence of botfly parasitism on nestling growth rate and survival, and (3) the association between nest site vegetation at different scales (i.e., nest tree, vegetation surrounding the nest tree, and landscape) and probability of botfly parasitism. Prevalence ol parasitism was 28% and was higher later in the breeding season. Botfly parasitism produced sub-lethal (lower growth rate of nestlings that survive) and lethal (lower nestling survival) effects. The lethal effect was negatively associated with age at the time nestlings were parasitized. Botfly parasitism was not associated with vegetation characteri sties at the level of nesting tree or vegetation surrounding the nesting tree, but was associated with landscape features. Parasite prevalence was higher in large continuous woodland patches than in small isolated patches. However, we did not observe increased use ol isolated patches of forest by Red-crested Cardinals, suggesting that use of nest sites with high botfly parasite intensity could be the consequence of high host density. Received 6 April 2010. Accepted 19 October 2010. Nestling birds are hosts to a wide range of ectoparasites that capitalize on the brief period of rapid host development and resource availability (Loye and Carroll 1995). Three dipteran families (Calliphoridae, Muscidae, and Piophilidae) repre¬ sent most of the hematophagous parasites of birds (Uhazy and Arendt 1986, Ferrar 1987). Many species of the genus Philornis (botflies) within the Muscidae parasitize nestlings and adults of cavity and open-nesting birds in the Neotropics (Arendt 1985a). Studies of the interactions between the genus Philomis and their hosts have been limited to a few species (i.e., P. downsi and Darwin’s finches in the Galapagos Islands) (Fessl et al. 2001; Fessl and Tebbich 2002; Fessl et al. 2006a, b’ Dudaniec et al. 2006; Dudaniec et al. 2007; Huber 2008; Kleindorfer and Dudaniec 2009; 0 Connor et al. 2010c), or to species distributed in tropical and subtropical regions (Dudaniec and Kleindorfer 2006). The genus Philomis includes —50 species of Hies, all ectoparasites of birds (Couri and Carvalho 2003, Dudaniec and Kleindorfer 2006). The life cycle of most of these species as well as relationships with their hosts is frequently un¬ known (Couri 1999, Teixeira 1999, Dudaniec and Kleindorfer 2006). Flies of this genus are distributed from central Argentina to the southern Laboratorio de Investigaciones en Sistemas Ecologicos ) Ambientales, Universidad Nacional de La Plata, Diagonal * *3 # 469, B1904CCA, La Plata, Argentina. Oepartamento de Ecologia, Genetica y Evolucion, acultad de Ciencias Exactas y Naturales, Universidad de uenos Aires, C1428EGA Buenos Aires, Argentina. Corresponding author; e-mail: lsegura79@yahoo.com. ar United States (Couri 1999, Fessl et al. 2001). Botflies have been reported to parasitize at least 127 species of birds without marked host specificity (Couri 1991, Teixeira 1999). Most botfly species have subcutaneous larvae (Couri et al. 2005) and nestlings can be parasitized as soon as they hatch (Arendt 1985b; Delannoy and Cruz 1988, 1991; Spalding et al. 2002; Rabuffetti and Reboreda 2007). Botfly larvae feed on red blood cells (Uhazy and Arendt 1986) and remain in nestlings for 5-8 days (Arendt 1985b, Young 1993, Rabuffetti and Reboreda 2007, Quiroga 2009) when they leave the nestling as third instars and pupate in nest material (Uhazy and Arendt 1986). Adult flies emerge after a pupation period of 1-3 weeks (Oniki 1983, Young 1993, Rabuf¬ fetti and Reboreda 2007, Quiroga 2009). Most studies indicate botfly parasitism produc¬ es sublethal (i.e., lower growth rates) or lethal effects on their hosts (Arendt 1985a, b; Delannoy and Cruz 1991; Young 1993; Fessl and Tebbich 2002; Rabuffetti and Reboreda 2007). One of the predictor variables for nestling survival is parasite intensity (number of larvae/nestling) (Dudaniec and Kleindorfer 2006). Some studies have report¬ ed only 5-6 larvae caused nestling death (Arendt 1985b, Delannoy and Cruz 1991), but others report similar intensities were not lethal (Nores 1995) and were only associated with lower growth rates (Young 1993). The other variable that influences nestling survival is age at the time they are parasitized (Arendt 1985a, 2000; Rabuf¬ fetti and Reboreda 2007) although this association has been less studied. Parasite prevalence (the percentage of nests with larvae) increases as the 107 108 THE WILSON JOURNAL OF ORNITHOLOGY • Vol. 123, No. 1, March 2011 host breeding season advances (Arendt 1985a, b; Young 1993; Rabuffetti and Reboreda 2007), although some studies did not find a trend (Nores 1995, Fessl and Tebbich 2002, Quiroga 2009). The role of nest-site vegetation on prevalence and intensity ol botfly parasitism has received little research attention, except for the work of O’Connor et al. (2010a) who reported higher prevalence and intensity of botfly ( P . downs i) parasitism in moist forest highlands than in arid lowlands of the Galapagos Islands and suggested that size and continuity of forest patches could influence botfly dispersal ability. Understanding the role of nest-site vegetation on parasite infestation may help predict the likelihood of parasitism for a given host in a given environment (Loye and Carroll 1998). We used a large set of observational data collected during three consecutive breeding sea¬ sons to study the interactions between Philornis seguyi and Red-crested Cardinals ( Pciroaria coronata ), a species that has been previously reported as a host of botflies in central Argentina (De la Pena et al. 2003). We examined: (1) seasonal trends in parasite prevalence and inten¬ sity, (2) the influence of botfly parasitism on nestling growth and survival, and (3) the associ¬ ation between nest-site vegetation at different scales and probability of botfly parasitism. We hypothesized that survival of Red-crested Cardi¬ nal nestlings may be negatively associated with parasite intensity and positively associated with age at time ot parasitism. We expected nests in small isolated patches of forest would have lower parasite prevalence than those in large continuous patches, because grassland areas that separate isolated from continuous patches may act as barriers for dispersal. METHODS Study Site. — The study was conducted near the town of Punta Indio, Buenos Aires Province, Argentina (35 20' S, 57° 1 1' W). The vegetation at the study site consists of woodlands arranged in several strips (50-100 m in width and up to several km in length) parallel to the edge of the “de la Plata” River surrounded by small areas of grassland. In addition, there are also small patches of forests (between 10 and 70 m in diameter) more distant from the edge of the river surrounded by large areas of grassland. These small patches are separated from woodland strips by 300-1,200 m. The woodlands are dominated by Celtis tala (Tala) and Scutia buxifolia (Coronillo). The annual rainfall for the study site is 891 mm and rainfall during the study period varied between 772 (2005) and 845 mm (2007). We collected data during Red-crested Cardinal breeding seasons (early Oct- mid Feb) 2005-2006 to 2007-2008. Average annual rainfall during the breeding season is typically 441 mm and, during the breeding seasons of 2005-2006, 2006-2007, and 2007-2008, it was 431, 439, and 487 mm, respectively. Ranges of mean monthly ambient temperatures during the study period were 14.8 (Oct) to 21.9° C (Jan) in 2005-2006, 17.0 (Oct) to 23.2° C (Feb) in 2005-2006, and 17.1 (Oct) to 24.6° C (Jan) in 2007-2008. Study Species. — Red-crested Cardinals inhabit semi-open areas with scattered trees and shrubs from east central Argentina to southern Brazil, Paraguay, eastern Bolivia, and Uruguay (Ridgely and Tudor 1994). Their nests at our study site were at a height of 2-6 m, primarily in Talas and secondarily in Coronillos and Molles ( Schinus longifolius) (Segura and Arturi 2009). Nests are open-cups with external and internal diameters of 13 and 6.5 cm, respectively, a depth of 4.5 cm and lateral translucent walls of 2 cm in width (LNS, unpubl. data). The wall of the nest is built with thin dry branches of Tala and small stems of grass while the chamber is lined with thin rootlets, vegetation fibers, and cattle hair. Clutch size varies between two and four eggs, nestlings hatch after 12 days of incubation and fledge ~14 days after hatching (LNS, unpubl. data). Average mass of nestlings at hatching is 3-3.5 g and 30-31 g at time of fledging (LNS, unpubl. data). The species of botfly recorded previously in our study area is P. seguyi (Couri et al. 2005, Rabuffetti and Reboreda 2007). We collected botfly larvae from Chalk-browed Mockingbird ( Mimus satuminus, n = 21), House Wren ( Troglodytes aedon, n = 9) and Bay wing ( Agelaioides bad i us, n = 3) nestlings, all identified (Martin Quiroga, INALI-CONICET, Argentina) as P. seguyi (Garcia 1952, Couri et al. 2009). Quiroga (2009) described the life cycle of this species. P. seguyi larvae feed and develop subcutaneously in the host for 5—6 days reaching a length of ~8-9 mm and a mass of 0.11-0.13 g. Larvae drop from the host to undergo pupation, emerging as adult flies after 9-10 days. Host larvae do not pupate at the bottom of the nest due to the scarce material that forms the cardinal nest, but drop to the ground where they undergo pupation (LNS, unpubl. data). Segura and Reboreda • BOTFLY PARASITISM OF RED-CRESTED CARDINALS 109 Data Collection — Nests were found by search¬ ing systematically in potential nest sites and by observing nesting behavior of territorial pairs (Martin and Geupel 1993) of Red-crested Cardi¬ nals. We found 367 nests {n = 108, 120, and 139 for the breeding seasons of 2005-2006, 2006- 2007, and 2007-2008, respectively). Nearly 50% of the nests (n = 111) were found during construction and laying with the remainder found during incubation ( n = 152) and after hatching (n = 38). We used 131 nests that survived at least 6 days after the first nestling hatched (n = 36, 45, and 50 for 2005-2006, 2006-2007, and 2007- 2008, respectively). We used this criterion in our study because botfly parasitism occurred while nestlings were between 1 and 6 days of age. Inclusion of nests depredated before nestlings were 6 days of age would result in underestima¬ tion of parasite prevalence. Nests were checked daily until all eggs hatched and then every 2 days until the nestlings fledged or the nest failed. Nestlings were marked after hatching on the tarsus with black ink for individual identification and color banded after day 6. We recorded: (1) day of hatching for each nestling, (2) number of nestlings hatched, (3) day we found the first larvae in the nestling, (4) day the nest failed or fledged young, and (5) number of young fledged for each nest. We recorded: (1) body mass, (2) lengths of the beak, right tarsus, and wing, and (3) parasite intensity (number of botfly larvae/nestling) for each nestling at each nest visit. We measured body mass with 30 and 50 g Pesola spring scales (accuracy ± 0.2 and ± 0.5 g, respectively), length of the tarsus and beak with a dial caliper (accuracy ± 0.1 mm), and length of the wing with a ruler (accuracy ±0.1 mm). We minimized the effect of daily variation in body mass and size by collecting these data between 1600 and 1900 hrs. We analyzed the structure of the vegetation surrounding the nest by measuring vegetation characteristics at three different scales: (1) nest tree, (2) vegetation surrounding the nest tree, and (3) landscape. We measured (1) tree species, (2) nest height, (3) distance from the nest to the edge °f the canopy, and (4) cover of the canopy at the nest tree scale. We measured the cover of tree canopy within a 15-m radius of the nest at the surrounding nest tree vegetation scale, and whether the nest tree was in the continuous strips °f forest parallel to the river or in small isolated forest patches more distant from the river at the landscape scale. We used images QuickBird (5 m) extracted from Google Earth (Digital Global Coverage, 6 October 2008) to calculate the cover of individual nest trees and proportion of canopies in the nest surrounding area using Program IDRISI Kilimanjaro 14.01 (Clark Labs 2003). Data Analysis.— We assumed a nest was successful if it fledged at least one young and depredated if all nestlings disappeared between two consecutive visits. We did not observe abandonment of nests with nestlings in circum¬ stances other than botfly parasitism. We assumed that a nestling died as a result of botfly parasitism if it was previously parasitized and found dead or disappeared between visits with no evidence of attack by predators (i.e., feathers or blood in the nest). We estimated the lethal effect of botfly parasitism by comparing nestling survival (pro¬ portion of nestlings that fledged) between non- and parasitized nests excluding nests that were depredated. We estimated the sub-lethal effects of botfly parasitism by comparing growth rates of: (1) body mass, (2) tarsus length, (3) beak length, and (4) wing length between non- and parasitized chicks that survived. We used brood means to avoid pseudoreplication. We calculated growth rates as the slope of a linear regression of the values of each variable versus age of nestlings between 2 and 8 days of age (hatching day = age 0). Growth rates of all the variables were almost linear for nestlings 2-8 days of age (body mass, y = 3.0 x + 1.6, r = 0.99, P < 0.001; tarsus length: y = 2. 1 x + 5 .9, r = 0.99, P < 0.00 1 ; beak length: y = 0.56 x + 4.9, r = 0.99, P < 0.001; and wing length: y = 4.7 x - 0.79, r = 0.99, P < 0.001; n = 222 data points from 66 non-parasitized nests). We only considered nests in which we had three or more measurements in that period (16 parasit¬ ized and 66 unparasitized nests). We used nests with nestlings during January and February only for analysis of the association between vegetation characteristics and botfly parasitism, as the occurrence of parasitism in nests with nestlings during the previous months was practically zero. We used parametric tests for normally distrib¬ uted data only, and nonparametric tests with corrections for ties. We used Mann-Whitney U or Ki'uskal- Wallis tests for independent compari¬ sons. We used logistic regressions to analyze the association between botfly parasitism (binary dependent variable) and one or more independent 110 THE WILSON JOURNAL OF ORNITHOLOGY • Vol. 123, No. 1, March 2011 TABLE 1 . Parasite prevalence (percentage of nests parasitized), parasite intensity (mean number of larvae/nestling and per nest), latency of parasitism (time elapsed since hatching of the first nestling and nest parasitism), and date first brood of Red-crested Cardinals was parasitized for three breeding seasons (2005-2008) in central Argentina woodlands. 2005-2006 2006-2007 2007-2008 Parasite prevalence 8/36 (22.2%) 12/45 (26.7%) 17/50 (34%) Parasite intensity 14.4 ± 1.6 10.8 ± 1.8 13.4 ± 1.7 (x ± SE of larvae/nest) (range: 9-22) (range: 3-26) (range: 3-29) Parasite intensity 6.7 ± 1.3 6.5 ± 1.4 6.4 + 0.9 (x ± SE of larvae/nestling) (range: 4.5-16) (range: 2.5-19) (range: 1.7-16) Latency of parasitism 3.0 ± 0.38 3.3 ± 0.35 3.2 + 0.39 (x ± SE of age of nestlings) (range: 2-5) (range: 2-6) (range: 1-6) Date first brood parasitized 10 Jan 31 Dec 11 Jan variables. We used Fisher’s exact or Chi-square tests for the analysis of contingency tables. Reported values are means itSE. All tests were two-tailed and differences were considered sig¬ nificant at P < 0.05. Statistical tests were completed using STATISTICA 7.0 (StatSoft Inc 2004). RESULTS Prevalence and Intensity of Parasitism during the Breeding Season.— The prevalence of botfly parasitism was 28.2% (37/131 nests) and did not differ between years (X22 = 0.85, P = 0.65; Table 1). There was a positive association be¬ tween occurrence of botfly parasitism and time of breeding for the three breeding seasons (logistic regressions: 2005-2006, X2x = 14.2, P < 0.001; 2006-2007, X2] = 17.1, P < 0.001 and 2007- 2008, Y2, = 36.1, P < 0.001) with most parasitized nests (36/37) occurring in January and February (Fig. 1). We divided the breeding season into 15-day intervals and calculated the proportion of nests that were parasitized with botflies for each interval to examine if the seasonal increase in parasite prevalence during January and February was associated with a decrease in availability of nests. We combined the data for the 3 years because of the small number of periods per year. There was no significant association between number of nests with nestlings and botfly prevalence (Spearman’s rank correlation: p = -0.20, P = 0.52, n = 12; Fig. 1). All nestlings were parasitized in 35 of 37 nests. Botfly intensity was 6.5 ± 0.66 larvae/ nestling (range: 1.6-19, n = 37 nests; Fig. 2A) and was not statistically different between years (Kruskal-Wallis test: H2 = 0.12, P = 0.93; Table 1). Mean parasite intensity per nestling did not differ between nests with one, two or three nestlings (Kruskal-Wallis test: H2 = 3.4, P = 0. 1 8, /2 = 37) and was not associated with date of hatching (Spearman’s rank correlation: p = 0.1, P = 0.55, n = 37). Latency of parasitism (time elapsed since hatching of the first nestling and nest parasitism) was 4.2 ± 0.2 days (range 2- 6 days, n = 35 nests; Fig. 2B) and did not differ across years (Kruskal-Wallis test; H2 = 0.6, P = 0.74; Table 1). Lethal and Sub- lethal Eff ects of Botfly Parasit¬ ism. — Thirteen of 37 nests parasitized by botflies were depredated and excluded from analysis of nestling survival. No nestlings fledged in 4/24 nests (17%), there was partial fledging (some nestlings fledged, some died) in 7/24 nests (29%), and all nestlings fledged in 13/24 nests (54%). Nestling survival was lower in parasitized than in non-parasitized nests (parasitized: 0.6 ± 0.07, n = FIG. 1 . Botfly parasitism of Red-crested Cardinals at different times of the breeding season in Buenos Aires Province, Argentina. White circles show the number of nests that produced nestlings during the 15-day interval and black circles = the percentage of those nests parasitized by botflies. Data correspond to the breeding seasons of 2005- 2006, 2006—2007. and 2007—2008 combined (n = 131 nests). Segura and Reboreda • BOTFLY PARASITISM OF RED-CRESTED CARDINALS 111 (A) Intensity (botflies/nestling) (B) FIG. 2. Frequency distributions of the number of botfly larvae per nestling of Red-crested Cardinals; (A) = parasite intensity and (B) = time elapsed since hatching of the first nestling and nest parasitism (latency). -4; non-parasitized: 0.86 ± 0.02, n = 74; Mann- Whitney U- test: Z = 3.35, P = 0.0008). We did not detect an association between nestling surviv- a* and parasite intensity/nestling (Spearman’s rank correlation; p = -0.19, P = 0.37, n = 24; 3A), but nestling survival was positively ass°ciated with latency of parasitism (Spearman’s rank correlation: p = 0.59, P = 0.002, n = 23; fig- 3B). Intensity and latency of parasitism were negatively associated (Spearman’s rank correla- tlon: P = -0.48, P = 0.02, n = 23). fiedation outcome did not differ between Parasitized and non-parasitized nests (. X2i = 133, df = 1, p = 0.56) for the three breeding seas°ns combined. Young that fledged from Parasitized nests had lower growth rates for body (A) (B) FIG. 3. Red-crested Cardinal nestling survival as a function of the number of botfly larvae/nestling; (A) = parasite intensity and (B) = time elapsed since hatching of the first nestling and nest infestation (latency). mass (Fig. 4A), tarsus length (Fig. 4B), beak length (Fig. 4C), and wing length (Fig. 4D) than young that fledged from non-parasitized nests (Mann-Whitney LMest; body mass: Z = -2.94, P = 0.003; tarsus length: Z = -3.02, P = 0.002; beak length: Z = -2.54, P = 0.01; wing length: Z = -2.13, P = 0.03). Characteristics of the Vegetation and Botfly Parasitism.— We did not detect a significant association between occurrence of botfly parasit¬ ism and species of nest trees (Tala: 22/44; Coronillo: 15/23; X2 = 0.04, P = 0.52). We also did not observe a significant association between botfly parasitism and other characteristics of the vegetation at the nest-tree level (logistic regres¬ sions for nest height: X2, = 1-24, P = 0.26; distance from the nest to the edge of the canopy: X2, = 0.04, P = 0.83; and cover of the canopy: 112 THE WILSON JOURNAL OF ORNITHOLOGY • Vol. 123, No. 1, March 2011 v 3.0 > TO TD X S2.0 ■o eg 0.5- (A) 0.0J ^ 2.5- _ -D 2.0- X . I1-5! - £ 1.0- u — i — m o snsj 1 I U.U I i NP NP E E _°6-, S’ 0.5- ■D ~ 0.4- 0.3- -L_ 05 J 02 "co 0.1- ngef t0 PC/,PE rat'0S may be 3 reSUlt °f migratoIT exercise> rather than migratory condition per se. Received 30 April 2010. Accepted 23 September 2010. Findings of several recent studies have gener¬ ated increased interest in muscle membrane alterations during exercise and how changes in membranes affect exercise performance (Ayre and Hulbert 1997, Infante et al. 2001, Guglielmo et al. 2002, Valencak et al. 2003, Nagahuedi et al. 2009) . Ornithologists, in particular, have been interested in how membrane composition could a^ect migration, a period of high-intensity endurance exercise (Guglielmo et al. 2002, Pierce et al. H)05. Maillet and Weber 2006. Price et al 2010) . Biological membranes are composed primarily of phospholipids which consist of a polar head group, a glycerol phosphate backbone, and two fatty acid tails. Exercise is known to affect both the fatty acid and head group moieties (class composition) of phospholipids in mammals and birds (Morgan et al. 1969, Ayre et al. 1998, Gorski et al. 1999, Mitchell et al. 2004, Turner et al. 2004, Price et al. 2010). Changes to membrane fatty acid composition brought about by dietary manipulation have been associated with exercise performance alterations in mammals, fish, and birds (Ayre and Hulbert 1997, McKenzie et al. 1998, Pierce et al. 2005), although the role of membranes in these studies has been questioned (Price and Guglielmo 2009). In addition, a comparative study of mammalian maximal run¬ ning speed demonstrated a correlation with membrane fatty acid composition (Ruf et al. The mechanism by which muscle membranes might affect migratory exercise is poorly under¬ 1 Department of Biology, University of Western Ontario London, ON N6A 5B7, Canada. 2 Corresponding author; e-mail: eprice3@uwo.ca or rrlemur@hotmail.com stood. It has often been ascribed to changes in membrane fluidity, permeability, or the local membrane-bound protein environment, which can in turn affect the activity of membrane-bound proteins, and could thereby impact key metabolic processes that affect exercise (Murphy 1990, Power and Newsholme 1997, Infante et al. 2001, Valencak et al. 2003, Guo et al. 2005, Nagahuedi et al. 2009). Both the fatty acid and class composition of phospholipids have the potential to affect these membrane properties (Pan et al. 1994, Hazel 1995, Hulbert and Else 1999, Li etal. 2006, Gerson et al. 2008. Guderley et al. 2008). Variation in the fatty acid composition of muscle membranes has been investigated in relation to migration (Guglielmo et al. 2002, Maillet and Weber 2006, Klaiman et al. 2009), but phospho¬ lipid class composition has not been studied in a migratory context. Our objective is to provide a first description of phospholipid class composition in migratory birds and how it changes seasonally, using photoperiod-manipulated captive birds as well as wild-caught migrating and wintering birds. METHODS Photoperiod-manipulated Captive Sparrows.— White-throated Sparrows ( Zonotrichia albicollis ) are short-hop, long-distance migrants common to eastern North America. Twelve White-throated Sparrows were captured near Long Point, Ontario by mist-netting in October. All birds were housed singly in 40 (height) X 45 X 45-cm cages, and were initially exposed to short day (8L.16D) photoperiod for 8 weeks to break photorefractori¬ ness (Agatsuma and Ramenofsky 2006). Small night lights were used during the dark periods to avoid complete darkness. Birds were initially fed 116 Springer et al. • CHANGES IN WHITE-THROATED SPARROW MUSCLE 117 standard bird seed and then weaned onto a ground commercial diet (Mazuri small bird maintenance, PMI Nutrition International, Brentwood, MO, USA) over 4 weeks. Food and water were changed on a daily basis and provided ad libitum. Room temperature ranged between 2 1 and 24 C. Five sparrows, after short day exposure, were switched to long days (16L:8D) for 28 days to stimulate migratory behavior (Agatsuma and Ramenofsky 2006), while the remaining birds were kept on short days. Hyperphagia and nightly hopping (Zugunruhe; characteristic of captive birds in migratory condition) were demonstrated by long day animals (D. J. Cerasale, D. M. Zajac, andC. G. Guglielmo, unpubl. data). Short day and long day birds were euthanized by decapitation following anesthesia with isofluorane at the end of this period. Right pectoralis muscle samples were rapidly removed and flash frozen in liquid nitrogen prior to storage (—80" C). Nearly all birds could be classified as juvenile or adult by the extent of skull ossification (DeHaven et al. 1974). Protocols were approved by the University of Western Ontario Council on Animal Care Animal Use Subcommittee (protocol #2005-060-08) and appropriate collection permits were obtained from the Canadian Wildlife Service (CA 0170, CA 0230) and the U.S. Fish and Wildlife Service (MB758364- 1 issued to F. R. Moore). Wild Sparrows. — Migratory White-throated Sparrows were captured using mist nets in April bpring, n = 8) and October (fall, n = 26) near Uong Point, Ontario. Eleven wintering sparrows were captured during January near Stone ville, Mississippi at the Delta Experimental Forest. Birds were anesthetized with isofluorane and euthanized by cervical dislocation. The right pectoralis muscle was removed and immediately frozen in liquid nitrogen. Samples were stored at C until analysis. Age was classified as juvenile or adult (DeHaven et al. 1974). Lipid Extraction and Analysis. — Lipids were extracted following a modified Folch procedure 1 Folch et al. 1957). Pectoralis samples (100 mg) Were homogenized in 2.5 mL chloroform/methanol (2;1 v/v) containing 25 mg/L butylated hydro- xytoluene as an antioxidant. Total lipid extracts were centrifuged (2,056 X g) for 15 min, 1 mL of - % KC1 so|utjon was added, and samples were leated in a water bath for 10 min at 70° C to ^eparate the aqueous and lipid-soluble components. e resulting organic layer was removed and dried Lincler a stream of nitrogen, followed by re¬ suspension in 1 mL chloroform/methanol (2:1 v/ v) containing 25 mg/L butylated hydroxytoluene. Extracts were stored at -20° C prior to analysis. Sphingomyelin from bovine brain (Sigma, Oak¬ ville, ON, Canada) was used as an internal standard in wild sparrow samples and L-oc-phosphatidyl-L- serine (PS) from Glycine max (Sigma) was used as the internal standard in captive sparrow samples to correct for sample loss during extraction. Both internal standards were chosen because sphingo¬ myelin and PS were below detection threshold in preliminary analyses of our tissues. We used thin layer chromatography coupled to a flame ionization detector (TLC-FID) to separate and quantify phospholipids (De Schrijver and Vermeulen 1991). Samples were spotted (1.5 pL) using a syringe (Pressure Lok VICI Precision Sampling, VICI Valeo Canada, Brockville, ON, Canada) and developed on a quartz rod coated with a thin layer of silica oxide (Chromarod, Shell-USA, Fredericksburg, VA, USA). The spotted samples were developed in a solvent system consisting of chloroform: methanol: water (20:12:1) (Sherma and Fried 2003). Chromarods were analyzed with an Iatroscan MK-6 instrument (Mitsubishi Kagaku Iatron, Tokyo, Japan) using the following settings: flow rate of 2 L/min air, 160 mL/min hydrogen, and scanning speed of 3.0 s/cm. FID results were analyzed with PeakSimple 3.29 software (SRI instruments, Torrance, CA, USA), which generated area counts (AC) for each separated lipid component. Phos¬ pholipid classes were identified by comparison to a mix of polar standards containing PC (L-ot- phosphatidylcholine, Type XVI-E —99%, Sigma), PE (L-a-phosphatidylethanolamine, Type III: from egg yolk -98%, Sigma), sphingomyelin, and PS. Standard curves were developed using phospholipid standards (PC and PE). Area count data for PC and PE were normalized based on the recovered internal standard, and were used for the final calculation of PC/PE ratios. Statistical Analysis.— The statistical signifi¬ cance level was set at oc = 0.05 for all statistical tests. SPSS software (Version 17, SPSS Inc., Chicago, IL, USA) was used for all analyses. Student’s /-tests were used to examine the effect of season on the PC/PE ratio in captive sparrows. A general linear model was used to test for effects of season and age, and their interaction on PC/PE ratios in wild birds. Student-Newman-Keuls test was used to examine differences among groups in wild birds. 118 THE WILSON JOURNAL OF ORNITHOLOGY* Vol 123, No. 1, March 2011 FIG. 1. Effects of migratory condition on muscle membrane PC/PE ratio in captive White-throated Sparrows subjected to photoperiod manipulation. There is no significant difference in the PC/PE ratios between long day (migratory) and short day (non-migratory) sparrows. Sample sizes for each group are presented across the top. Data are means + SE. A single long day adult had a PC/PE ratio of 3.42. FIG. 2. Effects of season and age on the muscle membrane PC/PE ratio in free-living White-throated Sparrows. There was a significant interaction between season and age. ^Wintering adults had a higher PC/PE ratio than adults in other seasons (P < 0.05). Sample sizes for each group are presented across the top. No juveniles were caught in spring. Data are means + SE; samples with unknown age are not shown. Two more wintering sparrows of unidentified age had PC/PE ratios of 2.1 and 3.4, and two more fall sparrows of unidentified age had PC/PE ratios of 1.41 and 1.17. RESULTS TLC-FID clearly resolved the phospholipid classes in the standard mix. The only measurable phospholipids in the muscle samples were PC and PE, we therefore concentrated our analyses on the ratio of PC to PE. The total PC concentration exceeded the total PE concentration in 89% of wild sparrows and 100% of captive sparrows. Age was not investigated as a factor influencing the PC/PE ratio in captive birds because only one of the captives was an adult; this bird had a notably high PC/PE ratio (3.42). The PC/PE ratio among captive sparrows did not vary by photo¬ period treatment ( P = 0.34; Fig. 1). The PC/PE ratio varied significantly with season and age among free-living sparrows, but there was a significant interaction between age and season (P = 0.032). There was no significant effect of season within juveniles (. P = 0.48) but, within adults, wintering birds had higher PC/PE ratios than migrants (P < 0.05, Fig. 2). Body mass had no effect when included as a covariate in the analysis. DISCUSSION Common polar head groups include serine, inositol, choline, and ethanolamine, but only the latter two are found in high concentrations in skeletal muscle (Mitchell et al. 2007); our results are in accordance with this previous observation. PC has a relatively large head group in relation to its fatty acid moieties, and forms a cylindrical molecular shape. Conversely, PE has a relatively small head group in relation to its fatty acid moieties, which results in a conical molecular shape and destabilizes membranes, making them more fluid (Logue et al. 2000). We focused on the ratio of PC/PE because the balance of these two phospholipids is important in affecting membrane characteristics (Logue et al. 2000). Membrane class composition may change adaptively for many reasons, including regulation of membrane fluidity, integrity, and interactions with membrane-bound proteins (Hazel 1995, Nagahuedi et al. 2009). Our results from wild sparrows are consistent with an increase in muscle membrane fluidity during migratory periods, although this may have been offset by a decrease in the double bond index of the fatty acid composition (Klaiman et al. 2009). It is unclear, however, why the season effect was only observed in adults. Our results are not consistent with any endogenous change to phospholipid class compo- Springer et al • CHANGES IN WHITE-THROATED SPARROW MUSCLE 119 sition associated with migratory condition. How¬ ever, the lack of adults in the captive study may have precluded observation of the seasonal pattern demonstrated by wild birds. It is also possible the photoperiod manipulation caused the birds to display classic migratory behavior (Zugunruhe and hyperphagia), yet was not sufficient alone to induce changes in the PC/PE ratio. Seasonal changes to the PC/PE ratio may only be induced by the higher intensity training of migratory flight itself, rather than pre-migratory conditioning, as suggested previously for membrane fatty acid composition (Price et al. 2010). A training effect is plausible, given that Gorski et al. (1999) found that PE increased relative to PC in the red gastrocnemius muscles of rats after exercise training. Klaiman et al. (2009) concluded that diet was a greater factor than exercise or migratory condition in producing the patterns they observed in their study of seasonal changes in membrane fatty acid composition in White-throated Sparrows. Diet can atfect phospholipid class composition as well (Innis and Clandinin 1981), and could explain the current results from wild birds, but only if adults and juveniles forage in different ways during winter. This is also supported by the high PC/PE ratios observed in the captive sparrows (relative to wild sparrows), as they were fed the same commercial diet that may differ from natural lorage. Our study indicates that composition of phospholipid classes in muscle membranes can vary seasonally, but data linking phospholipid class compositional changes directly to migratory exercise or migratory condition, rather than diet variation, remain equivocal. ACKNOWLEDGMENTS fhis work would not be possible without the organization Stance of collaborators D. J. Cerasale and D. M. ^jac. We thank J. T. McFarlan for help with field work. ar> Gartshore and Peter Carson generously provided pCC^ss t0 ^eir land and other assistance. Paul Hammil and Moore aided our fieldwork and provided a collection Permit for wintering birds. C. L. Milligan provided valuable ^'*ce an(l criticism. Funding was provided to CGG by an • kC Canada Discovery Grant, the Canada Foundation |0r Innovation, and the Ontario Ministry of Research and ^novation. literature cited Gatsuma, R. and jyj Ramenofsky. 2006. Migratory ehaviour of captive White-crowned Sparrows, Zono- trichia leucophrys gambelii. differs during autumn and spring migration. Behaviour 143:1219-1240. Ayre, K. J. and A. J. Hulbert. 1997. Dietary fatty acid profile affects endurance in rats. Lipids 32:1265-1270. Ayre, K. J., S. D. Phinney, A. B. Tang, and J. S. Stern. 1998. Exercise training reduces skeletal muscle membrane arachidonate in the obese (fa/fa) Zucker rat. Journal of Applied Physiology 85:1898-1902. De Schruver, R. and D. Vermeulen. 1991. Separation and quantitation of phospholipids in animal tissues by latroscan TLC/FID. Lipids 26:74-76. Dehaven, R. W., F. Crase, and M. R. Miller. 1974. Aging Tricolored Blackbirds by cranial ossification. Bird-banding 45:156-159. Folch, J.. M. Lees, and S. G. H. Sloane. 1957. A simple method for the isolation and purification of total lipids from animal tissues. Journal of Biological Chemistry 226:497-509. Gerson, A. R., J. C. Brown, R. Thomas, M. A. Bernards, and J. F. Staples. 2008. Effects of dietary polyun¬ saturated fatty acids on mitochondrial metabolism in mammalian hibernation. Journal of Experimental Biology 21 1:2689-2699. GDrski, J.. M. Zendzian-Piotrowska, Y. F. de Jong, W. Niklinska, and J. F. C. Glatz. 1999. Effect of endurance training on the phospholipid content of skeletal muscles in the rat. European Journal of Applied Physiology and Occupational Physiology 79:421-425. GUDERLEY, H., E. KRAFFE, W. BUREAU, AND D. P. BUREAU. 2008. Dietary fatty acid composition changes mito¬ chondrial phospholipids and oxidative capacities in rainbow trout red muscle. Journal ot Comparative Physiology, Series B: Biochemical, Systemic, and Environmental Physiology 178:385-399. Guglielmo, C. G., T. D. Williams, G. Zwingelstein, G. Brichon, and J.-M. Weber. 2002. Plasma and muscle phospholipids are involved in the metabolic response to long-distance migration in a shorebird. Journal ot Comparative Physiology, Series B: Biochemical, Systemic, and Environmental Physiology 172:409- 417. juo, W., W. Xie, T. Lei, and J. A. Hamilton. 2005. Eicosapentaenoic acid, but not oleic acid, stimulates p- oxidation in adipocytes. Lipids 40:815-821. Iazel, J. R- 1995. Thermal adaptation in biological membranes: is homeoviscous adaptation the explana¬ tion? Annual Review of Physiology 57:19^12. Iulbert, A. J. AND P. L. Else. 1999. Membranes as possible pacemakers of metabolism. Journal of Theoretical Biology 199:257-274. nfante, J. P., R- C. Kirwan, and J. T. Brenna. 2001. Hi ah levels of docosahexaenoic acid (22:6n3)-con- taining phospholipids in high-frequency contraction muscles of hummingbirds and rattlesnakes. Compar¬ ative Biochemistry and Physiology, Part B: Biochem¬ istry and Molecular Biology 130:291-298. [nnis, S. M. and M. T. Clandinin. 1981. Mitochondrial- membrane polar-head-group composition ^influenced by diet fat. Biochemical Journal 198:231-^4. Klaiman, J. M., E. R. Price, and C. G. Guglielmo. 2009. 120 THE WILSON JOURNAL OF ORNITHOLOGY • Vol 123, No. 1, March 2011 Fatty acid composition of pectoralis muscle mem¬ brane, intramuscular fat stores and adipose tissue of migrant and wintering White-throated Sparrows ( Zo - notrichia albicollis). Journal of Experimental Biology 212:3865-3872. Li, Z., L. B. Agellon, T. M. Allen, M. Umeda, L. Jewell, A. Mason, and D. E. Vance. 2006. The ratio of phosphatidylcholine to phoshatidylethanolamine influences membrane integrity and steatohepatitis. Cell Metabolism 3:321-331. Logue, J. A., A. L. De Vries, E. Fodor, and A. R. Cossins. 2000. Lipid compositional correlates of temperature-adaptive interspecific differences in mem¬ brane physical structure. Journal of Experimental Biology 203:2105-2115. Maillet, D. and J.-M. Weber. 2006. Performance¬ enhancing role of dietary fatty acids in a long-distance migrant shorebird: the Semipalmated Sandpiper. Journal of Experimental Biology 209:2686-2695. McKenzie, D. J., D. A. Higgs, B. S. Dosanjh, G. Deacon, and D. J. Randall. 1998. Dietary fatty acid composition influences swimming performance in Atlantic salmon (Sal mo solar) in seawater. Fish Physiology and Biochemistry 19:111-122. Mitchell, T. W., R. Buffenstein, and A. J. Hulbert. 2007. Membrane phospholipid composition may contribute to exceptional longevity of the naked mole-rat ( Heterocephalus glaber ): a comparative study using shotgun lipidomics. Experimental Geron¬ tology 42:1053-1062. Mitchell, T. W„ N. Turner, A. J. Hulbert. P. L. Else J A. Hawley, J. S. Lee, C. R. Bruce, and S. J. Blanksby. 2004. Exercise alters the profile of phospholipid molecular species in rat skeletal muscle. Journal of Applied Physiology 97:1823-1829. Morgan, T. E., F. A. Short, and L. A. Cobb. 1969. Effect of long-term exercise on skeletal muscle lipid composition. American Journal of Physiology 216:82-86. Murphy, M. G. 1990. Dietary fatty acids and membrane protein function. Journal of Nutritional Biochemistry 1:68-79. y Nagahuedi, S., J. T. Popesku, V. L. Trudeau, and J.-M. Weber. 2009. Mimicking the natural doping of migrant sandpipers in sedentary quails: effects of dietary n-3 fatty acids on muscle membranes and PPAR expression. Journal of Experimental Biology 212:1106-1114. Pan, D. A., A. J. Hulbert, and L. H. Storlien. 1994. Dietary fats, membrane phospholipids and obesity. Journal of Nutrition 124:1555-1565. Pierce, B. J., S. R. McWilliams, T. P. O’Connor, A. R. Place, and C. G. Guglielmo. 2005. Effect of dietary fatty acid composition on depot fat and exercise performance in a migrating songbird, the Red-eyed Vireo. Journal of Experimental Biology 208:1277- 1285. Power, G. W. and E. A. Newsholme. 1997. Dietary fatty acids influence the activity and metabolic control of mitochondrial carnitine palmitoyltransferase I in rat heart and skeletal muscle. Journal of Nutrition 127:2142-2150. Price, E. R. and C. G. Guglielmo. 2009. The effect of muscle phospholipid fatty acid composition on exercise performance: a direct test in the migratory White-throated Sparrow (Zonotrichia albicollis). American Journal of Physiology - Regulatoiy, Inte¬ grative, and Comparative Physiology 297 :R775— R782. Price, E. R., J. T. McFarlan, and C. G. Guglielmo. 2010. Preparing for migration? The effects of photoperiod and exercise on muscle oxidative en¬ zymes, lipid transporters, and phospholipids in White- crowned Sparrows. Physiological and Biochemical Zoology 83:252-262. Ruf, T., T. Valencak, F. Tataruch, and W. Arnold, 2006. Running speed in mammals increases with muscle n-6 polyunsaturated fatty acid content. PLoS One l:e65. Sherma, J. and B. Fried (Editors). 2003. Handbook of thin-layer chromatography. Marcel Dekker, New York, USA. Turner, N., J. S. Lee, C. R. Bruce, T. W. Mitchell, P L. Else, A. J. Hulbert, and J. A. Hawley. 2004. Greater effect of diet than exercise training on the fatty acid profile of rat skeletal muscle. Journal of Applied Physiology 96:974-980. Valencak, T. G., W. Arnold, F. Tataruch, andT. Ruf- 2003. High content of polyunsaturated fatty acids in muscle phospholipids of a fast runner, the European brown hare ( Lepus europaeus). Journal of Compara¬ tive Physiology, Series B: Biochemical, Systemic, and Environmental Physiology 173:695-702. The Wilson Journal of Ornithology 123(1): 12 1-1 25, 2011 GEOLOCATION TRACKING OF THE ANNUAL MIGRATION OF ADULT AUSTRALASIAN GANNETS ( MORUS SERRATOR ) BREEDING IN NEW ZEALAND STEFANIE M. H. ISMAR,1'5 RICHARD A. PHILLIPS,2 MATT J. RAYNER,1’3 AND MARK E. HAUBER1 4 ABSTRACT.— The long breeding period and high reproductive investment of seabirds make use of resource-rich foraging areas pivotal both during and between breeding seasons. We tracked adult Australasian Gannets {Morus senator) from their New Zealand breeding colony at Cape Kidnappers to Australia during the non-breeding period to assess wintering behavior and migratory routes for this species. Data from three recovered geolocation sensor (GLS) tags showed that both a ma i e an a female M. senator , and a hybrid M. capensis X M. senator migrated across the Tasman Sea to winter in Australian and Tasmanian coastal waters. Tracked birds covered distances of up to 13,000 km on their migration. These movements were consistent with historical records of band recoveries. Received 28 April 2010. Accepted 29 September 2010. Adults of many seabird species, in systems with obligate biparental care, invest heavily during breeding (Brooke 2004). Life history theory predicts that parents must balance the costs of current reproduction with future attempts, and the availability of good foraging conditions is criti¬ cally important (Quillfeldt et al. 2005, Rayner et al. 2008). This is especially true as the inter¬ breeding period may be a time of peak mortality in the breeding cycle (Barbraud and Weimers- kirch 2003). Increasing attention has focused on assessing migration strategies and foraging areas °f seabirds during the non-breeding period (Phillips et al. 2006, Bost et al. 2009, Catry et al- 2009), since emergence of economical archival low-impact geolocator sensor (GLS) loggers fRayner 2007) with long battery lives (Afanasyev 2°04, Shaffer et al. 2006). The Australasian Gannet ( Morus senator) is a predominantly monogamous seabird with an obli- Sately biparental system, endemic to Australia and ^ew Zealand (Nelson 1978, Ismar et al. 2010a). Migration strategies, particularly of the New Zealand population, are poorly known. Large numbers of recoveries in Australia from banded School of Biological Sciences, University of Auckland, vate Bag 92019, Auckland, New Zealand. British Antarctic Survey, Natural Environment Re- !?rch Council, High Cross, Madingley Road, Cambridge CB3 0ET, UK. National Institute of Water and Atmospheric Research ld- (NIWA), P. O. Box 99940, Newmarket 1149, New Zealand. Department of Psychology, Hunter College of the City diversity of New York, 695 Park Avenue, New York, NY 1q065, USA. Corresponding author; e-mail: sism007@aucklanduni.ac.nz New Zealand breeding gannets include only one record of a bird known to be of sufficient age to breed (5 years; Hitchcock and Carrick 1958). This suggests a westward migration during the non¬ breeding season from New Zealand. Single band recoveries from dead adult Australasian Gannets have been reported between 2007 and 2010 from several New Zealand locations: Opotiki, Bay of Plenty; Wellington, Shelley Bay; Fiordland, South Coast; as well as two band recoveries from the Cape Kidnappers breeding site, and two observa¬ tions of marked live birds from a gannetry at Farewell Spit (Mala Nesaratnam, Department of Conservation, Wellington, NZ, pers. comm.). One recovery has been reported from Wollongong in New South Wales, Australia; the gannet had last been recorded in New Zealand as a fledgling. Migration to warmer, more productive waters has been recorded for gannet fledglings from New Zealand (Ismar et al. 2010b) and for adults of the congeneric Northern Gannet (M. bassanus) and Cape Gannet (M. capensis) that breed at temper¬ ate latitudes (Nelson 1978, Kubetzki et al. 2009). Thus, we hypothesized that breeding adult Australasian Gannets from New Zealand migrate to similar wintering areas as conspecific fledg¬ lings. Our objectives were to: (1) test the hypothesis that adult New Zealand breeding Australasian Gannets migrate to Australia be¬ tween breeding seasons and to provide the first detailed information on migration routes and timing, and (2) test the use of GLS devices to monitor wintering behavior of the species. METHODS Five breeding adult Australasian Gannets (which raised chicks in the 2007-2008 breed- 121 122 THE WILSON JOURNAL OF ORNITHOLOGY • Vol. 123 , No. 1, March 2011 ing season, Ismar et al. 2010a) at the Plateau Colony, Cape Kidnappers Gannetry, New Zealand (39 38' S, 177° 05' E) were equipped with GLS loggers (Phillips et al. 2004) on 21 February 2008 and 12 March 2008. Deployments were timed for close to fledging at this location (Ismar et al. 2010a). Devices were placed (1 = left, r = right leg) on two male (M-77108 [1], A08 [r] and M- 74777 [1], 111 [r]) and two female (M-77177 [1], All [r] and M-74768 fl], 768 [r]) Australasian Gannets. The fifth bird (M-77260 [r], B60 [1]) was the putative male offspring of a male Cape Gannet (M. capensis) and a female Australasian Gannet hatched in 2001—2002 (Robertson and Stephenson 2005), which had returned to breed at its natal colony. Gender of these banded individuals was ascertained from DNA samples following Daniel et al. (2007). The 3.5-g loggers (<0.2% of adult body weight) were attached with two cable ties to darvic PVC plastic leg bands (Rayner et al. 2008), and retrieved from birds A08, A77, and B60 early in the subsequent breeding season. All three birds subsequently bred in the 2008-2009 season. Birds M-74768 and M-74777 also returned to the Cape Kidnappers Plateau colony to breed in 2008, but had lost the GLS devices from the plastic bands. Geolocator data from the three retrieved devices were processed following Phillips et al. (2004). Times of sunrise and sunset were estimated from light records, and converted to location estimates using TransEdit and Bird- Tracker software (British Antarctic Survey, Cam¬ bridge, UK). Transitions associated with poor quality light curves were identified during pro¬ cessing, and the resulting positions were exclud¬ ed, as appropriate, after visualization in a GIS. Only longitudes were available around equinoxes, when daylength is similar throughout the world. The primary areas frequented by tracked birds were mapped as kernel density plots with the Spatial Analyst extension of ArcMap 9.3 (ESRI Inc. 1999) applying an ITRF 2005 geographic coordinate system (Fig. 1 ). Density contours were set to display the top 80% of spatial use around the Cape Kidnappers Gannetry, New Zealand, and at Australian wintering areas. A conservative estimate of the distances covered during migration was calculated for each bird, based on core areas of the kernel estimates (Cape Kidnappers Gan¬ netry, New Zealand; and top 20% of the kernel densities on the Australian/Tasmanian coast) with minimum distances between landmarks calculat¬ ed, assuming direct travel over water. Estimated FIG. 1 . Migration routes of (A) a male and (B) a female adult Australasian Gannets ( Moms serrator), and (C) a male hybrid between M. serrator and M. capensis between breeding seasons 2007-2008 and 2008-2009 at Cape Kidnappers Gannetry, New Zealand; colored symbols: highest quality positions obtained using geolocators; dashed lines: approximate migration routes inferred, lines darker with advancing time. migration paths between breeding and wintering areas were plotted for orientation, but should be treated as approximations, given the typical measurement errors of —186-202 km recorded Ismar et al. • MIGRATION OF AUSTRALASIAN GANNETS 123 FIG. 2. Time of year over weekly means of longitude during the non-breeding period for three adult gannets equipped with geolocators at Cape Kidnappers Plateau Colony; A08 male Australasian Gannet, A77 female Australasian Gannet, B60 male Cape Gannet X Australasian Gannet. in previous geolocation studies of seabirds (Phillips et al. 2004, Shaffer et al. 2005). RESULTS Both Australasian Gannets and the M. capensis x M. senator hybrid migrated across the Tasman ^a, spending between 2 (hybrid B60) and 4 months (Australasian Gannets A08 and All) in Australian and Tasmanian coastal waters (Pig- 2) before returning to the same subcolony at Cape Kidnappers (Fig. 1). These wintering areas were straight-line distances of 3,450 km (A08) and 2,350 km (All and B60) from the gannetry. Distances covered during migration between breeding seasons were at least 1 3,000 km for A08 (Fig. 1A), 5,800 km for All (Pig- IB), and 10,000 km for B60 (Fig. 1C). The male Australasian Gannet A08 (Fig. 1A) Passed the North Cape (176.48° E, 32.66° S) on !3 March 2008 and subsequently crossed the Tasman Sea to reach Bass Strait (147.73 E, 40.07° S) on 15 April 2008, from where it continued to the area of Kangaroo Island, South Australia, in the Great Australian Bight (139.79° E, 38.24° S; 22 Apr 2008). This bird spent 93 days in this region, before it passed Bass Stiait again on 24 July 2008. A08 appeared to follow the Australian East Coast somewhat northward (153.97° E, 34.71° S on 14 Aug 2008) before it crossed the Tasman Sea again and reached Cook Strait (174.77° E, 40.88° S) on 21 August 2008. The bird subsequently left New Zealand waters a second time to fly to the East Australian Coast (154.06° E, 28.29° S; 28 Aug 2008), via North Cape New Zealand (174.39° E, 35.20° S; 21 Aug 2008). It followed the Australian coastline south to Bass Strait (150.35° E, 42.76° S; 30 Aug 2008), and flew across the Tasman Sea taking a route via Stewart Island (167.16 E, 50.1° S; 08 Sep 2008) to its breeding location. This second trip across 124 THE WILSON JOURNAL OF ORNITHOLOGY • Vol. 123, No. 1, March 2011 the Tasman Sea to Australian coastal waters and back to the New Zealand gannetry was completed in 21 days, covering a minimum distance of 6,900 km. The female Australasian Gannet All (Fig. IB) appeared to use Cook Strait (173.72° E, 40.70° S; 1 Apr 2008) to cross the Tasman Sea towards Bass Strait (150.11° E, 39.41° S; 7 Apr 2008). Its wintering areas extended from Bass Strait both south of Tasmania (146.55° E, 44.95° S) and north along the Australian East Coast (150.88° E, 34.82° S), from where it crossed the Tasman Sea again after 1 19 days, and reached the Cape Kidnappers Gannetry via Stewart Island and West Cape, and the East Coast of the South and the North islands New Zealand (167.87° E, 46.97° S; 16 Aug 2008). It subsequently left Cape Kidnap¬ pers again for 23 days for the regions further north along the New Zealand East Coast, off the Bay of Plenty and the Bay of Islands. This female returned via the East Cape (178.79° E, 36.85° S; 22 Oct 2008) to its Cape Kidnappers breeding areas. The hybrid male B60 (Fig. 1C) started its migration from the region of the Bay of Plenty (179.03 E, 37.40 S) on 8 April 2008, circum¬ vented the North Cape (176.35° E, 34.58° S) on 1 1 April 2008, and appeared to follow the New Zealand west coast southward before starting its cross-Tasman flight from West Cape (167.43° E, 48.54 S) on 15 April 2008. B60 stayed 59 days (21 Apr 2008—19 Jun 2008) in and around its wintering areas as defined by the highest 80% kernel density, which resembled that of All. B60 spent 9 days in the region of the Lord Howe Islands (160.39° E, 34.90° S; 25 Jun 2008) on its flight across the Tasman Sea back to New Zealand, before it was tracked to waters north of North Cape (172.29° E, 33.12° S) on 7 July 2008. B60 consequently returned for 11 days to mid Tasman Sea waters (164.89° E, 36.25° S), before reaching the Cape Kidnappers breeding area again via the North Cape (176.42° E, 35.76° S; 25 Aug 2009) and the Bay of Plenty (179.12° E 33 14° S- 27 Aug 2008). Longitudinal movements of the three birds varied (Fig. 2). These birds spent 180, 208, and 142 days, respectively, away from the colony before their final return to the breeding site. DISCUSSION We provide the first direct evidence that both male and female adult Australasian Gannets migrate from New Zealand breeding areas to winter in Australian waters. A hybrid (Cape X Australasian Gannet, Robertson and Stephenson 2005) also displayed the same general pattern. Our study is suggestive of a high level of individual variability in routes, timing of arrival and departure, and duration and destination, suggesting considerable plasticity in migration behavior. Our findings indicate the importance of the Bay of Plenty and Bay of Islands north of the gannetry on the east New Zealand coast, which were frequented by all three tracked birds before departure on their trans-Tasman flights, or upon return to New Zealand prior to breeding. All three potential migration routes around New Zealand landmasses between Cape Kidnappers and the Tasman Sea (i.e.. North Cape, Cook Strait, and Stewart Island) were used. One bird (B60) appeared to forage extensively in the open waters of the Tasman Sea. However, sample sizes were small and further studies are required. Our results suggest adult migration behavior is more variable than that of fledglings, which appear to minimize time spent in flight and distance traveled over the open ocean (Ismar et al. 2010b). There may be less pressure on adults to travel directly because of their higher foraging efficiency (Nelson 1978). The female Australasian Gannet covered the shortest distance during migration, and spent the longest time away from the gannetry. This fits with a male accnied task of territorial establish¬ ment in the early breeding season, as found in the congeneric Northern Gannet (Nelson 2002). Thus, males should be more constrained in foraging ranges than females at this time of year. Asynchronous arrival at the breeding site by males and females is also suggested for M. serrator (Ismar et al. 2010a). Further research is needed to gain sufficient sample sizes to fully investigate differences in migration between male and female Australasian Gannets, and to compare migratory pathways and dynamics with birds from other New Zealand and Australian breeding locations. ACKNOWLEDGMENTS This research was funded by Education New Zealand through an International Doctoral Research Scholarship and by the Faculty of Science, University of Auckland (to SMHI), the University of Auckland’s Faculty of Science Research Committee (to MEH), and the British Antarctic Survey Ecosystem Programme (RAP). All research was conducted under Animal Ethics and Department of Conservation (DoC) research permits. The DoC, Napier Ismar et al • MIGRATION OF AUSTRALASIAN GANNETS 125 Office, kindly provided accommodation in the field, and Cape Kidnappers landowners and farm managers kindly gave admission to the property. We thank Michael G. Anderson, Sandra H. Anderson, Donald C. Dearborn, Andrea Gager, Jethro S. Johnson, Angela F. Little, Gabriel Machovsky-Capuska, Craig D. Millar, Mala Nesaratnam, Stuart Parsons, David Raubenheimer, Rachel C. Shaw, Vivian Ward, Sarah J. Withers for help in the field, and Scott A. Shaffer and an anonymous referee for constructive comments on the manuscript. LITERATURE CITED Afanasyev, V. 2004. A miniature daylight level and activity data recorder for tracking animals over long periods. Memoirs of the National Institute of Polar Research 58:227-233. Barbraud, C. and H. Weimerskirch. 2003. Climate and density shape population dynamics of a marine top predator. Proceedings of the Royal Society of London, Series B 270:2111-2116. Bost, C. A., J. B. Thiebot, D. 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The Wilson Journal of Ornithology 1 23(1): 126 — 1 31, 2011 BIRDS CONSUMED BY THE INVASIVE BURMESE PYTHON ( PYTHON MOLURUS BIVITTATUS ) IN EVERGLADES NATIONAL PARK, FLORIDA, USA CARLA J. DOVE,1-4 RAY W. SNOW,2 MICHAEL R. ROCHFORD,3 AND FRANK J. MAZZOTTI3 ABSTRACT. We identified 25 species of birds representing nine avian Orders from remains in digestive tracts of 85 Burmese pythons {Python molurus bivittatus ) collected in Everglades National Park, Florida, USA, from 2003 to 2008. Four species of birds identified in this study are of special concern in Florida and a fifth, the Wood Stork (Mycteria americana ), is listed as federally endangered. This represents the first detailed analysis of the avian component of the diet of the introduced Burmese python, now established in Everglades National Park, Florida and highlights the potential for considerable negative impact of this invasive species on native bird populations. Received 9 June 2010. Accepted 21 September 2010. The Burmese python ( Python molurus bivitat- tus) is now well established in Everglades National Park (ENP), Florida (Snow 2006, Snow et al. 2007c). These snakes, often considered a subspecies ol the Indian python (P. molurus ), can grow to 6 m and weigh 90 kg (Ernst and Zug 1996). The Burmese python was first recorded in the Everglades in 1979 and has since frequently been observed or collected in canals, along main park roads, and even in remote mangrove (red mangrove, Rhizophora mangle ; black mangrove, Avicennia germinans ; white mangrove, Laguncu- laria racemosa; buttonwood, Conocarpus e recta) backcountry areas (Snow et al. 2007a). Large specimens of this snake were reported in ENP In the 1980s (Meshaka et al. 2000) but have only been documented as breeding in the United States since 2006 (Snow et al. 2007b). The Burmese python has spread throughout ENP over the past two decades and has also been recorded in the Florida Keys and elsewhere in Florida. Typical food items consumed by the closely related Indian python ( P . molurus molurus) include mammals, amphibians, lizards, snakes, birds, and fish (Ernst and Zug 1996). Researchers are just now beginning to investigate the dietary habits of the Burmese python in ENP to help identify the impact of this invasive species on the 1 Smithsonian Institution, Division of Birds, NHB E-600, MRC 116, Washington. D.C. 20560, USA. ' South Florida Natural Resources Center, Everglades National Park, 40001 State Road 9336, Homestead FL 33034, USA. 3 University of Florida, Fort Lauderdale Research and Education Center, 3205 College Avenue, Fort Lauderdale FL 33314, USA. Corresponding author; e-mail: dovec^ si.edu native fauna (Snow et al. 2007a). Mammal species recorded as prey by the Burmese python in ENP include rodents and carnivores (Snow et al. 2007a), and as repotted by Greene et al. (2007), the endangered Key Largo woodrat (Neotoma floriclanci small 7). We identified birds consumed by Burmese pythons in ENP from 2003 to 2008 using a combination of feather identification techniques and morphological comparisons of osteological fragments. Many of the same samples examined were used to identify mammalian prey (Snowetal. 2007a). Continued documentation of the prey species of this invasive snake will add to our knowledge of the diet of the Burmese python in ENP, and alert conservation agencies, park offi¬ cials, and the pet trade of the potential devastation this species can cause to native bird populations that did not evolve with this type of predator. METHODS Eighty-five of 343 Burmese pythons (25%) collected within Everglades National Park loca¬ tions (Fig. 1) during 2003-2008 were found to have bird remains in the intestinal tracts. Standard mass (g) and measurements (cm) of total length and snout-vent length were available for most of the pythons examined. Intestinal tracts or gut contents of individual Burmese pythons were sent to the Feather Identification Laboratory, National Museum of Natural History, Smithsonian Institution, in Washington, D.C. for bird species identification. Identification of species of birds from fragmen¬ tary feathers has frequently been applied to ecological studies of prey remains (Day 1966, Gilbert and Nancekivell 1982, Griffin 1982, Ward 126 Dove et al. • AVIAN DIET OF BURMESE PYTHONS IN THE EVERGLADES 127 . FIG. 1. Everglades National Park, Florida and surrounding area showing collection sites of Burmese pythons examined this study (Map by M. R. Rochford). ■ I I IA I H Fuxo; 128 THE WILSON JOURNAL OF ORNITHOLOGY • Vol. 123, No. 1, March 2011 TABLE 1 . Size and mass ( x ± SD) of Burmese pythons that were feeding on birds and collected in Everglades National Park, Florida, USA (2003-2008). Range data for all measurements are estimated to the nearest decimal point. n Total length (cm) n Snout-vent length (cm) n Mass (g) Male 37 231.8 ± 52.6; range 91-325 37 202.1 ± 45.7; range 80-286 36 6,415 ± 3,524; range 990-17,054 Female 44 276.0 ± 72.4; range 1 14-475 44 243.7 ± 65.2; range 99-424 42 12,158 ± 1 1,778; range 490-56,690 Totals 81 255.8 ± 67.4; range 91—475 81 224.7 ± 60.5; range 80-424 78 9,508 ± 9,371; range 490-56,690 and Laybourne 1985) when ample material is available. Python gut samples were first sorted and cleaned following methods used by Sabo and Laybourne (1994) for dry pellets. Many of these samples were wet or frozen and often odoriferous. Thus, we worked in a fume hood to sort and conduct initial cleaning. Species identification methods used depended on the type, quality, and quantity of material, and on the extent of digestion of each sample. Large items of whole feathers, feather fragments, or partial bones were sub¬ sampled and cleaned separately. This reduced the amount of time in the cleaning process and left some material with the original sample for future analysis of other food items. Microscope slides were made from downy feather barbules in gut samples following Dove et al. (2005) for fragmentary evidence. The leather identification technique involved examin¬ ing the vaiiation in the microscopic characters of the plumulaceous (downy) barbs and comparison of whole feathers or large pieces of feathers to museum study skins stored in the Division of Birds, National Museum of Natural History. Microscopic identifications were primarily used to identify the material to taxonomic Order or Family (i.e., Rallidae, Anatidae) of each sample, and then in combination with other feather fragments, osteological material, geographic lo¬ cation, and circumstantial evidence associated with the sample to corroborate species identifica¬ tions. We counted samples that contained more than one species of bird (e.g., sample #128; Anatidae and Anhingidae) accordingly but were unable to ascertain if more than one individual of the same species was consumed in heavily digested samples. We used measurements of ~260 cm TL for females and >200 cm TL for males provided by Reed and Rodda (2009), to ascertain if pythons were mature. RESULTS Gender, length, and mass were available for most pythons examined. The ratio of males to females was nearly equal (37 males, 44 females). Males were smaller than females in both mass and body measurements (Table 1). Sixty-eight of the 85 Burmese pythons in this study were ascer¬ tained to be mature based on measurements. Burmese pythons were collected throughout ENP during every month of the year with most being collected in December and January. We identified 25 species of birds representing nine avian Orders from the 85 Bumiese pythons (Table 2). Eighty-nine individual birds were re¬ corded including 54 that were identified to species level, one identified to Order, 18 identified to Family, and 16 that were identified only as Aves (bird), due to lack of diagnostic feather material. Gruiformes (rails and allies) were the most numerous bird prey of Bumiese pythons and represented eight species and 32 individuals (36% of birds consumed). Ciconiiformes (herons and bitterns) were also common in the samples (18%) and included six of the 13 species occurring in Florida. Pied-billed Grebe (Podilymbus podiceps ), White Ibis ( Eudocimus albus ), and Limpkin ( Ararnus guarauna) were the species most com¬ monly identified, each occurring in seven differ¬ ent python samples. The most interesting prey item encountered was a Magnificent Frigatebird (F re gat a magnificens; sample #744) collected ~50 km from a known roosting area for frigate- birds (R. W. Snow, pers. obs.). Domestic Chicken ( Gallus gallus domesticus) was found in two separate samples and Domestic Duck (Anas platyrhynchos domesticus) in one sample col¬ lected near agricultural areas that abut the park. Four species identified, Little Blue Heron (Egretta ccierulea), Snowy Egret (E. thula ), White Ibis, and Limpkin are considered species of special concern by the Florida Fish and Wildlife Conservation Commission (Gruver 2010) and a fifth, the Wood Stork (Mycteria americana), is listed as federally endangered (Federal Register: 27 September 2006, Volume 71, Number 187). We found no evidence of eggs or chicks in any of the python samples examined. Dow et al. • AVIAN DIET OF BURMESE PYTHONS IN THE EVERGLADES 129 TABLE 2. Eighty-nine individual birds representing nine avian Orders and 25 species consumed by Burmese pythons in Everglades National Park, Florida, USA. Birds were identified in 25% of the 343 pythons collected during -003^ • Python field numbers shown in bold indicate multiple bird species consumed by one snake. Numbers in parentheses % of Order in diet rounded to nearest decimal point. _ Order Species Number of individual birds Python field number Podicipediformes (9) Pied-billed Grebe ( Podilymbus podiceps ) Podicipedidae (unidentified species) Pelecaniformes (3) Magnificent Frigatebird ( Fregata rmgnificens ) Anhinga ( Anhinga anhinga ) Ciconiiformes (18) Great Blue Heron ( Ardea hewdicis) Great Egret (A. alba) Snowy Egret ( Egretta thula ) Little Blue Heron ( E . caerulea) White Ibis ( Eudocimus albus ) Wood Stork ( Mycteria americana ) Ardeidae (unidentified species) Threskiomithidae (unidentified species) Northern Pintail ( Anas acuta) Blue-winged Teal (A. discors) Domestic Duck (A. platyrhychos domesticus) Anatidae (unidentified species) Domestic Chicken ( Gall us gallus domesticus ) Purple Gallinule {Porphyria martinica) Common Moorhen (Gall inula chloropus ) American Coot ( Fulica americana) Clapper Rail (Rallus longirostris) King Rail (R. elegans ) Virginia Rail (R. limicola) Sora ( Porzana Carolina ) Limpkin (A ramus guarauna ) Rallidae (unidentified species) Charadriiformes (1) Whimbrel ( Numenius phaeopus) Columbiformes (1) Columbidae (species unidentified) Passeriformes (5) House Wren ( Troglodytes aedon ) Red-winged Blackbird (Agelaius phoeniceus ) Eastern Meadowlark (Sturnella. magna) Passerine (unidentified species) Aves (unidentified species) Anseriformes (7) Galliformes (2) Gruiformes (36) AVES (18) Totals 7 1 1 2 1 1 1 1 7 1 2 2 1 1 1 3 2 2 1 3 2 4 1 2 7 10 1 1 1 1 1 1 16 89 104,124,202,339,364,740,846 504 744 128,844 547 491 484 327 113,168,492,580,760,887,918 539 503,552 177,804 1141 310 731 128,513,870 653,731 509,1158 451 325,546,553 379,781 242,362,437,478 163 500,535 129,363,373,460,507,5 14,551 120,196,316,341,369,512,549, 567,568,754 451 653 77 85 603 494 283,374,469,508,510,515,519, 528,538,555,561,563,727, 756,854,871 85 DISCUSSION Identification of prey remains from fragmen¬ tary evidence is vital to help document the diets of invasive predators. Our analysis demonstrates that even if the dietary material was heavily digested nnd in poor condition, we were able to provide species-level identifications for many of the samples. Most species-level identifications were based on the presence of whole feathers or large fragments of feathers and bone which allowed exact morphological comparison. This allows high confidence in the species-level identifica¬ tions, and microscopic analysis allowed us to obtain Family-level identification of gut samples that did not contain sufficient macroscopic material for whole feather/bone comparison. Seventeen of the samples noted as heavily digested contained large portions of avian feet, partial bills and skulls that assisted greatly with species identifications; these anatomical parts apparently are the last to be processed within the pythons’ digestive system. The Rallidae (rails and allies) was the group most heavily consumed by Burmese pythons in ENP. The threat of this unfamiliar predator to rails 130 THE WILSON JOURNAL OF ORNITHOLOGY • Vol. 123, No. 1, March 2011 and other birds is eminent. The seven species of rails identified occupy habitats in ENP that are familiar to the Burmese python and include both freshwater and brackish marshes, riverbanks, mud flats, and areas of dense vegetation. Rails have been particularly vulnerable throughout history to extinction on islands, mainly from introduced predators. The extinction of the Guam Rail ( Gallirallus owstoni) was the first documented case of a snake (brown tree snake, Boiga irregularis) being implicated as an agent of extinction (Taylor 1996). Limpkin were recorded in nearly 8% of the samples analyzed. This species typically nests in Florida from February through June, roosts in trees or shrubs at night, and forages noctumally year-round (Bryan 1996) making it particularly vulnerable to predation by the Burmese python. This python in ENP is noted as being nocturnal during June-August and mainly diurnal in October-April (R. W. Snow, pers. obs.), the closely related Indian python is active both day and night (Zug and Ernst 2004). The dietary habits of invasive pythons are broad and represent a threat to the native fauna of the diverse habitats that it is capable of inhabiting. Giound-dwelling birds such as rails and egrets are particularly threatened because not only are they susceptible to predation of eggs and young by resident carnivores and birds, but the adult age cohort has a newly established effective predator. The high reproductive rate, longevity, ability to consume large prey (Rodda et al. 2009), and consumption of avian species by pythons, is cause for serious conservation, educational, and eradi¬ cation measures. This predator is particularly hazardous to native bird populations in North America because birds have not evolved in conjunction with a large predator that has both diurnal and nocturnal feeding habits and is capable of consuming large and small prey items. Despite continuing discussions over the potential northward spread of these pythons by Rodda et al. (2009) and Pyron et al. (2008), Federal species recovery plans should seriously consider and address this novel threat in future plans. ACKNOWLEDGMENTS We are grateful to the many cooperators who collected and processed the samples that were analyzed in this study including Bob Hill, Mark Peyton, Jennifer Fells, Alex Wolf, Edward Lamivee, Rafael Crespo, and Brian Greeves. S. L. Olson (Smithsonian Institution) assisted with the identifi¬ cations of osteological material. Marcy Heacker (Smithso¬ nian Institution, Feather Identification Laboratory) present¬ ed these results to the Subcommittee on National Parks, Forests, and Public Lands of the House Committee on Natural Resources in Washington, D.C. Nancy Russell, South Florida Collection Management Center, Everglades and Dry Tortugas National parks coordinated shipping of samples and maintains the collections of ENP material. S. L. Olson, C. M. Milensky. R. W. McDianrtid (Smithsonian Institution), and two reviewers provided comments on the manuscript. The Feather Identification Laboratory is supported by interagency agreements with the U.S. Air Force, U.S. Navy, and Federal Aviation Administration. LITERATURE CITED Bryan, D. C. 1996. Family Aramidae (Limpkin). Pages 90-95 in Handbook of the birds of the world. Volume 3. Hoatzin to auks (J. del Hoyo, A. Elliott, and J. Sargatal, Editors). Lynx Edicions, Barcelona. Spain. Day, M. F. 1966. Identification of hair and feather fragments in the guts and faeces of stoats and weasels. Journal of Zoology of London 148:201-217. Dove, C. J., P. G. Hare, and M. Heacker. 2005. Identification of ancient feather fragments found in melting alpine ice patches in southern Yukon. Arctic 58:38^13. Ernst, C. H. and G. R. Zug. 1996. Snakes in question. Smithsonian Institution Press, Washington, D.C., USA. Gilbert, F. F. and E. G. Nancekivell. 1982. Food habits of mink ( Mustela vison ) and otter ( Ultra canadensis) in northeastern Alberta. Canadian Journal of Zoology 60:1282-1288. Griffin, C. R. 1982. The ecology of Bald Eagles wintering near a waterfowl concentration. Special Report 247. USDI, Fish and Wildlife Service, Washington. D.C., USA. Greene, D. U., J. M. Potts, J. G. Duquesnel, and R. W. Snow. 2007. Python molurus bivittatus (Burmese python). Herpetological Review 38:355. Gruver, B. J. 2010. Florida’s endangered species, threatened species, and species of special concern. Florida Fish and Wildlife Conservation Commission. June 2010, Tallahassee, USA. Meshaka Jr., W., F. Loptus, and T. Steiner. 2000. The herpetofauna of Everglades National Park. Florida Science 63:84-103. Pyron, R. A., F. T. Burbrink, and T. J. Guiher. 2008. Claims of potential expansion throughout the U.S. by invasive python species are contradicted by ecological niche models. PLoS One 3(8):e2931. doi: 10.1371/ journal. pone 0002931. Reed, R. N. and G. H. Rodda. 2009. Giant constrictors: biological and management profiles and an establish¬ ment risk assessment for nine large species of pythons, anacondas, and the boa constrictor: USDI, Geological Survey Open-File Report 2009-1202. Rodda, G. H., C. S. Jarnevich, and R. N. Reed. 2009. What parts of the US mainland are climatically suitable for invasive alien pythons spreading from Dove et al. • AVIAN DIET OF BURMESE PYTHONS IN THE EVERGLADES 131 Everglades National Park? Biological Invasions 11:241-252. Sabo, B. A. and R. C. Laybourne. 1994. Preparation of avian material recovered from pellets and as prey remains. Journal of Raptor Research 28: 192-193. Snow, R. W. 2006. Disposable pets, unwanted giants: pythons in Everglades National Park. Proceedings from Florida Exotic Plant Council, 21st Annual Symposium, Gainesville, USA. Snow, R. W., M. L. Brien, M. S. Cherkiss, L. Wilkins, and F. J. Mazzotti. 2007a. Dietary habits of the Burmese python, Python molurus bivittatus, in Ever¬ glades National Park, Florida. Herpetological Bulletin 101:5-7. Snow, R. W., V. M. Johnson, M. L. Brien, M. S. Cherkiss, and F. J. Mazotti. 2007b. Python molurus bivitatus (Burmese python) nesting. Herpetological Review 38:93. Snow, R. W., K. L. Krysko, K. M. Enge, L. Oberhofer, A. Warren-Bradley, and L. Wilkins. 2007c. Introduced populations of Boa constrictor (Boidae) and python Molurus bivittatus (Pythonidae) in southern Florida. Pages 416-438 in Biology of the boas and pythons (R. W. Henderson and R. Powell. Editors). Eagle Mountain Publishing, Eagle Mountain, Utah, USA. Taylor, P. B. 1996. Rallidae (Rails, gallinules, and coots). Pages 108-209 in Handbook of the birds of the world. Volume 3. Hoatzin to auks (J. del Hoyo, A. Elliott, and J. Sargatal, Editors). Lynx Edicions, Barcelona, Spain. Ward, F. P. and R. C. Laybourne. 1985. A difference in prey selection by adult and immature Peregrine Falcons during autumn migration. ICBP Technical Publication 5:303-309. Zug, G. R. and C. H. Ernst. 2004. Smithsonian answer book: snakes. Smithsonian Books, Washington, D.C., USA. The Wilson Journal of Ornithology 123(1): 132-1 36, 2011 INTERBREEDING OF AECHMOPHORUS GREBES ANDRE KONTER1 ABSTRACT. — I analyzed the occurrence of intermediates between Western ( Aechmophorus occidentalis) and Clark’s (A. clarkii ) grebes, of mixed pairings, and of species composition in populations of Aechmophorus grebes in California and Oregon, USA. Western Grebes comprised 69% of the aggregated total of grebes identified while intermediates represented ~3.5% (41-46 individuals) in the populations investigated. I conclude that numbers of intermediates between purebred parental individuals have increased. Higher percentages of mixed pairings were observed at Lake Almanor; an aggregated 7.9% of nesting pairs were not composed of two purebred grebes of the same species. Statistically, mating remained strongly assortative. Received 1 June 2010. Accepted 22 September 2010. The American Ornithologists’ Union split the two North American Aechmophorus grebes in 1985 into Western (A. occidentalis) and Clark’s (A. clarkii) grebes (AOU 1985). Both arose from a common ancestral population that divided into northern and southern subpopulations; differences between both developed during a period of geographical isolation (Storer and Nuechterlein 1985). More recently the ranges of both have become largely sympatric and differences in their advertising calls were identified as critical to their reproductive isolation (Nuechterlein 1981b). Genetic investigations suggest the taxonomy of Aechmophorus grebes might not be entirely settled (Ahlquist et al. 1987, Bledsoe and Sheldon 1989, Guerra and Speed 1996, Hebert et al. 2003, Savolainen et al. 2005, Ratnasingham and Hebert 2007). However, genetically low levels of differ¬ entiation cannot be used alone to establish species boundaries as they reflect the time of divergence of lineages (Ahlquist et al. 1987). A crucial question to be answered in the field is whether barriers to random mating between Western and Clark’s grebes are increasing or vanishing. My objectives were to investigate: (1) mixed pairings of Aechmophorus grebes, (2) the occur- lence of intermediates, and (3) the proportions of Clark’s and Western grebes at different locations in northern California and southern Oregon, USA. METHODS Study Sites. — Sites visited during the study and having grebes were Upper Klamath Lake, Lake Ewauna and Drews Reservoir, all in Oregon, Tule Lake National Wildlife Refuge (NWR), Lake Almanor, Lake Shastina, East Park Reservoir, all in California, and Goose Lake, straddling both 1 Museum of Natural History, 25, rue Munster, Luxem- ourg, L-2150 Luxembourg; e-mail: podiceps@pt.lu states. Water surfaces, elevations, and geograph¬ ical coordinates of study sites varied (Table 1). An additional survey was made along the Pacific Coast, south of Fort Ross, California when I unexpectedly encountered a group of Aechmo¬ phorus grebes at sea on 7 August 2009. Timing and Recording of Data— Study sites were visited for 1 2 days between 25 July and 5 August 2009. Three different areas were screened for grebes at Upper Klamath Lake: Moore Park and the Marina, Wocus Bay, and Eagle Ridge. Two screens were made at Lake Ewauna from Timber Mill Shores. Few grebes were observed at Goose Lake due to low water levels and the site was not further explored. Tule Lake NWR was visited by driving along the shore on two access roads. Each time grebes were encountered, I stopped to identify them. Two grebe colonies were present in the northwest part of Lake Almanor. Observations there occurred from the shore. East Park Reservoir was screened at four different access points. Low water levels at Lake Shastina permitted access by walking to a small island from where data were recorded. Aechmophorus grebes present were counted with the help of 10 X 25 Zeiss binoculars. All grebes sufficiently close for species identification were scanned using a Konica Minolta Dynax 7D camera with a Sigma AF 800 mm auto focus lens mounted on a tripod. After identification, the species (Western, Clark’s, or intermediate grebes) was registered by an assistant. The composition of all pairs encountered was also recorded. Photos were immediately taken of each intermediate, of each grebe with a doubt about a pure-bred species status, of mixed pairs, and of pairs comprising individuals with uncertain species status. Species status for nesting pairs at Lake Almanor was assessed per nest platform. Species status was also recorded for displaying pairs. Species distribution 132 Konter • AECHMOPHORUS GREBES 133 TABLE 1. Characteristics of study sites in California and Oregon, USA. Geographical coordinates Name Water surface (ha) Upper Klamath Lake ±25,000 Lake Ewauna ±100 Tule Lake NWR ±16,000 Goose Lake ±50,000 Drews Reservoir ±800 Lake Shastina ±740 Lake Almanor ±11,000 East Park Reservoir ±700 Elevation (m asl) N 1,260 42° 18' 839 1,245 42° 13' 170 1,220 41° 55' 956 1,435 41° 98' 910 1,495 42° 07' 208 845 41° 30' 854 1,395 40° 15' 334 365 39° 19' 311 E 121° 32' 675 121° 46' 457 121° 32' 675 120° 41' 085 120° 37' 145 122° 23' 346 121° 14' 055 122° 29' 417 and composition at each location was estimated based on identification from all samples. A x2_test using the VassarStats web site for statistical computation was applied to test if pairing by the grebes was random or assortative with respect to species. Identification of Grebe Species ( Western vs. Clark’s).— Species identification of exclusively adults followed the descriptions provided by Storerand Nuechterlein (1985) and their subdivi¬ sion of diverging areas of the face between Western and Clark’s grebes into lores, above eye, behind eye, and below eye (Storer and Nuechterlein 1985: 103, fig. 1) complemented by descriptions in Ratti (1981), Eichorst and Parkin (1991), and Konter (2009). Little interme¬ diacy and no overlap between both species is to be found in adults during the breeding season from April to October. Individuals were classified as Clark’s Grebes if they had an orange-yellow bill with a sharply defined black culmen, white lores and white feathers above, behind, and below the eye so the black crown ended clearly above the eye. Individuals were classified as Western Grebes if they had a dull yellow-green bill and the black of the crown extended to below the eyes. All grebes not entirely conforming to the descriptions of purebred Western or Clark s grebes were a priori classified as intermediates, unless divergence was minimal, in which case they were classified as ±Westem or ±Clark’s grebes. The term “intermediate” as applied here ts not limited to first generation hybrids, but may include backcrosses. RESULTS Numbers and species composition of popula¬ tions observed varied (Table 2). Not considering possible intermediates, I found an aggregated 69% of Western Grebes, which represented the majority of the grebes at Tule Lake NWR, Lake Almanor and, to a lesser extent, Lake Shastina. Western Grebes were present over three times as often as Clark’s Grebes in the group seen along the Pacific Coast. Forty-one grebes were classified as intermedi¬ ates between Clark’s and Western grebes. Another five differed only slightly from purebred grebes and their status was unclear. Intermediates represented between 0.6% (Tule Lake NWR) and 4.4-6. 6% (East Park Reservoir) of local populations, or an aggregated 33-3.1% of all grebes identified in this study (Table 2). Most grebes at Lake Almanor were nesting and no pairs tending young were found. Several pairs were building on rather recent platforms and others searched the colony lor a nesting space. Some individuals were still engaged in water courtship. The owners for 267 platforms could be identified: 246 were occupied by purebred pairs composed of either two Western (n = 197, 80.1%) or two Clark’s grebes ( n = 29, 12.0%). Four pairs (1.5%) were mixed, com¬ posed of one Western and one Clark’s grebe. Nine of the observed intermediates (3.4%), were paired with partners that remained unidentified, another seven (2.6%) were paired to purebred Western (n = 4) or Clark s grebes (n — 3), and one pair (0.4%) was composed of two interme¬ diates. Thus, 7.9% of the aggregated nesting pairs were not composed of two purebred grebes of the same species. This percentage was 27.8% (n = 5) for 18 displaying pairs: one pair was composed of two intermediates, two additional intermediates displayed with two Western Grebes, and two pairs were composed of one Western and one Clark’s Grebe. 134 THE WILSON JOURNAL OF ORNITHOLOGY • Vol. 123, No. 1, March 2011 TABLE 2. Adult Clark’s (CG), Western (WG), and intermediate grebes (IG, ±CG, ±WG) in surveys and proportions of pure and intermediate grebes by survey site. Location CG WG Intermediates IG ±CG ±WG Total population % CG-WG % IG, ±CG, ±WG East Park Reservoir 60 25 4 1 1 94a 66-27% 4.4-6.6% Drews Reservoir 4 2 1 ~30 67-33% c Upper Klamath Lake 143 123 12 1 ~350a 5 1 — 44% 4.3-47% Lake Ewauna 48 21 90 70-30% 0 Tule Lake NWR 3 158 1 ~180a 2-97% 0.6% Lake Shastina 52 59 1 225 46-53% 0.9% Lake Almanor 77 462 23 1 2,112 14-82% 4. 1-4.3% Totals 387 850 41 2 3 3,081 31-69% 3.3-37% Pacific Coastb 19 64 170 23-77% Total population counted in areas surveyed. Birds were too far out for identifying intermediates. L Few grebes could be correctly identified at Drews Reservoir. The composition of observed pairings with known partners was strongly assortative (%2 = 236.49, df = 5, P < 0.0001) at Lake Almanor. This did not change if the nine intermediates with unknown partners were included, assuming an expected distribution of the partner’s species status (x2 = 230.13, df = 5, P < 0.0001, Table 3). No historical data about mixed pairings could be found for Lake Almanor. All pairs tending young at Tule Lake NWR were composed of purebred Western Grebes ( n = 34). DISCUSSION My study confirms strongly assortative mating between the two Aechmophorus species although, at Lake Almanor, the percentage of nesting pairs not composed of two purebred grebes of the same species (7.9%) largely exceeds those found in earlier studies in California and Oregon. For instance, Ratti (1979) recorded one mixed pair (2.8%, n = 36) in 1977 at Upper Klamath Lake and none at Tule Lake NWR (n = 139). Nuechterlein (1981a) observed only one mixed pair at Upper Klamath Lake in 1979, too. He found mixed pairs represented 3% of male-female courtship displays at Tule Lake NWR, but only 1.1% in breeding pairs (n = 91) in 1979. Ratti (1979), in over 600 independent observations of pairs in California and Oregon, found that mixed pairs represented 1 .2% of pre-nesting pairs and 0.25% (n = 766) of pairs with young. Lindvall and Low (1982), in other areas of sympatry, observed 0.6% (n = 161; 1974), Ratti (1979) 1.9% (n = 719; 1975) and 0.8% of mixed pairs (n = 506; 1976) at Bear River Migratory Bird Refuge. Ratti (1979) calculated that 1.2% of 1,185 pairs observed in 1975-1977 for all of Utah represented mixed pairs. The current study found increased numbers of intermediates representing ~3.5% in the popula- l , °bsei7ed and exPecte19 days, the precocial young departe t e nest wi in hatching, and 66% of nests successfully produced young. At least two adults participated in parenta care anc pair 1 appear to be maintained year-round. The home range of an adult radio-tracked for 7 months was . . ia in s^on fT selectively-logged forest contiguous to primary forest. This easily overlooked species may e more resi icn o levels of habitat degradation than previously suspected, but extensive deforestation throughout its range justifies status as ‘Vulnerable to Extinction’. Received 24 February 2010. Accepted 28 July 2010. Twenty species of Rallidae have become extinct since 1600, and 33 of the remaining 133 extant species (24%) are currently globally threatened (Taylor 1996). Cryptic habits compli¬ cate adequate assessment of conserv ation require¬ ments for many of these species (BirdLife International 2000). For example, population size, conservation status and, in some cases, even geographic distribution of the six species of Wood Rail that comprise the South American genus Aramides are currently unclear (Taylor 1996). Aramides Wood Rails are relatively large, primarily terrestrial birds that favor more wooded environments than many other rails (Ridgely and Greenfield 2001). Four members of the genus are thought to be globally threatened (Taylor 1996), including the Brown Wood Rail ( Aramides wolfi). This species is distributed at lower elevations aI°ng the western slope of the Andes in Colombia, Ecuador, and perhaps Peru (BirdLife International 2000). It is recorded from streams and swampy areas inside humid forest and secondary wood- iands (Ridgely and Greenfield 2001). The Brown ^ood Rail is reclusive, hard to observe, and vocalizes infrequently; its basic biology remains poorly known. Widespread habitat destruction within its range (Sierra 1996, Conservation International 2001) and its apparent absence from Department of Ecology and Evolutionary Biology, Llane University, 400 Lindy Boggs Center, New Orleans, LA 70118, USA. Center for Tropical Research, Rumipamba Oel41 y 10 Agosto, Quito, Ecuador. ’51 rue de Nantouar, 22660 Trelevem, France. Corresponding author; e-mail: jk@tulane.edu many localities (Ridgely and Greenfield 2001), have caused it to be considered ‘Vulnerable to Extinction’ globally (BirdLife International 2000) and ‘Endangered’ in Ecuador (Hilgert 2002). We provide the first detailed report of the basic biology, including nest site selection, nesting biology, and habitat use of the Brown Wood Rail. METHODS Field work was conducted at Bilsa Biological Station (79° 45' W, 0° 22' N, 330-730 m eleva¬ tion), a 3,500-ha private reserve operated by Fundacion Jatun Sacha within the 70,000-ha Mache-Chindul Ecological Reserve in Esmeraldas Province, Ecuador. Bilsa is approximately two- thirds undisturbed humid rain forest and one-third secondary forests (extensively logged with 10- 20 years of regeneration) or selectively-logged forests (high-graded 10-20 years ago). The surrounding area contains patches of primary, selectively logged, and secondary forests inter¬ spersed among areas used for cacao (Theobroma cacao ) cultivation, grazing livestock, and other agricultural uses. We conducted systematic surveys for Brown Wood Rail nests throughout Bilsa from January ?007 to January 2009. We monitored activity at nests from blinds using 10X binoculars to record status and behaviors, and recorded nest location and elevation using hand-held global positioning system (GPS) units. We quantified habitat char¬ acteristics around all but one nest by measuring canopy height, canopy openness (with a spherical densiometer), and number of trees with diameter at breast height (DBH) between 10 and 50 cm in 137 138 THE WILSON JOURNAL OF ORNITHOLOGY • Vol. 123, No. 1, March 2011 10-m diameter circular plots and >50 cm in 20-m diameter circular plots. We compared these data to equivalent measurements from 87 points at 200-m intervals along 17.5 km of trails in Bilsa that we used to survey for Aramides nests. We classified these 87 points as being in primary, altered, or secondary forest based on visual inspection and knowledge of land use history, and used a discriminant analysis to build a predictive model of group membership based on habitat characteristics. This model correctly assigned 85% of the 87 training points as primary (n = 41), selectively-logged ( n = 23) or secondary ( n = 23) forest. The two discriminant analysis functions were significant (Function 1, Wilks’ Lambda = 0.280, P < 0.001; Function 2, Wilks’ Lambda = 0.866, P = 0.008) and were subsequently used to classify the type of forest where Brown Wood Rail nests were found. We captured three adult Brown Wood Rails in mist nets between March 2007 and January 2009, and took morphological measurements and ap¬ plied three colored leg bands. We applied a lightweight radio transmitter (model PD-2; Holo- hil Systems, Carp, ON, Canada) using a Rappole harness (Rappole and Tipton 1991) to a breeding individual of unknown gender captured on 12 March 2008. The 3.8-g radio weighed <1% of the bird's total body mass. We tracked the individual using a TR4 receiver and a RA-2AK “H” antenna (Telonics, Mesa, AZ, USA) until the radio battery failed in November 2008. We suspended radio-tracking during nesting to mini¬ mize disturbance. We obtained locations of the bird at 30-min intervals during each radio¬ tracking session and recorded UTM coordinates using a handheld GPS unit. We plotted these cooidinates using the Animal Movement exten¬ sion in ArcView GIS 3.2 (ESRI 2006) and describe home ranges as minimum convex polygons (MCP’s) (Mohr 1947), and 95 and 50% fixed kernel isopleths using least-squares cross validation (Worton 1989, Seaman and Powell 1996). Means ± SD are provided for all measurements. RESULTS We found nine active nests and seven addition¬ al nests that had evidence of recent activity but which were not active when discovered. Nests were found in February (n = 3), March (n = 10), and April (/? = 3). Median clutch size was four eggs (mean = 3.7 ± 0.7, range = 2-4). Eggs were oval in shape and cream-colored with brown spotting at the ends; dimensions of one were 4.7 X 3.5 cm (Fig. 1 A). At least two adults shared incubation duties with replacement triggered by sharp, cracking vocalizations by the arriving adult. At most only a single adult was banded at any given nest, and we could not confirm whether more than two birds incubated. Maximum incubation period observed was 19 days, which should be considered the minimum for this species because all active nests had full clutches with discovered. Two of nine active Wood Rail nests were apparently depredated, one was abandoned, and six successfully fledged four young each. Hatch¬ ing was synchronous (on the same day) and young left the nest within 24 hrs of hatching. Chicks hatched with eyes open and were brooded almost continuously until departing the nest; we observed no feeding while the chicks were still in the nest. Chick plumage was dark brown with light brown longitudinal streaking and highly cryptic (Fig. IB), similar to that described for other Rallidae. At least two adults continued to care for the young for up to 10 days of age. Young chicks stayed together and were twice observed among the roots of a palm (Iriartea deltoidea) with stilt roots but were cryptic, moved rapidly, and difficult to observe. Nests were open cups atop stumps of fallen trees (n = 5 cases; mean tree DBH = 31.1 ± 16.2 cm, mean tree height = 1.5 ± 0.6 m), at the intersection of multiple trunks and/or lianas (n = 3 cases; DBH = 5.03 ± 1.0 cm, height = 4.1 ± 2.9 m), or in understory shrubs (n = 8 cases; DBH = 6.6 ± 3.6 cm, height = 2.8 ± 1.4 m). Average nest height was 1.8 ± 0.5 m (range = 1 .2-2.6) above the ground. Nests were constructed primar¬ ily of large, dead leaves (e.g., Araceae, Cecropia- ceae, Piperaceae, and ferns) and a few small pieces of dried vine, and were relatively bulk}' (exterior dimensions; 26.8 ± 8.3 X 28.2 ± 6.0 X 12.3 ± 4.0 cm; interior dimensions: 12.0 ± 1-7 X 20.0 ± 2.6 X 3.8 ± 1.0 cm). The interior was lined with a mixture of live and dead, smaller leaves (primarily Melastomataceae). Nests were constructed beneath leaves and ferns in low light environments, making them relatively cryptic despite their large size (Fig. 1C). Nests were found in forest areas where elevation averaged 551 ± 31 m asl (range = 448—587), canopy height averaged 15.2 ± 6.5 m, densiometer measures of canopy openness aver¬ aged 14.1 ± 6.9%, and there were 3.13 ± 2.1 Karubian et al. • BIOLOGY OF BROWN WOOD RAILS 139 (B) FIG. 1. Brown Wood Rail in Bilsa Biological Station, northwest Ecuador. (A) Interior of a nest with the average clutch size of four eggs. (B) Two recently-hatched chicks with two eggs about to hatch. (C) A nest 1 .6 m agl on top o a ree s up with vegetation temporarily pulled back for purposes of the photograph. (D) Adult. (Photograp s y photograph D by L. Carrasco). trees with DBH between 10 and 50 cm, and 0.44 ' 0.9 trees with DBH > 50 cm. Eleven nests were in secondary forest, four in selectively- l°gged forest, and one in primary forest. Com¬ parison of nest site to habitat availability in the Bilsa area (based on 87 sampled points) revealed Brown Wood Rails used secondary forests as nesting sites in a larger proportion than this habitat is available in the area we sampled (x22 = 13-74, P = 0.001). Morphological measurements for three individ- L'als of unknown gender were: mass (506.7 ± 61-1 g), tarsus (73.9 ± 1.0 mm), wing chord '175.8 ± 1.8 mm), tail length (52.4 ±1.7 mm), beak depth (16.5 ± 3.3 mm), beak width (8.9 ± H 9 mm), culmen from the distal edge of the nare *79.4 ± 1.8 mm), and exposed culmen (55.6 ± 9 1 mm). The eye ring and the iris were intensely bright red in all individuals (Fig. ID). We conducted 24 radio- tracking sessions and °btained 150 independent locations of a radio- marked bird of unknown gender between 12 March and 9 October 2008. This individual used a clearly defined territory whose overall MCP home range Slze was 13.5 ha; 95 and 50% kernel home range sizes were 9.0 and 0.9 ha, respectively. The radio- equipped individual was active throughout the day and at night was observed roosting 5 m above the forest floor in a ~7-m tall Melastomataceae tree, suggesting a diurnal pattern of activity. We opportunistically observed adults eating tadpoles from small puddles (10 cm2) in muddy trails and small streams on five separate occasions. The radio-marked bird was seen and/or heard with at least one other adult throughout the radio¬ tracking period. We recorded three distinct types of vocalizations: (1) a sharp, crackling vocaliza¬ tion audible at short distances used when nesting, heard when adults replace each other incubating or when adults called recently-hatched young; (2) a low frequency call audible for long distances used by adults of the same pair, perhaps to establish territoriality; and (3) a loud crackling call also audible over long distances which corresponds to the “kyow” of Ridgely and Greenfield (2001). DISCUSSION This is the first published account of the nesting biology and home range for any member of the 140 THE WILSON JOURNAL OF ORNITHOLOGY • Vol. 123, No. 1, March 2011 Aramides Wood Rails, a poorly known neotropical premontane rain forest averaging ~3 m of rain genus with several globally threatened members. Breeding of Brown Wood Rails coincided with peak rainfall and, although the clutch size of four eggs is relatively small compared to other Rallidae (Taylor 1996), nesting success was relatively high (66%). However, post-hatching mortality of young may also be high; at least one adult that successfully hatched young re-nested 14 days later, suggesting the young had been depredated. At least two adults contributed to incubation, brooding, and post-hatching care. We also observed and/or heard a second individual accompanying a radio-marked bird throughout the 7-month tracking period. We did not observe more than two adults together at any time. These preliminary data suggest Brown Wood Rails may form long-term, socially monogamous pair bonds. The home range size of 9.0-13.5 ha (95% kernel and MCP, respectively) for Brown Wood Rails is intermediate relative to other terrestrial rain forest species. Home range of the Chestnut Wood Quail ( Odontophorus hyperythrus, 275 g) in the Colombian Andes was 5.2 ha (Franco et al. 2006) and home range of the Chowchilla ( Orthonyx spaldingii . 150 g) in the Australian Wet Tropics was <2 ha (Jansen 1999). In contrast, the Banded Ground Cuckoo {Neomor- phus radiolosus , 433 g) we tracked for a similar time period in Bilsa had a home range of —50 ha (Karubian and Carrasco 2008). Movements of the radio-marked Brown Wood Rail suggest a clearly demarcated territory, and regular observations of footprints in the established core home range of this individual after the completion of radio¬ tracking suggest year-round residency. Brown Wood Rails in our study area appeared to exhibit a preference for secondary and selectively-logged forests. The entire home range of the radio-marked individual was restricted to secondary and selectively-logged forest, and a disproportionately high number of nests (15 of 16) we discovered were in secondary or selectively- logged forest. In contrast, the Banded Ground Cuckoo we tracked in the same general area of Bilsa restricted nesting and movements almost exclusively to primary forest (Karubian et al. 2007, Karubian and Carrasco 2008). Some A) amides species have been reported in drier habitats such as deciduous woodlands (Taylor 1996; R. S. Ridgely, pers. comm.), but the Brown Wood Rail may depend upon year-round avail¬ ability of water: the study area was humid per year (J. Karubian, unpubl. data). All foraging observations were of tadpoles in standing puddles or along creeks, and the individual we tracked was often in close proximity to water or muddy areas. Brown Wood Rails are cryptic, difficult to observe, unlikely to be captured by passive mist netting, and do not reliably respond to playback making censuses using traditional methods unre¬ liable. Local population size can be estimated with home range data with the caveat these data are only from a lone individual tracked for 7 months. Assuming that Bilsa contains 1,500 ha of suitable habitat (e.g., secondary and selectively- logged forest; Jatun Sacha Foundation, unpubl. data) and that the species forms socially monoga¬ mous pairs with territories 10-15 ha in size, Bilsa could possibly support 100-150 pairs. Interviews with local residents and our own observations suggest this species is relatively common when suitable forest occurs outside the boundaries of Bilsa. We observed four old nests (not included in the analyses) and footprints in fragments of secondary forest and cacao plantations outside Bilsa (but <500 m from continuous forest). Our preliminary conclusion is that population size of this species in the 70,000-ha Mache-Chindul Reserve may be several hundred pairs. Bilsa and surrounding areas where Brown Wood Rail presence was inferred or confirmed consist of a mosaic of habitat types in which secondary forests are often contiguous to primaiy forest. Brown Wood Rails may persist in and even prefer secondary forests, but more extensive land clearing that increases isolation of forest fragments is likely to adversely affect this species. Our findings suggest Brown Wood Rails may be relatively resilient to intermediate levels of habitat degrada¬ tion encountered in our study area, but we consider its’ current status as ‘Vulnerable to Extinction' to be justified given the continued and widespread deforestation occurring throughout its range. ACKNOWLEDGMENTS We thank the staff of Bilsa Biological Station and Fundacion Jatun Sacha for support, especially Carlos Aulestia and Juliet Birmingham. We also extend special thanks to T. B. Smith for support. This article was improved by comments by C. E. Braun, R. S. Ridgely, and an anonymous reviewer. All research was conducted with permission from Fundacion Jatun Sacha and approval from the Ecuadorian Ministry of the Environment (Permit Number 009-CI-FAU-DRE-MA) and the University of California, Los Angeles Institutional Animal Care and Use Karubian et al • BIOLOGY OF BROWN WOOD RAILS 141 Committee (ARC 2005-132-01). This project was support¬ ed by the Audubon Society (Los Angeles Chapter); Ecociencia; Disney Wildlife Conservation Fund; Chicago Zoological Society; Conservation, Food and Health Foun¬ dation; National Geographic Society; and the National Science Foundation (OISE-0402137). LITERATURE CITED BirdLife International. 2000. Threatened birds of the world. BirdLife International and Lynx Editions, Barcelona, Spain. Conservation International. 2001. Ecosystem profile: Choco-Manabi conservation corridor of Choco- Darien-westem Ecuador hotspot. Conservation Inter¬ national, Washington, D.C., USA. ESRI. 2006. ArcGIS 3.2. Environmental Systems Research Institute, Redlands, California, USA. Franco, P., K. Fierro-Calderon, and G. Rattan. 2006. Population densities and home range sizes of the Chestnut Wood-quail. Journal of Field Ornithology 77:85-90. Hilgert, N. 2002. Aramides wolfi . Pages 128-129 in Libro rojo de las aves del Ecuador. (T. Granizo, C. Pacheco, M. B. Ribadeneira, M. Guerrero, and L. Suarez, Editors). Simbioe, Conservation International, Eco- Ciencia, Ecuadorian Ministerio del Ambiente and IUCN, Quito, Ecuador. Jansen, A. 1999. Home ranges and group-territoriality in Chowchillas Orthonyx spaldingii. Emu 99:280-290. Karubian, J. and L. Carrasco. 2008. Home range and habitat preferences of the Banded Ground-cuckoo Neomorphus rcidiolosus. Wilson Journal of Ornithol¬ ogy 120:205-209. Karubian, J., L. Carrasco, D. Cabrera, A. Cook, and J. Olivo. 2007. Nesting biology of the Banded Ground- cuckoo. Wilson Journal of Ornithology 119:222-228. Mohr, C. O. 1947. Table of equivalent populations of North American small mammals. American Midland Naturalist 37:223-249. Rappole, J. H. and A. R. Tipton. 1991. New harness design for attachment of radio transmitters to small passerines. Journal of Field Ornithology 62:335-337 Ridgely, R. S. and P. J. Greenfield. 2001. The birds of Ecuador. Cornell University Press, Ithaca, New York, USA. Seaman, D. E. and R. A. Powell. 1996. An evaluation of the accuracy of kernel density estimators for home range analysis. Ecology 77:2075—2085. Sierra, R. 1996. Vegetacion remanente del Ecuador Conti¬ nental. Circa 1996. 1:1,000,000. Proyecto INEFAN/GEF and Wildlife Conservation Society, Quito, Ecuador. Tayuor, P. B. 1996. Family Rallidae (Rails, gallinules, and coots) in Handbook of the birds of the world. Volume 3. Hoatzin to auks (J. del Hoyo, A. Elliott, and J. Sargatal, Editors). Lynx Editions, Barcelona, Spain. Worton, B. J. 1989. Kernel methods for estimating the utilization distribution of home range studies. Ecology 70:164-168. Short Communications The Wilson Journal of Ornithology 1 23( 1 ): 142—145, 2011 First Description of Nests and Eggs of Chestnut-headed Crake ( Anurolimnas castcineiceps ) from Ecuador Galo Buitron-Jurado,1'2’3 Juan M. Galarza,1 and Danny Guarderas1 ABSTRACT. — We describe the nest and eggs of the Chestnut-headed Crake ( Anurolimnas castaneiceps) based on observations of two nests found in the border of the Lliquino River, Pastaza Province, Ecuador. Nests were found in June and December with birds incubating eggs. Both nests were on fallen logs covered by vines and epiphytes in natural small gaps. They were open cups and built principally with dead leaves. The coloration of the eggs was pinkish white with scattered brown spots, similar to other Amazonian rails and crakes. The nests were similar in structure to those of wood rails (Aram ides spp.) suggesting a close relation¬ ship between Anurolimnas and Aramides. Received 24 May 2010. Accepted 14 October 2010. Information about nesting of birds such as nest architecture and placement may help clarify either phylogenetic relationships among taxa or selec¬ tive pressures on breeding biology (Zyskowski and Prum 1999, Greeney et al. 2008). Nesting data are also useful for conservation because they may allow predicting potential impacts of land use practices on bird populations (Monterrubio-Rico and Escalante-Pliego 2006, Greeney et al. 2008). Crakes, gallinules, and coots (Rallidae) are a nearly cosmopolitan group of marsh- and swamp- inhabiting birds. Some species are common and widespread in many tropical habitats, but infor¬ mation on the natural history of several species remains unknown because of their secretive habits. Details about the breeding biology of eight neotropical species of rails, including the Chest¬ nut-headed Crake (Anurolimnas castaneiceps ) are still lacking (Taylor 1996). The range of the Chestnut-headed Crake is in western Amazonia from eastern Colombia to northwestern Bolivia (Hilty and Brown 1986, 1 Museo de Zoologia, Escuela de Biologfa, Pontificia Universidad Catolica del Ecuador, Casilla 17-01-2184. Quito, Ecuador. - Current address: Laboratory de Biologfa de Organis- mos, Centro de Ecologfa, Instituto Venezolano de Investi- gaciones Cientfficas, Apartado 2032, Caracas 1020- A Venezuela. Corresponding author; e-mail: galobuitronj@yahoo.es Taylor 1996, Tobias and Sheldon 2007). It is a fairly common bird in Ecuador and occurs in secondary woodlands, humid forests, and season¬ ally-flooded forests in the eastern lowlands (Ridgely and Greenfield 2001). It is a cryptic species and there are few data available about its behavior and natural history. We present the first description of the nest and eggs of the Chestnut- headed Crake from Lliquino River, Pastaza Province in Ecuadorian Amazonia. METHODS We conducted several surveys at seven local¬ ities as part of a bird diversity study in the Lliquino and Villano river drainages from Febru¬ ary to December 2008, Pastaza Province, Ecua¬ dor. The Lliquino and Villano rivers are small tributaries of the Pastaza River in the Ecuadorian Amazonia. The area is characterized by continu¬ ous lowland evergreen rain forest (Sierra 1999). The forest canopy was 25 m tall with scattered emergent trees 35 m in height. Common tree species included Iriartea deltoidea , Otoba glyci- carpa, Grias neubertii, and several species of Inga. The topography of the basin was hilly and many streams flow through it. The climate is wet and rainy. Climatic data for the locations are not available but the average annual precipitation recorded at the closest meteorological station in Puyo is 4,500 mm (6-year average) (INAMHI 2006). Nests were discovered inside the vegetation during walks through the area. The first was ~5 km from the Kichwa village of Pandanuque, ~27 km southeast of the town of Sarayacu (01 44' S, 77 29' W, 427 m asl), Pastaza Province. The second nest was near the Kichwa village of Huito, 1 0 km west of the location of the first nest. Access was by helicopter. Dimensions of eggs and nests were measured with calipers to the nearest 0.1 mm. The egg found in the second nest was weighed using a pesola scale. Color names follow Smithe (1975). 142 SHORT COMMUNICATIONS 143 description of nests and eggs We discovered the first nest at — 1730 hrs on 13 Jane 2008 with an adult incubating two eggs. It was in a gap within the forest next to a trail, —200 m from the Lliquino River margin (01° 31' S, 77 33' W. 327 m asl), Pastaza Province, Ecuador. At first contact, the bird’s identity could not be accurately ascertained because it rapidly flushed. However, several photographs were obtained at a later visit in the afternoon of 19 June (Fig. 1A). We found a second nest on 8 December 2008 on the border of the Lliquino River (01° 28' S, 77° 32' W, 442 m asl) near the Kichwa community of Huito. An adult flushed quickly from the nest that contained only one egg. We visited the nest during the night of 12 December 2008 to properly identify the nest owner and take photographs (Fig. 2A) and mea¬ surements. We visited nests at night because of the tendency of adults incubating both nests to flush when we tried to photograph them during the day. Birds at both nests were identified as Chestnut¬ headed Crake because of their chestnut head with an olive-brown mid-line extending from the nape to the back. The bill was black and yellow, legs pinkish red, and irises red (Figs. 1 A, 2A). The first nest (Fig. IB) was on a fallen tree trunk (69 cm diameter), covered by abundant epiphytes and vines, 1.3 m above ground. Vegetation around the nest was dominated by vines, large-leaved plants (Maranthaceae), Iriar- tea deltoidea palms, and Melastomataceae with nearby bamboo (Guadua august ifolia) patches. The canopy above the nest was open, but many live plants around and above the nest provided shade. The nest was oriented to the west and we estimate it received sunlight from mid-day to mid- afternoon. The nest was surrounded by abundant leaves and attached to the twigs of a vine-tangle growing on the trunk. The second nest was also on a fallen trunk, 0.5 m above the ground next to a ravine. The nest was surrounded by abundant vegetation with many vine leaves ( Alchornea , Anthurium ), which concealed and provided shade t0 toe cup. The second nest was also in a gap with an open canopy. Both nests were similar in shape. The first nest Was a flat and bulky bowl-shaped platform (Pig- 1C). The nest base and exterior consisted °f a broad mass of large dead leaves, including an Anthurium (Araceae) leaf with a length of 430 mm. The cup included Virola spp. (Myristi- caceae) leaves, as well as woody material (i.e., FIG 1 (A). Chestnut-headed Crake ( Anurolimnas castaneiceps) incubating, June 2008, Lliquino River Pastaza, Ecuador. (B). First nest of the chestnut-headed Crake with two eggs, June 2008, Lliquino River, Pastaza, Ecuador. (C). Detail of the interior of the first nest, Lliquino River, Pastaza, Ecuador. (Photographs by G. Buitron-J). sticks, vine twigs). Sticks were the main material supporting and surrounded the eggs. Moss abun¬ dantly grew over the trunk next to the nest but it was not part of the nest materials. The outer diameter of the nest was 200 X 170 mm (measured at perpendicular angles). The inner cup diameter was 53.9 X 70.1 mm and the depth was 100 mm. The second nest was also a bulky bowl-shaped platform built with many dead 144 THE WILSON JOURNAL OF ORNITHOLOGY • Vol 123, No. 1, March 2011 Many dead leaves were the base of the second nest increasing the depth. Eggs were sub elliptical and pale pinkish buff (Smithe 1975: #12 ID) with a white wash and scattered tiny dark grayish brown (Smithe 1975: # 20) marks and spots (Fig. 2C). Dimensions of the egg in the second nest were 38.3 X 28.4 mm and it weighed 16 g. DISCUSSION FIG. 2. (A). Second nest of incubating Chestnut-headed Crake. December 2008. Lliquino River, Pastaza. Ecuador. (B). Detail of the interior of the second nest with one egg Lliquino River. Pastaza, Ecuador. (C). Details of Chestnut¬ headed Crake egg. December 2008. Lliquino River, Pastaza Ecuador. (Photographs by G. Buitron-J). leaves (2B). Twigs and leaves provided support for the egg as in the first nest. Nests dimensions were: outer diameter = 151.5 X 106 mm, inner cup diameter = 104.5 mm, and depth = 205 mm. The two nests of the Chestnut-headed Crake were similar in building materials and architecture to nests of wood rails (A ram ides spp.) (Hilty and Brown 1986, Taylor 1996, Vaca et al. 2006; J. Karubian, unpubl. data). These non-aquatic Ralli- dae inhabit tropical lowland rain forest and have nests built with loosely attached leaves. Informa¬ tion concerning nest architecture of Aramides is incomplete as nests of two species remain to be described (Taylor 1996). The nest is a bowl¬ shaped platform for the rest of Aramides species and primarily composed of leaves or weeds (Taylor 1996). Nests of the Red-winged Wood Rail ( Aramides calopterus) and Brown Wood Rail (A. wolfi) are bulky bowl-shaped platforms built with twigs and covered by leaves or weeds (Vaca et al. 2006, Carrasco and Mena 2008; J. Karubian, unpubl. data). Species inhabiting more open habitats (scrubby pastures, rice fields), including Giant (A. ypecaha) and Gray-necked (A. cajanea) wood rails, have nests that are deep bowls which also include green and dead leaves (Taylor 1996, Di Giacomo and Krapovickas 2005). This type of nest is also reported for the Uniform Crake ( Amaurolimnas concolor ), a species closely relat¬ ed to Aramides (Stiles 1981). Nests of the Chestnut-headed Crake, Uniform Crake, and Aramides wood rails share a similar bowl shape. They are not domed and are built mainly of leaves and woody material. The nests of the Chestnut-headed Crake differed from those of the Russet-crowned ( Laterallus viridis) and Black-banded (L. fasciatus) crakes. Both species have been included with the Chestnut-headed Crake in Anurolimnas by some authorities (e.g- Taylor 1996, Remsen et al. 2008) because of their similar plumage pattern. The nest of the Russet- crowned Crake is a ball of dead grass with a side entrance, while that of the Black-banded Crake is a domed and bulky ball of grass with a side entrance (Hilty and Brown 1986, Taylor 1996). This type of nest architecture is similar to that reported for species of Laterallus whose nests are SHORT COMMUNICATIONS 145 a ball of grasses or a semi- domed cup without leaf masses (Ripley and Beehler 1985, Taylor 1996). Our observations of the nest structure of the Chestnut-headed Crake suggest a closer relationship of this species with Aramides and Amurolimnas than with the Russet-crowned or Black-banded crakes. Previous information concerning Chestnut- headed Crakes in the Neotropics reports birds in breeding condition in June (Colombia) and nearly grown young in June (Bolivia) (Hilty and Brown 1986, Taylor 1996). One of our nests coincides with a probable breeding period in June within the end of the wet season in the Ecuadorian Amazon. We observed and photographed a nestling, presumably of a Grey-breasted Crake (Latercillus exilis ) in a nearby locality in July, suggesting that breeding activity of rallids may occur between May and July in Ecuadorian lowlands, during the rainless period. The breeding season of the Chestnut-headed Crake appears to not be con¬ strained to a short period and it is possible this species is an opportunistic breeder, nesting whenever appropriate conditions exist. This is suggested by the different dates of the two nests we discovered with eggs. Higher breeding activity in northeastern Ecuador has been reported during the months of August to September, although nests have been reported throughout the year for a large variety of avian species (Greeney et al. 2004. Greeney and Gelis 2008). We suggest this topic requires further study because there are few data available concerning breeding season of birds in Ecuadorian Amazonia. ACKNOWLEDGMENTS We are grateful to Hugo Navarrete for inviting us to be Part of the team of the Scientific Biodiversity Assessment tor the Villano Project performed by the Pontificia Universidad Catolica del Ecuador. This study was funded by Eni E&P Division and Agip Oil Ecuador and has been conducted with the participation of Fauna & Flora International. Any comments, interpretations or conclusions ln this study are those of the authors, and are not necessarily agreed with or supported by Agip Oil Ecuador or Eni E&P hi vision. Our research near the Lliquino and Villano rivers authorized by the Ecuadorian Ministry of Environment, Permit # 010-1C-FAU/FLO-DREN-P/MA. We also ac¬ knowledge Victor Navarrete and Marco Benalcazar for logistic support. Christian Borja and Augusto Sola assisted tinring fieldwork. We thank Luis Carrasco, who shared the unpublished observations concerning nests of Aramides Wolfi- Corrections that improved the manuscript were provided by Juan Fernando Freile, Diego Lombeida, Gifford Keil, and two anonymous referees. LITERATURE CITED Carrasco, L. and J. Mena. 2008. Conservacion de Aramides wolfi en el Choco ecuatoriano. Informe Tecnico de medio termino. Programa Becas Fernando Ortiz-Crespo. Fundacion Ecociencia, Quito, Ecuador. Di Giacomo, A. and S. F. Krapovickas. 2005. Aves de la Reserva El Bagual. Temas de Naturaleza y Conservacion 4:201—465. Greeney, H. and R. Gelis. 2008. Further breeding records from the Ecuadorian Amazonian lowlands. Cotinga 29:62-68. Greeney, H., R. Gelis, and R. White. 2004. Notes on breeding birds from an Ecuadorian lowland forest. Bulletin of the British Ornithological Club 124:28-37. Greeney, H. F., R. C. Dobbs, P. R. Martin, and R. A. Gelis. 2008. The breeding biology of Grallaria and Grallar- icula antpittas. Journal of Field Ornithology 79: 113-129. Hilty, S. L. and W. Brown. 1986. A field guide to the birds of Colombia. Princeton University Press, Prince¬ ton, New Jersey, USA. INAMHI. 2006. Anuario Meteorologico Instituto Nacional de Meteorologfa e Hidrografia. Quito, Ecuador. Monterrubio-Rico, T. and P. Escalante-Pliego. 2006. Richness, distribution and conservation status of cavity nesting birds in Mexico. Biological Conservation 1 18: 67-78. Remsen Jr., J. V., C. D. Cadena, A. Jaramillo, M. Nores, J. F. Pacheco, M. B. Robbins, T. S. Schulenberg, F. G. Stiles, J. M. C. da Silva, D. F. Stotz, and K. J. Zimmer. 2008. A classification of the bird species of South America. American Ornithologists’ Union, http:// www.museum.lsu.edu/~Remsen/SACCBaseline.html. Ridgely. R. S. and P. Greenfield. 2001. The birds of Ec¬ uador. Cornell University Press, Ithaca, New York, USA. Ripley, S. D. and B. M. Beehler. 1985. Rails of the world, a compilation of new information, 1975-1983 (Aves: Rallidae). Smithsonian Contribution of Zoology 417: 1-28. Sierra, R. (Editor). 1999. Propuesta preliminar de un sistema de clasificacion de vegetacion para el Ecuador Continental. Proyecto INEFAN/GEF-BIRF, ECO¬ CIENCIA. Quito, Ecuador. Smithe, F. B. 1975. Naturalist’s color guide. American Museum of Natural History. New York, USA. Stiles, F. G. 1981. Notes on Uniform Crake in Costa Rica. Wilson Bulletin 93:107-108. Taylor, P. B. 1996. Family Rallidae (Rails, crakes, and gallinules). Pages 108-209 in Handbook of the birds of the world. Volume 3. Hoatzin to auks (J. del Hoyo, A. Elliott, and J. Sargatal, Editors). Lynx Editions, Barcelona, Spain. Tobias, J. and N. Seddon. 2007. Nine bird species new to Bolivia and notes on other significant records. Bulletin of the British Ornithological Club 127:49-84. Vaca, J. F.. H. F. Greeney, R. A. Gelis, C. Dingle, N. Krabbe, and M. Tidwell. 2006. The nest and eggs of Red-winged Wood-Rail Aramides calopterus in the foothills of north-east Ecuador. Cotinga 26:13-14. Zyskowski, K. and R. Prlim. 1999. Phylogenetic analysis of the nest architecture of neotropical ovenbirds (Fumariidae). Auk 116:891-911. 146 THE WILSON JOURNAL OF ORNITHOLOGY • Vol. 123, No. 1, March 2011 The Wilson Journal of Ornithology 123(1): 146-150, 2011 Breeding Biology of the Snowy-cheeked Laughingthrush 0 Garrulax sukatschewi) Jie Wang,1 2 Chen-Xi Jia,1 Song-Hua Tang,1 Yun Fang,1 and Yue-Hua Sun1,3 ABSTRACT. — Breeding of the poorly known Snowy¬ cheeked Laughingthrush ( Garrulax sukatschewi) was studied in a conifer-dominated forest at Lianhuashan (southern Gansu), China. Snowy-cheeked Laughing- thrushes nested at sites with fewer conifers and denser shrubs compared with the available vegetation. Bowl¬ shaped nests were 2.4 ± 0.1 m (x ± SE, n = 31) above ground in six plant species. Spruce (Picea spp.) was used (74%) more often than expected based on availability at nest sites. The breeding season (early May to mid Jul) was shorter than for other timaliids. Twelve of 20 (60%) nests with known outcomes were successful. The average clutch size was 3.5 ± 0.2 eggs (2-5, n = 21) with 2.7 ± 0.2 hatchlings (2-4, n = 15) and 2.2 ± 0.2 fledglings (1-3, n = 12) per nest. Incubation was by both males and females and lasted 14 days ( n = 1); both parents cared for the nestlings for 16-18 days (n = 3). Received 5 April 2010. Accepted 12 August 2010. The Snowy-cheeked Laughingthrush ( Garrulax sukatschewi) is largely restricted to a range of 28,500 km2 in the Min Shan Mountains of southern Gansu and northcentral Sichuan, China at elevations of 2,000-3,500 m (Collar et al. 2001). It is inferred to have a small, declining, severely fragmented population because of the destruction of temperate forests in its range through logging and conversion to agriculture (Collar et al. 2001). The species is categorized as Vulnerable by the IUCN (2009). Understanding a bird’s habitat requirements, social behavior, and breeding is essential for successful species conservation (Primack 1993). Apart from a few distribution records (Collar et al. 2001) and the description of a few nesting attempts (Li 1993, Bi et al. 2003), there is little published information on the ecology and conser¬ vation status of the Snowy-cheeked Laughing¬ thrush. We provide detailed information on the 1 Key Laboratory of Animal Ecology and Conservation Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China. "Current address: Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, Chinar Corresponding author; e-mail: sunyh@ioz.ac.cn breeding biology of this species with particular emphasis on nest-site selection and breeding parameters. METHODS Study Area. — The study was conducted in a conifer-dominated forest in the Lianhuashan Natural Reserve, southern Gansu (34° 57' N, 103° 46' E) as described by Sun et al. (2003). The forest occurs on north-facing slopes at elevations of 2,600-3,300 m; only grasses and shrubs grow on south-facing slopes. Coniferous forest, the most prevalent cover type (42%) in the study area, is dominated by Dragon spruce ( Picea asperata ) and Fargese fir (Abies fargesii). The other vegetation types are: (1) mixed coniferous-decid¬ uous forest, including variable amounts of willow (Salix spp.) and birch (Betula utilis and B. albo- sinensis ), and (2) shrublands, including willow, Sea buckthorn ( Hippophae rhamnoides ), and barberry ( Berberis spp.). Deciduous forest is uncommon in the area and, where it occurs, is adjacent to mixed deciduous-coniferous forest. The mean annual temperature at the study area is ~5. 1-6.0 C with a maximum of 34.0° C and minimum of —27.1° C. The climate is semiarid, and the annual precipitation is ~65 cm. Field Procedures. — We located Snowy-cheeked Laughingthrushes during four breeding seasons (Apr-Jul 2003, 2005, 2007, and 2008) and three non-breeding seasons (late Jul-mid Aug and Oct-Dec 2006, Sep 2007-Jan 2008) within 100 m of a 10.3-km long trail system by direct observations, and noted flock size and social interactions. We also played back calls, i.e., “hwii-u, hwii-u” (Collar et al. 2007), of the birds and recorded their response. Nests (27 active and 4 previously used) were located by systematically checking individual trees and shrubs during the breeding seasons. We measured the following variables for each nest after termination of nesting similar to the method of James and Shugart (1970): altitude, distance to forest edge, species and diameter at SHORT COMMUNICATIONS 147 breast height (DBH) of supporting plants (if >2 tree species, all species were recorded), height of the nest above ground, and distance between the nest and the stem of supporting plant. Slope exposure and orientation of the nest relative to the stem of supporting plant were recorded in 45 octants. The surrounding cover was estimated as the average proportion of the nest camouflaged when viewed from three different sides at a distance of 5 m. Overhead cover was estimated as cover that prevented light penetration, in 10% intervals. Locations of nests and inter-nest distances were ascertained with a global position¬ ing system (GPS) (Garmin eTrex Legend® HCx, Olathe, KS, USA). Habitat structure in a 10 X 10 m plot with each nest site or site where laughingthrushes occurred as the center was also measured. Vegetation type was classified as coniferous forest, mixed conif¬ erous-deciduous forest, deciduous forest, or shrubs. Cover (amount of sky obscured), and the numbers of conifers and shrubs with a DBH of >3 cm were also recorded. We made similar measurements to assess the preference of nesting habitats at 38 available sites within 19 territories (2 sites per territory) for comparison. We took measurements of the eggs and nestlings, once a nest was located, and monitored the nest every 2-4 days, or 1-2 days at critical times, to ascertain laying date, length of incuba¬ tion, time to fledging, nestling growth, fledging success, and incidence of nest predation. Laying dates were calculated by backdating for nests located when incubation had already begun or nestlings had hatched, using reproductive param¬ eters obtained from clutches for which complete data were obtained. Incubation or brooding behavior was docu¬ mented by occasional observations at four nests from a blind to reduce disturbance. Parental behaviors at one nest (containing 2 nestlings) were recorded during days 9-18 after hatching with an infrared video camera placed 0.5 m above the nest. One bird was caught in a mist net 20 m from the nest and marked with red lacquer sP0ts at the end of the tail to check whether both parents (morphologically indistinguishable) incu¬ bate or brood at night. Blood (200 pL) was taken for amplification of the CHD gene using the universal P2/P8 primers to ascertain gender (Griffiths et al. 1998). Data from all years were pooled for analysis using SPSS 13.0 for Windows (SPSS Inc. 2004). The percent values were arcsine transformed for f-tests and all tests were two-tailed. Values are given as mean ± SE. RESULTS Habitat Use and Social Behavior— Singles, pairs, and groups of Snowy-cheeked Laughing- thrushes accounted, respectively, for 10, 78, and 12% of observations (n = 132) in the non¬ breeding season (Sep-Apr). The corresponding figures were 75, 24, and 1% {n = 120) for the breeding season (May— Jun). The mean size of groups was 4.0 ± 0.2 (3-6) in the non-breeding season, and most groups (69%) included four individuals. Snowy-cheeked Laughingthrushes occurred in mixed deciduous-coniferous forests (88%), shrublands (9%), and coniferous forests (3%) at elevations of 2,400-3,200 m during all observations (n = 252). They seldom foraged in the abundant areas of moss and fallen needles under pure conifer stands, and were absent at higher elevations (3,200-3,560 m), dominated by dwarf willows and barberries, and absent at lower elevations (2,100-2,400 m) where crops, low shrubs, and human dwellings predominated. Snowy-cheeked Laughingthrushes appeared to be territorial in late April and May. Calls of one pair usually resulted in three to five neighboring pairs calling simultaneously (30 occasions). Playback of calls also initiated calling and/or approaches by 1-2 neighboring pairs to the speaker (7 of 20 occasions at 10 territory boundaries). Two pairs were observed chasing each other on the ground and performing a series of rapid pivoting and ducking movements from side to side while calling harshly in mid May (2 occasions), seemingly to defend territories. Dis¬ tances between the closest nests (found in 2007) averaged 100 — 30 m (55—250 m, n — 10). Nest Cycle: Days in Each Period.— Our earliest observation of nest building was on 3 May (2008) and the latest known fledging date was 13 July (2005) with an overall breeding season of ~72 days. Nest building lasted ~8 days (1 nest). There was a lull of 9 ± 1 day (7-12, n = 5) after nest completion. Onset of laying extended from 7 May (2008) to 10 June (2005) with a peak in late May. One unspotted greenish-blue egg was laid per day (n = 8 eggs in 2 sufficiently monitored nests). Scattered observations at four nests indicated continuous incubation started after laying of the last egg. All nestlings hatched in the same day (n = 2 nests) after 14 days of incubation (n = 1 nest), 148 THE WILSON JOURNAL OF ORNITHOLOGY • Vol. 123, No. 1, March 2011 TABLE 1 . Habitat characteristics at nest sites in > 1 4 independent home ranges of Snowy-cheeked Laughingthrushes at Lianhuashan, Gansu, China, during 2003-2008 in comparison with available sites. Habitat components Nest sites ( n Mean — 31) SE Available sites (n Mean = 38) SE t p Canopy cover (%) 72 4 55 3 3.15 000 Spruce-fir density (trees/ha) 455 68 674 66 -2 28 003 Birch density (trees/ha) 206 52 329 59 -1 52 0 13 Shrub density (shrubs/ha) 1,035 95 618 156 2 17 003 Shrub cover (%) 66 6 32 4 4.27 0.00 during which each egg lost -0.07 g (1.2%) of its mass per day on average. Hatchlings, weighing 4.7 ± 0. 1 g (4.60-4.75 g; n = 3), were largely naked with dull grayish-red skin and only a few gray-white down feathers on the capital, occipital, middle spinal, and femoral tracts. Nestlings opened their eyes at 7 days of age and fledged at 16-18 days of age (n = 3 nests). Mean nestling mass was 38.9 ± 0.7 g (n = 5) at 15-18 days post-hatching, about 54% of the adult mass (67.8- 74.0 g, n = 4). Growth rate (logistic regression model) was estimated to be 0.80 ± 0.01 g/day for three nestlings in one nest. Nest L°cc>tion and Description. — ' Thirty-one nests were in coniferous-deciduous forests (74%) or coniferous forests (26%); they were 13 ± 3 m 2 sn^om0"1 ^ f°reSt Cdge- at elevations of 2,800-^.900 m. Laughingthrushes favored north- east-facing slopes (30% of nests) with the mean steepness of 27 ± 1 ° (5-40°). Nest sites had lower pi uce-fir density, higher shrub density, and c-reater canopy cover and shrub cover than available sites (Table 1), suggesting the birds preferred nest sites with fewer conifers and denser shrubs. W®re. PIaced spruce (74.2%), fir c), or deciduous shrubs (honeysuckle [Loni- 7ZTV = 12'9%' wilIows = 3.2%, vines = f /0)- ;Spruce was used more often than expected rom observed availability at nest sites (y* = in thr’efrv 2' V ° °0)' NeStS Were constructed m three types of positions: 2.0 ± 0.1 m n 3_ = 34* °Ut from the trunk in larger conifers (DBH f45, >50, <112, and <125 min, respectively. Only the marked bird (i.e., female) incubated at night (4 observations). Video recordings at one nest (86.8 total hrs) indicated both adults brooded the young in the day but not at night on days 9-18 of the nestling period. Diurnal activities ended at 1841 hrs ± 10 min in 6 days. Length of on-nest bouts decreased slightly as nestlings grew larger, whereas length of off-nest bouts increased with means of 12.3 ± 0.9 min (2—65 min) and 18.8 ± 1.8 min (1-133 min), respectively. Brooding attentiveness decreased from 57% (day 11) to 21% (day 17), except for a sharp rise (58%) on day 14. Parents provisioned nestlings at a frequency increasing from 2.0 (day 11) to 6.0 times/hr (day 16) and decreased to 0 times/hr (day 18) with an overall average of 4.0 ± 0.2 times/hr (0-9 times/hr). Adults provisioned nestlings more intensively in the morning than in the afternoon, but with two peaks at 1200-1300 and 1700-1800 hrs. Frequency of removing (or eating) feces from the nest averaged 1.5 ± 0.2 times/hr (0-4 times/ hr, n = 65). The two young fledged synchro¬ nously at 0713 hrs on day 18. DISCUSSION Nesting Phenology and Nests. — Egg-laying (7 May-10 Jun) by Snowy-cheeked Laughingthrushes was similar to the Giant Babax ( Babax waddelli ) (Lu 2004). It was shorter than other common Garrulax species at similar latitudes, including Plain Laughingthrush (G. davidi) (late Apr-late Jul; Luo et al. 1992) and Brown-cheeked Laugh¬ ingthrush (G. henrici) (May-Aug; Lu et al. 2008). Nests of Snowy-cheeked Laughingthrush were placed higher than those of other Garrulax species in low bushes (1.1-3. 8 vs. 0.5-1. 5 m) (Cheng et al- 1987, Ali and Ripley 1996, Lu et al. 2008). Nest sites were lower than those of Giant Laugh¬ ingthrush (C. maxima) (2. 4-7.0 m), which were built in conifers (Wang et al. 2010). Nesting Success. — We observed partial loss of broods and unhatched eggs, possibly removed by parents but not predators. Similarly, the Chinese Hwamei (G. conorus) was reported to move eggs to a new nest when adults found people approaching the ongoing nest (Zhang 2002). Human predation of eggs or nestlings was not considered a threat, as local people were discour¬ aged from frequenting our study area because of research on other endemic birds. Possible preda¬ tors range from the diurnal Spotted Nutcracker (Nucifraga caryocatactes). Northern Goshawk (Accipiter gentilis ), and Siberian chipmunk ( Eu - tamias sibiricus) to the nocturnal leopard cat ( Prionailurus bengalensis ), all of which are common in the study area. Social Unit and Breeding Density. — Snowy¬ cheeked Laughingthrushes were in pairs (78%) during the non-breeding seasons, and most groups (69%) appeared to be units of two pairs, as two birds each foraged close and moved in different directions when we approached, similar to the previous description “It was in pairs in both winter and summer’’ (Dresser and Morgan 1899:271). The Snowy-cheeked Laughingthrush has been described as “rare”, “fairly common’’, and “uncommon’’ (Collar et al. 2001). The shortest distance (55 m) between nests was greater than that of Elliot’s Laughingthrush (G. elliotii) (30 m, Li and Huang 1991; 35 m, Jiang et al. 2007). Ten active nests were found in an area of 1 .2 km in 2007 (17 birds/ 100 ha), suggesting the density of Snowy-cheeked Laughingthrush is possibly mod¬ erate in the well-managed natural reserve. CONSERVATION IMPLICATIONS Spruce rather than fir was highly selected as nest substrates (70 vs. 6%), even though both are dominant (513 ± 71 vs. 161 ± 42 trees/ha, Sun et al. 2007), possibly because firs mainly occur inside coniferous forest, where the birds seldom nest. Snowy-cheeked Laughingthrushes preferred to nest in spruce and forage in mixed deciduous- coniferous forest, indicating the presence of spruce with abundant shrubs may be essential habitat requirements and the importance of protecting alpine scrub vegetation adjacent to and within the coniferous forest. The birds at Lianhuashan were restricted to narrower altitudes (2,400—3,200 m) than has been reported by others (2,000-3,500 m; Stattersfield et al. 1998), possibly due to previous logging and conversion of forest to croplands. The forest in the Lianhuashan Mountains is highly fragmented and 77% of forest patches are smaller than 10 ha due to logging over the past 30—40 years (Sun et al. 2006). Arrow bamboo ( Sinarundinaria nitida) clumps within the coniferous and coniferous- deciduous forests were nearly clear-cut by local people. The short breeding season, the degraded 150 THE WILSON JOURNAL OF ORNITHOLOGY • Vol. 123, No. 1, March 2011 and fragmented habitat, and the restricted range suggest the critical vulnerability of the Snowy¬ cheeked Laughingthrush. ACKNOWLEDGMENTS We are grateful to staff members of our research group and the Lianhuashan Natural Reserve, including Y.-X. Jiang, J.-L. Li, Y.-S. Zhang, X.-S. Liu, P.-P. Luo, and H.-Z. Chang for field assistance. We sincerely thank two anonymous reviewers, C. E. Braun, Gang Song, and J.-Z. Chen for comments on the manuscript, and Dan Strickland for help with English. Financial support was provided by the Chinese Academy of Sciences (Grant kscx2-yw-z-1021) and the National Natural Science Foundation of China (Grant 30620130110). LITERATURE CITED Ali, S. and S. D. Ripley. 1996. Handbook of the birds of India and Pakistan. Second Edition. Volume 7. Oxford University Press, New Delhi, India. Bi, Z.-L., Y. Gu, C.-X. Jia, Y.-X. Jiang, and Y.-H. Sun. 2003. Nests, eggs, and nestling behavior of the Snowy¬ cheeked Laughingthrush ( Garrulax sukatschewi ) at Lianhuashan Nature Reserve, Gansu, China. Wilson Bulletin 115:474-477. Cheng, T.-S., Z.-Y. Long, and B.-L. Zheng. 1987. Fauna Sinica, Aves. Volume 1 1 . Science Press, Beijing, China C0LLm'uur!' AN° C' Robson- 2007- Family Timaliidae (Babblers). Pages 70-291 in Handbook of birds of the : di uV°lu“ >2- Picathartes to tits and chickadees a del Hoyo. A. Elliott, and D. Christie, Editors). Lynx Edicions, Barcelona, Spain. Collar, N. J„ a. V, Adreev, S. Chan. M. J. Crosby S Subram anya, and J. a. Toblas. 2001. Threatened lrds of Asia: the BirdLife International Red Data Book. BirdLife International, Cambridge, United Kingdom Dresser. H. E. and E. D. Morgan. 1899. On new species 5:25o 277btained “ by M' Ber“°vsky. Ibis GR'™' a' nvCA °OUBLE’ K' °RR- and R' 1 Daws°n. Ecology^ 7:^071-1075 tQ *“ M°IeCUlar ILCrl."0<|9' IUCN Red List of Threatened Species. IUCN Gland, Switzerland. James, C. and H. H. Shugart Jr. 1970. A quantitative 24 72°7-7°36habltat deSCripti°n' Audubon Field Notes Jiang, Y.-X., Y.-Z. Zhu, and Y.-H. Sun. 2007. Notes on reproductive biology of Elliot’s Laughing Thrush at Zhuoni, Gansu. Sichuan Journal of Zoology 26: 555-556. Li, G. Y. 1993. The colour handbook of the birds of Sichuan. Chinese Forestry Press. Beijing, China. Li, H.-C. and Y. Huang. 1991. Ecology and habits of the Elliot’s Laughing Thrushes. Sichuan Journal of Zoology 10:34-35. Lu, X. 2004. Conservation status and reproductive ecology of Giant Babax Babax waddelli (Aves, Timaliinae), evidence to the Tibet plateau. Oryx 38:418^425. Lu, X., G.-H. Gong, and X.-H. Zeng. 2008. Reproductive ecology of Brown-cheeked Laughing Thrushes {Gar- rulax benrici ) in Tibet. Journal of Field Ornithology 79:152-158. Luo, S.-Y., Y.-T. Yang, and Y.-M. Zhang. 1992. Observation on ecology of the Plain Laughingthrush Garrulax davidi. Sichuan Journal of Zoolog}' 11:20-21. Primack, R. B. 1993. Essentials of conservation biology. Sinauer Associates, Sunderland, Massachusetts. USA. SPSS Inc. 2004. 13.0 User guide, Version 13.0 for Windows. SPSS Inc.. Chicago, Illinois, USA. Stattersfield, A. J., M. J. Crosby, A. J. Long, and D.C. Wege. 1998. Endemic bird areas of the world: priorities for biodiversity conservation. BirdLife International, Cambridge, United Kingdom. Sun, Y.-H., J. E. Swenson, Y. Fang, S. Klaus, and W. Scherzinger. 2003. Population ecology of the Chi¬ nese Grouse, Bonasa sewerzowi, in a fragmented landscape. Biological Conservation 110:177-184. Sun, Y.-H, S. Klaus, Y. Fang, P. Selsam, and C.-X. Jia. 2006. Habitat isolation and fragmentation of the Chinese Grouse {Bonasa sewerzowi) at Lianhuashan Mountains, Gansu, China. Acta Zoologica Sinica 52 (Supplement): 202-204. Sun, Y.-H., Y. Fang, C.-X. Jia, S. Klaus, J. E. Swenson, and W. Scherzinger. 2007. Nest site selection of Chinese Grouse Bonasa sewerzowi at Lianhuashan. Gansu, China. Wildlife Biology 13 (Supplement 1): 68-72. Wang, J., C.-X. Jia, S.-H. Tang, Y. Fang, and Y.-H. Sun 2010. Nests and breeding of the Giant Laughingthrush {Garrulax maximus) at Lianhuashan, southern Gansu. China. Wilson Journal of Ornithology 122:388—391. Zhang, X.-F. 2002. Studies on the propagational ecological habits and characteristics of wild Garrulax conorus. Acta Laser Biology Sinica 11:45-49. SHORT COMMUNICATIONS 151 The Wilson Journal of Ornithology 123(1): 151-154, 201 1 Reproductive Status of the Shiny Cowbird in North America William Post1,3 and Paul W. Sykes Jr.2 ABSTRACT. — We collected 17 (13 females, 4 males) Shiny Cowbirds ( Molothrus bonariensis) during the passerine nesting season in July 1999 and 2003 in Jasper County, southwestern South Carolina. Five females (38%) were laying eggs, as ascertained from the condition of their reproductive organs. Two females collected on 1 July 1999 and 19 July 2003 had eggs in their oviducts, and would have deposited eggs within 1 day. Shiny Cowbirds have been in North America for at least 24 years, but only males had been collected before this study. Most of those collected had enlarged testes, as did the four collected in the present study, but these data are not proof that breeding actually occurred. The reproductive condition of the females we collected provides material evidence that the species breeds in North America. It is not known which species are being parasitized by Shiny Cowbirds, but several species widespread in the southeastern United States are highly suitable hosts. Received 23 August 2010. Accepted 3 November 2010. The Shiny Cowbird ( Molothrus bonariensis ) in its expansion from South America was first recorded in Cuba in 1982, the northern Florida Keys in 1985, and the Florida mainland in 1987. Shiny Cowbirds were reported at nine coastal localities north of Tampa, Florida, north to northeastern North Carolina and west to south¬ western Louisiana from 1988 to 1990. They also appeared at interior localities, including Ft. Hood Texas and Winbom Springs, Oklahoma (Post et al. 1993, Cruz et al. 2000). Despite the Shiny Cowbird’ s expanding distribution, and relatively extended residency in North America, their breeding status has not been documented. This may be due, in part, to the similarity of Shiny Cowbird females and fledglings to Brown-headed Cowbirds (M. ater ), making it difficult to distin¬ guish them in the field. Shiny Cowbirds lay immaculate and spotted eggs (Lowther and Post 1999); the latter are similar to those of Brown- ' Charleston Museum, 360 Meeting Street, Charleston, SC 29403, USA. "USGS, Patuxent Wildlife Research Center Athens, darnel] School of Forest Resources, The University of Ge^gia, Athens, GA 30602, USA. Corresponding author; e-mail: grackler@aol.com headed Cowbirds (Lowther 1993). Shiny Cowbirds have been on the North American mainland for at least 24 years, but only a few reports provide evidence, all indirect, that breeding has actually occurred. Other than direct observations of females laying eggs, breeding can be verified by finding Shiny Cowbird eggs or young associated with an identified host species, and by genetic analysis of eggs, nestlings, and fledglings to distinguish them from Brown-headed Cowbirds. METHODS The study area bordered a dredge spoil-site next to the Savannah River in southwestern Jasper County, South Carolina (32 04.52' N, 80° 57.83' W). We captured Shiny Cowbirds in mist nets placed in coastal scrub at the edge of the spoil- site. About 30% of the net site consisted of open ground, either bare or covered with patches of grasses and forbs <30 cm in height. The remainder consisted of stands of woody vegeta¬ tion which, in order of importance, were com¬ posed of hackberry (Celt is laevigata ), cherry ( Prunus spp.), sweet gum ( Liquidambar styraci- flua ), and blackberry (Rubus spp.). We captured birds at one site, using three mist nets (6 m length, 30 mm mesh) placed in a triangular array around an elevated feeder provi¬ sioned with millet ( Panicum milleaceum ) seeds (Sykes 2006). The cowbirds were euthanized and then frozen. We recorded diameters of the three largest follicles and of any oviducal egg, the area (length X width) of the ovaries (females), and the dimensions of the testes (males) during examina¬ tion of the thawed specimens. We assigned age of the birds from plumage characteristics (Pyle 1997). Female Shiny Cowbirds and Brown¬ headed Cowbirds are about the same size, based on birds collected in or near our study site (mean mass of 13 M. ater = 34.2 g; 13 M. bonariensis = 33.6 g). We assumed the reproductive physiology of the two species is similar, and used the criteria of Scott and Ankey (1983) to ascertain laying rates. We estimated that laying would occur (1) within 1 day if an egg was in the oviduct, or (2) within 2 days, if the ovaries contained at least one 152 THE WILSON JOURNAL OF ORNITHOLOGY • Vol. 123, No. 1, March 2011 TABLE 1. Measurements of reproductive tracts of female Shiny Cowbirds collected in Jasper County, South Carolina in 1999 and 2003. SY (second-year): hatched the previous year. ASY (after-second-year): hatched at least 2 years earlier. Charleston Museum specimen # Date Age Area of ovaries (mm2) Diameter (mm) of: Largest follicle Oviducal egg 99.22.075 1 Jul 1999 SY 2.3 02.46.051 1 Jul 1999 ASY 71.4 5.0 05.2.036 1 Jul 1999 ASY 117.5 7.2 13.0 05.2.043 1 Jul 1999 ASY 110.0 7.8 05.2.044 1 Jul 1999 ASY 41.9 1.3 99.22.037 2 Jul 1999 ASY 160.2 8.8 99.22.048 2 Jul 1999 SY 8.1 99.22.069 2 Jul 1999 SY 116.5 9.7 99.22.072 2 Jul 1999 ASY 13.3 05.2.041 18 Jul 2003 SY 32.0 2.5 05.2.033 19 Jul 2003 ASY 21.8 8.3 10.3 05.2.040 19 Jul 2003 ASY 33.0 2.5 05.2.042 19 Jul 2003 ASY 30.0 2.5 pre-ovulatory (round, cream-colored or yellowish) follicle >7.9 mm diameter. Specimens were identified by bill shape and wing formula (Pyle 1997) and were saved as study skins. Identifica¬ tions were verified by comparisons with a series of M. b. minimus collected in the West Indies. rviiCiUJLtj) We collected 17 (13 female and 4 male) Shiny Cowbirds in 1999 and 2003. We collected nine females on 1-2 July 1999; six were after-second- year (ASy) and three were second-year (SY) birds # ns 9 t°ne/SY female (Charleston Museum UP.-.036), had an oviposited (oviducal) egg 3 mm in diameter, indicating she would have # 99a22e0387rtl!i,n ' day‘ An°ther ASY female ( V — 037 ) With an unovulated follicle 8.8 mm lameter had an extremely dilated cloaca, and presumably had laid an egg the day she was C#P99^n^l f* f6males (# 99-22-048 and : i?9'22'1°J69) had follicles >7.9 mm diameter nd would have laid eggs within 2 days. 1 A^‘r^'°Ur females (3 ASY and 1 SY) on u y 2003; one ASY female (# 05 2 033) had an oviposited egg 10.3 mm in diameter’ and mheTth1316 She W°Uld haVC Iaid within 1 dar the (3 h:r,rrYn0t Iaying (Table D- Thus five we examined Four males collected on 1-2 July 1999 had enlarged Mea. The lengths of ,he larges, lesres of two ASY males were 8.4 and 7.3 mm; those of two SY males were 6.2 and 6.3 mm. The testes of non-breeding Shiny Cowbirds usually diminish to <2 mm in diameter (WP, unpubl. data). Neither males nor females were molting. DISCUSSION The first suggestion that Shiny Cowbirds breed in North America was based on a 1991 observa¬ tion near Homestead, Florida. A Red-winged Blackbird ( Agelaius phoeniceus) was seen feeding a “very young” Shiny Cowbird which was “just starting song” (Pranty 2000: 516). The report is questionable, because fledglings of the Brown¬ headed Cowbird and Shiny Cowbird are not known to sing (Lowther 1993, Lowther and Post 1999) and, if they do, it is not known if their vocalizations can be used to differentiate them. Larry Manfredi (pers. comm, in Pranty 2000) saw a female cowbird, which he identified as a Shiny Cowbird, in April 1998, near Kendall, Florida, fly to an unattended Red-winged Blackbird nest. The cowbird sat on the nest 3^4 min, but it is not known if she laid an egg (Pranty 2000). Enlarged testes suggest the possibility of breeding, but verification depends on the repro¬ ductive status of females. The four males collected in this study had enlarged testes, as did one collected 1 0 August 2000 at the same site. Seven males collected in South Carolina and Florida during 30 April-25 July 1989-1991 had enlarged testes (Post et al. 1993). A male obtained at Ft. Hood, Texas on 23 May 1990 had enlarged testes (Greg Lasley, pers. comm.) as did one collected 21 May 2009 on Sullivan’s Island, South Carolina (WP, unpubl. data). We provide evidence that Shiny Cowbirds were laying eggs in South Carolina in 1999 and, based on the sizes of preovulatory follicles and the presence of oviducal eggs, estimate that five (38%) of 13 females collected in South Carolina in 1999-2003 were laying (Table 1). Additional evidence of breeding in North America has been provided by collection of two females, each with an egg in her oviduct: in Georgia in 2000 (Sykes and Post 2001), and in northcentral Florida in 2009 (Reetz et al. 2010). Shiny Cowbirds occur during the passerine breeding period on the Atlantic and Gulf coasts from South Carolina to Alabama (Lowther an Post 1999, Pranty 2000). They have been in the southeastern U.S. at least 24 years; this study and those of Sykes and Post (2001) and Reetz et al. SHORT COMMUNICATIONS 153 (2010) confirm that females are breeding, but it is not known which species they parasitize. Several hypotheses may explain why no information is available. (1) Competition with Brown-headed Cowbirds. This hypothesis is difficult to test, because of the scarcity of both species of cowbirds in regions where they co-occur (Post and Gauthreaux 1989, Stevenson and Anderson 1994, Beaton et al. 2003). Parasitism rates are low: Whitehead et al. (2002) on the central coast of South Carolina found only 13% of 346 nests parasitized, all by Brown-headed Cowbirds. Prather and Cruz (2002) in southwestern Florida found only 2% of 108 nests parasitized. Other studies in the southeastern U.S. have found cowbird-parasitized nests (Sargent et al. 1997, Kilgo and Moorman 2003) but, on the upper coastal plain and piedmont, outside the range of the Shiny Cowbird. (2) The similarity of eggs and young of the two cowbird species. This hypothesis has not been tested, because studies conducted in areas where Shiny Cowbirds occur have docu¬ mented few cases of parasitism by any cowbirds (Prather and Cruz 2002); another study found cowbird eggs, but all were believed to have been laid by two color-banded Brown-headed Cow¬ birds (Whitehead et al. 2000). (3) Lack of research in areas occupied by Shiny Cowbirds. This cowbird occurs on the coast from Alabama to South Carolina during the passerine breeding period but, other than Prather and Cruz (2002) and Whitehead et al. (2002), no recent studies of breeding songbird communities on the coast appear to have been published. Several species widespread in the southeastern U.S. are parasitized by Brown-headed Cowbirds and presumably would be used by Shiny Cow¬ birds. Whitehead et al. (2002) found 37% of 30 Yellow-breasted Chat ( Icteria virens ), 36% of 14 Painted Bunting ( Passerina ciris ), and 24% of 17 Blue Grosbeak (P. caerulea) nests parasitized in coastal South Carolina. The clutch sizes of three species were reduced by cowbird parasitism, and the seasonal fecundity of Blue Grosbeaks was lowered (Whitehead et al. 2000). These authors found two Red-winged Blackbird nests parasit¬ ized. This species is potentially a highly suitable host, considering its similarity to the Yellow¬ shouldered Blackbird ( Agelaius xanthomus), which is heavily parasitized in Puerto Rico (Post 1981). Prather and Cruz (2002) also found Red¬ winged Blackbirds parasitized in southern Florida, where they nests in mangroves, the habitat in which Shiny Cowbirds most often breed in Puerto Rico (Post and Wiley 1977), and in cordgrass (Spartina alterniflora ), which is similar to grami- noid vegetation used by Yellow-hooded Black¬ birds ( Chrysomus icterocephalus) parasitized by Shiny Cowbirds in Trinidad (Cruz et al. 1990). The Shiny Cowbird’ s population growth is correlated with a decrease of Yellow-shouldered Blackbirds in Puerto Rico (Post 1981), but cowbird control appears to have helped in slowing the blackbird’s decline (Wiley et al. 1991, Cruz et al. 2005). If Shiny Cowbirds continue to increase in North America, it is important to examine their effect on potential hosts such as Painted Buntings, which, because of other factors, are already at risk in portions of their range (Sykes and Holzman 2005, Sykes et al. 2006). ACKNOWLEDGMENTS The paper benefited from the reviews and useful comments of Peter Lowther, an anonymous reviewer, and the editor of this journal. Steve Calver, U.S. Army Corps of Engineers, arranged access to the study site. LITERATURE CITED Beaton, G., P. W. Sykes Jr., and J. W. Parrish Jr. 2003. Annotated checklist of Georgia birds. Occasional Publication Number 14. Georgia Ornithological Soci¬ ety, Atlanta, USA. Cruz, A., T. D. Manolis, and R. W. Andrews. 1990. Reproductive interactions of the Shiny Cowbird ( Molo - thrus bonariensis) and the Yellow-hooded Blackbird ( Agelaius icterocephalus) in Trinidad. Ibis 132:436-444. Cruz, A., J. W. Prather, W. Post, and J. W. Wiley. 2000. Spread of Shiny and Brown-headed cowbirds into the Florida region. Pages 47-75 in Ecology and management of cowbirds and their hosts (J. N. M. Smith, T. L. Cook, S. 1. Rothstein, S. C. Robinson, and S. G. Sealy, Editors). University of Texas Press, Austin, USA. Cruz, A., R. Lopez-Ortiz, E. Ventosa-Febles, J. W. Wiley, T. K. Nakamura, K. R. Ramos- Alvarez, and W. Post. 2005. Ecology and management of Shiny Cowbirds ( Molothrus bonariensis ) and endangered Yellow-shouldered Blackbirds ( Agelaius xanthomus ) in Puerto Rico. Ornithological Monographs 57:38-44. Kilgo, J. C. and C. E. Moorman. 2003. Patterns of cowbird parasitism in the southern Atlantic coastal plain and piedmont. Wilson Bulletin 115:277-284. Lowther, P. 1993. Brown-headed Cowbird ( Molothrus ater ). The birds of North America. Number 47. Lowther, P. and W. Post. 1999. Shiny Cowbird (Molothrus bonariensis). The birds of North America. Number 399. Post, W. 1981. Biology of the Yellow-shouldered Blackbird- Agelaius xanthomus on a tropical island. Bulletin of Florida State Museum Biological Science 26:125-202. 154 THE WILSON JOURNAL OF ORNITHOLOGY* Vol. 123, No. 1 , March 2011 Post, W. and S. A. Gauthreaux Jr. 1989. Status and distribution ot South Carolina birds. Contributions from the Charleston Museum, Number 18. Charleston, South Carolina, USA. Post, W. and J. W. Wiley. 1977. Reproductive interac¬ tions of the Shiny Cowbird and the Yellow-shouldered Blackbird. Condor 79:176-184. Post, W„ A. Cruz, and D. B. McNair. 1993. The North American invasion pattern of the Shiny Cowbird. Journal of Field Ornithology 64:32-41. Pranty, B. 2000. Possible anywhere: Shiny Cowbird. Birding 32:514-526. Prather, J. W. and A. Cruz. 2002. Distribution, abundance, and breeding ecology of potential cowbird hosts on Sanibel Island, Florida. Florida Field Naturalist 30:21-35. P\ le. P. 1997. Identification guide to North American birds. Part I. Slate Creek Press, Bolinas, California, USA. Reetz, M. J., J. M. Musser, and A. W. Kratter. 2010. Further evidence of breeding by Shiny Cowbirds in North America. Wilson Journal of Ornithology 122:365-369. Sargent, R. a., J. C. Kilgo, B. R. Chapman, and K. V. Miller. Nesting success of Kentucky and Hooded warblers in bottomland forests of South Carolina Wilson Bulletin 109:233-238. Scott, D. M. and C. D. Ankey. 1983. The laying cycle of Brown-headed Cowbirds: passerine chickens9 Auk 100:583-592. Stevenson, H. M. and B. H. Anderson. 1994. The birdlife of Florida. University Press of Florida, Gainesville USA. Sykes Jr., P. W. 2006. An efficient method of capturing Painted Buntings and other small granivorous passer¬ ines. North American Bird Bander 31:110-115. Sykes Jr.. P. W. and S. Holzman. 2005. Current range of the eastern population of Painted Bunting (Passerine ciris). Part 1: breeding. North .American Birds 59:4-17. Sykes Jr., P. W. and W. Post 2001. First specimen and evidence of breeding by the Shiny Cowbird in Georgia. Oriole 66:45-5 1 . Sykes Jr., P. W„ L. Manfredi, and M. Padura. 2006. A brief report on the illegal cage-bird trade in southern Florida: a potentially serious negative impact on the eastern population of Painted Bunting ( Passerina ciris). North American Birds 60:310-313. Whitehead, M. A., S. H. Schweitzer, and W. Post. 2000. Impact of brood parasitism on nest survival and seasonal fecundity of six songbird species in south¬ eastern old-field habitat. Condor 102:946-950. Whitehead, M. A., S. H. Schweitzer, and W. Post. 2002. Cowbird/host interactions in a southeastern old-field: a recent contact area? Journal of Field Ornithology 73:379-386. Wiley, J. W., W. Post, and A. Cruz. 1991. Conservation of the Yellow-shouldered Blackbird Agelaius xantho- mus, an endangered West Indian species. Biological Conservation 55:1 19-138. The Wilson Journal of Ornithology 123(1): 154 _ 158, 2011 Shift to Later Timing by Autumnal Migrating Sharp-shinned Hawks Robert N. Rosenfield,1-5 Dan Lamers,2 David L. Evans,3 Molly Evans,3 and Jenna A. Cava4 ABSTRACT.— Increasing proportions of Shar shinned Hawks (Accipirer striatus) migrated later autumn at the Hawk Ridge Bird Observatory, Dulut Minnesota during 1974-2009. Migration average about 4 days later over 35 years since 1974. and aboi days later during late September through October i the last 16 years of the study. Our results augme. previous findings demonstrating recent shifts in phene ogical events for birds. The proximate causes an potential consequences of this later timing of migratio 1 Department of Biology, University of Wiscom btevens Point, WI 54481, USA. 3 N4840 Foley Drive, Waupaca, WI 54981, USA. n ,H!WwI^ge Bird °bservatory, 2928 Greysolon Ro Duluth, MN 55812, USA. 5305^ USA8473 Schndder Drive’ Menomonee Falls, ’ Corresponding author; e-mail: rrosenfi@uwsp.edu should be investigated. Received 22 March 2010. Accepted 27 July 2010. Earlier timing of spring migration and egg- Jaying have been documented in relation to higher spring temperatures in a wide variety of temper¬ ate- zone birds in the Northern Hemisphere (e.g., Jenni and Kery 2003, Lyon et al. 2008, Miller- Rushing et al. 2008). Changes in bird migration times, with most attention on spring migration of passerines, are among the best-documented biological responses to increased temperatures (Miller-Rushing et al. 2008). Our objective was to investigate timing of autumnal migration of Sharp-shinned Hawks (Accipiter striatus) at Hawk Ridge Bird Observa¬ tory during 1974-2009. We chose the Sharp- SHORT COMMUNICATIONS 155 FIG. 1. Relationship between Julian dates of the 50th percentile of the seasonal total of migrating Sharp-shinned Hawks and year of migration at Hawk Ridge Bird Observatory, Duluth, Minnesota, 1974-2009. shinned Hawk as a focal species because its migration is likely linked to spatial and temporal movement of its neotropical songbird prey (Rosenfield and Evans 1980, Viverette et al. 1996, Goodrich and Smith 2008). METHODS Study Site and Data Collection. — The Hawk Ridge Bird Observatory (HRBO) is in boreal forest at the western end of Lake Superior in Duluth, Minnesota (49° N, 92° W), and is a well known concentration point for migrant raptors (Goodrich and Smith 2008). Raptors are counted hourly at HRBO from about 15 August through 30 November using standardized techniques estab¬ lished by the Hawk Migration Association of North America (HMANA) (Ruelas Inzunza 2005, Farmer et al. 2008). Detailed descriptions of daily and seasonal coverage of counts at HRBO are provided by Fanner et al. (2008). Migration of Sharp-shinned Hawks primarily occurs from mid- August through October at HRBO with peak monthly totals of migrating birds typically occurring in September (Rosenfield and Evans 1980, Goodrich and Smith 2008). We obtained HRBO count data for Sharp-shinned Hawks during 1974-2009 from HMANA’ s Hawkcount. org/month web site (www.hawkcount.org/month_ summary, php). Data Analyses.— We used simple linear regres¬ sion to assess how Julian date for the 50th percentile of the total number of autumnal migrating hawks in each of 36 study years changed across time (i.e., to ascertain if a shift in migration had occurred). We also used Julian dates for four percentiles (25, 50, 75, and 99.5) of total migration counts in each year to describe the extent of the shift (in days) of the migration. We truncated the 100th percentile at 99.5 to minimize the effect of late-migrating “stragglers” that might skew results. We calculated the difference in number of Julian dates (days) for each percentile in each year for 1975-2009 relative to Julian dates for the respective percentiles in 1974, the first year of the study. Julian dates earlier and later than those in respective percentiles for 1974 were assigned negative and positive values, respectively. We used the average (± SE) of those differences to enumerate the approximate shift in days in migration for each respective percentile since 1974. We chose 1974 as the comparative year to demonstrate the extent of the shift in timing of migration because it was representative of the earlier timing of migration at the outset of the study (Fig. 1). We also report the shift for all combined percentiles, 1975-2009. Further, we separate the percentiles in the first 19 years of study (1975-1993) from those during 156 THE WILSON JOURNAL OF ORNITHOLOGY • Vol. 123, No. 1, March 2011 TABLE 1. Timing of autumnal migration of Sharp-shinned Hawks at Hawk Ridge Bird Observatory, Duluth Minnesota, 1 974-2009. Julian dates for 1 974 indicate when the specified proportion of the total number of migrating hawks was attained; Julian dates for other years are rounded approximations of percentile attainment based on mean values (in parentheses ± SE) of shift in days relative to Julian dates in 1974. Calendar dates are provided for descriptive reference. Percentile 1974 1975-1993 1994-2009 1975-2009 25 50 75 99.5 254; 11 Sep 258; 15 Sep 269; 26 Sep 289; 16 Oct 253 (-1.37 ± 0.85) 261 (3.16 ± 0.77) 272 (2.63 ± 0.75) 293 (3.47 ± 0.87) 257 (2.5 ± 0.96) 266 (7.69 ± 1.0) 278 (8.87 ± 0.83) 298 (9.3 ± 0.99) 254 (0.4 ± 0.71) 263 (5.23 ± 0.72) 275 (5.49 ± 0.76) 295 (6.14 ± 0.82) the last 16 years (1994—2009) because a greater shift occurred since 1994. We calculated proba¬ bility values using SYSTAT (Wilkinson 1992). Statistical significance was accepted at a < 0.05. RESULTS There was a statistically significant increase in Julian dates for the 50th percentile of the seasonal totals of migrating Sharp-shinned Hawks across 36 years at HRBO (Fig. 1); greater proportions of hawks were migrating later in autumn. The extent of the shift was on average ~3 days later in the second through fourth percentiles during the first 19 years since 1974 (1975-1993), but increased to a consistent average of ~8 or 9 days later compared to 1974 in the second through fourth percentiles during 1994-2009 (Table 1). Twenty- two (29%) of the 76 total Julian dates registered an earlier day of percentile attainment during 1975-1993 versus 1974 (9 of the 22 earlier dates occurred in percentiles >25%). Only 5% ( n = 3) of 64 Julian dates were earlier during 1994-2009 versus 1974 (all earlier dates occurred in the first percentile; i.e„ the first month of migration). here was a consistent later shift in the last 1.5 months of migration during the last 16 years of the study. The shift in migration was on average 4.31 (±0.42) days later for all percentiles combined, and consistently ~5 days later on average in the last three percentiles across 35 years since 1974 (Table 1). DISCUSSION This study is to our knowledge the first to show a shift m timing of the autumnal migration of a raptor We demonstrated that Sharp-shinned Hawks since m?nrna!T migrated on average -4 days later at HRBO during 1975-2009. We speculate on possible factors influencing this phenomenon. There is a sequence in movements of age cohorts of Sharp-shinned Hawks at HRBO; juvenile birds (<1 yr) precede adults (>2 yrs) by ~2 weeks and, within age groups, females precede males by ~1 week (Rosenfield and Evans 1980). This sequence in the migration of cohorts, as indexed by trapping data obtained during the same days and months in each year that counts are conducted at HRBO, has not changed during our study years (DLE and RNR, unpubl. data). It appears that juveniles still migrate principally during the first month of migration, and adults predominate in the last 1 .5 months (DLE and RNR, unpubl. data). Precisely which cohort movements may have changed temporally in the overall migration of Sharp-shinned Hawks at HRBO is not known because counters cannot identify age and gender of the majority of migrating individuals. About 13,300 Sharp-shinned Hawks were counted at HRBO annually during 1974-2009. Farmer et al. (2008) reported a low, non-signi¬ ficant, average percent change per year (~0.7) for Sharp-shinned Hawks observed at HRBO across most of our study years (1974-2004) based on standardized count effort. Sharp-shinned Hawks moving through HRBO originate from northern Minnesota and a large part of interior and, possibly, western Canada (Evans and Rosen¬ field 1985, Goodrich and Smith 2008). The long¬ term duration of our study ensures that we have cross-generational data for Sharp-shinned Hawks (Bildstein and Meyer 2000). The long-term shift in timing of the migration we documented is not likely due to variation in inter-year counts of migrating birds (cf. Miller-Rushing et al. 2008), or to behavioral plasticity of an age cohort ( cf. Miller-Rushing et al. 2008), nor to some local geographical effect (Lyon et al. 2008). Climate change may have an influence on the availability of food for higher trophic species such as birds as a result of advanced phenology of lower trophic organisms and a prolonged summer season (Penuelas and Filella 2001). Several SHORT COMMUNICATIONS 157 European passerines have delayed autumnal migration, although other species have advanced departure dates (Jenni and Kery 2003). It is possible the migratory songbird prey of Sharp- shinned Hawks in boreal forests north of HRBO (Bildstein and Meyer 2000) could delay their migration if their food was available for longer summers ( cf Penuelas and Filella 2001), which in turn could cause a later migration of hawks that track the movement of passerines. Raptorial species, such as accipiters, use powered flight for migration and must hunt regularly while on migration (Ydenberg et al. 2007, Goodrich and Smith 2008). However, we know of no data indicating temporal changes in autumnal songbird migrations north of or at HRBO (G. J. Neimi, pers. comm.). A possible explanation for the shift in timing may be migratory short-stopping, whereby Sharp- shinned Hawks north of HRBO may be moving less, and perhaps less per day, in response to increased prey availability (possibly at bird feeders) north of HRBO. This could result in hawks taking longer to pass through HRBO. This phenomenon was suggested as one explanation for declining, inter-year autumnal numbers of Sharp- shinned Hawks observed at Hawk Mountain, Pennsylvania and Cape May Point, New Jersey (Viverette et al. 1996). However, there has been no significant inter-year variation in counts of Sharp-shinned Hawks at HRBO. Further, the decline in observations of Sharp-shinned Hawks at Cape May particularly involved juveniles (Viverette et al. 1996), and the shift in later timing of migration at HRBO is likely by adults. There is no pattern of agreement in trends of counts of migrating Sharp-shinned Hawks at different watch sites (including HRBO) in eastern North America. This suggests there is consider¬ able spatial structure in a regional population or that migration geography varies with sub-region (Farmer et al. 2008). Our results augment findings demonstrating recent shifts in phenological events for birds and other animals (Root et al. 2003, Crick 2004, Miller-Rushing et al. 2008), and we examined factors possibly altering the timing of Sharp- shinned Hawk autumnal migration in northcentral North America. The potential proximate causes, such as the timing of autumnal songbird migration north of HRBO, and the consequences of the later timing of migration of hawks should be investi¬ gated. Changes in environmental conditions could influence the survivorship of maladjusted individ¬ uals given potential decoupling between migra¬ tion schedules of Sharp-shinned Hawks and their songbird prey (Both et al. 2006, Heller and Zavaleta 2008). ACKNOWLEDGMENTS We thank the many individuals who counted migrating birds of prey at HRBO. Partial funding for this study came from the Personnel Development Committee at the University of Wisconsin at Stevens Point. This manuscript was improved by the comments of E. A. Anderson, John Bielefeldt, T. L. Booms, M. A. Bozek, C. E. Braun, W. E. Stout, and two anonymous reviewers. LITERATURE CITED Bildstein, K. L. and K. Meyer. 2000. Sharp-shinned Hawk {Accipiter striatus). The birds of North America. Number 482. Both, C., S. Bouwhuis, C. M. Lessels, and M. E. Visser. 2006. Climate change and population declines in a long-distance migratory bird. Nature 44:81-83. Crick, H. Q. P. 2004. The impact of climate change on birds. Ibis 146 (Supplement 1 ):48-56. Evans, D. L. and R. N. Rosenfield. 1985. Migration and mortality of Sharp-shinned Hawks ringed at Duluth, Minnesota, USA. Pages 311—316 in Conservation studies on birds of prey (I. Newton and R. D. Chancellor, Editors). World Conference on Birds of Prey, Thessaloniki, Greece and International Council on Birds of Prey, Cambridge, United Kingdom. Farmer, C. J., R. J. Bell, B. Drolet, L. J. Goodrich, E. Greenstone, D. Grove, D. J. T. Hussell, D. Mizrahi, F. J. Nicoletti, and J. Sodergren. 2008. Trends in autumn counts of raptors in northeastern North America, 1974-2004. Pages 179-215 in State of North America’s birds of prey (K. L. Bildstein, J. P. Smith, E. Ruelas Inzunza, and R. R. Veit, Editors). Nuttall Ornithological Club, Cambridge, Massachu¬ setts, and American Ornithologists' Union, Washing¬ ton, D.C., USA. Goodrich, L. J. and J. P. Smith. 2008. Raptor migration in North America. Pages 37-149 in State of North America’s birds of prey (K. L. Bildstein, J. P. Smith, E. Ruelas Inzunza, and R. R. Veit, Editors). Nuttall Ornithological Club, Cambridge, Massachusetts, and American Ornithologists’ Union, Washington, D.C., USA. Heller, N. E. and E. S. Zavaleta. 2008. Biodiversity management in the face of climate change: a review of 22 years of recommendations. Biological Conservation 142:14-32. Jenni, L. and M. Kery. 2003. Timing of autumn bird migration under climate change: advances in long¬ distance migrants, delays in short-distance migrants. Proceedings of the Royal Society of London, Series B 2003:1467-1471. Lyon, B. E., A. S. Chaine, and D. W. Winkler. 2008. A matter of timing. Science 321:1051-1052. 158 THE WILSON JOURNAL OF ORNITHOLOGY • Vol. 123, No. 1, March 2011 Miller-Rushing, A. J., T. L. Lloyd-Evans, R. B. Primack, and P. Satzinger. 2008. Bird migration times, climate change, and changing populations sizes. Global Change Biology 14:1959-1972. Penuelas, J. and I. Filella. 2001. Phenology: responses to a warming world. Science 294:793-797. Root, T. L., J. T. Price, K. R. Hall, S. H. Schneider, C. Rosenzweig, and J. A. Pounds. 2003. Fingerprints of global warming on wild animals and plants. Nature 421:57-60. Rosenfield, R. N. and D. L. Evans. 1980. Migration incidence and sequence of age and sex classes of the Sharp-shinned Hawk. Loon 52:66-69. Ruelas Inzuna, E. R. 2005. The Raptor Population Index (RPI) project in its second year. Hawk Migration Studies 32:4-6. Viverette, C. B., S. Struve, L. J. Goodrich, and K. L. Bieldstein. 1996. Decreases in migrating Sharp-shinned Hawks (Accipiter striatus) at traditional raptor-migration watch sites in eastern North America. Auk 113:32-40. Wilkinson, L. 1992. SYSTAT: the system for statistics. SYSTAT, Evanston, Illinois, USA. Ydenberg, R. C., R. W. Butler, and D. B. Lank. 2007. Effects of predator landscapes on the evolutional}1 ecology of routing, timing and molt by long-distance migrants. Journal of Avian Biology 38:523-529. The Wilson Journal of Ornithology 1 23(1 ): 1 58— 1 60, 2011 Lunar Influence on the Fall Migration of Northern Saw-whet Owls Jackie Speicher,1-2 Lisa Schreffler,1 and Darryl Speicher1 ABSTRACT. Seasonal migration is an importai component in the life cycle of Northern Saw-whet Ow (Aegolius acadicus). We evaluated the influence of tf tour lunar events (new moon, first quarter moon, fu moon, and last quarter moon) on nocturnal activity c orthem Saw-whet Owls based on captures during fa migration, 2000-2008. We found deferences betlee he lunar events with decreased capture rates during th full moon and the new moon. These results sugge< unar phase influences migratory movements In, behaviors in this species. This may be attributed ti predator avoidance during periods of relative brightnes 19 OaTfr'toTt1' ****** '° ^ 2°°9' AcceP'« The amount of light at night should be important variable to nocturnal migrants C potentially important influence on timing flights is the lunar cycle, which is described its four predictable conditions (first quarter moc full moon, last quarter moon, and new moo yle et al. (1993) reported that decreased lur hght was correlated with an increased number epartures during fall migration by landbirt S f eCtS behaV1OT * either mcreasi foraging behavior or predator avoidance. Lead- Storm Petrels (Oceanodroma leucorhoa) decrea activity during times of increased moonlight wh, PA18326°USVr ReSearCh Cent£r’ R °‘ B°* Cresc 2 Corresponding author; e-mail: Poconoavian@hotmail.com gull (Larus spp.) predation rates are relatively high (Watanuki 1986). This behavior modification suggests that petrels assess the risk of predation. Tropical Nightjars and other caprimulgids also increase foraging activity during periods of lunar illumination (Brigham and Barclay 1992, Jetz et al. 2003). Changes in feeding behavior in association with changes in moonlight have also been noted for small mammals which are prey species (Price etal. 1984, Gannon and Willig 1997, Lang et al. 2006. Schmidt 2006). Foraging activity typically decreas¬ es with increased lunar light. The Northern Saw-whet Owl (Aegolius acadi¬ cus) is a short-distance migrant that breeds in coniferous or mixed deciduous forests of North America. The adults are approximately 15-21 cm long (wingspan: 43 cm). Their weight ranges from 65 to 151 g with females averaging slightly larger than males (Cornell Laboratory of Ornithology 2009). Northern Saw- whet Owls prey primarily on small rodents, including mice (Peromyscus spp.) and voles ( Microtus spp.). The Northern Saw- whet Owl is also the potential prey of larger owls. Competing biological needs likely mean that owls react to lunar events in the context of foraging, avoiding predation, and movement. The full moon would be predicted to increase vigilance for predators leading to a decrease in foraging effort. Light conditions may also prompt a temporary pause in migratory flights or extended stopovers. We assessed the influence ot the lunar condition on the capture rate of Northern SHORT COMMUNICATIONS 159 FIG. 1. Mean(± SE) capture rates (birds/net hr) of Northern Saw-whet Owls during the four lunar events (n - 178 individuals). Saw-whet Owls to examine if illumination was a factor in timing of migration. METHODS The study area was in Skytop, Pennsylvania (41° 22' N, 75° 24' W, elevation 513 m) on the south side of West Mountain. It is a semi -permanently flooded cold deciduous forest dominated by eastern hemlock ( Tsuga canadensis ), red maple (Acer rub rum), and rhododendron ( Rhododendron caro- linensis). Northern Saw-whet Owls were not recorded at this location before this study and their status as residents remains unknown. The study period lasted from 1 October to 15 November, 2000-2008. Each calendar day was assigned a corresponding lunar cycle code from one to 28 (NASA 2009). Day 1 represents the new moon, day 7 represents the first quarter moon, day 14 represents the full moon, and day 21 represents the last quarter moon. Five mist nets (12 X 2.5 m X 60 mm mesh) were placed in a continuous line oriented in a north-south direction. A conspecific audio lure was positioned at the center of the net array . Nets were opened each evening from 1900 to 2300 hrs and mist nets were visited every 30 min. Individuals captured were weighed (g), measured, banded, and released using standard Bird Banding Laboratory protocols. Data were recorded for each encountered individual. We calculated the rate at which owls were captured each evening by dividing the total number of birds caught by each evening’s net effort. Data were pooled and averaged for each lunar day. Data were analyzed using ANOVA. RESULTS Each field season included all four lunar events (first quarter moon, full moon, last quarter moon, and new moon). No significant difference in net hours was evident between the four individual lunar events. No significant differences in capture rate were evident between each of the four lunar events (ANOVA: df = 3, P = 0.09) (Fig. 1). Mean capture rate was lowest during the new moon and full moon. The only exception to this pattern occurred in 2004 when there was an increase in captures associated with a total lunar eclipse. DISCUSSION Weather variables including precipitation, high winds, and cloud cover had a negligible effect on capture data during the 9-year study. However, there was a decrease in capture rates during the full and new moon relative to the last quarter moon. 160 THE WILSON JOURNAL OF ORNITHOLOGY • Vol. 123, No. 1, March 2011 Our study design incorporated an audio lure to attract migrating owls into the nets. This increases the probability of captures (Whalen and Watts 1999, Project Owlnet 2000). Longland and Price ( 1 99 1 ), in a study ot Barred Owls ( Strix varia) using a taped audio playback, ascertained that Barred Owl response diminished with increased light. The risk of predation during the full moon may have deterred owls from investigating the audio lure. This explains decreased capture rates during full moon. The anomaly of a total lunar eclipse in 2004 caused an uncharacteristic increase in capture rate. Increased light may prompt increased predator vigilance. Our results indicate owls are less likely to be moving or respond to an acoustic lure, when it was bright or dark. The Northern Saw-whet Owl has ditficult trade-offs as they must assess risk and combine feeding with predator vigilance. Increased predator vigilance was shown with lower capture rates during (he full and new moons. The Northern Saw-whet Owl apparently waits for a low risk situation to continue on migration and feeding. Significant differences in capture rates during each lunar event suggest the full moon effectively interrupts typical migration patterns. There was a total lunar eclipse during the full moon in 2004 which was associated with a substantial increase in number of Northern Saw- whet Owls captured. This small natural experi¬ ment provides further evidence that migratory movements by Northern Saw-whet Owls are influenced by lunar illumination. Moonlight is an exogenous factor that effectively decreases nocturnal activity in a variety of prey species. A 1 varez-Castaneda et al (2004) found that number of rodents in Barn Owl (Tyto alba ) pellets ecreased during the full moon. In our study, body mass (unpubl . data) was lowest in the third quarter, suggesting a period of decreased foraging may occur prior to that interval. Further study may provide more insight into Northern Saw-whet Owl foraging behaviors during migration. Studies incorporating use of telemetry may enhance our understanding of night patterns of this species. Combining data from multiple studies will be a valuable resource in understanding the overall influence of lunar condi- tions on nocturnal migratory owls. for their support of this project. We also appreciate the support and encouragement of researchers connected with Project Owlnet. We especially thank Dawn Konkoly, Dan Zmoda, Doug Burton, Steve Clay, and John Leiser. Two anonymous reviewers provided exceptional comments on this manuscript. LITERATURE CITED ACKNOWLEDGMENTS This research was funded by the sponsors of the Pocono Avian Research Center. We thank the staff at Skytop Lodge Alvarez-Castaneda, S. T., N. Cardenas, and L. M£ndez. 2004. Analysis of mammal remains from owl pellets ( Tyto alba), in a suburban area in Baja California. Journal of Arid Environments 59:59-69. Brigham, R. M. and R. M. R. Barclay. 1992. Lunar influence on foraging and nesting activity of Common Poorwills ( Phalaenoptilus nuttallii). Auk 109:315-320. Cornell Laboratory of Ornithology. 2009. All about birds: Northern Saw-whet Owl. Laboratory of Orni¬ thology, Cornell University, Ithaca, New York, USA. http://www.allaboutbirds.com Gannon, M. R. and M. R. Willig. 1997. The effect of lunar illumination on movement and activity of the red fig¬ eating bat ( Stenoderma rufum). Biotropica 29:525-529. Jetz, W., J. Steffen, and K. E. Linsenmair. 2003. Effects of light and prey availability on nocturnal, lunar and seasonal activity of tropical Nightjars. Oikos 103:627- 639. Lang, A. B., E. K. V. Kalko, H. Romer, C. Bockholdt, and D. K. N. Dechmann. 2006. Activity levels of bats and katydids in relation to the lunar cycle. Oecologia 146:659-666. Longland, W. S. and M. V. Price. 1991. Direct observations of owls and heteromyid rodents: can predation risk explain microhabitat use? Ecology 72:2261-2273. National Aeronautics and Space Administration (NASA). 2009. Phases of the moon. National Aero¬ nautics and Space Administration, Washington, D.C., USA. www.eclipse.gsfc.nasa.gov/phase Price, M. V., N. M. Waser, and T. A. Bass. 1984. Effects of moonlight on microhabitat use by desert rodents. Journal of Mammalogy 65:353-356. Project Owlnet. 2000. Migrant Northern Saw-whet Owl netting methodology. Ned Smith Center for Nature and Art, Millersburg, Pennsylvania, USA. www.projectowlnet.org Pyle, P., n. Nur, R. p. Henderson, and D. F. Desante. 1993. The effects of weather and lunar cycle on nocturnal migration of landbirds at Southeast Farallon Island, California. Condor 95:343-361. Schmidt, K. A. 2006. Non-additivity among multiple cues of predation risk: a behaviorally-driven trophic cascade between owls and songbirds. Oikos 113:82-90. Watanuki, Y. 1986. Moonlight avoidance behavior in Leach s Storm-Petrels as a defense against Slaty- backed Gulls. Auk 103:14-22. Whalen, D. M. and B. D. Watts. 1999. Influence of audio lures on capture patterns of migrant Northern Saw- whet Owls. Journal of Field Ornithology 70:163-168. SHORT COMMUNICATIONS 161 The Wilson Journal of Ornithology 123(1): 161—164, 2011 First Detection of Night Flight Calls by Pine Siskins Michael L. Watson,1 Jeffrey V. ABSTRACT— Nocturnal migration is a common strategy among North American passerines. Birds of the Fringillidae have typically been labeled as predominately diurnal migrants. We used pressure-zone microphones and automated sound detection software to record flight calls of noctumally migrating birds from 2 to 16 October 2008 from 2000 to 0600 hrs EST at three locations near Gardiner, Maine. We detected and recorded 190 Pine Siskin ( Spinus pirns) flight calls from throughout the night at three separate locations. This is the first published documentation of apparent nocturnal migration in this species. Nocturnal migration may be a facultative migration strategy in the Fringillidae that occurs only in years in which large irruptive movements occur as for Pine Siskins in fall 2008. Received 30 October 2009. Accepted 3 November 2010. Most North American passerines are known to be nocturnal migrants. Theories for why nocturnal migration is more common than diurnal migration among passerines include: nocturnal migration maximizes day-time feeding opportunities, pro¬ vides more stable atmospheric conditions for migration, allows migrating birds to take advan¬ tage of cooler temperatures to lower heat stress and dehydration, and minimizes predation pres¬ sure from diurnal raptors (Alerstam 1990, Able 2001). Predominantly diurnal migration is rela¬ tively rare in passerines, having been documented in only a few families, including Corvidae, Stumidae, Hirundinidae, Fringillidae, and some Icteridae (Evans and Rosenberg 2000, Able 2001, Evans and O’Brien 2002). Detecting the specific identity of noctumally migrating birds is largely limited to two tech¬ niques: (1) scavenging birds killed during night migration at radio towers, lighted buildings, and other human made structures, and (2) identifying species by listening to or recording their flight '32 Vassal Lane, Cambridge, MA 02138, USA. "Boreal Songbird Initiative, 1904 Third Avenue, Suite 305, Seattle, WA 98101, USA. ? Department of Biology, Bates College, Lewiston, ME 04240, USA. 4 Corresponding author; e-mail: jeffwells@borealbirds.org Wells,2’4 and Ryan W. Bavis3 calls. Many migratory songbirds produce flight calls, a primary vocalization given during sus¬ tained flight. Flight calls are prevalent among North American passerines, although not all species produce them. For example, species of Tyrannidae, Laniidae, Vireonidae, Troglodytidae, and Mimidae are not known to give flight calls but are nocturnal migrants (Evans and O'Brien 2002, Farnsworth 2005). Passerine flight calls are typically between two and 10 kHz and <1 sec in duration (Ball 1952, Evans and O Brien 2002). Flight calls, like songs and other calls, are species- specific, varying in frequency, duration, modula¬ tion, and pattern among taxa (Farnsworth and Lovette 2005). Flight calls are theorized to maintain flock stability (Hamilton 1962) or spacing by communicating information among migrating birds in close proximity to each other (Thake 1981). Flight calls were first documented in 1899 when Orin Libby detected over 3,000 flight calls in a single night (Libby 1899). Advances in spectrographic analysis and inexpen¬ sive recording devices (Evans 1994, Farnsworth 2005) and, especially a well-documented catalog of flight calls that allows identification of most species (Evans and O’Brien 2002), have made it possible to identify species and document their temporal and spatial nocturnal migration patterns (Evans and Rosenberg 2000). Migratory movements of North American spe¬ cies or subspecies of fringillids, although occa¬ sionally detected in pre-dawn hours, have not previously been documented in night passage migration (Evans and O’Brien 2002). Both diurnal and occasional nocturnal passage migration have been documented in two European species, Com¬ mon Chaffinch ( Fringilla coelebs) and European Greenfinch ( Carduelis chloris) (Clement 1999), and in Greenland and Eurasian subspecies of Common Redpoll ( Acanthis flammed) (Knox and Lowther 2000). We document for the first time the apparent nocturnal migration of Pine Siskins {Spinus pirns), a species normally considered a diurnal migrant but whose flight calls are readily distinguishable among the fringillid species. 162 THE WILSON JOURNAL OF ORNITHOLOGY* Vol. 123, No. 1, March 2011 METHODS Waterproof pressure-zone microphones were used to concurrently record nocturnal flight calls from 2 to 16 October 2008 at three locations within 6 km of Gardiner, Maine, USA. Site #1 was at 44° 13' N, 69° 46' W; Site #2 was at 44° 13' N, 69 47' W; and Site #3 was at 44° 16' N, 69 47' W. Two microphones were within 2 km of each other and the third was ~6 km distant. Two microphones were in suburban neighborhoods with low level street-light illumination while the third was on the border of an extensive forested area with no artificial lighting. All three locations were within 1 km of the Kennebec River, a major southward flowing river. Each microphone was placed and pointed upwards so that it had an unobstructed path to the sky. Acoustic XLR cable connected the microphone to a Rolls MP13 pre¬ amplifier housed in a nearby building. The signal was sent from the pre-amplifier into a computer which automatically activated two simultaneously running bird flight call detection software pro¬ grams (Thrush-r.exe and Tseep-r.exe; both distrib¬ uted as shareware from www.oldbird.org) at 2000 his EST and de-activated the programs by 0600 hrs EST the next morning (the detector programs at one station at times were allowed to continue slightly past 0600 hrs EST). Each potential bird flight call detected by either program was saved as a WAV tile with a file name reflecting the date and time it was detected. All sound files collected were reviewed aurally and spectrograms inspected visually using Glassofire sound analysis and file sorting software (distributed as shareware from www.oldbird.org). Non-bird sounds were re¬ moved and bird sounds were sorted and saved by date. More detailed spectrographic analysis and measurements were completed using Raven sound analysis software (available from Cornell Laboratory of Ornithology, Ithaca, NY, USA). Flight calls that we considered to be of Pine Siskins because they were identical to the well-known and described “Kdeew” flight call of the spe¬ cies (Sibley 2000), based on our own field experience, were saved and sent to flight call and bird identification experts William Evans Michael O’Brien, and David Sibley for external review. RESULTS We identified 212 of 2,432 flight calls detected at all three stations that we considered likely characteristic of Pine Siskins. Our three expert reviewers independently concurred that 90% of the calls were clearly identifiable as Pine Siskin flight calls. We were left with 190 calls that were confiimed as those of Pine Siskins after removing calls for which there was not consensus among our experts. All flight calls were archived at Macaulay Library of Natural Sounds at Cornell Laboratory of Ornithology (catalog numbers 140388-140396). Our stations recorded Pine Siskin flight calls from 10 to 16 October 2008 when all three stations were shut down for the season. Calls were detected as early as 2146 hrs EST and as late as 0606 hrs EST (Fig. 1), but detections occurred throughout the night with calls detected in every hour between 2300 and 0600 hrs EST the following morning. Approximately 90% of re¬ corded flight calls were between 0000 and 0500 hrs EST, and ~80% of calls were at least 1 hr before sunrise (Table 1). One hundred and thirty of the 190 recorded calls occurred on 15 October 2008. Recording stopped on 16 October and the full extent of migration dates is unknown. DISCUSSION Many species of North American finches thought to be virtually exclusive diurnal migrants, including Pine Siskin, have been recorded producing flight calls in the hour before sunrise as they begin their diurnal migrations (Evans and O'Brien 2002). Flight calls of Pine Siskins were recorded in our study in significant numbers throughout the night over multiple nights and multiple locations, sug¬ gesting these birds were likely undergoing noctur¬ nal migration. To our knowledge, this is the first documented observation of apparent nocturnal migration in this species. The migratory irruptive behavior of Pine Siskins is apparently induced proximately by a lack of food resources, primarily conifer seeds (Dawson 1997). Pine Siskins are known to make long-distance migratory movements biennially on average (Bock and Lepthien 1976, Yunick 1983, Hochachka et al. 1 999), apparently due to broad scale synchronicity of conifers in their biennial cycle of cone production (Pielou 1988). Birds will not show these long-distance migratory movements when cone production is high in a particular region, while in poor seed production years, large numbers will move in search of food (Dawson 1997). Nocturnal migration could be a behavioral trait that is only expressed by finches under extreme SHORT COMMUNICATIONS 163 FIG. 1. Number of nocturnal flight calls of Pine Siskins detected at three sites near Gardiner, Maine during 10-16 October 2008, by hourly interval (EST). Sunrise occurred at 0551 hrs EST. conditions of food shortage which induce long¬ distance migratory movements similar to those seen in determinate long-distance migrants (Ho- chachka et al. 1999). There was an unusually large migratory irruptive event for Pine Siskins during the 2008-2009 season, especially in the eastern United States. The average flock size reported by Project FeederWatch participants in the eastern U.S. doubled from the prior year’s migration (7.2 to 15.5), and the number of feeders visited increased by 31% (D. N. Bonter, pers. comm.). Data from eBird across —480 sites in Maine, New Hampshire, Vermont, and Massachusetts showed a detectable pulse in the frequency of checklists reporting Pine Siskins in the second week of October 2008 from 1 .7% in week one to 1 1.2% in week two and 7.1% in week three (eBird 2010). This pulse corresponded with the period when we detected Pine Siskin night flight calls suggesting that a broad-scale migratory movement of the species was underway across New England. The frequency of 1 1 .2% in the second week of October 2008 was the highest observed for Pine Siskins in October since 2001 (eBird 2010). Another irruptive cardueline finch that occurs in North America, Common Redpoll, has been heard migrating nocturnal ly in Greenland and Eurasia (Knox and Lowther 2000), but there are few data on the extent and timing of this behavior. These and our observations suggest this is a rare behavior among finches. Future study of nocturnal migration during irruptive years could help explain if nocturnal migration is a plastic behavior induced under conditions that lead to broad scale TABLE 1 . Number of Pine Siskin flight calls detected per night at each of three sites near Gardiner, Maine from 10 to 16 October 2008. Recordings were not made at all sites on all nights, as indicated by N/A . Site io Oct 1 1 Oct 12 Oct _ 13 Oct _ \A Oct _ 15 Qct _ 16 Uct 1 28 0 0 0 11 80 N/A 2 2 16 3 0 N/A N/A N/A 3 N/A 1 0 0 0 50_ 4 164 THE WILSON JOURNAL OF ORNITHOLOGY • Vol. 123, No. 1, March 2011 irruptions in contrast to a seemingly determinate migration strategy as seen in virtually all other passerines. ACKNOWLEDGMENTS We thank the Tyler and Hynes families for use of their homes as recording sites. We thank the Biology Department at Bates College for funding all travel expenses for M. L. Watson. We also thank W. R. Evans. M. O'Brien, and D. A. Sibley for reviewing our recorded flight calls. LITERATURE CITED Able, K. P. 2001. Birds on the move: flight and migration. Page 65 in Handbook of bird biology (S. Podulka, R. Rohrbaugh Jr., and R. Bonney, Editors). Laboratory of Ornithology, Cornell University, Ithaca, New York, Alerstam, T. 1990. Bird migration. Cambridge University Press, Cambridge, United Kingdom. Ball, S. C. 1952. Fall bird migration in the Gaspe Peninsula. Bulletin Number 7. Peabody Museum of Natural History, Yale University, New Haven, Connecticut, Bock, C. E. and L. W. Lepthien. 1976. Synchronous eruptions of boreal seed-eating birds. American Naturalist 1 1 0:559-57 1 . Clement. P. 1999. Finches and sparrows. Princeton University Press, Princeton, New Jersey USA Z ^ ^ Pine Sisk,n (Carduelis pinus). The birds of North America. Number 280. EBlRD. 2010. eBird: an online database of bird distribution and abundance. Version 2. Laboratory of Ornithology Cornell University, Ithaca, New York, USA. http-// www.ebird.org ” EVAThrWh ^.'994DNocturnaI flight call of Bicknell’s Thrush. Wilson Bulletin 106:55-61. Evans, W. R. and M. O’Brien. 2002. Flight calls of migratory birds: eastern North American landbirds. [CD-ROM]. Oldbird, Ithaca, New York, USA. Evans, W. R. and K. V. Rosenberg. 2000. Acoustic monitoring of night-migrating birds: progress report. Pages 151-159 in Strategies for bird conservation: the partners in flight planning process (R. Bonney. D. N. Pashley, R. J. Cooper, and L. Niles, Editors). Laboratory of Ornithology, Cornell University, Ithaca, New York, USA. http://birds.comeIl.edu/pifcapemay Farnsworth, A. 2005. Flight calls and their value for future ornithological studies and conservation re¬ search. Auk 122:733-746. Farnsworth, A. and I. J. Lovette. 2005. Evolution of nocturnal calls in migrating wood-warblers: apparent lack of morphological constraints. Journal of Avian Biology 36:337-347. Hamilton III, W. J. 1962. Evidence concerning the function of nocturnal call notes of migratory birds. Condor 64:390-401. Hochachka, W. M., J. V. Wells, K. V. Rosenberg, D. L. Tessaglia-Hymes, and A. A. Dohndt. 1999. Eruptive migration of Common Redpolls. Condor 101:195-204. Knox, A. G. and P. E. Lowther. 2000. Common Redpoll ( Carduelis flammed). The birds of North America. Number 543. Libby, O. G. 1899. The nocturnal flight of migrating birds, Auk 16:140-145. Pielou, E. C. 1988. The world of northern evergreens. Cornell University Press, Ithaca, New York, USA. Sibley, D. A. 2000. The Sibley guide to birds. Chanticleer Press, New York, USA. Thake, M. A. 1981. Calling by nocturnal migrants: device for improving orientation? Die Vogel warte 31:111. Yunick, R. P. 1983. Winter site fidelity of some northern finches (Fringillidae). Journal of Field Ornithology 54:254-258. The Wilson Journal of Ornithology 123(1): 1 64-1 67, 2011 Onemation of Sap Wells Excavated by Yellow-bellied Sapsuckers Ashley M. Long1 selechon o^f 1 temPerature may influe f §mg SUeS by or8amsms that use sap S0UrCe' 1 6Xamined the sPatlal orienta of sap wells excavated by Yellow-bellied Sapsucl ff 'TCUJ Varius) on Pine (Pinus spp. n = in eastern Kansas. Sap wells were oriented toward southwest (d = 246.04. y = 6x46 . P = a004T un in previous studies. Benefits of southwesterly sap well orientation may include avoidance of high winds while foraging and increased flow of sap on the sides of trees warmed by afternoon light. Received 2 November 2009. Accepted 25 October 2010. ' Department of Biological Sciences, University, Emporia, KS, 66801, USA; e-mail: ashley_long@tamu.edu Emporia State The Yellow-bellied Sapsucker (Sphyrapicus varius) is a small-medium, migratory woodpecker (21—22 cm) that breeds throughout Canada and portions of the northern United States and SHORT COMMUNICATIONS 165 overwinters throughout much of Mexico, the eastern United States, and Canada (Howell 1952, Walters et al. 2002). The Yellow-bellied Sap- sucker, like other North American woodpeckers, forages on a variety of foods including fruits and insects; however, sapsuckers are also known to consume sap as a primary food source (Beal 1911, Howell 1952, Tate 1973, Williams 1975, Wilkins 2001, Walters et al. 2002). Sapsuckers in winter and early spring, obtain sap from small, circular wells excavated in the xylem tissue of trees (Foster and Tate 1966, Tate 1973). Wells excavated in phloem tissue of trees are used for foraging during the summer months (Tate 1973, Eberhardt 1994). The placement of sap wells excavated by Yellow-bellied Sapsuckers has been previously studied in relation to preferred tree species (Conner and Kroll 1994, Eberhardt 1994), bark- and phloem thickness (Wilkins 2001), tree health (i.e., fungal infections and wounds from lightening) (Ohman and Kessler 1964, Lawrence 1967), bark moisture (Eberhardt 2000), tree density (Eberhardt 2000), proximity to nest site (Eberhardt 1994), and sucrose content of sap (Kilham 1964, Tate 1973, Wilkins 2001). How¬ ever, factors that influence spatial orientation of sap wells around tree boles remain unclear. Observations by Kilham (1956) imply that sunlight and sap flow rates may dictate sap well orientation. He noted that Yellow-bellied Sap¬ suckers could be observed excavating wells in the morning hours and returning to these wells to feed in the afternoon when sap flow was at its peak. My objective was to ascertain if orientation of sap wells excavated around tree boles in eastern Kansas is nonrandom. I predicted that sap wells would be oriented toward the south-southwest, the side of the tree most exposed to sunlight during daylight hours at this latitude throughout months when sapsuckers are present. METHODS I measured the orientation of sap wells (relative to magnetic north; 0-359°) excavated by Yellow- bellied Sapsuckers in March and April 2008 at five sites in Emporia, Kansas, USA (38" 24' 29" N, 96° 11' 13" W; Lyon County). The study sites were on public property (e.g., city parks) within the city limits of Emporia and were landscaped with a variety of native and non-native deciduous and coniferous tree species generally planted in single, evenly spaced rows to serve as wind blocks around the perimeter of each property. Detailed temperature- (collected from 1971 to 2010) and wind data (collected from 2005 to 2010) were obtained through the National Climatic Data Center (http://www.ncdc.noaa.gov/oa/ncdc.html). Emporia’s average monthly temperatures ranged from 2 to 21° C during the time of year when Yellow-bellied Sapsuckers are present in this region (Oct-Mar; Walters et al. 2002). Average monthly wind speeds for this same time period (i.e., Oct-Mar), ranged from 16.8 to 19.9 kph and average monthly wind orientations (relative to magnetic north) were between 1 and 36°, indicating that prevailing winds are from the north when sapsuckers are present. Sap wells were identified as small, evenly distributed holes excavated in horizontal lines on tree boles. Other sapsuckers excavate wells in similar patterns, but the Yellow-bellied Sapsucker is the only sapsucker species known to overwinter in this region. Sap well orientation was measured as the direction of highest sap well concentration when >10 sap wells were observed on a single tree. I estimated the area of highest sap well concentration as the side of the tree bole containing >50% of the sap wells excavated and recorded sap well orientation from the center of the sap well cluster. No distinction was made between newly- and previously excavated wells due to uncertainties regarding time since sap well excavation. I also measured the diameter at breast height (DBH; cm) and distance from ground to sap well cluster (m) for each tree where sap well orientation was recorded. Mean DBH, mean distance from ground to sap well cluster, and their associated standard devia¬ tions were calculated. Analyses for circular distributions (Zar 1999) were used to examine mean orientation (a) and circular standard devi¬ ation (s) of sap wells excavated by Yellow-bellied Sapsuckers. I used Rayleigh’s test of uniform distribution to examine if sap well orientation was nonrandom (Zar 1999). Approximate P-values were obtained using 5,000 permutations and macros created for the SAS system (SAS Institute Inc. 2003) by Kolliker and Richner (2004). The alpha level for Rayleigh’s test was set at 0.05. RESULTS Sap wells excavated by Yellow-bellied Sap¬ suckers were observed exclusively on pine trees (Pinus spp.) at the study sites. Thirty-eight percent of the pine trees examined ( n = 1 14) contained evidence of foraging by Yellow-bellied Sapsuck- 166 THE WILSON JOURNAL OF ORNITHOLOGY • Vol 123, No. 1, March 2011 N 0 180 S FIG. I . Orientation (relative to magnetic north" n '3sq°\ nf >. trees (Pinus spp.) ( n = 43) in eastern r ’ 9 ^ of sap wells excavated by Yellow-bellied Sapsuckers on pine ansas. Bars along the radial axes indicate the number of trees within 30° intervals. ers and a sufficient number of sap wells tc ascertain the orientation of the sap well cluster. ree species loraged upon included Austrian pine n ' ,llSra' n ~ ^ trees), red pine (P. resinosa\ n = - trees), and white pine (P. strobus ; n = 38 trees) Average DBH was 37.87 ± 13.78 cm (SD) and average distance from ground to sap well cluster was 1.16 ± 0.48 m (SD). Sap wells were not randomly distributed around tree boles and L- = 5^Si§nifiCant southwesterly orientation (a 246.04 , s = 65.46°, P = 0.004; Fig. 1). DISCUSSION Observed patterns of nonrandom sap well orientation on pines in eastern Kansas may be a .esult of Yellow-bellied Sapsucker avoidance of e northern side of tree boles, rather than selection of the southwestern side. Trees foraged upon by this species in this region of the United States are often planted as single row wind breaks, greatly exposing foraging sapsuckers to high velocity winds from the north during the winter months Benefits of southwesterly sap well orientation may include decreased metabolic stress (i.e., fewer calories burned and/or reduced probability of desiccation) or increased perching stability as a result of wind avoidance. Exposure to solar radiation can result in significant temperature differences between ex¬ posed and shaded sides of trees (Derby and Gates 1 966). More optimal foraging opportunities exist for sap feeding organisms that select feeding sites where ambient temperature or solar radiation positively influence the rate of sap flow (Gold- ingay 1987, Howard 1989, Pejchar and Jeffrey 2004). Pejchar and Jeffrey (2004) found that the Akiapolaau ( Hemignathus munroi ), an endan¬ gered endemic species of Hawaiian Honeycreeper that uses similar foraging techniques as sapsuck¬ ers, feeds preferentially on ohia (. Metrosideros polymorpha) trees on slopes that receive the greatest intensity of sunlight and, therefore, have the highest rates of sap flow. Yellow-bellied Sapsuckers in eastern Kansas may similarly SHORT COMMUNICATIONS 167 benefit from increased sap flow on the sides of trees most exposed to sunlight during daylight hours at this latitude. Secondary benefits of increased sap flow may also exist. This species feeds primarily on sap, but they are also known to forage on insects that congregate near sap wells (Foster and Tate 1966, Tate 1973). Sapsucker foraging opportunities on arthropods may increase along with greater sap¬ foraging opportunities if insects are drawn to sunlight during the cooler days of early spring. However, there is little evidence supporting the idea that insects have a dominant role in orientation of sap wells, as other studies report few insects around wells during the winter months (Wilkins 2001); it has been suggested that sapsuckers may perceive insects in close proximity to sap wells as compet¬ itors rather than prey (Walters et al. 2002). My research indicated a pattern of southwestern sap well orientation, but other studies examining the distribution of sapsucker wells on tree boles found sap well orientation to be oriented to the north (Varner et al. 2006) or random (Wilkins 2001). In the southern United States where these studies were conducted, sap flow may be less influenced by ambient temperature and tree exposure to wind may be greatly reduced. The significant southwest orientation of sap wells in this study, and lack thereof in other studies, may be a result of variation in solar angle, wind speed, and wind direction, in addition to physiological differences among tree species used by foraging sapsuckers. Future research regarding this topic should examine latitudinal variation in sap well orientation and the influence of tree physiology on sapsucker foraging behavior. ACKNOWLEDGMENTS I thank B. R. Smith and S. E. Delmott for assistance with data collection. I also thank R. B. Thomas and W. E. Jensen for the use of equipment and helpful discussions. C. E. Braun, h. D. Wilkins, and one anonymous reviewer provided helpful comments on an early draft of this manuscript. LITERATURE CITED Beal, F. E. L. 1911. Food of the woodpeckers of the United States. USDA, Biological Survey Bulletin 37:1-64. Conner, R. n. and .1. C. Kroll. 1994. Food-storing by Yellow-bellied Sapsuckers. Auk 96:195. Derby, R. w. and D. M. Gates. 1966. The temperature of tree trunks-calculated and observed. American Journal of Botany 53:580-587. Eberhardt, L. S. 1994. Sap-feeding and its consequences for reproductive success and communication inYel- low-bellied Sapsuckers ( Sphyrapicus varius). Disser¬ tation. University of Florida, Gainesville, USA. Eberhardt, L. S. 2000. Use and selection of sap trees by Yellow-bellied Sapsuckers. Auk 117:41-51. Foster, W. I. and J. Tate Jr. 1966. The activities and coactions of animals at sapsucker trees. Living Bird 5:87-113. Goldingay, R. L. 1987. Sap feeding by the marsupial Petaurus australis: an enigmatic behavior? Oecologia 73:154-158. Howard, J. 1989. Diet of Petaurus breviceps (Marsupialia: Petauridae) in a mosaic of coastal woodland and heath. Australian Mammalogy 1 2:15-2 1 . Howell, T. R. 1952. Natural history and differentiation in the Yellow-bellied Sapsucker. Condor 54:237-282. Kilham, L. 1956. Winter feeding on sap by sapsucker. Auk 73:451^452. Kilham, L. 1964. The relations of breeding Yellow-bellied Sapsuckers to wounded birches and other trees. Auk 81:520-527. Kolliker, M. and H. Richner. 2004. Navigation in a cup: nestling positioning in Great Tit, Parus major , nests. Animal Behaviour 68:941-948. Lawrence, L. D. 1967. A comparative life-history study of four-species of woodpeckers. Ornithological Mono¬ graphs Number 5. Ohman, J. H. and K. J. Kessler Jr. 1964. Black bark as an indicator of bird peck defect in sugar maple. USDA, Forest Service, Research Paper LS-14. Lake States Forest Experiment Station, St. Paul. Minnesota, USA. Pejchar, L. and .1. Jeffrey. 2004. Sap-feeding behavior and tree selection in the endangered Akiapolaau (Hemignathus munroi) in Hawaii. Auk 121:548-556. SAS Institute Inc. 2003. SAS/STAT User’s Guide. Version 9.1, SAS Institute Inc., Cary, North Carolina, USA. Tate Jr, J. 1973. Methods and annual sequence of foraging by the sapsucker. Auk 90:840—856. Varner III, J. M., J. S. Kush, and R. S. Meldahl. 2006. Characteristics of sap trees used by overwintering Sphyrapicus varius (Yellow-bellied Sapsucker) in an old-growth pine forest. Southeastern Naturalist 5:127- 134. Walters, E. L., E. H. Miller, and P. E. Lowther. 2002. Yellow-bellied Sapsucker ( Sphyrapicus varius). The birds of North America. Number 662. Wilkins, H. D. 2001. The winter foraging ecology of Yellow-bellied Sapsuckers, Sphyrapicus varius , in east-central Mississippi. Dissertation. Mississippi State University, Mississippi State, USA. Williams, J. B. 1975. Habitat utilization by four species of woodpeckers in a central Illinois woodland. American Midland Naturalist 93:354-367. Zar, J. H. 1999. Circular distributions: descriptive statistics and circular distributions: hypothesis testing. Pages 592-663 in Biostatistical analysis. Fourth Edition. Prentice Hall, Upper Saddle River, New Jersey, USA. 168 THE WILSON JOURNAL OF ORNITHOLOGY • Vol. 123, No. 1, March 2011 The Wilson Journal of Ornithology 123(1): 168-171, 2011 Consumption of Larvae by the Austral Parakeet (Enicognathus ferrugineus) Soledad Diaz1,3 and Salvador Peris2 ABSTRACT. — We report observations of the Austral Parakeet ( Enicognathus ferrugineus ) feeding on larvae in the northern part of its distribution in the austral temperate forests of Argentine Patagonia during the pre- and post-reproductive seasons. Larvae consumed were Aditrochus fagicolus (Chalcidoidea: Pteromalidae) in leaf galls of Nothofagus pumilio (79 observations), larvae from Homoptera, Lepidoptera, and Diptera in seed galls of N. pumilio (12 observations), and larval Nemonychidae (Coleoptera) in male cones of Araucaria araucana (69 observations). Our observations suggest Enicognathus ferrugineus could be more insectivorous than previously thought, perhaps to help meet their demand lor high-quality food during the pre- and post- reproductive seasons. Received 3 December 2009. Accepted 8 October 2010. Temperate birds apparently time breeding tc coincide with annual peaks in food availability a; tood can be an important limiting factor, espe¬ cially in habitats with sharply defined cold anc warm seasons (Newton 2003). Breeding behavioi involves a large parental investment prior to the laying period, when birds search for high-quality food to attain adequate physiological condition (Krebs and Davies 1993). Parrots (Psittaciformes) are generally known tor being mostly seed-eaters (Collar 1997), but their diet can vary depending on the habitat. arrots breeding in temperate forests experience a markedly seasonal environment where protein- rich food (important during pre-breeding stage- Martin 1987. Koutsos et al. 2001) is scarce prior to summer, and is limited primarily to pollen and nectar, which become available in late sprint ?Q7Z “d Klt/hcr8cr 20068 or larvae (Moorhouse tyy/). Protein requirements are high for nestlings and females with large broods (Koutsos et al f°°l)- Parrots with large broods inhabiting temperate habitats must find an extra protein nio'fxanmn ^°T°’ INIBIOMA-CONICET, Quintral 1250, (8400) Banloche, Rfo Negro, Argentina. IT :Dep"nt0 de Zoologfa, Facultad de Biologfa Spain de Salamanca, 37071 Salamanca, Espana / ’Corresponding author; e-mail: jisdiaz@gmail.com supply before and during the reproductive season, just when protein rich-foods may be most scarce. The Austral Parakeet ( Enicognathus ferrugi¬ neus) is restricted to Andean temperate forests in Patagonia from 36 to 54° S (southern Argentina and Chile; Collar 1997), and information on its biology, ecology, and population status is scarce. Given their extreme southern distribution, the lack of knowledge about their adaptations to the austral climate highlights the importance of understand¬ ing their ecological and reproductive require¬ ments. Pairs breed once per year; laying starts in December (late spring) and nestlings fledge in March (late summer). Broods are large with respect to body size with females laying between five and eight eggs (Collar 1997). Only anecdotal data concerning the bird’s ecology (mainly diet and breeding aspects) were available prior to 2001. Leaves, flowers, fruits and seeds, and occasionally larvae comprise its known diet (Forshaw 1989, Collar 1997, Dfaz and Kitzberger 2006). Diaz and Kitzberger (2006) report that diets of Austral Parakeets in lenga beech ( Notho¬ fagus pumilio) forest varied seasonally, following forest phenology and availability of food resourc¬ es. The diet of the Austral Parakeet includes buds and pollen from lenga beech and its hemiparasite Misodendrum in the pre -reproductive period, leaves of both species and seeds of Misodendrum during the reproductive season; and lenga beech seeds during the first part of the post-reproductive season. Food becomes scarce as winter approach¬ es, and their diet is then comprised of low nutritional food such as Cyttaria spp. fruit bodies and buds. We found sporadic intake of larvae was more frequent than previously known and report observations of these unusual feeding habits of this species. OBSERVATIONS We conducted field research from 2007 until 2009 designed to document the basic foraging behavior of the Austral Parakeet in an Argentine mixed lenga beech and pehuen (or monkey puzz'e tree) ( Araucaria araucana) forest (hereafter Mr), SHORT COMMUNICATIONS 169 within the northern part of the Austral Parakeet’s distribution (37° S, 71° W) near the Chilean border at 1 ,050 m elevation. Feeding behavior of Austral Parakeets from a southern location was also recorded during November-December 2005, 2008, and 2009 in a pure old-growth Nothofagus pumilio forest (hereafter PF) at 41° S, 71° W; 1,300 m elevation. Observations were made while systematically walking along human and animal trails, covering the entire study area between 0800 and 1 1 00 hrs in the morning (720 hrs in MF and 288 hrs in PF). We recorded the exact location each time a parakeet or flock was detected, and the identity of food items consumed to species level. If the parrots changed to another food source during the period of observation, the new material was recorded as a different feeding bout (Galetti 1993). Each feeding bout varied from a few seconds to several minutes with the entire flock participating in each observation. Flocks of five to 39 birds were observed within MF on 43 occasions during November and December eating Aditrochus fagicolus (Chalci- doidea: Pteromalidae) larvae (Nieves- Aldrey et al. 2009) in lenga beech leaf galls. Additionally, we recorded occasional consumption of lenga leaf galls 36 times during November-December in 2005, 2008, and 2009 in PF. Flocks of between 60 and 80 individuals were seen eating the contents of leaf galls, always in the same PF patch within each of the 3 years. We observed 221 Austral Parakeets (flocks between 4 and 7 birds) during December between 2007 and 2009 in MF on 69 different occasions eating larvae of Nemonychi- dae (Coleoptera) inside male pehuen cones. Austral Parakeets were observed 12 times (136 individuals in flocks of 8-1 1 birds) eating lenga beech seed galls (Mar-Jun 2008 and 2009). These galls housed insects in the Orders Homoptera, Lepidoptera, and Diptera. The parakeets ate only the larvae and discarded the vegetative parts of the gall (lenga beech leaf and seed galls) or pehuen male cone in all cases. DISCUSSION Consumption of larvae was mainly concentrat¬ ed during the pre-reproductive period (92.5% of the observations), indicating synchronization be¬ tween demand for high-quality food, and the sporadic and concentrated appearance of galls and cones. Food availability in MF throughout the pre- reproductive period (Dec) of Austral Parakeets is relatively low and primarily consists of pollen of 10 different species (SD, unpubl. data). Austral Parakeets were selective during this period and only consumed lenga beech, pehuen, and Mis- odendrum pollen. All observations of Austral Parakeets foraging on larvae contained within male pehuen cones were obtained during this period. These cones take half a year to complete their development and are hard to open while green. December, when the pollen is released, is the only time of the year when the male cones are fully developed and easy for Austral Parakeets to open and take advantage of the opportunity to forage on them. Larvae develop partially inside the cones until the cones are mature and fall from the trees, making them unavailable to parakeets. There are no observations of Austral Parakeets feeding on male cones or larvae contained within them once they have fallen to the ground. Lenga beech leaf gall consumption was also concentrat¬ ed in the pre-reproductive period in both loca¬ tions. Parakeets consumed mature and immature galls, which are distinguishable by their color, suggesting that larvae of different sizes were ingested. Parakeets were not observed to feed on larvae or insects during the reproductive season, when alternative sources of food were more available. The parakeets fed primarily on leaves and seeds (SD, unpubl. data for MF; Diaz and Kitzberger 2006 for PF) during this period. The consumption of larvae contained in lenga beech seed galls was only observed during the post- fledging period, when almost all lenga beech seeds are mature. These larvae may represent an important protein source for juveniles as the galls are available until winter (SD, unpubl. data), and lenga beech seeds have only 12% protein and 19% lipids (Diaz and Kitzberger 2006). This suggests post-reproductive events, including ju¬ venile dispersal and molting, rather than nesting, coincide with a short period of elevated protein- rich food availability. Adult arthropods infest galls and cones in a locally aggregated way (e.g., stand of trees) (J. L. Nieves-Aldrey, pers. comm.). Parakeets appear to know the precise location and timing of this food source, because they used it year after year in the pre-reproductive season. Thus, Austral Parakeets maximize exploitation of ephemeral protein sources during the period of high nutritional demand that occurs after winter scarcity. Forshaw (1989) indicated parrots are far more insectivorous than generally suspected. Insects are 170 THE WILSON JOLJRNAL OF ORNITHOLOGY • Vol 123, No. 1, March 2011 common in the diet of some Australian parrots, including Major Mitchell’s Cockatoo (. Lopho - chroa leadbeateri) (Rowley and Chapman 1991), Western Corella ( Cacatua pastinator) (Smith and Moore 1991), and New Zealand Kaka ( Nestor meridionalis septentrionalis ) (Moorhouse 1997), as well as RiippeH’s Parrot ( Poicephalus rueppellii ) (Selman et al. 2002), but only when other food is scarce. The consumption of arthropods by neotropical parrots may be more common and widespread than previously thought. Seasonal variations in diet with occasional ingestion of adult insects and spiders have been noted for some species (Galetti 1993, Wermundsen 1997). Diptera larvae have been found in stomach contents of Blaze-winged Parakeet ( Pyrrhura clevillei) (Moojen et al. 1941) and Peach-fronted Parakeet ( Aratinga aurea) (Schubart et al. 1965). The Painted Parakeet ( Pyrrhua picta) has been reported extracting and eating arboreal termites from their nests (de Faira 2007). Cockle et al. (2007) reported Vinaceous- breasted Amazons ( Amazona vinacea) presum¬ ably foraging on caterpillar larvae during a severe drought. Aramburu and Corbalan (2000) detected several arthropod species in the stomach contents of nestling Monk Parakeets ( Myiopsitta mona- chus), presumably from preening ectoparasites. It seems less common for psittacids to consume larvae from leaf galls, although such larvae constituted 6.6% of the diet of Lilac-crowned Amazons (Amazonci finschi) (Renton 2001) and were consumed daily for at least 2 weeks by a group of Maroon-bellied Parakeets ( Pyrrhura frontalis) (Martuscelli 1994). Our results suggest the Austral Parakeet is more insectivorous than previously thought. They inhabit temperate forests with marked seasonal shortages of food which may have led them to occupy a broader dietary niche than other parrots by supplementing their intake of high-quality ood, such as pollen (Diaz and Kitzberger 2006), uring the pre- and post-reproductive season with novel items such as insect larvae. AC KNOWLEDGMENTS The authors thank Cameron Naficy for his support Jot Blake, Kristina Cockle and Nigel Collar for theifconstm ve comment5 that helped to improve this manuscript, ar of T m qUeS Nacionales and especially the sta of Lanin National Park. Financial support was from «Mfi 7J£Ct CGL2°04-0I716-Feder. and CONICET doctoral grant to S.D. This research is part < the Doctoral studies of the senior author. LITERATURE CITED Aramburu, R. and V. CorbalAn. 2000. Dietade pichones de cotorra Myiopsitta monachus monachus (Aves: Psittacidae) en una poblacion silvestre. Omitologia Neotropical 11:241-245. Cockle, K.. G. Capuzzi, A. Bodrati, R. Clay, H. del Castillo, M. Velazquez, J. I. Areta. N. Farina, and R. Farina. 2007. Distribution, abundance, and conservation of Vinaceous Amazons (Amazona vina¬ cea) in Argentina and Paraguay. Journal of Field Ornithology 78:21-39. Collar, N. J. 1997. Family Psittacidae (Parrots). Pages 280-477 in Handbook of the birds of the world. Volume 4. Sandgrouse to cuckoos (J. del Hoyo, A. Elliott, and J. Sargatal, Editors). Lynx Editions, Barcelona, Spain. de Faria, I. P. 2007. Peach- fronted Parakeet ( Aratinga aurea) feeding on arboreal termites in the Brazilian Cerrado. Revista Brasileira de Omitologia 15:457— 458. Diaz, S. and T. Kitzberger. 2006. High Nothofagus flower consumption and pollen emptying in the southern South American Austral Parakeet ( Enicog - nathus ferrugi neiis). Austral Ecology 31:759-766. Forshaw, J. M. 1989. Parrots of the world. Third Edition. Blandford Press, London, United Kingdom, Galetti, M. 1993. Diet of the Scaly-headed Parrot (. Pionus maximiliani) in a semi-deciduous forest in southeast¬ ern Brazil. Biotropica 25:419-425. Koutsos E. A, K. D. Matson, and K. C. Klasing. 2001. Nutrition of birds in the Order Psittaciformes: a review. Journal of Avian Medicine and Surgery 15:257-275. Krebs, J. R. and N. B. Davies. 1993. An introduction to behavioral ecology. Third Edition. Blackwell Scien¬ tific Publications, Oxford, United Kingdom. Martin, T. E. 1987. Food as a limit on breeding birds: a life-history perspective. Annual Review of Ecology and Systematics 18:453-487. Martuscelli, P. 1994. Maroon-bellied Conures feeding on gall-forming homopteran larvae. Wilson Bulletin 106:769-770. Moojen, J., J. Candido De Carvalho, and H. Souza- Lopes. 1941. Observa9oes sobre o conteudo gastrico das aves brasileiros. Memorias do Instituto Oswaldo Cruz 36:405-444. Moorhouse, R. J. 1997. The diet of the North Island Kaka (Nestor meridionales septentrionalis) on Kapiti Island. New Zealand Journal of Ecology 21:141-152. Newton, I. 2003. Population limitation in birds. Academic Press, San Diego, California, USA. Nieves-Aldrey J. l, J. Liljebland, M. Hernandez Nieves, A. Grez, and J. A. Nylander. 2009. Revision and phylogenetics of the genus Pataulax Kieffer (Hymenoptera, Cynipidae) with biological notes and description of a new tribe, a new genus and five new species. Zootaxa 2200:1-40. Renton, K. 2001. Lilac-crowned Parrot diet and food resource availability: resource tracking by a pa170* seed predator. Condor 103:62-69. SHORT COMMUNICATIONS 171 Rowley, I. and G. Chapman. 1991. The breeding biology, food, social organization, demography and conservation of the Major Mitchell or Pink Cockatoo, Cacatua leadbeateri, on the margin of the western Australian wheatbelt. Australian Journal of Zoology 39:211-261. Schubart, 0., A. C. Aguirre, and H. Sick. 1965. Contribuicao para o conhecimento da alimentacao das aves brasileiras. Arquivos de Zoologia S. Paulo 12:95-249. Selman, R. G., M. R. Perrin, and M. L. Hunter. 2002. The feeding ecology of Ruppell’s Parrot, Poicephalus rueppellii, in the Waterberg, Namibia. Ostrich 73: 127-134. Smith, G. T. and L. A. Moore. 1991. Foods of corellas Cacatua pastinator in western Australia. Emu 91:87-92. Wermundsen, T. 1997. Seasonal change in the diet of the Pacific Parakeet Aratinga strenua in Nicaragua. Ibis 139:566-568. The Wilson Journal of Ornithology 123(1): 171-173, 2011 Greater Anis ( Crotophaga major) Commensal Foraging with Freshwater Fish in the Pantanal Floodplain, Brazil Flavio Kulaif Ubaid1 ABSTRACT. — Foraging associations between birds and other groups of animals have been widely reported in the literature. I report the first observation of a foraging tactic involving a flock of Greater Ani ( Crotophaga major), which deliberately followed fish along an artificial ditch in the Pantanal wetlands, feeding on animals flushed by the movement of the vegetation on the ditch banks. Further observations of the feeding behavior and foraging tactics of Greater Anis are necessary to ascertain if this type of behavior is a frequent event or merely sporadic. Received 22 June 2010. Accepted 11 October 20/0. Commensal foraging associations, where indi¬ vidual foraging opportunities are enhanced by actions of other unaffected individuals, are well known in nature and there are a relatively large number of reports in the scientific literature (King and Cowlishaw 2009). Birds are one of the groups most frequently studied as many species have the capacity to forage by catching prey flushed from a variety of substrates by other terrestrial animals (Willis and Oniki 1978, Dean and MacDonald 1981, Roberts et al. 2000). Among the best known associations of commensal foraging are those between birds and army ants (Oniki and Willis 1972, Willis and Oniki 1978, Willis 1983). During their sorties, ants moving in large numbers disturb a variety of insects and other small animals, which 1 Programa de Pos-gradua^ao em Zoologia, Instituto de Biociencias, Universidade Estadual Paulista, Rubiao Junior, 18618-100 Botucatu, Sao Paulo, Brasil; e-mail: flavioubaid@yahoo.com.br become potential prey for birds (Willis and Oniki 1988). Similarly, birds have been observed catching prey flushed by a wide variety of animals including primates (Fontaine 1980, Boinski and Scott 1988, Siegel et al. 1989, Ferrari 1990, Warkentin 1993), white-nosed coatis (Nasuci narica) (Booth-Binczik et al. 2004), nine-banded armadillos ( Dasypus novemcinctus ) (Komar and Hanks 2002), maned wolves ( Chrysocyon bra- chyurus) (Silveira et al. 1997), ungulates (Heat- wole 1965, Dean and MacDonald 1981, Kallander 1993), and other birds (Baker 1980, Robbins 1981). Reports also exist that involve birds in foraging associations with aquatic animals. These accounts come from observations in marine environments where birds were observed foraging in association with cetaceans (Au and Pitman 1986, Camphuy¬ sen et al. 1995, Camphuysen and Webb 1999, Santos et al. 2010), pinnipeds (Rijder 1957), tuna (Au and Pitman 1986), and stingrays (Kajiura et al. 2009). These marine animals, during their hunting forays, frequently confine their prey close to the surface to facilitate capture; these aggrega¬ tions attract seabirds that dive to feed (Martin 1986, Camphuysen and Webb 1999, Clua and Grosvalet 2001). However, I found no reports of foraging associations involving birds and fresh¬ water animals. The Greater Ani ( Crotophaga major) ranges from northern Argentina to Panama in South America; it typically occurs along riverbanks with vegetation and in gallery forests, flooded areas, 172 THE WILSON JOURNAL OF ORNITHOLOGY • Vol. 123, No. 1, March 2011 marshlands, and mangrove swamps (Payne 1997, Sick 1997). Greater Anis are gregarious and live in groups of four to >100 individuals (Hilty and Brown 1986) foraging on arthropods and small vertebrates from mid-canopy to the ground. They occasionally venture into the forest, usually to follow army ant columns (Willis 1983, Hilty and Brown 1986). I describe the first record of a commensal foraging association involving a flock of Greater Anis and freshwater fish, based on an opportunistic observation along a man-made waterway in the northern region of the Pantanal, Brazil. STUDY AREA The Pantanal of Mato Grosso is the plain formed by the upper reaches of the Paraguay River and its tributaries in western Brazil, in the states of Mato Grosso and Mato Grosso do Sul with a small portion in Bolivia and Paraguay. The plain slopes gently in the region creating a complex system of river flooding and ebbing with slow run-off (Antas 2004). This annual cycle of flooding and ebbing in the Pantanal has caused local residents to depend upon boats for transport during the rainy season, as well as in flood and ebb periods when roads are impassible. Boat transport during the latter two periods, when travel by road is difficult, has been enhanced by digging ditches parallel to roads to retain sufficient volume of water for use of boats, extending their use before and after the peak of the rainy season. These ditches have been dug to facilitate transportation of materials and people to and from the (RPPN) ‘Private Natural Heritage Reserve' SESC Pantanal. The RPPN SESC Pantanal is in the northern Pantanal (16° 41' 11" S, 56 10' 32" W) in the municipality of Barao de Melga^o, State of Mato Grosso and covers an area of 106,782 ha. Digging of one of the ditches egan in 2002 and it is cleared every year during the dry season to remove the accumulation of vegetal material. The ditch is ~2 m wide with a depth of between 0.5 to 1 5 m OBSERVATIONS At -0800 hrs on 3 February 2007, a group of mne Greater Anis was observed moving along a ditch tor about 20 min. The anis were foraging close to the water’s edge, catching insects amid the nverbank vegetation. Throughout this obser¬ vation, the group stayed within ~l-2 m of each other, moving at a constant pace (~1 m every 10 sec). From a vantage point, 30 m distant, I observed the anis were catching insects that flushed from vegetation emerging from the water that was being disturbed by fish that were darting back and forth along the edge of the ditch. The water surface remained calm and without current, allowing partial view of fish that were closer to the water surface. At times I noticed the fish performed more abrupt movements, such as a fight, when I could see many insects flushed by the movement of vegetation. All anis in the group foraged along the ditch, including five young (short tail, opaque plumage, bill not yet hooked, dark irises). The birds eventually dispersed, probably due to an approaching boat. DISCUSSION This is the first account of which I am aware involving birds and freshwater fish in a commen¬ sal foraging association. However, there are reports in the literature of commensal foraging behavior that involve Greater Anis associating with army ants (Willis 1983), as well as groups of monkeys ( Cebus spp.) and Hoatzins ( Opisthoco - mus hoaziri) (Sigrist 2006). Fish may congregate in the shaded waters of riverside galleries to take advantage of the remains of fruit and insects that fall on to the water surface (Sigrist 2006), thus providing opportunities for birds to forage on the insects flushed by the activities of fish at the surface. It has been shown for some species of birds that visual orientation is of great importance in catching prey (Eriksson 1985). However, it is unlikely in the present account that the birds focused their foraging based on the presence of fish, due to the turbidity of the water. It is more likely the birds detected the movement of the vegetation and the resulting movement by poten¬ tial prey. The frequency of this type of opportu¬ nistic behavior by Greater Anis, and birds in general, may be low in relation to broader foraging tactics. The paucity of reports involving birds and freshwater fish suggest it may be sporadic. However, I believe this event can occur more frequently in the late ebb, when the flooded area decreases and concentration of fish increases. Further observation of the feeding behavior and foraging tactics of Greater Anis is necessary. ACKNOWLEDGMENTS I am grateful to P. T. Z. Antas for important contributions, and the Superintendent of RPPN SESC Pantanal for financial and logistical support. SHORT COMMUNICATIONS 173 LITERATURE CITED Antas, P. T. Z. 2004. Pantanal, guia de aves: especies da Reserva Particular do Patrimonio Natural do SESC- Pantanal. SESC, Departamento Nacional, Rio de Janeiro, Brazil. Au, D. W. K. and R. L. Pitman. 1 986. Seabird interactions with dolphins and tuna in the eastern tropical pacific. Condor 88:304-317. Baker, B. W. 1980. Commensal foraging of Scissor-tailed Flycatchers with Rio Grande Turkeys. Wilson Bulletin 92:248. Boinski, S. and P. E. Scott. 1988. Association of birds with monkeys in Costa Rica. Biotropica 20:136-143. Booth-Binczik, S. D., G. A. Binczik, and R. F. Labisky. 2004. A possible foraging association between White Hawks and white-nosed coatis. Wilson Bulletin 116:101-103. Camphuysen, C. J. and A. Webb. 1999. Multi-species feeding associations in North Sea seabirds: jointly exploiting a patchy environment. Ardea 87:177-198. Camphuysen, C. J., H. J. L. Heessen, and C. J. N. Winter. 1995. Distant feeding and associations with cetaceans of Gannets Morus bassanus from Bass Rock, May 1994. Seabird 17:36-43. Clua, E. and F. Grosvalet. 2001. Mixed-species feeding aggregation of dolphins, large tunas and seabirds in the Azores. Aquatic Living Resources 14:11-18. Dean, W. R. J. and I. A. W. MacDonald. 1981. A review of African birds feeding in association with mammals. Ostrich 52:135-155. Eriksson, M. O. G. 1985. Prey detectability for fish-eating birds in relation to fish density and water transparency. Omis Scandinavian 16:1-7. Ferrari, S. F. 1990. A foraging association between two kite species ( Ictinia plumbea and Leptodon cayanen- sis) and buffy-headed marmosets (Callithnx flaviceps) in southeasthem Brazil. Condor 92:781-783. Fontaine, R. 1980. Observations on the foraging associ¬ ation of Double-toothed Kites and white-faced capu¬ chin monkeys. Auk 97:94-98. Heatwole, H. 1965. Some aspects of the association of Cattle Egrets with cattle. Animal Behaviour 13:79-83. Hilty, S. L. and W. L. Brown. 1986. A guide to the birds of Colombia. Princeton University Press, Princeton, New Jersey, USA. Kajiura, S. M., L. J. Macesic, T. L. Meredith, K. L. Cocks, and L. J. Dirk. 2009. Commensal foraging between Double-crested Cormorants and a Southern stingray. Wilson Journal of Ornithology 121:646-648. Kallander, H. 1993. Commensal feeding associations between Yellow Wagtails Motacilla flava and cattle. Ibis 135:97-100. King, A. J. and G. Cowlishaw. 2009. Foraging opportu¬ nities drive interspecific associations between Rock Kestrel and desert baboons. Journal of Zoology 277:111-118. Komar, O. and C. K. Hanks. 2002. Fan-tailed Warbler foraging with nine-banded armadillos. Wilson Bulletin 114:526-528. Martin, A. R. 1986. Feeding association between dolphins and shearwaters around the Azores Islands. Canadian Journal of Zoology 64:1372-1374. Oniki, Y. and E. O. Willis. 1972. Studies of ant-following birds north of the eastern Amazon. Acta Amazonica 2:127-151. Payne, R. B. 1997. Family Cuculidae (cuckoos). Pages 508-607 in Handbook of the birds of the world. Volume 4. Sandgrouse to cuckoos (J. del Hoyo, A. Elliott, and J. Sargatal, Editors). Lynx Edicions, Barcelona, Spain. Robbins, M. B. 1981. Two cases of commensal feeding between passerines. Wilson Bulletin 93:391-392. Roberts, D. L., R. J. Cooper, and L. J. Petit. 2000. Flock characteristics of ant-following birds in premontane moist forest and coffee agroecosystems. Ecological Applications 10:1414-1425. Rijder, R. A. 1957. Avian-pinniped feeding associations. Condor 59:68-69. Santos, M. C. O., J. E. F. Oshima, E. S. Paci'fico, and E. Silva. 2010. Feeding associations between Guiana dolphins, Sotalia guianensis (Van Beneden, 1864) and seabirds in the Lagamar Estuary, Brazil. Brazilian Journal of Biology 70:9-17. Sick, H. 1997. Ornitologia Brasileira. Nova Fronteira, Rio de Janeiro, Brazil. Siegel, C. E., J. M. Hamilton, and N. R. Castro. 1989. Observations of the Red-billed Ground-Cuckoo (Neo- mo rphus pucheranii ) in association with tamarins (Saguinas) in northeastern Amazonian Peru. Condor 91:720-722. SlGRlST, T. 2006. Aves do Brasil: uma visao artistica. Fosfertil, Sao Paulo, Brazil. Silveira, L., A. T. A. Jacomo, F. H. G. Rodrigues, and P. G. Crawshaw Jr. 1997. Hunting association between the Aplomado Falcon (Falco femomlis) and the maned wolf ( Chrysocyon brachyurus) in Emas National Park, central Brazil. Condor 99:201-202. Warkentin, 1. G. 1993. Presumptive foraging association between Sharp-shinned Hawks (Accipiter striatus) and white-faced capuchin monkeys ( Cebus capucinus). Journal of Raptor Research 27:46-47. Willis, E. O. 1983. Anis (Aves, Cuculidae) as army ant followers. Revista Brasileira de Biologia 43:33^44. Willis, E. O. and Y. Oniki. 1978. Birds and army ants. Annual Review of Ecology, Evolution and Systematics 9:243-263. Willis, E. O. and Y. Oniki. 1988. Na trilha das formigas camivoras. Ciencia Hoje 8:27-32. 174 THE WILSON JOURNAL OF ORNITHOLOGY • Vol. 123, No. 1, March 2011 The Wilson Journal of Ornithology 123(1): 174-1 76, 2011 Adoptions of Young Common Buzzards in White-tailed Sea Eagle Nests Ivan Literak1,3 and Jakub Mraz2 ABSTRACT. — Documentation of interspecific adop¬ tion of young is rare in the published literature among birds. We survey six cases of young Common Buzzards ( Buteo buteo) adopted in nests of White-tailed Sea Eagle ( Haliaeetus albicilla) in central Europe (Czech Republic and Hungary). Common Buzzard nestlings adopted were in good condition and adult White-tailed Sea Eagles fed and cared for them properly. Young Common Buzzards successfully hedged and left the White-tailed Sea Eagle nests. The most probable explanation of this phenomenon is a non-lethal predation of Common Buzzards followed by White¬ tailed Sea Eagle parental care as a result of parental recognition error. Similar cases of adoption of Red¬ tailed Hawk (Buteo jamaicensis) nestlings in nests of Bald Eagle ( Haliaeetus leucocephalus) have been documented in North America. Received 17 May 2010. Accepted 27 July 2010. Adoption is defined in the ornithological litera¬ ture as caregiving to young or eggs by unrelated adults but interspecific adoption has rarely been reported (Capek et al. 2000). Repeated cases of the same type of interspecific adoption have been described only in nesting Bald Eagles ( Haliaeetus leucocephalus) in North America which adopted young Red-tailed Hawks ( Buteo jamaicensis) (Stefanek et al. 1992, Watson et al. 1993, Watson and Cunningham 1996). We observed adoption of a Common Buzzard ( B . buteo) nestling in a White¬ tailed Sea Eagle (H. albicilla) nest in the Czech Republic in 2007. In addition, we found notes about other such cases in the Czech Republic and Hungary in the local literature, suggesting this type of interspecific adoption by raptors is probably more frequent in central Europe then we had supposed. We report cases of adoptions of young Common Buzzards by nesting White-tailed Sea Eagles and speculate on possible explanations for this phenomenon. 'Department of Biology and Wildlife Diseases, Faculty of Veterinary Hygiene and Ecology, University of Veter¬ inary and Pharmaceutical Sciences, Palackeho 1-3, 612 42 Brno, Czech Republic. * Dvorecka 264, 37901 Brilice-Trebon, Czech Republic. Corresponding author: e-mail: literaki@vfu.cz OBSERVATIONS We originally observed a young Common Buzzard reared in a nest of White-tailed Sea Eagles near the village of Hrachoviste, southwest¬ ern Czech Republic (48° 55' N, 14° 46' E). The nest was in a forest close to a clearing and was built on a Scots Pine ( Pinus sylvestris) tree at a height of ~20 m. The nest was checked by the second author on 20 May 2007 to see if the young eagles were at an age suitable for ringing. There were two eagles ~3 weeks of age and, surpris¬ ingly, also a live Common Buzzard chick ~2 weeks of age. All young were in good condition. Adult eagles were flying above the nest and an adult Common Buzzard also was observed flying above the nest but it was not evident whether this individual could be a parent of the young buzzard in the eagle nest. The nest was checked again on 12 June 2007 during which time the young buzzard had already fledged and was sitting in a tree at a distance of ~ 150 m. The two young eagles (~6 weeks of age) stayed on the nest. This proved that adult White-tailed Sea Eagles from this nest had adopted a young Common Buzzard and cared for it during a period of at least ~3 weeks. No adult Common Buzzard was observed near the nest during the second visit. The second author personally checked 21 nests ot White-tailed Sea Eagles in the Czech Republic and found a young Common Buzzard only in the nest described. DISCUSSION A young Common Buzzard was observed in 2000 by P. Kurka in the nest of a White-tailed Sea Eagle in the northern part of the Czech Republic (Schropfer 2002). P. Kurka was checking the nest on a pine tree on 4 June 2000 and found one young White-tailed Sea Eagle and one young Common Buzzard both alive, as well as two dead young Common Buzzards ~1 week of age. No more information is available for this case. A nest of White-tailed Sea Eagles with two Common Buz¬ zard chicks of different ages plus a White-tailed Sea Eagle nestling was found in Hungary in 2007 SHORT COMMUNICATIONS 175 (Horvath 2009). All three young successfully fledged and left the nest. Three more cases in which young Common Buzzards were found in White-tailed Sea Eagle nests originated also from Hungary (Palko 1997, Fenyosi and Stix 1998, Horvath 2006). Interspecific brood parasitism, placement of nestling hawks in eagle nests by humans, and non- lethal predation followed by parental care have been considered as causes of this phenomenon for young Red-tailed Hawks adopted in Bald Eagle nests in North America (Stefanek et al. 1992, Watson et al. 1993, Watson and Cunningham 1996). Interspecific brood parasitism has not been recorded in the Accipitridae (Yom-Tov 2001), and this scenario was considered unlikely for the cases of adopted nestlings of Red-tailed Hawk (Stefa¬ nek et al. 1992, Watson et al. 1993). We support this contention regarding the cases of adopted nestlings of Common Buzzards in nests of White¬ tailed Sea Eagles. For brood parasitism to have occurred, Common Buzzard females would have had to enter the eagle nests, contend with an adult White-tailed Sea Eagle with newly hatched nestlings, and laid its eggs. The eggs would have had to be incubated by the adult eagles, the eagle nestlings or both. White-tailed Sea Eagles begin to nest (lay eggs) in central Europe in February and incubation lasts 34-46 days. Common Buzzards begin to nest at the end of March and incubation lasts 33-35 days. There is no tendency among Common Buzzards for brood parasitism and the time difference between the start of nesting for both species makes brood parasitism improbable. Thus, we do not believe brood parasitism is a realistic explanation of these phenomena. Placing of Common Buzzards nest¬ lings into White-tailed Sea Eagle nests by humans also was unlikely due to the difficulties in climbing the high trees and there is no obvious rational reason to do it in different places and years. The most plausible explanation for these phenomena is non-lethal predation followed by parental care. This scenario was considered the more likely explanation for the occurrence of live young Red-tailed Hawks in Bald Eagle nests (Stefanek et al. 1992, Watson et al. 1993, Watson and Cunningham 1996), and we suggest the same explanation for cases in which young live Common Buzzards occurred in White-tailed Sea Eagle nests. One of the adult White-tailed Sea Eagles may have captured the nestling Common Buzzard as prey for it own nestlings and failed to kill it during capture and transport. Food-begging calls of Common Buzzard chicks that survived the transport apparently stimulated feeding from the White-tailed Sea Eagles (Horvath 2009). The adopted Common Buzzards were usually in good condition with no apparent signs of abuse by the adult or nestling eagles. It suggests the adult eagles fed them properly and/or the Common Buzzards were able to scavenge sufficient food to stay alive and fledge. Corroborating this hypothesis is infor¬ mation that birds, including chicks from nests of Grey Herons ( Ardea cine re a), commonly occur in White-tailed Sea Eagle diets (Balat and Belka 2005, Belka and Horal 2009, Horvath 2009). The presence of raptor species also was found in an analysis of Bald Eagle prey items collected at nests in the USA (Stefanek et al. 1992). Moreover, raptors at times bring prey that is still alive to their nests (Spofford and Amadon 1993). In addition to Red-tailed Hawks in Bald Eagle nests, another case of an apparent nonlethal predation was a Glaucous¬ winged Gull ( Lotus glaucescens ) chick and subse¬ quent adoption by a pair of Bald Eagles as noted in Alaska (Anthony and Fans 2003). The adoption of Common Buzzard chicks by White-tailed Sea Eagles could be explained as a parental recognition error because there are no benefits for parents to adopt chicks of an unrelated species. The Common Buzzard nestlings benefit¬ ed, however, from the recognition error of the eagles. The White-tailed Sea Eagle and Bald Eagle, as are non-colonial bird species, are probably unable to distinguish their offspring from other species (Alcock 1997). We consider this type of adoption as a surprising phenomenon in central Europe. Numbers of nesting pairs of White-tailed Sea Eagles in the Czech Republic and Hungary were relatively low; they numbered —50 and 180 nesting pairs in the Czech Republic and Hungary in 2007, respectively (Belka and Horal 2009, Horvath 2009). Conversely, the Common Buzzard is the most common raptor species in this area and the last census for a nesting population in the Czech Republic revealed 1 1,000-14,000 nesting pairs (Stastny et al. 2006). We consider noteworthy that this phenomenon of interspecific adoption occurs in raptors with similar ecological niches in both North America and Europe. The Bald Eagle is a North American ecological equivalent of the White-tailed Sea Eagle, and the Red-tailed Hawk is among the most common raptors in North America just as the 176 THE WILSON JOURNAL OF ORNITHOLOGY • Vol. 123, No. 1, March 2011 Common Buzzard is in Europe (Thiolley 1994). Mixed broods of Red-tailed Hawks and Bald Eagles in the USA occurred at a frequency of 0.5% (3 of 662) of eagle broods observed during 1987-1991 (Watson et al. 1993). Our data are presently too limited to calculate a frequency of adoptions of Common Buzzards in White-tailed Sea Eagle nests in Europe. ACKNOWLEDGMENTS This study was funded by Grant Number MSM62 157 12402 of the Ministry of Education, Youth and Sports of the Czech Republic. LITERATURE CITED Alcock, J. 1997. Animal behavior. Sixth Edition. Sinauer Associates Inc., Sunderland, Massachusetts, USA. Anthony, R. G. and J. T. Faris. 2003. Observations of a live Glaucous-winged Gull chick in an active Bald Eagle nest. Wilson Bulletin 1 15:481-483. Balat, F. and T. Belka. 2005. Potrava, Haliaeetus albicilla (Linnaeus, l758)-orel morsky. Pages 67-68 in Fauna CR ptaci (K. Hudec and K. Stastny, Editors). Academia, Prague, Czech Republic. Belka, T. and D. Horal. 2009. The White-tailed Sea Eagle ( Haliaeetus albicilla ) in the Czech Republic. Denisia 27:65-77. Capek, M.. M. Honza, and V. Mrlik. 2000. Female Blackcap adoption of Yellowhammer clutch. Wilson Bulletin 112:542-543. Fenyosi, L. and J. Stix. 1998. Megjegyzesek a “Retisas { Haliaeetus albicilla) altat nevelt egereszolyv ( Buteo buteo) fiokak” cimu irashoz. Tuzok 3:64. Horvath, Z. 2006. Ujabb adat egereszolyvfioka retisas- feszekben torteno megfigyeleserol. Aquila 113:165, 179-180. Horvath, Z. 2009. White-tailed Sea Eagle ( Haliaeetus albicilla ) population in Hungary between 1987-2007. Denisia 27:85-95. Palko, S. 1997. Retisas ( Haliaeetus albicilla ) altal nevelt egereszolyv ( Buteo buteo ) fiokak. Tuzok 2:109-111. Schropfer, L. 2002. Zprava o cinnosti Skupiny pro ochranu a vyzkum dravcu a sov CSO v roce 2000. Zpravodaj Skupiny pro ochranu a vyzkum dravcu a sov pri Ceske spolecnosti omitologicke 8:2-20. Spofford, W. R. and D. Amadon. 1993. Live prey to young raptors-incidental or adaptive? Journal of Raptor Research 27: 1 80-184. Stastny, K., V. Bejcek, and K. Hudec. 2006. Atlas hnizdniho rozsireni ptaku v Ceske republice 2001— 2003. Aventinum, Prague, Czech Republic. Stefanek, P. R., W. W. Bowerman, T. G. Grubb, and J. B. Holt. 1992. Nestling Red-tailed Hawk in occupied Bald Eagle nest. Journal of Raptor Research 26:40-41. Thiolley, J. M. 1994. Family Accipitridae (hawks and eagles). Pages 52-205 in Handbook of the birds of the world. Volume 2. New World vultures to guineafowl (J. del Hoyo, A. Elliott, and J. Sargatal, Editors). Lynx Edicions, Barcelona, Spain. Watson, J. W. and B. Cunningham. 1996. Another occurrence of Bald Eagles rearing a Red-tailed Hawk. Washington Birds 5:51-52. Watson, J. W., M. Dawison, and L. Leschner. 1993. Bald Eagles rear Red-tailed Hawks. Journal of Raptor Research 27:126-127. Yom-Tov, Y. 2001. An updated list and some comments on the occurrence of intraspecific nest parasitism in birds. Ibis 143:133-143. The Wilson Journal of Ornithology 123(1): 176— 178, 2011 Cruise Ships as a Source of Avian Mortality During Fall Migration Carol I. Bocetti1’2 ABSTRACT. — Avian mortality during fall migrati has been studied at many anthropogenic structures, mi of which share the common feature of bright lightii An additional, unstudied source of avian mortal during fall migration is recreational cruise ships that £ brightly lit throughout the night. I documented a sins mortality event of eight Common Yellowthroi ( Geothlypis trie has) on one ship during part of o 1 USGS, Patuxent Wildlife Research Center, 250 Uni¬ versity Avenue, Box 45, California, PA 15419, USA. Current address: California University of Pennsylvania 250 University Avenue, Box 45, California, PA 1541 9' USA; e-mail: bocetti@calu.edu night in fall 2003, but suggest this is a more wide-spread phenomenon. The advertised number of ship-nights for 50 cruise ships in the Caribbean Sea during fall migration in 2003 was 2,981. This may pose a significant, additional, anthropogenic source of mortal¬ ity that warrants further investigation, particularly because impacts could be minimized if this source of avian mortality is recognized. Received 21 October 2009. Accepted 23 August 2010. Mortality during migration of neotropical migratory songbirds is an important topic to bird conservationists. Anthropogenic causes of mor- SHORT COMMUNICATIONS 177 tality are additive to natural causes, and may pose a threat to many declining species. Avian mortality during fall migration has been attributed to multiple anthropogenic structures, including vehicles, communication structures, buildings and windows, powerlines, and wind turbines (Erick¬ son et al. 2001). Avian mortality during migration has also been documented at off-shore oil derricks (Hope-Jones 1980) and at navigational lightships (Bullis 1954). The common element among most of these sources of avian mortality is lighting. The bright lights may attract night-migrating birds (Gauthreaux and Belser 2006, Gehring et al. 2009). An additional source of modem avian mortality during fall migration is impact and death by exhaustion on the open decks of recreational cruise ships. OBSERVATIONS On 28 September 2003, while aboard a 14- story, 3,114-passenger cruise liner in the Carib¬ bean Sea (~80 km south of Miami, Florida, USA), I observed a massive, mixed-species flock of migratory songbirds and egrets flying around the ship. Flock size could not be estimated due to the erratic, non-directional flight behavior of the flock, but a visual snapshot would suggest the flock was in the magnitude of thousands. During a 45-min sweep (0015 to 0100 hrs, EDT) of parts of the open area of two decks, I found eight dead Common Yellowthroats ( Geothlypis trichas). The mortality was due to impacts with glass windows of upper decks (based on location of two carcasses directly below windows) and exhaustion from flight within the wind drafts of these open decks (4 deaths witnessed). Many birds were trapped within partially enclosed portions of these decks. The most common species observed within these partial enclosures was the Common Yellowthroat. Other species observed resting on the ship included Louisiana Waterthrush ( Parke sia mota- cilla), American Redstart ( Setophaga ruticilla ), Tree Swallow ( Tachycineta bicolor ), and Barn Swallow ( Hirundo rustica). Cattle Egrets ( Bubul - cus ibis ) were observed flying around the ship, but they did not land on the vessel. Cattle Egrets were likely preying upon the aggregated flock of songbirds (P. W. Sykes Jr., pers. comm.), adding an additional source of mortality. It appeared the birds were attracted to the lights of the ship, and then became confused and caught in the wind draft associated with the ship’s movement ( 22 knots/hr). The weather condition was overcast with air temperature —23° C. About 3 hrs prior to the observation period, it rained hard for about 1 .5 hrs. Migrants may have lowered the altitude of their migratory path due to weather conditions of that evening. However, songbirds were observed in partially enclosed portions of the ship during the daytime of the previous 4 days. The weather conditions of preceding nights were clear skies with similar air temperatures, suggesting the rain event was not what brought the songbirds into close proximity of the ship. Egrets were also observed flying in the wind draft of the ship on three previous nights, during clear sky conditions. Unfortunately, I did not visit the open decks or watch carefully for songbird migrants on any of the other nights during the cruise. Considering that in 2003 there were ~50 large cruise ships that carry 1 ,200 or more passengers operating in the Caribbean Sea (with destinations in the Bahamas, East Caribbean, South Caribbean, West Caribbean, and East coast of Mexico only) during the fall migration (Aug-Oct), this source of avian mortality may not be trivial (Table 1). These ships are advertised as 207 to 311 m in length, and are 10-14 stories in height. They are all well lit at night. The general design of these vacation cruise ships is to have 3-5 decks with open areas, a few of which have partial enclo¬ sures. On the ship I observed, the area I searched covered ~ 1 /4th of the open areas on the ship, excluding balconies (wind draft of ship does not swirl into these areas). My 45-min observation period represented — 1/1 5th of the dark hours of the night. To extrapolate from the mortality I directly observed (4 deaths, excluding the 4 birds that were found already dead); this single ship on this single night may have resulted in four bird deaths X 4 X 15 = 240 bird deaths. The cleaning staff of the cruise ship acknowledged removal of songbirds from the deck during early morning hours prior to guest activities, although they did not admit how often or how many dead birds were removed. Based on advertised sail dates and itineraries, the 50 large (>1,200 passengers) cruise ships operating in the Caribbean Sea during August through October result in an estimated 2,981 ship-nights (Table 1). Assuming 240 bird deaths per ship-night, an estimated 715,440 bird deaths may have occurred on large cruise ships in the Caribbean Sea during fall migration 2003. Given the small sample size and low sampling intensity, I am uncertain whether the mortality I 178 THE WILSON JOURNAL OF ORNITHOLOGY • Vol. 123, No. 1, March 2011 TABLE 1. Cruise ship companies and number of large (>1,200 passengers) ships (and ship-nights8) sailing in the Caribbean Sea during fall migration (Aug-Oct) 2003. Cruise ship company Number of ships Number of passengers Speed (knots) Number of ship-nights Royal Caribbean 11 2,020-3,114 19-22 777 Carnival 17 1,452-2,974 21-22 1,267 Princess 6 1,950-2,600 284 Celebrity 5 1,354-1.950 21-24 148 Holland America 5 1,266-1.848 22-24 134 Norwegian Cruise Line 4 1,748-2,400 21-25 147 Disney Cruise 2 1,750 224 Totals 50 2,981 Ship-night = sum of advertised nights of all cruises for all ships of each company. observed is representative of a typical fall night. I assumed the estimated kill for the single ship- night on 28 September was representative of the entire fall migration season simply to produce an approximate estimate of avian mortality to begin considering the impact of this additional anthro¬ pogenic structure. I also assumed the ship I observed was representative of other large ships. I only included large ships (>1,200 passengers) in my estimate of ship-nights to strengthen that assumption. Many smaller ships also sail the Caribbean during the fall season, but their deck arrangement and lighting patterns may be differ¬ ent from the larger cruise ships. DISCUSSION The Caribbean Sea is crossed by millions of neotropical migrants every fall. The decline of many of these species is of significant conservation concern. Perhaps even more alarming is the known presence of the endangered Kirtland’s Warbler ( Dendroica kirtlandii ), the entire population of which must cross these waters during fall migration to reach wintering areas in the Bahamas. This issue warrants further investigation given the multitude of anthropogenic sources of avian mortality during fall migration and the additive nature of this mortality (Erickson et al. 2001). At a minimum, proper studies designed to estimate the magnitude and species composition of avian mortality on cruise ships during the fall migration period are warranted. Studies should address species-specific causal factors including light attraction, weather conditions, time of day and time of year. Efforts to work with the industry to minimize impacts would be prudent. If studies show lights are attracting birds, it is possible that alternative lighting options for these ships could reduce the impact on migratory birds. For example, light covers could prevent the light from illuminating skyward. This may eliminate the attraction to overhead migrating birds. Also, the wavelength of the light bulbs could be changed to be less attractive (Gauthreaux and Belser 2006). Flash pattern could also be manipulated to minimize attraction to night-migrating birds (Gauthreaux and Belser 2006, Gehring et al. 2009). Finally, most lights could be completely turned off after 0200 hrs when the ships' daily activities are terminated. This could reduce by half the number of night-lighted hours on the ship. ACKNOWLEDGMENTS I thank R. P. Dettmers for an early review of the manuscript. C. E. Braun, C. S. Robbins, and an anonymous reviewer provided comments on the submitted manuscript. All provided valuable improvements. LITERATURE CITED Bullis Jr., H. R. 1954. Trans-Gulf migration, spring 1952. Auk 71:298-305. Erickson, W. P„ g. D. Johnson, M. D. Strickland, D. P. Young Jr., K. J. Sernka, and R. E. Good. 2001. Avian collision with wind turbines: a summary of existing studies and comparisons to other sources of avian collision mortality in the United States. West Inc., Cheyenne, Wyoming, USA. Gauthreaux, S. A. and C. G. Belser. 2006. Effects of artificial night lighting on migrating birds. Pages 67- 93 in Ecological consequences of artificial night lighting (C. Rich and T. Longcore, Editors). Island Press, Washington, D.C., USA. Gehring, J., P. Kerlinger, and A. M. Manville II. 2009. Communication towers, lights, and birds: successful methods of reducing the frequency of avian collisions. Ecological Applications 19:505-514. Hope-Jones, P. 1 980. The effect on birds of a North Sea gas flare. British Birds 73:547-555. SHORT COMMUNICATIONS 179 The Wilson Journal of Ornithology 123(1): 179-1 80, 2011 First Record of Aplomado Falcon (Falco femoralis) for the West Indies Blake A. Mathys1 ABSTRACT. — I report the first sighting of Aplo¬ mado Falcon ( Falco femoralis ) for Puerto Rico and all of the West Indies. I observed a single individual at Laguna Cartagena National Wildlife Refuge (south¬ western Puerto Rico) on 15 January 2008; the individual stayed until 25 January 2008. Photographs establishing the bird’s identity were obtained during prolonged periods of observation by several observers. Received 30 January 2010. Accepted 4 August 2010. The Aplomado Falcon (Falco femoralis) occurs from the southern United States, through Central America, to Argentina in South America. It is generally sedentary, although individuals in the extreme northern and southern part of the range are partially migratory (Keddy-Hector 2000). It is a medium-sized falcon (200 to 500 g), and primarily preys on birds and insects, although small mammals and reptiles are also taken (Keddy-Hector 2000). The Aplomado Falcon occurs in open habitats including grasslands, savannahs, and prairies. It has not been previously recorded on any Caribbean island (excluding Trinidad, which is biogeographically South Amer¬ ican; Raffaele et al. 1998). I report the first record of this species for the West Indies. OBSERVATIONS I observed an Aplomado Falcon on 15 January 2008 at Laguna Cartagena National Wildlife Refuge (18°0r N, 67 ' 06' W) in southwest Puerto Rico. I was observing West Indian Whistling Ducks ( Dendrocygna arborea) on the southwest side of the refuge. I scanned several dead trees for a Peregrine Falcon (Falco pere- grinus) that I had regularly seen in the area. At 1320 hrs (AST) I saw a raptor, smaller than a Peregrine, perched in one of the dead trees on the northwest shore of the lagoon at a distance of ^400 m. It was observed through a 60 X spotting scope. I immediately recognized it as an Aplo¬ mado Falcon, due to the long tail, dark vest-like 1 Natural Sciences and Mathematics, The Richard Stock- ton College of New Jersey, P. O. Box 195, Pomona, NJ 08240, USA; e-mail: Blake.Mathys@stockton.edu coloration on the chest, and pronounced light stripe over the eye. I was familiar with this species, having previously seen multiple individ¬ uals in Venezuela and Mexico. It stayed at this perch for —25 min, spending most of the time preening. I took special care to observe the legs to look for bands or jesses, clues to probable captive provenance. The left leg was completely free of any objects. The bird then flew directly toward me, eventually landing in larger trees —65 m to the west of the observation tower. I later returned to these trees to look for the falcon. It flushed from the trees, circling a few times before landing again in a tree — 10 m from me. I was able to closely observe both legs and confirm there were no bands or jesses on either. It was also at this perch that I obtained the best photographs by “digi-scoping” with a four megapixel digital camera through the ocular lens of my spotting scope (at 20 X). The bird flushed and flew to the west, and later flew east of the observation tower and roosted at the top of a tree. I observed it later in the afternoon on the north side of the lagoon perched on fence posts and at the tops of trees. The Aplomado Falcon was seen frequently over the next 10 days, generally on the north side of the lagoon. I left Puerto Rico on 20 January, last personally seeing the falcon at 1100 hrs on 19 January. It was well photographed by Mike Morel on 21 January, and last reported on the morning of 25 January by Maiia Camacho and Eduardo Ventosa. DISCUSSION I identified the bird as an Aplomado Falcon during the initial observation on 15 January 2008 as I was familiar with the species in Mexico and Venezuela. Peregrine Falcon, Merlin (Falco columbarius ), and American Kestrel (F. sparver- ius) were observed at Laguna Cartagena on most days, and it was immediately obvious due to size and well-defined marking that the falcon was not any of the expected species. Other physically similar falcon species includ¬ ing Bat Falcon (F. rufigularis ), Orange-breasted Falcon (F. deiroleucus ), and Eurasian Hobby (F. 180 THE WILSON JOURNAL OF ORNITHOLOGY • Vol. 123, No. 1, March 2011 subbuteo) were considered and rejected as candi¬ dates during the initial viewing. Bat Falcon would be most likely having been recorded as a vagrant to Grenada (Raffaele et al. 1998). The Bat Falcon, a species I have seen multiple times in Venezuela and Mexico, is smaller with a shorter tail and full dark hood, the latter character especially being quite different from the distinctive facial pattern of the Aplomado Falcon. The bird was first seen perched on a dead tree that a Peregrine Falcon had been frequenting. It appeared slightly smaller than a Peregrine Falcon, therefore much too large to be a Bat Falcon. The distinct black vest, combined with the light superciliary stripe and dark facial markings, clinched the identification. The long, banded tail was observed well during the bird’s preening, a character with which I had been particularly impressed while previously observing Aplomado Falcons in Venezuela. Australian Hobby (F. longipennis ) can be eliminated due to lacking a dark vest and not showing a complete superciliary stripe (Ferguson-Lees and Christie 2005). In addition, its range is geographically distant from Puerto Rico. Lanner Falcon ( F biarmicus ), similarly unlikely based on range, can also be eliminated by lack of a dark vest' shorter tail, and less distinct superciliary stripe when present (Ferguson-Less and Christie 2005). There are three subspecies of Aplomado Falcon; F. femoralis septentrionalis and F. femoralis femoralis are geographically the best candidates for a vagrant to Puerto Rico. The other subspecies, F. f pinchinchae , is geographically distant and shows a much richer rufous coloration than the bird observed. The nominate subspecies is geographically the closest to Puerto Rico. I was able to observe the falcon for -8 hrs over 5 days. It was perched on fence posts or small trees (<7 m tall) for the majority of this time. Its observed hunting style was similar to a female Merlin that I observed daily at the lagoon. This Merlin successfully captured dragonflies, and the Aplomado Falcon’s prey items were assumed to be similar. However, no specific prey items were identified. This species is rare in Central America south of Mexico. It was first recorded in Honduras and Costa Rica during the last 30 years (Koford et al. 1980, Marcus 1983). It is rare in Trinidad, although breeding has been recorded (ffrench and ffrench 1966, ffrench 1991). The closest stable breeding population is in Venezuela, —800 km south of Puerto Rico. ACKNOWLEDGMENTS I thank many Puerto Rican birders for sharing their sightings with me, especially during the period after I left. Sergio Colon, Mike Morel, Manuel Cruz, and Fred Schaffner all communicated sightings and misses toward the end of the falcon's stay. I also thank the National Geographic Society Committee for Research and Explora¬ tion (Grant #8261-07), for providing all of the funding for my research in Puerto Rico. My advisor, J. L. Lockwood, was instrumental in encouraging my work in Puerto Rico. LITERATURE CITED Ferguson-Lees, J. and D. A. Christie. 2005. Raptors of the world. Princeton University Press, Princeton, New Jersey, USA. ffrench, R. 1991. A guide to the birds of Trinidad and Tobago. Second Edition. Cornell University Press, New York, USA. ffrench, R. P. and M. ffrench. 1966. Recent records of birds in Trinidad and Tobago. Wilson Bulletin 78:5— 11. Keddy-Hector, D. P. 2000. Aplomado Falcon ( Falco femoralis). The birds of North America. Number 549. Koford, R. R.. g. S. Wilkinson, and B. S. Bowen. 1980. First record of an Aplomado Falcon ( Falco femoralis) in Costa Rica. Brenesia 17:23-25. Marcus, M. J. 1983. Additions to the avifauna of Honduras. Auk 100:621-629. Raffaele, H., J. W. Wiley, O. Garrido, A. Keith, and J. Raffaele. 1998. A guide to the birds of the West Indies. Princeton University Press, Princeton. New Jersey, USA. SHORT COMMUNICATIONS 181 The Wilson Journal of Ornithology 123(1): 181-183, 201 1 Idle Lobster Traps Kill Blue Jays Mason H. Cline1,3 and Joanna L. Hatt* 2 3 ABSTRACT. — We report observations of Blue Jay (Cyanocitta cristata) mortality in idle lobster traps stored on Merepoint Neck in the Town of Brunswick, Maine. Three of nine individual Blue Jays found inside the traps were alive but emaciated. Each of the live Blue Jays was seen picking off and swallowing pieces of pectoral muscles from Blue Jay carcasses also inside the traps. We could not find literature describing or warning of the attractive nuisance posed to birds by improperly stored fishing gear, such as lobster traps. Our observa¬ tions identify a previously undocumented threat to local bird populations, and likely the first documentation of adult-adult cannibalism for the Blue Jay. We suggest some simple solutions to mitigate avian mortality due to improperly stored fishing gear. Received 22 June 2010. Accepted 9 October 2010. It is widely known that idle and derelict fishing gear cause unintended mortality to marine organ¬ isms (Macfadyen et al. 2009). However, we found no documentation describing the threat that idle fishing equipment poses to terrestrial organisms, such as passerine birds. Until this report, idle and improperly stored fishing gear has not been acknowledged as a real and serious threat to survival of terrestrial birds. We describe observa¬ tions of inadvertent trapping and subsequent mortality of a terrestrial songbird, the Blue Jay ( Cyanocitta cristata ), in idle fishing equipment. We also document adult-adult cannibalism by Blue Jays. Reports of adult-adult cannibalism in wild birds are uncommon. Generally, in wild birds, cannibalistic behavior is thought to be the product of either extreme aggression or opportu¬ nistic nutritional exploitation (Stanback and Koenig 1992). Conversely, reports of captive birds exhibiting cannibalistic behavior are fairly common. Cannibalism by captive birds is often cited as the product of social and environmental stresses associated with captivity (Duncan and Hawkins 2010). '585 Butter Hill Road, Chatham, NH 03813, USA. 2 164 Federal Street, Wiscasset, ME 04578, USA. 3 Corresponding author; e-mail: mason.cline@gmail.com OBSERVATIONS Observations were made during a Christmas Bird Count on Merepoint Neck in the Town of Brunswick, Maine. On 3 January 2010 at 0930 hrs EST, while surveying for birds at a public boat launch near the southern terminus of Merepoint Neck, we noticed —80 metal lobster traps stacked in a rectangular formation. The lobster traps were on property adjacent to the public boat launch. Upon closer inspection, we detected three live Blue Jays caught in three separate lobster traps. The birds could enter the traps, but once inside they were unable to escape. The trapped Blue Jays were initially observed through binoculars from a distance of —50-75 m. During our initial observation, we noticed a number of Blue Jay carcasses within the lobster traps, in addition to the three live birds. Furthermore, the trapped Blue Jays were observed tearing off and swallowing flesh from the dead Blue Jays. We approached the traps to extract the live birds. Two of the live individuals had pieces of Blue Jay muscle tissue on their bills. In hand, all three live jays appeared to have reduced muscle mass and felt abnormally bony and light. Upon release, two jays flew strongly while one was noticeably weak and barely able to fly. After the live birds were freed, we carefully examined the six carcasses remaining in the traps. We noted the pectoral muscles of the carcasses were absent and there was no evidence of the missing muscle tissue in the traps or on the snow around or beneath the traps. Our direct observations of live birds swallow¬ ing conspecifics’ muscle tissue coupled with an absence of pectoral muscle tissue on the snow around the traps (which would have been clearly visible on the white background), provides unambiguous evidence for adult-adult cannibal¬ ism by the Blue Jay. Displacement behavior has been documented for Blue Jays (Jones and Kamil 1973), but we did not observe this behavior. If displacement behavior had been occurring, we believe that plucked-off and discarded flesh would have been visible in or around the traps. 182 THE WILSON JOURNAL OF ORNITHOLOGY • Vol. 123, No. 1, March 2011 It is uncertain whether the Blue Jay mortality was due to starvation, hypothermia, antagonistic interactions, or a combination of these factors. Blue mussels ( Mytilus edulis) and pieces of fish, possibly from a species of clupeid, were also inside the traps. We did not see the jays consuming these items, but believe this lobster bait likely attracted them to the traps. DISCUSSION Little consideration is given to the influence of inactive fishing gear on survival of terrestrial organisms, such as passerine birds. Conversely, the effects of derelict fishing gear on marine organisms are well documented (Dayton et al. 1995). We did not find literature addressing capture and subsequent mortality of terrestrial birds in idle fishing gear. This lack of acknowl¬ edgment is perhaps surprising since devices similar to traditional lobster traps have been used to capture landbirds lor decades (Weaver and Kadlec 1970). Information concerning the preva¬ lence of this phenomenon and its potential effect on terrestrial bird populations would be valuable to avian conservation efforts. More than 3 million lobster trap tags were issued in the State ot Maine in 2009 (Maine Department of Marine Resources 2010). This figure accounts for the number of traps currently authorized to harvest lobsters in Maine, but certainly underestimates the total number of traps present in the state, most notably unused traps. If even a small fraction of lobster traps are stored in a way that attracts, captures, and kills terrestrial birds, the resulting mortality could influence local bird populations. This is likely the first documentation of cannibalism by Blue Jays in addition to the conservation implications of our observations. Reports of filial cannibalism exist for the family Corvidae (Richter 1965, Baida and Bateman 1976). However, a search of the ornithological literature yielded no evidence of adult-adult Blue Jay cannibalism and only one record in which adult corvids consumed the flesh of another conspecific adult ( Andersen 2004). This observed behavior of Blue Jays ingesting the tissue of adult conspecifics was probably the product of a high-stress situation. The observed birds were previously wild and became captive Confined in traps without food, the Blue Jays faced both starvation and social stress. Given this context of captivity and our observations of the emaciated live birds, the motivation for intraspe¬ cific predation appears to be, mainly, nutritional. Wild-caught birds held in captivity in previous reports of cannibalism in non-corvids were provided food and water ad libitum. Social stresses (e.g., high densities, lack of necessary stimuli) were cited as causes of cannibalism in these cases (Rodenburg and Koene 2007). The social stress of captivity may have had a role in inducing the Blue Jays we observed to cannibal¬ ize, but we believe, based on the poor body condition of the birds, nutritional stress was a major reason for cannibalism. We argue that improper storage of lobster traps and other fishing gear poses a serious risk to certain local passerine species, especially during periods of low food availability. Simple and inexpensive solutions exist to minimize bird capture, stressed behavior (e.g., cannibalism), and mortality in inactive fishing traps. Thorough removal of bait would prevent luring of birds to stored traps. Elimination of residual bait is especially important if trap storage occurs during periods when food for terrestrial birds is limited. During times of low food availability, birds are more likely to seek out new or additional food sources. Method of storage could also be used to discourage Blue Jays and other species from entering idle traps. Fishing traps stored indoors will not attract birds. Entrance funnels of traps stored outdoors should be obstructed, thus pre¬ venting unintended capture of terrestrial birds. Traps could also be covered (e.g., with a tarpaulin) to further protect against inadvertent trapping. These simple precautions would mini¬ mize capture of birds and situations of extreme nutritional stress in which birds may exhibit cannibalistic behavior, and would aid in conser¬ vation of local bird populations. ACKNOWLEDGMENTS We thank two anonymous reviewers. We also thank W. Donald Hudson Jr. for organizing the Christmas Bird Count for Brunswick, Maine and Brittany B. Cline for encourag¬ ing preparation of this manuscript. literature cited Andersen, E. M. 2004. Intraspecific predation among Northwestern Crows. Wilson Bulletin 116:180-181. Balda, R. P. and G. C. Bateman. 1976. Cannibalism in the Pinyon Jay. Condor 78:562-564. Dayton, P. k., S. F. Thrush, M. T. Agardy, and R. J- Hofman. 1995. Environmental effects of marine fishing. Aquatic Conservation: Marine and Freshwater Ecosystems 5:205-232. SHORT COMMUNICATIONS 183 Duncan, I. J. H. and P. Hawkins. 2010. The welfare of domestic fowl and other captive birds. Animal Welfare. Volume 9. Springer Science and Business Media, Dordrecht, Netherlands. Jones, T. B. and A. C. Kamil. 1973. Tool-making and tool-using in the Northern Blue Jay. Science 180:1076-1078. Macfadyen, G., T. Huntington, and R. Cappell. 2009. Abandoned, lost, or otherwise discarded fishing gear. UNEP Regional Seas Reports and Studies, Number 185; FAO Fisheries and Aquacul¬ ture Technical Paper Number 523. UNEP/FAO, Rome, Italy. Maine Department of Marine Resources. 2010. Lobster zone license and trap tag annual summary 1997-2009. Maine Department of Marine Resources, Augusta, USA. Richter, C. H. 1965. Cannibalism in Gray Jays. Passenger Pigeon 27:11. Rodenburg, T. B. and P. Koene. 2007. The impact of group size on damaging behaviours, aggression, fear and stress in farm animals. Applied Animal Behaviour Science 103:205-214. Stanback. M. T. and W. D. Koenig. 1992. Cannibalism in birds. Pages 277-298 in Cannibalism: ecology and evolution among diverse taxa (M. A. Elgar and B. J. Crespi, Editors). Oxford University Press, New York, USA. Weaver, D. K. and J. A. Kadlec. 1970. A method for trapping breeding gulls. Bird Banding 41:28-31. The Wilson Journal of Ornithology 123(1): 183-185, 2011 Mobbing of Common Nighthawks as Cases of Mistaken Identity Jeffrey S. Marks,15 C. Scott Crabtree,* 2 Dedrick A. Benz,3 and Matthew C. Kenne4 ABSTRACT. — We report five instances of small birds mobbing Common Nighthawks ( Chordeiles mi¬ nor). In each case, the nighthawk was roosting in a tree during daytime and was mobbed by a group of birds in a manner typical of that directed toward an avian predator. We found only four previously published accounts of perched caprimulgiforms being mobbed. Mobbing birds probably mistake caprimulgiforms for owls because of convergence in plumage coloration and pattern between these two groups of crepuscular- nocturnal birds. Received 29 September 2010. Accepted 9 December 2010. Most species of “typical” owls (Strigidae) and nightjars (Caprimulgidae) have variegated brown, black, gray, and white plumage that helps provide camouflage for individuals at nests and roosts (Cleere 1998, Marks et al. 1999). Many owls prey on small birds and are frequently mobbed by them (Altmann 1956, Gehlbach and Leverett 1995). In contrast, nightjars feed almost exclusively on aerial insects and are not normally targeted by mobbing birds, presumably because they pose no threat to them. We describe five instances in which a Common Nighthawk ( Chordeiles minor ) '4241 SE Liebe Street, Portland, OR 97206, USA. 2 2847 Cox Neck Road, Chester, MD 21619, USA. 3 422 West 11th Street, Winona, MN 55987, USA. 4 709 North Phillips Street, Algona, IA 50511, USA. s Corresponding author; e-mail: jeffl7_marks@msn.com was mobbed by a group of small birds. We also review the scant literature on mobbing of perched caprimulgiforms, none of which appears in the most recent reviews of caprimulgiform biology (e.g., Poulin et al. 1996; Cleere 1998, 1999, 2010). The behavior probably results from similarities in plumage between caprimulgiforms and owls. OBSERVATIONS On 23 August 1998, at 1330 hrs MST, JSM encountered a group of warblers mobbing a Common Nighthawk perched on a horizontal limb about 7 m high in an ash tree ( Fraxinus sp.) in the town park at Scobey, Montana. During the next few minutes, the warblers gave chip notes, flicked their wings, and hopped from branch to branch <1.0 m from the nighthawk, always facing it while they mobbed. The group consisted of at least 10 Yellow Warblers (Den- droica petechia ), two Blackpoll Warblers ( D . striata ), and two American Redstarts ( Setophaga ruticilla). The warblers did not strike the night- hawk, which was oriented parallel to the branch and made no obvious movements in response to the mobbing birds. The warblers departed from the tree in <10 min, while the nighthawk remained on its perch. JSM later found several other perched nighthawks in the park that were not mobbed while he was present. On 4 August 2001, CSC heard mobbing calls 184 THE WILSON JOURNAL OF ORNITHOLOGY • Vol. 123, No. 1, March 2011 from a stand of trees near O wings Mills, Maryland, and found a perched Common Nighthawk being mobbed by a group of birds that included several juvenile Eastern Bluebirds ( Sialia sialis) and a Pine Warbler ( Dendroica pinus ), Prairie Warbler (D. discolor ), Black-and-white Warbler ( Mniotilta varia), Canada Warbler ( Wilsonia canadensis ), and Baltimore Oriole ( Icterus galbula). After about 2 min, CSC accidentally flushed the nighthawk; the mobbing birds flew but did not pursue the nighthawk. About 1 5 min later, CSC encountered another group of birds vigorously mobbing a second perched nighthawk in the same manner as the earlier observation, although he did not record the species composition of the group. The mobbers exhibited typical behaviors of hopping from branch to branch within 1 m of the nighthawks, giving scolding calls, and flicking their wings, but they did not strike either nighthawk. On 19 September 2007, at 1600 hrs CST, DAB heard scolding calls as he walked along a road near Winona, Minnesota. He looked up and found a Common Nighthawk perched on a horizontal branch above the road, surrounded by a group of mobbing birds that consisted of a Downy Woodpecker ( Picoides pubescens), an Eastern Phoebe (Sayornis phoebe), two Eastern Bluebirds, and a Magnolia Warbler ( Dendroica magnolia) . A passing car flushed the nighthawk, which flew from view. The mobbing birds immediately dispersed as well. On the morning of 25 August 2009, MCK spotted a Common Nighthawk perched on a dead branch in a maple tree (Acer sp.) near Algona, Iowa. Shortly thereafter a Black-capped Chicka¬ dee (Poecile atricapillus ) landed nearby and mobbed the nighthawk. It was soon joined by six more chickadees and a Black-and-white Warbler. The birds mobbed for several minutes and then flew away. The nighthawk remained on its perch the entire time. DISCUSSION We found only three previous accounts of a perched nightjar being mobbed. Pickwell and Smith (1938:212) reported that “8 or 10 English Sparrows and 6 robins were noted mobbing an Eastern Nighthawk ( Chordeiles minor) as it sat lengthwise on an elm tree... on May 12, 1927 ” Ficken et al. (1967) watched five Carolina Chickadees (Poecile caro linens is), five Tufted Titmice (Baeolophus bicolor), two Blue-gray Gnatcatchers (Polioptila caerulea), and 10 war¬ blers of four species mobbing a Chuck-will’s- widow ( Caprimulgus carolinensis) that was perched in a tree. The mobbing lasted ~10 min, during which the nightjar did not change its posture. More recently, Kent (1999) observed a group of about 40 small birds mobbing a Common Nighthawk in Iowa on 30 August 1999. Mobbing species included Northern Flicker ( Colaptes auratus). Downy Woodpecker, Blue Jay (Cyano- citta cristata). Black-capped Chickadee, Tufted Titmouse, White-breasted Nuthatch (Sitta caroli¬ nensis), American Robin ( Turdus migratorius ), Gray Catbird ( Dumetella carolinensis), eight species of warblers, Northern Cardinal (Cardina- lis cardinalis), and Rose-breasted Grosbeak (Pheucticus ludovicianus ); the mobbing behavior lasted —10 min. In each case, the authors suggested the mobbers mistook the nightjar for an owl. Castro-Siqueira (2010) watched a Common Potoo (Nyctibius g rise us) in central Brazil being mobbed by three Rufous Horneros ( Fumarius rufus), two Great Kiskadees ( Pitangus sulphur- citus), and seven Chalk-browed Mockingbirds (Minins satum inus) for 15 min before the mobbers left the tree in which the potoo was perched. The same group of mockingbirds returned in 5 min and resumed mobbing the potoo; less than 5 min later they were joined by three horneros, two kiskadees, a Tropical Kingbird (Tyrannus mel¬ ancholic us), and a Rufous-collared Sparrow (Zonotrichia capensis), each of which mobbed the potoo for another 10 min. None of the mobbers struck the potoo, which remained motionless on its perch during both mobbing bouts. Castro-Siqueira (2010) considered the mobbers to mistake the potoo for an owl but cast doubt on that notion because a Burrowing Owl (Athene cunicularia) that was perched in plain view 20 m from the potoo was not mobbed. Owls and capri mulgiforms have converged in evolving cryptic plumage and thus resemble one another, at least superficially. We agree with Pickwell and Smith (1938), Ficken et al. (1967), and Kent (1999) that this resemblance at times causes small birds to mistake perched caprimulgi- forms for owls and mob them accordingly. An alternative hypothesis is that nighthawks and potoos are mobbed because they resemble Chuck-will’s-widows, which occasionally prey on birds (Thayer 1899, Owre 1967). We cannot reject this hypothesis but consider it unlikely because birds that mobbed the potoo in Brazil and SHORT COMMUNICATIONS 185 the nighthawk in Montana would not overlap in range with a Chuck- will’s- widow at any time of year. Mobbing of a nighthawk, potoo, or any other strictly insectivorous caprimulgiform in either scenario would be a case of mistaken identity. The scarcity of published observations of capri- mulgiforms being mobbed suggests the behavior is uncommon. The topic is worthy of attention because it could reveal new information on mobbing behavior, predator recognition, and interactions among caprimulgiforms and other birds. ACKNOWLEDGMENTS We thank R. M. Brigham, C. E. Braun, Paul Hendricks, M. T. Nolen, and T. A. Sordahl for valuable comments on the manuscript. LITERATURE CITED Altmann, S. A. 1956. Avian mobbing behavior and predator recognition. Condor 58:241-253. Castro-Siqueira, L. de. 2010. Observation of mobbing towards a Common Potoo ( Nyctibius griseus). Boletm SAO 20:1-4. Cleere, N. 1998. Nightjars: a guide to the nightjars, nighthawks, and their relatives. Yale University Press, New Haven, Connecticut, USA. Cleere, N. 1999. Family Caprimulgidae (nightjars). Pages 302-331 in Handbook of the birds of the world. Volume 5. Barn-owls to hummingbirds (J. del Hoyo, A. Elliott, and J. Sargatal, Editors). Lynx Edicions, Barcelona, Spain. Cleere, N. 2010. Nightjars, potoos, frogmouths, Oilbird, and owlet-nightjars of the world. Princeton University Press, Princeton, New Jersey, USA. Ficken, R. W., M. S. Ficken, and E. S. Hadaway. 1967. Mobbing of a Chuck-will’s-widow by small passer¬ ines. Auk 84:266—267. Gehlbach, F. R. and J. S. Leverett. 1995. Mobbing of Eastern Screech-Owls: predatory cues, risk to mobbers and degree of threat. Condor 97:831-834. Kent, T. H. 1999. Common Nighthawk draws a crowd. Iowa Bird Life 69:107. Marks, J. S., R. J. Cannings, and H. Mikkola. 1999. Family Strigidae (typical owls). Pages 76-151 in Handbook of the birds of the world. Volume 5. Barn- owls to hummingbirds (J. del Hoyo, A. Elliott, and J. Sargatal, Editors). Lynx Edicions, Barcelona, Spain. Owre, O. T. 1967. Predation by the Chuck-will’s- widow upon migrating warblers. Wilson Bulletin 79:342. Pickwell, G. and E. Smith. 1938. The Texas Nighthawk in its summer home. Condor 40:193-215. Poulin, R. G., S. D. Grindal, and R. M. Brigham. 1996. Common Nighthawk ( Chordeiles minor). The birds of North America. Number 213. Thayer, G. H. 1899. The Chuck-will’s-widow on ship¬ board. Auk 16:273-276. The Wilson Journal of Ornithology 123(1): 185-1 87, 201 1 Observation of Ground Roosting by American Crows Cory M. Shoemaker12 and Richard S. Phillips13 ABSTRACT. — Communal winter roosts of Ameri¬ can Crows ( Corvus brachyrhynchos ) often occur in urban areas and may number in the thousands of individuals. We documented the distribution of urban roosts of American Crows in central Ohio and, on 12 January 2010, we observed a roost of —2,500 individuals with —250-300 birds roosting on the ground. The ground roosting birds remained stationary for the entire observation period of —45 min indicating this location was not a stopover site. This behavior may increase thermoregulatory benefits during cold nights assuming decreased predation threats in urban environ- 1 Department of Biology, Wittenberg University, Spring- field, OH 45501, USA. 2 Current address: 235 Barbara Deer Kuss Science Center, Department of Biology, Wittenberg University, Springfield, OH 45501, USA. 3 Corresponding author; e-mail: rphillips@wittenberg.edu ments. We suggest urban ground roosting behavior by crows may be adaptive in colder environments. Received 16 February 2010. Accepted 11 November 2010. Communal roosts of nonbreeding birds have been the subject of study across taxa. Possible factors driving communal roosting are threefold: protection from predation, informational purposes such as relaying food locations, and potential thermal benefits (Beauchamp 1999). Communal winter roosts of corvids have been documented for several species (Everding and Jones 2006, Zmihorski et al. 2010). The increasing occurrence of corvid roosts in human-dominated landscapes and the potential impact of disease transmission 186 THE WILSON JOURNAL OF ORNITHOLOGY • Vol. 123, No. 1, March 2011 have led to increased attention of urban roosts (Ward et al. 2006). American Crows ( Corvus brachyrhynchos) roost communally during the winter, often forming flocks of >1,000 birds (Emlen 1938, Stouffer and Caccamise 1991). Winter roost dynamics of American Crows in North America have long been the focus of study (Caccamise et al 1997, Preston 2005). Despite efforts to dissuade urban roosting behavior of crows (Gorenzel and Salmon 1992, Avery et al. 2008), studies through¬ out the range suggest urban winter roosts and habitat associations are becoming more common (Gorenzel et al. 2000, Marzluff et al. 2001). However, why crows may exhibit strong winter roost site fidelity and the mechanisms of winter roost selection remain elusive (Fiedler 1969, Gorenzel and Salmon 1995). Early studies suggest congregation of roosts in Ohio may be impacted by temperature and wind (Haase 1963). Crow roosts have consisted of both deciduous and coniferous trees as well as artificial structures including buildings and bridges (Stouffer and Caccamise 1991, Gorenzel and Salmon 1995, Gorenzel et al. 2000). Examination of winter roosts of American Crows has occurred for over a century (Edwards 1888) but, to our knowledge, ours is the first published observation of urban ground roosting behavior by the American Crow. OBSERVATIONS We observed American Crows roosting on the ground in Springfield, Ohio on the evening of 12 January 2010 during a study examining patch- occupancy in urban winter crow roosts. Spring- field is a city of ~60,000 people in the Miami Valley region of southcentral Ohio. Average winter temperatures range from -7 to 1° C. The crows observed were part of a larger roost estimated at 2,500 individuals discovered during an ongoing study of urban winter roost selection. At 2015 hrs EST, 2.45 hrs after sunset, we noticed a roost on the roof of a public library building and in nearby trees. Temperatures reached a low of - 1 2 C before midnight with winds up to 79 km/ hr reported by the National Weather Service in Dayton. Road surface temperatures in areas susceptible to hazardous road conditions ranged from -8 to —16° C overnight according to DOT records (Clark County, Ohio Department of Transportation, pers. comm.). We noticed roosting birds on neighboring structures and adjacent trees. The site was illuminated by numerous street lights and was bordered by industrial and office buildings. Six streets and an active railroad track bisected the site and crows were observed roosting in parking lots near these roost structures. Approximately 15 cm snow was on the ground but the parking lot had been cleared of snow. Drifting snow had covered about 50% of the lot. A combined total of 250-300 crows was ground roosting in three separate parking lots. Each roost had small trees (DBH <25 cm) bordering the ground roost site with additional birds roosting in these trees. Most birds in the roost showed little response to human activity (i.e., cars driving by, people walking nearby, and a train passing within 25 m of the roost). Ground-roosting birds remained stationary for the duration of our observation (~45 min) with most birds exposing as much surface area as possible to substrate in what may be described as a resting or roosting position. The presence of crows was not confirmed the following morning, but the stationary nature of the crows, their lack of response to human activity, the length of the observation, and the time frame with respect to sunset, all suggest this was not an observation of a staging event. DISCUSSION Studies suggest American Crows may be deriving substantial benefit from close association with humans. American Crow populations in urban areas achieve higher densities and experi¬ ence more rapid population growth yet costs in terms of survivorship and reproduction may be insufficient to explain this growth (Marzluff et al. 2001). Despite winter roosts in northern latitudes, crows do not possess major physiological modi¬ fications tor existence in cold winter climates other than large body size and possible benefits afforded through nasal feathers (Wunder and Trebella 1976). The available evidence suggests thermoregulation may be a driving factor in American Crow foraging decisions during tem¬ peratures below an estimated lower critical temperature (Kilpatrick 2003). Our observations occurred well below estimated lower critical temperatures based on metabolic studies of other corvids, and could provide insight into the potential benefits of urban associations at northern latitudes. Possible thermoregulation benefits from potential wind shelter and heat conductance from the pavement may explain why crows roosted on the ground when trees were available. The road SHORT COMMUNICATIONS 187 temperatures recorded were warmer than the air, potentially leading some individuals to roost on the ground in spite of potential increased preda¬ tion risk. The anecdotal nature of our report requires caution, but we suggest future studies examining urban roost selection by crows evalu¬ ate not only structural features but thermal features as well. A better understanding of roost selection criteria may better inform management directed at winter roosts in urban environments. ACKNOWLEDGMENTS We thank M. C. Brittingham, W. P. Gorenzel, F. S. Guthrey, and J. M. Marzluff for providing valuable comments on the manuscript. We also acknowledge Wittenberg University for financial support through the Wittenberg Student Research Grant Program (SDB-2-09- 10). LITERATURE CITED Avery, M. L., E. A. Tillman, and V. S. Humphrey. 2008. Effigies for dispersing urban crow roosts. Proceedings of the Vertebrate Pest Conference 23:84-87. Beauchamp, G. 1999. The evolution of communal roosting in birds: origin and secondary losses. Behavioral Ecology 10:675-687. Caccamise, D. F., L. M. Reed. J. Romanowski, and P. C. Stouffer. 1997. Roosting behavior and group territo¬ riality in American Crows. Auk 1 14:628-637. Edwards, C. L. 1888. Winter roosting colonies of crows. American Journal of Psychology 1 :436-459. Emlen Jr, J. T. 1938. Midwinter distribution of the American Crow in New York State. Ecology 19: 264-275. Everding, S. E. and D. N. Jones. 2006. Communal roosting in a suburban population of Torresian Crows ( Corvus orru). Landscape and Urban Planning 76:2 1 — 33. Fiedler, L. A. 1969. Winter roosting behavior of the Common Crow. Thesis. Bowling Green State Univer¬ sity, Bowling Green. Ohio, USA. Gorenzel, W. P. and T. P. Salmon. 1992. Urban crow roosts in California. Proceedings of the Vertebrate Pest Conference 15:97-102. Gorenzel, W. P. and T. P. Salmon. 1995. Characteristics of American Crow urban roosts in California. Journal of Wildlife Management 59:638-645. Gorenzel, W. P., T. P. Salmon, G. D. Simmons, B. Barkhouse, and M. P. Quisenberry. 2000. Urban crow roosts, a nationwide phenomena? Proceedings of the Wildlife Damage Management Conference 25:158-170. Haase, B. L. 1963. The winter flocking behavior of the Common Crow ( Con>us brachyrhynchos brehm). Ohio Journal of Science 63:145-151. Kilpatrick, A. M. 2003. The impact of thermoregulatory costs on foraging behavior: a test with American Crows {Corvus brachyrhynchos ) and eastern grey squirrels {Sciurus carol inensis). Evolutionary Ecology Research 5:781-786. Marzluff, J. M., K. J. McGowan, R. Donnelly, and R. L. Knight. 2001. Causes and consequences of expanding American Crow populations. Pages 33 1 363 in Avian ecology and conservation in an urbanizing world (J. M. Marzluff, R. Bowman, and R. Donnelly, Editors). Kluwer Academic Publishers, Norwell, Massachusetts, USA. Preston, M. L. 2005. Factors affecting winter roost dispersal and daily behavior of Common Ravens {Corvus corax ) in southwestern Alberta. Northwestern Naturalist 86: 123-1 30. Stouffer, P. C. and D. F. Caccamise. 1991. Roosting and diurnal movements of radio-tagged American Crows. Wilson Bulletin 103:387-400. Ward, M. P., A. Raim, S. Yaremych-Hamer, R. Lamp- man, and R. J. Nowak. 2006. Does the roosting behavior of birds affect transmission dynamics of West Nile virus? American Journal of Tropical Medicine and Hygiene 75:350-355. Wunder, B. A. AND J. T. Trebella. 1976. Effects of nasal tufts and nasal respiration on thermoregulation and evaporative water loss in the Common Crow. Condor 78:564-567. Zmihorski, M, R. Halba, and T. D. Mazgajski. 2010. Long-term spatio-temporal dynamics of corvids win¬ tering in urban parks of Warsaw, Poland. Ornis Fennica 87:61-68. The Wilson Journal of Ornithology 1 23( 1 ): 1 88 — 1 97, 2011 Ornithological Literature Robert B. Payne, Book Review Editor EARLY TASMANIAN ORNITHOLOGY: THE CORRESPONDENCE OF RONALD CAMP¬ BELL GUNN AND JAMES GRANT 1836-1838. Nuttall Ornithological Club Memoir 16. Edited by William E. Davis Jr. 2009: 263 pages, 30 figures. ISBN 1-877973-47-5. $37.50 (cloth).— William E. Davis Jr. has edited and the Nuttall Ornithological Club has published a small gem of ornithological history. It gives unusual insight into what it must have been like to try to identify birds before the days of well-written regional books and field guides. Some 180 years ago. Van Diemen’s Land (now Tasmania, Australia’s island state) was sparsely settled and little explored ornithologically. It was at that time that Ronald Gunn, a public official, and James Grant, a physician, began to produce for eventual publication a list of Tasmanian birds. Each had a private collection of birds, owned many of the books then available, and was an avid and very serious amateur ornithologist. A serious drawback to their efforts was that most of the information in their books was brought together by European authors who had never seen the" birds alive and whose descriptions and hand-colored plates were frequently less than helpful. At best, reference was to mainland Australian forms. Each of these authors arranged the species in widely varying taxonomic sequence and with disparate ideas of relationships. In 1836-1838, Gunn, the better-known of the two, was a magistrate in Circular Head in northwestern Tasmania. Davis provides a most welcome biographical sketch of Gunn, who had a long career in public service and was a pioneer of natural history study in Tasmania. Grant was a physician in Launceston, northeastern Tasmania, about whom little is known. During these 2 years, they corresponded regularly and sent specimens back and forth, discussing identifications and relationships of the birds they collected. At various times Gunn also sent specimens to Sir William Hooker in Scotland and to John Edward Gray in London, perhaps for identification, although there is no information in the correspon¬ dence that this was provided. Davis has published the Gunn-Grant correspon¬ dence verbatim, interspersed with modern identi¬ fications of the birds and page references with frequent commentary on the contemporary refer¬ ences they used. These additions make accessible correspondence that would otherwise prove cryp¬ tic to today’s readers. The outlook of these unsung Tasmanian orni¬ thologists was surprisingly modern. Not only did they wish to publish a list of Tasmanian birds; they also wanted to incorporate into it the natural history information they had gathered by watch¬ ing birds in the field. Even though their work pre¬ dated Darwin’s concept of evolution through natural selection, they (page 3) “flirted in several places with evolutionary ideas,” as observed by Davis. The Gunn and Grant list unfortunately was never completed. Their correspondence ended when Gunn moved to Hobart and his increased civic responsibilities became very time-consum¬ ing, although an incomplete synopsis of their ideas on the taxonomic ordering of birds is dated as late as 1840. This cessation of letters also approximately corresponds to the 1838-1839 visit by John Gould to Tasmania, where he met Gunn, and to the beginning of Gould's publications on Australian birds. It is known that Gunn provided some notes and specimens to Gould subsequent to his visit. I recommend this book for the rare glimpse it gives into the early difficulties associated with ornithological research and hope it causes every¬ one to appreciate the splendid books and field guides available to us today.— MARY LeCROY, Department of Ornithology, American Museum of Natural History, Central Park West at 79th Street, New York, NY 10024, USA; e-mail: lecroy@amnh.org LOOKING FOR A FEW GOOD MALES: FEMALE CHOICE IN EVOLUTIONARY BI¬ OLOGY. By Erika Lorraine Milam. The Johns Hopkins University Press, Baltimore, Maryland, USA. 2010: 168 pages and 13 figures. ISBN: 978- 0-8018-9419-0. $60.00 (cloth). — Charles Darwin, with just a few short sentences in the Origin of 188 ORNITHOLOGICAL LITERATURE 189 Species, proposed a form of selection to account for morphological and behavioral differences between the sexes within a species: sexual selection. Evolution by common descent quickly gained acceptance, but sexual selection by female choice faced significant skepticism and remained a discredited area of research on the fringe of evolutionary biology until the late 1970s, when it finally received its due as an important mecha¬ nism for species formation. So the story goes. Or does it? In Looking for a Few Good Males , Erika Milam seeks to replace what she calls this “eclipse narrative” of loss and recovery with a more complex one that stresses the broader scientific and social context in which sexual selection theory was debated. The result is a carefully researched, fascinating history of rich detail on a part of evolutionary biology that has so far garnered little attention among historians, scientists, and the public. This is a thoughtful book that appeals to anyone with an interest in animal behavior or the uneasy relationship between evolution science and the study of human social relationships. Milam begins by pinning the discomfort raised by Darwin’s theory of sexual selection upon the threat to human exceptionalism posed by cogni¬ tive choice in other animals. Darwin was explicit in Descent of Man and Selection in Relation to Sex : when evaluating the extravagant plumages and energetic displays of male pheasants (Phasia- nidae), for example, female pheasants compared competing males and chose the most beautiful from among them. Anticipating his readers’ discomfort Darwin reassured them that, although some of the lower animals undoubtedly possessed a sense of beauty and actively chose their mates, cultivated man (i.e., white Western man) repre¬ sented the pinnacle of an evolutionary progression of cognitive ability and aesthetic sense. Man alone was capable of rational choice. Most of Darwin’s colleagues, including Alfred Russell Wallace, co- discoverer of natural selection, rejected both choice and an aesthetic sense in other animals, preferring natural selection for male “vigor” as an explanation for male traits that attracted female attention. Unfortunately, the ladder of evolution¬ ary progress appealed to many 19th and 20th century readers, and framed (and constrained) the debate over sexual selection for years to come. Milam continues with a description of the state of animal behavior research in the decades leading up to the Second World War. Not surprisingly, much of the focus on sexual selection in Europe during that period centered on the eugenic potential for female choice to improve human populations, although interest understandably faded with the end of the war. Darwin’s attri¬ bution of aesthetic sense to animals had largely been abandoned while concerns over the en¬ croachment of animals upon the uniqueness of human cognitive ability remained. Despite excel¬ lent work by amateur biologists like George and Elizabeth Peckham (spiders) and William Pycraft (birds) that supported female choice and sexual selection, professional evolutionary biologists in¬ creasingly rejected conscious female choice for their mates in favor of physiological reactions to external (male displays) and internal (gonadal sex hormones) stimuli. Eventually, a critical shift in focus occurred from animal mating behavior as precursor to human behavior (the “ladder” metaphor) to animal mate choice and its effect on the process of evolution. This shift was accompanied by new methods that strove to create experimental conditions that mimicked nature as much as possible, and widened the scope of animal behavior science. Researchers increasingly fo¬ cused on the role that sexual selection might have in reinforcing or breaking down species bound¬ aries. Some (e.g., Gladwyn Kingsley Noble) reported evidence of female choice, while others (e.g., Lester Aronson), concluded that females mated randomly. Female mate choice, with the rise of ethology in postwar Britain, was rejected outright in favor of mechanistic models of behavior in which a stimulus (male behavior) overcame female inertia. Ethologists placed critical importance on the genetic basis of behaviors, which they saw as innate, ritualistic responses to environmental stimuli. This idea, coupled with advancements in experimental genetics, enabled animal behavior- ists like Claudine Petit and Lee Ehrman to investigate the impact of mating behavior on the genetic dynamics of populations and species. Both found strong evidence for female choice. None¬ theless, prominent evolutionists like Theodosius Dobzhansky and Ernst Mayr continued to dis¬ count its importance for speciation. Finally Robert Trivers, in his paper “Parental Investment and Sexual Selection,” interpreted Petit and Ehrman’ s results in the light of evolutionary game theory, and demonstrated that mate choice must be widespread as well as critically important for 190 THE WILSON JOURNAL OF ORNITHOLOGY • Vol. 123, No. 1, March 2011 population dynamics. After the publication of E. O. Wilson’s Sociobiology (edited by Robert Trivers), interest in sexual selection surged. Birds, with their obvious sex differences in plumage and behavior and their anthropomorphic appeal, remained a centerpiece of the debate over sexual selection. British naturalist Edmund Selous concluded from hours of observing wild birds that some animals must choose their mates, as did Julian Huxley from his early work on the courtship behavior of Great Crested Grebes ( Podiceps cristatus) (although he later rejected that view). Bower birds (Ptilonorhynchidae), with their elaborate mating arenas and innate prefer¬ ences for colorful decorative objects, were invoked for decades by some scientists as proof of conscious animal aestheticism, an idea dis¬ credited by Australian ornithologist Jock Mar¬ shall. Surprisingly, preeminent ornithologist Ernst Mayr conducted his research on female mate choice not in birds but in Drosophila fruit flies; readers might be chagrined to learn of his declaration that “there is not as much difference as you might imagine.” Despite this rich history of inquiry, the decades separating Descent of Man and Sociobiology are frequently dismissed by modem biologists as bereft of significant advancements in sexual selection. Milam attributes this narrative of ‘renewal of sexual selection and female choice partly to efforts by organismal biologists to reclaim evolution from molecular biologists, whose recent triumphs in biochemistry threatened to monopolize public attention and funding. For Milam, this “eclipse narrative” served to paint evolutionary organismal biology as a dynamic field with pressing new questions that could be addressed only in nature, not in the laboratory. Fortunately, the momentum of synthesis cannot be contained, and today Darwin’s second great idea is actively tested by dyed-in-the-wool field biologists and genomic technocrats alike — some¬ times, even in tandem.— ELEN ONEAL, Post¬ doctoral Researcher, Duke University, 125 Science Drive, Durham, NC 27708, USA; e- mail: eo22@duke.edu BIRDS. By Dale Serjeantson. Cambridge Man¬ uals in Archaeology. Cambridge University Press Cambridge, UK. 2009: xxvi + 486 pages, numerous illustrations. ISBN: 978-0-521-86617-0 (hard¬ back); 978-0-521-75858-1 (paperback). $85.52 (hardback); $46.67 (paperback). — It is unfortunate that the title of this book, even with inclusion of the series name, is singularly uninformative. The intention of the volume is to summarize the importance of birds to the field of zooarcheology. This entails interpretation of avian remains, mostly bones, but also including eggshells, feathers, skin, and other traces found in depositional environ¬ ments that were created mainly by human activity. The content goes well beyond bones and stones, however, and includes an overview of human/bird interactions that also uses evidence from ancient depictions and writings. The topics cover not just birds as food and sources for bone implements, but also uses of birds for sport (e.g., hawking), aesthetics (pets, ornaments), ritual and symbolism, and environmental reconstruction. Treatment of some of these subjects is at times perfunctory. The introductory parts include some general informa¬ tion about birds, and mainly deal with zooarcheo- logical methodology such as ascertaining age and sex, species identification, collecting and recording techniques, the processes by which bones become incoiporated in deposits (taphonomy), differential survival of various skeletal elements, and their modification by humans. Much of this is too elementary to be of use to anyone with experience in the field but insufficiently comprehensive for someone with no experience at all. I began reading this book in the middle, in the chapters on domestication, which gave me a much more favorable impression than I was able to maintain with further reading. It is this section that I hope will prove most useful and informative for ornithologists. An entire chapter is devoted to the “chicken” ( Gallus gallus ), which may originally have been domesticated for cockfight¬ ing rather than for meat or eggs. Most intriguing is the increasing evidence for pre-Columbian intro¬ duction of chickens into the New World along a Pacific coastal route. Shorter accounts deal with turkeys, geese, ducks — including Muscovy Duck ( Cairina moschata ), pigeon ( Columba livia), pea¬ fowl ( Pavo ), guineafowl ( Nurnida ), and Scarlet Macaw ( Ara macao). The accounts include his¬ torical and archeological evidence for timing and origin of domestication, and the morpholog¬ ical changes that took place subsequently as a result. Whereas the background of paleontologists is in biology and geology, most zooarcheologists receive their training in the cultural milieu of the social sciences, which often imparts a different ORNITHOLOGICAL LITERATURE 191 mindset and Weltanschauung regarding proce¬ dures and results, and the treatment of literature. Some insight into the different ways of thinking may be gained by Serjentson’s characterization of bones brought into a human archeological site by wild animals as “intrusives,” whereas in a paleontological site all the stuff trucked in by humans is “intrusive.” Serjeantson has relied almost entirely on the archeological literature for her sources. A glaring omission that is not mentioned is Pierce Brodkorb’s Catalogue of Fossil Birds (5 parts, 1963-1978). Brodkorb went to great lengths to attempt to include every reference he could find to avian remains in archeological deposits; his Catalogue has to be a much more inclusive source for the zooarcheol¬ ogy of birds than anything cited by Serjeantson. Lack of ornithological knowledge has resulted in the commission of some “clangers” of unusual plangency. From page 4 alone we have the following. “Birds evolved from therapod [sic] dinosaurs in the Late Cretaceous era (Feduccia 1999).” Whatever birds evolved from, the divergence took place long before the Late Cretaceous, which is a geological period , part of the Cenozoic Era, and citing Feduccia is seriously misleading because he is by far the most outspoken opponent of the theropod derivation of birds. “Cordata” should be “Chordata.” The Linnean classification was established in the 1 8th, not the 19th century; the idea that it remained basically the same from then until cladistics and DNA analyses brought about “changes in the accepted relationships between families” is beyond nonsensical, especially considering that the taxonomic family is a post-Linnean concept. Hildegarde Howard did not begin her career studying fossils from Rancho La Brea and then move on to the zooarcheology of the Emeryville shellmound (page 5). Quite the opposite — the Emeryville study was the topic of her Disserta¬ tion. The wings of the Galapagos flightless cormorant are not used for swimming, whereas those of all penguins are, not just the larger ones (page 8). Hummingbirds do not feed only on nectar (page 14). Bitterns (Botaurinae) do not ‘walk on the surface of water” (page 32). The gizzard is not equivalent to the crop (page 32). We learn that a newly fledged gannet is “known locally as a guga ” (pages 36-37), but the locality (Hebrides) is never specified. More importantly, there are numerous errone¬ ous statements concerning avian skeletal anatomy. There are many exceptions to the categorical statement that a “pneumatic foramen of the humerus is characteristic of all flying birds” (page 20). The elements of the skull are probably not all “fully fused at the time of hatching” (page 21) in any bird. The structure “at the bifurcation of the trachea in some waterfowl” (page 21) is not the syrinx. Radiale and ulnare are incorrectly rendered as “radial” and “ulnar” (page 28). What is described as the major digit (page 29) is actually the first phalanx of the major digit. This is indeed perforated in gulls (and terns) but not in “some owls” and instead occurs in caprimulgids. The generalization about the presence of a triangular patella in birds (page 29), is invalid as an ossified patella is rare in birds and, when present, its shape is extremely variable. The descriptions of the configuration of the tarsometa- tarsus in zygodactyl birds are badly confounded (page 30). The tarsal cap of the tarsometatarsus is wrongly termed the “hypotarsus” (page 39). Once the terminology has been straightened out, the statement that the “pelvis becomes attached to the synsacrum in the mature bird” (page 23) is not true for many kinds of birds. Here (and pages 110-111) “pelvis” is synonymous with the “innominate bone” consisting of the fused ilium, ischium, and pubis, whereas synsacrum is used to mean only the fused sacral vertebrae (as in Appendix Fig. 2b, where the rendering is so crude as to be unrecognizable). Elsewhere (e.g., page 24) “synsacrum” is used to indicate what I would call the entire pelvis, that is, both innominates plus the fused sacral vertebrae. The wording of the assertion that the “vertebral column includes two sections which fuse in the adult bird: the notarium and the synsacrum” (page 23), probably is intended to mean that each of those elements consists of fused vertebrae, but almost anyone would interpret the statement as meaning that the notarium and synsacrum are fused to each other, which is never true. The two sentences (page 21) devoted to directionality in the avian skeleton are of absolutely no use to anyone and do not even mention the schism over anterior/posterior versus cranial/caudal. It is hardly surprising that the coracoid “is one of the elements most superfi¬ cially distinct from mammal bones” (page 26), considering that mammals do not have a coracoid. Although the geographical coverage of the book is supposedly worldwide, it is in fact heavily Eurocentric. There is no treatment whatever of 192 THE WILSON JOURNAL OF ORNITHOLOGY • Vo/. 123, No. 1, March 2011 the West Indies. No mention is made of the human/ bird interface in the Hawaiian Islands that resulted in the extinction of birds nearly as spectacular and peculiar as those of New Zealand. As hinted above, poor or idiosyncratic writing hinders communication throughout the book. One of my peeves is the pernicious and often seemingly affected substitution of “which” for “that.” Though by no means the only transgres¬ sors, the Brits are among the greatest sinners in this practice and Sarjeantson is the worst I have ever encountered. The word “that” has been totally abrogated in this book and is not used, except when utterly unavoidable. The most glaring example is the last sentence on page 19 where “which” appears six times, all but five of which should have been “that” according to the standards of Bernstein {The Careful Writer , 1965). Pronouns with ambiguous or distant antecedents are another cause of poor writing. One has to backtrack through live sentences to discover that the last “it” in the paragraph spanning pages 50- 51 refers to medullary bone. Can anyone figure out what the following sentence means? “Ireland has more than one tenth as many records of open ground species and water-birds as Britain and a similar number of woodland birds but fewer than 4 per cent as many records of owls” (page 367). Peculiar turns of phrase are “during the time of lay” rather than “laying” (page 49 and else¬ where), and repeated statements that various kinds of artifacts were made “on” a given kind of bone when of or “from" would normally be used. The extensive bibliography, although not com¬ prehensive, includes many references that the ornithologist would probably never encounter. Many of these, in addition to being obscure, border on, or fall squarely within, the category of gray literature, which does not seem to create the kind of discomfort and skepticism among anthropologists that it does for most biologists. There are errors in the bibliography as well. Bickart is consistently misspelled Bickhart here and in the text. At least one reference is glaringly misalphabetized. To be fair, there is a lot of information in this ook that has not been summarized in any other source of which I am aware. The researcher should be forewarned that this information can at times be erroneous or incomplete. Personally I would not cite any fact from this book without going back to the original literature, which in many cases would probably prove very difficult to do. Nevertheless, the book represents a first source that one may turn to try to get a start on any subject involving avian zooarcheology or the history of human/bird interactions. An expanded and corrected edition would be a primary asset in any ornithological library. — STORRS L. OLSON, Curator Emeritus, Division of Birds, National Museum of Natural History, Smithsonian Insti¬ tution, Washington, D.C. 20560, USA; e-mail: olsons@si.edu THE STATUS OF BIRDS IN BRITAIN & IRELAND. By David T. Parkin and Alan G. Knox. Christopher Helm, London, England. 2010: 440 pages and 86 color illustrations. ISBN: 978-1- 4081-2500-7. £50 (hard cover). — This volume updates a 1971 review by the same name, covering 580 species instead of the 466 of the earlier one. The 25% increase reflects both taxonomic changes and, primarily, new distribu¬ tional information. The well written Introduction is important fora full understanding of the species accounts. This includes sections on Geography and Climate, Flora and Vegetation, and Geographic Divisions and Habitats that provide the basis for the ecological distribution of the birds. A section on the Structure of Ornithology treats key organiza¬ tions, coordinated fieldwork, and publications, showing how the knowledge of bird distribution and abundance has been developed and is being sustained. Notably lacking in this section is any mention of the great museum collections that provide vouchers for much of the accumulated knowledge. A section on Evolution and Taxono¬ my emphasizes modem molecular analyses with a discussion of subspecies. There is a thorough section on Migration and Movement, one on Biogeographical Affinities, and a final one on Conservation. Information in all these sections relates to points made in the species accounts. The carefully selected 86 color photos on 32 pages illustrate points made in the introductory text or in species accounts. Each species account includes paragraphs on Taxonomy, Distribution, and Status. The first may discuss relationships within the family or genus, and the number of subspecies worldwide, citing evidence from recent morphologic or molecular studies. In a number of instances, however, taxonomic changes suggested by the molecular evidence discussed have not been ORNITHOLOGICAL LITERATURE 193 implemented. Among many examples, a study suggesting that American Black-billed Magpies [Pica hudsonia ) should be separated from those in Europe at the species level is cited but the split is not made. The paragraph on Distribution notes the worldwide range of the species, sometimes with information on habitat and migratory behavior, particularly where the latter is geographically variable. The paragraph on Status is, as the book title suggests, the heart of the account. For rarer species, there is usually a record of first occurrence in Britain and/or Ireland, and an indication of the number of records with the amount of detail depending on frequency of occurrence. Some interesting tidbits show up, such as the first Wilson’s Phalarope ( Phalaropus tricolor ) being recorded within —80 km (50 miles) of the birthplace of Alexander Wilson. The first record of Pallid Swift ( Apus pallidus ), a museum specimen, was not identi¬ fied until 75 years after its collection. For more abundant or regularly occurring species, there may be information on the size of populations in various places, including increases or declines over time and probable reasons for such changes. Extensive long-term monitoring studies, dis¬ cussed in the Introduction, permit detailed analysis for some species, particularly seabirds and waterfowl. The amount of detail in these sections is impressive. An Appendix provides useful species lists, by subspecies, coded by category of occurrence and origin (native, introduced), for each of four geopolitical areas — Great Britain, Republic of Ireland, Northern Ireland, and The Isle of Man. A second Appendix is a list of species whose occurrence in those islands is believed not to be of natural causes, such as escaped cage birds. There is a wealth of information in this book, probably more than most of us in North America want or need to know about British birds. Actually, it might make us jealous that we don’t know as much about most American birds, or at least don’t have it all in one handy volume. I recommend this book not only as a source of information but as a model of how to present important information. It is a worthy addition to both individual and institutional libraries. — RICHARD C. BANKS, Department of Verte¬ brate Zoology, National Museum of Natural History, P. O. Box 37012, Washington, D.C. 20013, USA; e-mail: banksr@si.edu THE BIRDS OF BARBADOS. By P. A. Buckley, Edward B. Massiah, Maurice B. Hutt, Francine G. Buckley, and Hazel F. Hutt. British Ornithologists’ Union Checklist Number 24. 2009: 295 pages, 78 color plates, and 5 line drawings. ISBN: 978-0-907446-29-3. $70.40 (cloth). — An isolated outcrop of coral limestone — 160 km east of the main chain of Lesser Antillean islands, the island of Barbados unsur¬ prisingly hosts a relatively depauperate avifauna for its size, represented by only 30 native breeding species of which only one is endemic, plus one that is extinct and seven introduced species that have become successfully established. As a consequence it may seem odd that a hefty 295- page monograph, the 24th contribution to the British Ornithologists’ Union checklist series, could be dedicated to the birds of Barbados. But what the island lacks in native species is made up for by an astonishingly long list of visitors, migrants, and vagrants due to its unique geograph¬ ical position in the migrator)' crossroads between North America and South America, and especially as a landfall for trans-Atlantic vagrants of Palearc- tic birds — including some that have occurred nowhere else in the Western Hemisphere, which gives Barbados its ornithological fame. Initiated in 1954 by Barbadian residents Maurice B. Hutt and Hazel F. Branch Hutt, The Birds of Barbados is the long-anticipated culmination of more than half a century of compilation and writing. In 1993 the Hutts invited P. A. Buckley and Francine G. Buckley to join them as coauthors of a growing manuscript and shortly afterward they were joined by Barbadian birders Edward B. Massiah and Martin D. Frost. Unfortunately, the Hutts died before the manuscript was completed, first Hazel in 1 997 and then Maurice in 1998, and Frost later dropped out of the project as a coauthor due to other commitments, although his substantial contributions clearly merit his inclusion as a coauthor. Typical of the BOU’s checklist series, The Birds of Barbados comprises much more than an “annotated checklist.” It is an exceptionally scholarly and detailed summary of not just the island’s avifauna, but also many aspects of its natural history, which partially explains why it took so long for the authors to complete the manuscript. No less than 25 pages are devoted to detailed descriptions of the island’s topogra¬ phy, geology, pedology, climate, weather, winds, freshwater and wetlands, vegetation and floristics, freshwater fishes, amphibians, reptiles, mammals, 194 THE WILSON JOURNAL OF ORNITHOLOGY • Vol. 123, No. 1, March 2011 human history, and conservation concerns. Sur¬ prisingly, the controversial issue of hunting migratory shorebirds — which has become highly publicized in recent years — is relegated to a single paragraph. Five maps illustrate the geographical position of Barbados, its elevation and bathymetry, rainfall, human population density, and land use. The introductory sections on the island’s natural history are followed by 33 pages of detailed discussions on the avifauna of Barbados. The obligatory sections on ornithological history are followed by a glossary of terms used in the book, highlighted by an informative discussion of the term “vagrancy.” The composition of the avifauna is extensively analyzed and augmented by nine tables. The authors make extensive comparisons between the avifaunas of Barbados, St. Lucia, and the Cayman Islands. However, I think comparisons with nearby Grenada, Trinidad, and Tobago would have been more relevant and interesting. A fascinating panoply of subjects are discussed, including vicariance, dispersal, geo¬ graphic origins, historical changes (including extinctions and introductions), vagrancy, ende¬ mism, molecular insights on phylogenetic rela¬ tionships, migration (including radar and mist-net studies), and fossil birds. The authors note the potential role of Barbados as a gateway for Palearctic species colonizing the Western Hemi¬ sphere. In 1994 the hemisphere’s first breeding population of Little Egret ( Egretta garzetta ) became established in Barbados and the authors suggest that increasing numbers of Grey Heron (Ardea cinerea ) and Western Reef Heron (E. gularis) arriving in Barbados may soon colonize Barbados or nearby regions. A research agenda provides a long list of potential ornithological projects awaiting researchers. The introductory appetizers are followed by the main course: an annotated account for each of 261 species of birds whose occurrence on Barbados is considered to be adequately documented-plus an additional two species in a “Note added in proof” on page 75. Each species account includes sections succinctly describing its status in the “World,” “West Indies,” and “Barbados,” respectively, plus a “Comments” section. A “Breeding” sec¬ tion summarizes breeding for resident species and the museum acronym is given in a “Specimens” section for any species represented by one or more specimens. Species of dubious occurrence in Barbados are also discussed. The English names of birds follow the British spelling conventions of F. Gill and M. Wright (2006, Birds of the world: recommended English names, Princeton University Press), but with several exceptions (Appendix 20). Perhaps unsurprising, given the instability of avian taxonomy, the authors have not followed the current species-level taxon¬ omy of the American Ornithologists’ Union’s (AOU) North American Classification Committee and South American Classification Committee. Instead, several taxa recognized as subspecies by the AOU are treated as distinct species, including the North American (Anas carol inensis) and Eurasian (A. crecca) forms of Green- winged Teal, dark and white fonns of Great Blue Heron (Ardea herodias ). eastern and western forms of Willet ( Tringa semipalmata ), North American and Eurasian forms of Whimbrel ( Numenius phaeopus) and Black Tern ( Chlidonias niger ), and North American ( Dendroica aestiva) and West Indian (Mangrove [D. petechia ]) forms of Yellow Warbler. Each of these forms has been recorded in Barbados, thus elevating the number of species recorded on the island. The authors appear to be hedging their bets that these forms will all eventually be formally split into separate species by the relatively conservative AOU. The center of the book includes 40 color plates illustrating maps and habitats, and another 38 color plates illustrate birds, including many excellent documentary photos of vagrants. The back of the book provides 24 appendices, including the number of specimens in each of 12 museums for 112 species (Appendix 22), recovery data for 163 birds of 23 species banded in nine other countries (Appendix 23), and a gazetteer of localities (Appendix 24). A lengthy list of references is followed by separate indices of scientific and English bird names. The book is an admirable compilation of information on the birds of Barbados, and sets a high standard that will be difficult to eclipse. The authors deserve accolades for their careful schol¬ arship. However, I was frustrated with a few features of the book’s organization. More than six pages near the beginning of the book are devoted to summarizing 12 tables, five figures, and 78 plates, but no page numbers are given. This was unfortunate because the tables are not numbered sequentially and do not always appear near where they are first cited, which makes them difficult to locate. For example. Table 2 appears on page 9 but is not cited until page 3 1 , and Table 12 is cited on page 27 but does not appear until page 74. I could not find any obvious errors in spelling, ORNITHOLOGICAL LITERATURE 195 although I couldn’t overlook my middle initial several features that make the Phillipps’ book a appearing as “B” instead of “E” and the wonderful introduction to the birds of Borneo. But surname of my friend Courtenay Rooks being experienced birders and ornithologists need not spelled as “Rookes” on page 61. I was also fear that the Phillipps’ book is an irritatingly surprised that the middle initial(s) of authors was incomplete guide for novices. On the contrary, it left out of the Literature Cited section, which has a complete set of outstanding plates of the 664 hopefully won’t be repeated by researchers who Bornean species, and it also has range maps for all use the book as a source of references. non-migratory (and most migratory) birds on the Although Barbados is unlikely to ever become island. And this is just the beginning, a prime destination for birders or ornithologists The Phillipps’ book is not really a field guide, it who are more interested in hotspots of endemic is a guide to the natural history of birds of Borneo species, The Birds of Barbados is an essential that also happens to be handy tor identifying resource for anybody who is seriously interested species. There is another newly minted book, in birds of the eastern Caribbean. Birders who Myers (2009), that is an excellent traditional field relish searching for and finding vagrants will be guide to Bornean birds. It contains all the especially interested in the book because of its information expected in a modem field guide wealth of detail on the occurrence of vagrant for identifying species (Sheldon 2010). The two species, especially trans- Atlantic Palearctic va- books complement one another. The Phillipps do grants, many of which have occurred nowhere not bother with bird descriptions; instead, they else in the Western Hemisphere. Field biologists emphasize general information on bird biology, and amateur naturalists interested in other aspects habitat characteristics, and ornithological anthro- of natural history in the eastern Caribbean will pology. This information makes the book much also find the book useful for its detailed more interesting to read than a field guide. Lots of descriptions of the natural history of Barba- information is provided for each species on dos.— FLOYD E. HAYES, Department of Bio- occurrence, behavior, song, and nesting, but much logy, Pacific Union College, l Angwin Ave- of the really good stuff appears outside the species nue, Angwin, CA 94508, USA; e-mail: fhayes@ accounts. For example, each group of birds is puc.edu introduced with an extensive paragraph that often features unexpected insights, e.g., tailorbirds (' Orthotomus ) secure their sewn nests with “... PHILLIPPS’ FIELD GUIDE TO THE BIRDS spider silk teased out to make a knot” (page 238); OF BORNEO. By Quentin Phillipps, illustrated ioras ( Aegithina ) are “...frequent unknowing by Karen Phillipps. Beaufoy Books, Oxford, hosts to Cacomantis cuckoos” (page 218); Green England. 2009: 369 pages, 141 color plates, 644 Broadbills ( Calyptomena viridis) show signs of range maps, and 7 regional maps. ISBN: 978-1- polygyny and maybe even lekking (page 212); 906780-10-4. $25.00 (paper). — This is the book I nesting barbets make numerous starter holes, wish I had when I first visited Sabah, north possibly “...to deceive snakes which systemati- Bomeo. Upon arrival, 1 took a bus from the cally investigate such holes” (page 200). In capitol, Kota Kinabalu, to Tanjung Aru, a nearby addition to these taxic introductions, numerous coastal site with a small park featuring casuarinas, yellow-highlighted paragraphs are interspersed palms, pandans, and garden plants. The park was around the book. These convey snippets of natural full of pigeons, sunbirds, tailorbirds, ioras, trillers, history that display the Phillipps remarkable woodswallows, munias, babblers, and bulbuls, knowledge of Bornean botany, history, and and I had no clue how to identify any of them. anthropology. One of these paragraphs describes With the Phillipps’ book, I could have turned red bean creepers ( Caesalpinias ) as a strong three pages and seen most of the pertinent species attractant for bulbuls, leafbirds, flowerpeckers, illustrated on one lively plate. The same is true for and sunbirds. Another relates that spiderhunters visits to the beach, rice padi, river, or the summit ( Arachnothera ) are divided into two ecological of Mt. Kinabalu, Southeast Asia’s highest moun- groups, one that feeds in the canopy and the other tain; summary plates are provided by the Phillipps that “trap-lines” bananas and gingers. This for each of these habitats, as well as lowland and explains why Little Spiderhunters (A. longirostra) montane forest. These plates and a 10-page guide zoom through the understory and like traplining to the island’s natural history sites are two of hermit hummingbirds in the Neotropics (Gill 196 THE WILSON JOURNAL OF ORNITHOLOGY • Vol. 123, No. 1, March 2011 1988) — are the most commonly mist-netted birds of the Bornean forest. Yet another yellow paragraph describes the traditional native method for snaring pheasants using a “pagar”, or herding fence, and another explains that egrets are the eyes and ears of forest spirits. At the beginning of the Phillipps’ book is an extensive introduction, full of facts on Bornean birds, geography, habitats, weather, etc., virtually everything needed to get started as a birdwatcher or ornithologist in Borneo. I wish I had read this section before traveling to Mt. Pueh in westernmost Sarawak in January 2010. The map and accompanying bar graphs on page 35 indicate that part of Sarawak to be the wettest place in Borneo in January, and I can now vouch that it is true. The authors are remarkably well suited to produce a natural history guide for Bornean birds. Brother and sister, they grew up in Sabah, spending their childhood exploring such famous sites as Mt. Kinabalu, Sepilok Orangutan Reserve, and the Crocker Range, not to mention many lesser known places. As a boy, Quentin Phillipps wrote a series of papers on the occurrence and nesting of birds (e.g., Phillipps 1970, Phillipps and Phillipps 1970), and has contributed to Bornean ornithology ever since (e.g., Phillipps 1982). The Phillipps family is well known in Sabah for their knowledge of botany and ecology (e.g., Phillipps 1985), and Karen Phillipps is famous for her illustrations in ground-breaking Asian field guides (Viney and Phillipps 1977; Payne et al. 1985; MacKinnon and Phillipps 1993, 2000). Quentin Phillipps’ long-term fascination with birds, Karen Phillipps’ artistic skills, and their combined experiences as Bornean explorers and naturalists come together in this wonderful book, which I could not recommend more highly. — FREDERICK H. SHELDON, Louisiana State University, Museum of Natural Science and Department of Biological Sciences, Baton Rouge, LA 70803, USA; e-mail: fsheld@lsu.edu LITERATURE CITED Gill, F. B. 1988. Trapline foraging by hermit hum¬ mingbirds: competition for an undefended, renew¬ able resource. Ecology 69:1933-1942. MacKinnon, J. and K. Phillipps. 1993. A field guide to the birds of Borneo, Sumatra, Java, and Bali. Oxford University Press, Oxford, United King¬ dom. MacKinnon, J. and K. Phillipps. 2000. A field guide to the birds of China. Oxford University Press, Oxford, United Kingdom. Myers, S. 2009. A field guide to the Birds of Borneo. New Holland Publishers, London, United King¬ dom. Payne, J., C. M. Francis, and K. Phillipps. 1985. A field guide to the mammals of Borneo. Sabah Society, Kota Kinabalu, Sabah; and World Wildlife Fund Malaysia, Kuala Lumpur. Phillipps, A. 1985. Diary report on the Marai-Parai Spur Expedition, Kinabalu Park, 11-15 February 1985. Sabah Parks, Kota Kinabalu, Sabah, Malaysia. Phillipps, Q. 1970. Some important nesting notes from Sabah. Sabah Society Journal 5:141-144. Phillipps, Q. 1982. Notes on the birds and mammals of Mt. Tamboyukon. Sabah Parks, Kota Kinabalu, Sabah, Malaysia. Phillipps, Q. and J. Phillipps. 1970. Bird banding in the Kinabalu National Park. Annual Report to the Sabah National Park Trustees 1970:29-32. Sheldon, F. H. 2010. Review of: S. Myers, Birds of Borneo. Wilson Journal of Ornithology 122:410— 411. Viney, C. and K. Phillipps. 1977. A colour guide to the birds of Hong Kong. Government Printer, Hong Kong, China. BIRDS OF AUSTRALIA. Eighth Edition. By Ken Simpson and Nicolas Day. Princeton Field Guides, Princeton, New Jersey, USA. 2010: 381 pages and 132 color plates. ISBN: 978-0-691- 14692-8. $39.50 (flexible waterproof cover). — This book is a substantial revision of the authors’ earlier editions, a series that has become a standard field guide for Australian birds with over 600,000 copies in print. A table of contents (or “Key”) gives a quick description of each family, color figures of representative birds, and the pages where the families are illustrated in the color plates. The 132 color plates include the common name of each species, and the facing Field information” page has the common and scientific names, a concise description of the species as it appears in the field, notes on different ages and plumage moiphs (especially in raptors), an index of status (resident, migratory nomadic, partially resident), abundance, size, voice, and habitat, and a distribution map (including distinc¬ tive races or subspecies); for some species it has alternative and prior names and comments on species relationships where these were only recently discovered. A “Vagrant bird bulletin” after the main color plates is a section for 85 uncommon species and rarities, especially sea- ORNITHOLOGICAL LITERATURE 197 birds and shorebirds, which have been accepted by the Australian rare birds records committee. This section includes, on a single page for each set of species, the color figures, descriptions, and maps with smaller figures than in the main color plates. End plates sketch the bill profile and plates for the larger petrels, shearwaters, and albatross, life size and with a length calibration; the sketches are useful for identification of beach-washed birds. The biological information and the common and scientific names are consistent with the regional standard on Australian birds (HANZAB 1990-2006), and the family names are those of Christidis and Bowles (2008). The information summarizes a wealth of other recent publications as well. The Birds of Australia is not only a field guide (it is mainly a field guide, pages 1 8—302); it is also a concise handbook of all the 780 species. The color plates are the best I have seen of Australian birds, colorful and clear, and generally true to the shape, plumage color, and details of the birds. Perhaps most amazing are the diverse and colorful Australian parrots and the cuckoos. The color plates show the variation in age, male and female, appearance in flight and perched, plumage morphs, and distinctive races. However, the head patterns of the three jaegers ( Stercorarius ) are not shown as distinctive as they are in the field (adults have a black helmet in Pomarine Jaeger [S. pomarinus], a cap to just below the eye in Paras¬ itic Jaeger [S. parasiticus], and a smaller cap in Long-tailed Jaeger [S. longicaudus]). The male western Splendid Fairywren (Malurus splendens splendens) is too purplish; the plumage in Western Australia is bright blue not purple. The “yellow¬ faced morph” of Gouldian Finch (. Erythrura gouldiae) is only slightly less red (to me, “dark orange” or “orange”) than the red-faced morph; nevertheless this plumage has long been known as the “yellow-faced morph”. The birds on a plate are shown on the same scale with additional views of birds in flight and in the distance illustrated at smaller scales. The illustrations are lifelike; all show the identifying features. Some birds are illustrated on a plain background and other birds are shown with a view of their natural habitat. The number of birds on a plate varies according to the species. For examples, the plate for two species of Diomedea albatross has 16 color figures and the facing descriptive page has 15 additional black and white figures of birds seen in flight from below and on the water from the front; the plate for five species of kites shows 25 birds; and the plate for eight species of bulbuls, thrushes, and starlings has 14 birds and a footnote refers to six additional species that are illustrated and described elsewhere in the “Vagrant bird bulletin.” The “Field information” pages are short on bird descriptions; they point out the unique features for identification of the species, and the color figures of the birds largely speak for themselves. There are more than 900 black and white illustrations of chicks, differences between males and females (as in the black cockatoo [Calyptorhynchus] species by bill shape, color and facial pattern), geographic races, face patterns, wing patterns, undertail patterns, tails of snipe ( Gallinago ) and gerygone ( Gerygone ) species, and relative size of similar species (one page shows 17 “black bush birds” of Australia), and typical behaviors. The distribution maps show the areas of breeding, nonbreeding, and irregular or nomadic occurrence. End sections describe and illustrate the habitats in Australia; breeding information about each family including nest site and structure, eggs, parental care (role of male and female, duration of parental care), and breeding season of each species; checklists of Australian island territories; and appendices of hints for birding, an extensive glossary, lists of Australian naturalist organizations and bird books, and indices of Latin names and common names. The book is a complete and attractive field guide and also a concise source of information on the biology of Australian birds. It is nearly 25 mm (1 inch) taller and wider than the National Geographic Field Guide to the Birds of North America . I recommend the book to everyone with an interest in the birds of Australia. — ROBERT B. PAYNE, Professor Emeritus, University of Michigan, 1306 Granger Avenue, Ann Arbor, MI 48104, USA; e-mail: rbpayne@umich.edu LITERATURE CITED Christidis, L. and W. Boles. 2008. Systematics and taxonomy of Australian birds. CSIRO Publishing, Collingwood, Victoria, Australia. HANZAB. 1990-2006. Handbook of Australian, New Zealand and Antarctic birds. Volumes 1-7. Oxford University Press, Melbourne, Australia. THE WILSON JOURNAL OF ORNITHOLOGY Editor CLAIT E. BRAUN 5572 North Ventana Vista Road Tucson, AZ 85750-7204 E-mail: TWILSONJO@comcast.net Editorial NANCY J. K. BRAUN Assistant Editorial Board RICHARD C. BANKS JACK CLINTON EITNIEAR SARA J. OYLER-McCANCE LESLIE A. ROBB Review Editor ROBERT B. PAYNE 1 306 Granger Avenue Ann Arbor, MI 48104, USA E-mail: rbpayne@umich.edu GUIDELINES FOR AUTHORS Please consult the detailed “Guidelines for Authors” found on the Wilson Ornithological Society web site (http://www.wilsonsociety.org). All manuscript submissions and revisions should be sent to Clait E. Braun, Editor, The Wilson Journal of Ornithology, 5572 North Ventana Vista Road, Tucson, AZ 85750-7204, USA. The Wilson Journal of Ornithology office and fax telephone number is (520) 529-0365. The e-mail address is TWilsonJO@comcast.net NOTICE OF CHANGE OF ADDRESS Notify the Society immediately if your address changes. Send your complete new address to Ornithological Societies of North America, 5400 Bosque Boulevard, Suite 680, Waco, TX 76710. The pennanent mailing address of the Wilson Ornithological Society is: %The Museum of Zoology, The University of Michigan, Ann Arbor, MI 48109, USA. Persons having business with any of the officers may address them at their various addresses given on the inside of the front cover, and all matters pertaining to the journal should be sent directly to the Editor. MEMBERSHIP INQUIRIES Membership inquiries should be sent to Timothy J. O’Connell, Department of Natural Resources Ecology and Management, Oklahoma State University, 240 AG Hall, Stillwater, OK 74078; e-mail: oconnet@ okstate.edu THE JOSSELYN VAN TYNE MEMORIAL LIBRARY The Josselyn Van Tyne Memorial Library of the Wilson Ornithological Society, housed in the University < Michigan Museum of Zoology, was established in concurrence with the University of Michigan in 1930. Uni 1947 the Library was maintained entirely by gifts and bequests of books, reprints, and ornithological magazim from members and friends of the Society. Two members have generously established a fund for the purchai of new books; members and friends are invited to maintain the fund by regular contribution. The fund is administer* by the Library Committee. Jerome A. Jackson, Florida Gulf Coast Univeristy, is Chairman of the Committee. T1 Library currently receives over 200 periodicals as gifts and in exchange for The Wilson Journal of Ornithology. Fi information on the Library and our holdings, see the Society’s web page at http://www.wilsonsociety.org. With ft usual exception of rare books, any item in the Library may be borrowed by members of the Society and will be se. prepaid (by the University of Michigan) to any address in the United States, its possessions, or Canada. Retu, postage ,s paid by the borrower. Inquiries and requests by borrowers, as well as gifts of books, pamphlets, reprinl and magazmes should be addressed to: Josselyn Van Tyne Memorial Library. Museum of Zoology, The Universi, of Michigan 1109 Geddes Avenue, Ann Arbor. Ml 48109-1079, USA. Contributions to the New Book Fund shou be sent to the Treasurer. This issue of The Wilson Journal of Ornithology was published on 25 February 2011. Continued from outside back cover 121 Geolocation tracking of the annual migration of adult Australasian Gannets ( Morus senator) breeding in New Zealand StefanieM. H. Lsmar, Richard A. Phillips, Matt]. Rayner, and Mark E. Hauber 126 Birds consumed by the invasive Burmese python {Python molurus bivittatus) in Everglades National Park, Florida, USA Carla J. Dove, Ray W Snow, Michael R. Rochford, and Frank J. Mazzotti 132 Interbreeding of Aechmophorus grebes Andre Konter 13 7 Nesting biology, home range, and habitat use of the Brown Wood Rail {Aramides wolfi) in northwest Ecuador Jordan Karubian, Luis Canasco, Patricio Mena, Jorge Olivo, Domingo Cabrera, Fernando Castillo, Renata Duraes, and Nory El Ksabi Short Communications 142 First description of nests and eggs of Chestnut-headed Crake {Anurolimnas castaneiceps) from Ecuador Galo Buitrdn-Jurado, Juan M. Galarza, and Danny Guarderas 146 Breeding biology of the Snowy-cheeked Laughingthrush {Garrulax sukatschewi) fie Wang, Chen-Xi Jia, Song-Hua Tang, Yun Fang, and Yue-Hua Sun 151 Reproductive status of the Shiny Cowbird in North America William Post and Paul W. Sykes Jr. 154 Shift to later timing by autumnal migrating Sharp-shinned Hawks Robert N. Rosenfield, Dan Lamers, David L. Evans, Molly Evans, and Jenna A. Cava 158 Lunar influence on the fall migration of Northern Saw-whet Owls Jackie Speicher, Lisa Schrejfler, and Darryl Speicher 161 First detection of night flight calls by Pine Siskins Michael L. Watson, Jeffrey V Wells, and Ryan W. Bavis 1 64 Orientation of sap wells excavated by Yellow-bellied Sapsuckers Ashley M. Long 168 Consumption of larvae by the Austral Parakeet {Enicognathus ferrugineus) Soledad Diaz and Salvador Peris U1 Greater Anis (C rotophaga major) commensal foraging with freshwater fish in the Pantanal floodplain, Brazil Flavio KulaifUbaid 1 74 Adoptions of young Common Buzzards in White- tailed Sea Eagle nests Ivan Literak and Jakub Mraz 176 Cruise ships as a source of avian mortality during fall migration Carol I. Bocetti 179 First record of Aplomado Falcon {Falco femoralis) for the West Indies Blake A. Mathys 181 Idle lobster traps kill Blue Jays Mason H. Cline and Joanna L. Hatt 1 83 Mobbing of Common Nighthawks as cases of mistaken identity Jeffrey S. Marks, C. Scott Crabtree, Dedrick A. Benz, and Matthew C. Kenne 1 85 Observation of ground roosting by American Crows Cory M. Shoemaker and Richard S. Phillips !88 Ornithological Literature Robert B. Payne, Book Review Editor A The Wilson Journal of Ornithology (formerly The Wilson Bulletin) Volume 123, Number 1 CONTENTS March 201 1 Major Articles 1 Species limits in an thirds (Thamnophilidae): the Scale-backed Antbird ( Willisornis poecilinotus) complex Morton L. Isler and Bret M. Whitney 15 High apparent annual survival and stable territory dynamics of Chestnut-backed Antbird ( Myrmeciza exsut) in a large Costa Rican rain forest preserve Stefan Woltmann and Thomas W. Sherry 24 Ornithological records from a campina/campinarana enclave on the upper Jurua River, Acre, Brazil Edson Guilherme and Sergio H. Borges 33 Stable nitrogen and carbon isotopes may not be good indicators of altitudinal distributions of montane passerines Yuan-Mou Chang, Kent A. Hatch, Hsin-Lin Wei, Hsiao-Wei Yuan, Cheng-Feng You, Dennis Eggett, Yi-Hsuan Tu, Ya-Ling Lin, and Hau-Jie Shiu 48 Seasonal fecundity and source-sink status of shrub-nesting birds in a southwestern riparian corridor L. Arriana Brand and Barry R. Noon 59 Wintering bird response to fall mowing of herbaceous buffers Peter J. Blank, Jared R. Parks, and Galen P. Dively 65 Interspecific variation in habitat preferences of grassland birds wintering in southern pine savannas Matthew E. Brooks and Philip C Stoujfer 76 Geographic song variation in the non-oscine Cuban Tody ( Todus multicolor ) Eneider E. Perez Mena and Emanuel C. Mora 85 Observations on the natural history of the Royal Sunangel ( Heliangelus regalis ) in the Nangaritza Valley, Ecuador Juan E Freile, Paolo Piedrahita, Galo Buitron-Jurado, Carlos A. Rodriguez, Oswaldo Jaddn, and Elisa Bonaccorso 93 Nesting behavior of Szechenyi s Monal- Partridge in treeline habitats, Pamuling Mountains, China Kai Zhang, Nan Yang, Yu Xu, Jianghong Ran, Huw Lloyd, and Bisong Yue 97 Reproductive status of Swallow-tailed Kites in east-central Arkansas Scott J. Chiavacci, Troy J. Bader, Amy M. St. Pierre, James C. Bednarz, and Karen L. Rowe 102 Nestling behavior and parental care of the Common Potoo (Nyctibius griseus) in southeastern Brazil Cesar Cestari, Andre C. Guaraldo, and Carlos O. A. Gussoni 107 Botfly parasitism effects on nestling growth and mortality of Red-crested Cardinals Luciano N. Segura and Juan C. Reboreda 11 6 Muscle membrane phospholipid class composition in White-throated Sparrows in relation to migratio Jeremy Springer, Edwin R. Price, Raymond Thomas, and Christopher G. Guglielmo . / Continued on inside back cover QL 671 .W7 v.123 no. 2 ^Wilson Journal of Ornithology Volume 123 , Number 2, June 2011 Ewell Sale Stewart Library JUN 2 0 2011 Academy of Natural Sciences of Philadelphia Published by the Wilson Ornithological Society .Wl v. I THE WILSON ORNITHOLOGICAL SOCIETY FOUNDED 3 DECEMBER 1888 Named after ALEXANDER WILSON, the first American ornithologist. rU>» iL President— Robert C. Beason, P. O. Box 737, Sandusky, OH 44871, USA; e-mail: RoberLC.Beason@ gmail.com First Vice-President — Robert L. Curry, Department of Biology, Villanova University, 800 Lancaster Avenue, Villanova, PA 19085, USA; e-mail: robert.curry@villanova.edu Second Vice-President — Sara R. Morris, Department of Biology, Canisius College, 2001 Main Street, Buffalo, NY 14208, USA, e-mail: morris@canisius.edu Editor — Clait E. Braun, 5572 North Ventana Vista Road, Tucson, A Z 85750, USA; e-mail: TWILSONJO@ comcast.net Secretary— John A. 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The Wilson Journal of Ornithology is sent to all members not in arrears for dues. THE WILSON JOURNAL OF ORNITHOLOGY (formerly The Wilson Bulletin) THE WILSON JOURNAL OF ORNITHOLOGY (ISSN 1559-4491) is published quarterly in March, June, September, and December by the Wilson Ornithological Society. 810 East 10th Street, Lawrence, KS 66044-8897. The subscription price, both in the United States and elsewhere, is $40.00 per year. Periodicals postage paid at Lawrence, KS. POSTMASTER: Send address changes to OSNA. 5400 Bosque Boulevard, Suite 680. Waco, TX 76710. All articles and communications for publication should be addiessed to the Editor. Exchanges should be addressed to The Josselyn Van Tyne Memorial Library, Museum of Zoology. Ann Arbor, MI 48109. USA. Subscriptions, changes of address, and claims tor undcliycred copies should be sent to OSNA, 5400 Bosque Boulevard, Suite 680. Waco. TX 76710, USA. Phone: (254 ) 399-9636; e-mail: business@osnabinls.org. Back issues or single copies are available for $ 1 2.00 each. Most back issues of the journal arc available and may be ordered from OSNA. Special prices will be quoted for quantity orders. All issues of the journal published before 2000 are accessible on a free web site at the University of New Mexico library (http://clibrary.unm.edu/sorari. The site is fully searchable, and full-text reproductions of all papers ( including illustrations) are available as cither PDF or DjVu files. © Copyright 2011 by the Wilson Ornithological Society Printed by Allen Press Inc., Lawrence, KS 66044, USA. COVER: Wilson’s Storm Petrel ( Oceanites oceanicus). Illustration by Don Radovich. © This paper meets the requirements of ANSI/NISO Z39.48-1992 (Permanence of Paper). FRONTISPIECE. Kirtland's Warblers ( Dendroica kinUindii) are habitat specialists, typically breeding in young jack pine (Pinus banksiana) stands. The species was only known to nest in Michigan, USA. but recently Kirtland's Warblers were found nesting in a red pine (Pinus resinosa) plantation in central Wisconsin. USA. Photograph of adult male sinaing from red pine in Adams County, Wisconsin by Joel A. Trick. U.S. Fish and Wildlife Sen-ice. y library j ^ Wilson Journal of Ornithology Published by the Wilson Ornithological Society VOL. 123, NO. 2 June 2011 PAGES 199-428 The Wilson Journal of Ornithology 123(2): 1 99-205, 2011 CHARACTERISTICS OF A RED PINE PLANTATION OCCUPIED BY KIRTLAND’S WARBLERS IN WISCONSIN NICHOLAS M. AN ICH, 1,2,7 JOEL A. TRICK,1 2 3 KIM M. GRVELES,4 AND JENNIFER L. GOYETTE56 ABSTRACT. — We studied a newly established population of Kirtland's Warbler ( Dendroica kirtlandii ) in Adams County, Wisconsin, nesting in a red pine ( Pirns resinosa) plantation. We found eight males and five females in Adams County in 2008 and 10 males and 10 females in 2009. Five of seven (71%) males color-banded in 2008 returned in 2009, and at least eight successful nests produced an estimated 33 young over the 2 years. Red pine comprised 66.9% of trees on the main site, 20.6% were northern pin oak/blaek oak {Quercus eliipsoidalis/Q. ve/uillia), and 12.5% were jack pine (Finns banksiana). Total tree density at the main site was 1.876 trees/ha, lower than generally reported in Michigan. Percent canopy cover and ground cover types were similar to Michigan sites. Lowest live branch height of jack pine was similar to Michigan sites, but lowest live brunches of red pine at our site were closer to the forest door. Significant red pine. die-off at our site combined with substantial natural jack pine recruitment created a landscape matrix of openings and thickets that produced suitable Kirllund's Warhler habitat. We suggest young red pine-dominated plantations should be searched when surveying for Kirtland’s Warblers as some lower-density red pine plantations could provide important supplemental habitat as the species expands its range. Received K April 2010. Accepted II November 2010. Kirtland's Warbler ( Dendroica kirtlandii) is a habitat specialist that typically breeds in young jack pine ( Pinas banksiana ) on sandy soils. It is a 1 2414 Fellman Circle, Ashland. WI 54806. USA. 2 Current address: Wisconsin Department of Natural Resources. 2501 Golf Course Road. Ashland. WI 54806. USA. ‘U.S. Fish and Wildlife Service. 2661 Scott Tower Drive. New Franken. WI 54229, USA. J Wisconsin Department of Natural Resources. P. O. Box 7921. Madison. WI 53707. USA. 'Cofrin Center for Biodiversity. Department of Natural and Applied Sciences, University of Wisconsin-Green Bay. Green Bay. WI 54311, USA. "Current address: BioDivcrsity Research Institute. 9 Flaggy Meadow Road, Gorham. ME 04038, USA. ’Corresponding author; e-mail: nicholas.m.anich @gmail.com ground-nester that often exhibits breeding site fidelity and has a tendency to settle in aggrega¬ tions rather than disperse widely throughout suitable habitat (Mayfield I960). The only known breeding locality until 1995 was in several counties in the northern Lower Peninsula of Michigan (Mayfield 1992). This species is federally endangered because of its small popu¬ lation size, limited range, and persistent threats. Decennial censuses showed a 60% decline between 1961 and 1971, likely due to Brown¬ headed Cowbird ( Molothms ater ) parasitism and dwindling suitable habitat (Mayfield 1972). Forest management and cowbird removal at the primary breeding site in Michigan helped reverse the population decline, and small numbers of Kirt- land s Warblers have nested in the Upper 199 200 THE WILSON JOURNAL OF ORNITHOLOGY • Vol. 123, No. 2, June 2011 Peninsula of Michigan since 1995 (Probst et al. 2003) and in Ontario. Canada since 2007 (Richard 2008). Occasional observations of Kirtland's Warblers have been reported in Wisconsin. Early observa¬ tions were of single birds during migration (e.g., Taylor 1917), and there were only nine confirmed observations prior to 1978 (Tilghman 1979). Singing males were occasionally found in young jack pines in Wisconsin beginning in 1978 during the breeding season. Statewide surveys of jack pine stands on sandy soils in 1978 and 1988 turned up two and eight singing males, respectively (Tilgh¬ man 1979, Hoffman and Abernathy 1988). Three singing males were discovered in a red pine ( Pinus resinosa) plantation in Adams County, Wisconsin in May 2007. Subsequent intensive searches in 2007 revealed al least eight, males, three females, and three nests at that site, but without evidence of fledging (Trick et al. 2008). Typically sites are only occupied by Kirtland's Warbler when trees are young (1.5-5 in in height; Mayfield 1992). Pines in these stands generally retain green needles on branches low to the ground (Mayfield I960. Probst and Weinrich 1993). Occupied stands are also typically charac¬ terized by both dense pine thickets and open grassy areas. Kirtland’s Warbler habitat was historically generated and maintained primarily by wildfires, but forest fragmentation and fire suppression drastically reduced the extent of this habitat type (Mayfield 1992). Currently, the majority of Kirt¬ land’s Warblers breed in jack pine plantations created specifically for the species with die pines planted in opposing sine-wave patterns that alternately create thickets and openings (Donner et al. 2008). Nesting has been infrequently reported in red pine plantations (Mayfield I960, Anderson and Storer 1976. Walkinshaw 1983, Probst and Weinrich 1993), but with few details. Occupancy of red pine-dominated areas has been considered rare (Huber et al. 2001). We began monitoring the pioneering popula¬ tion of Kirtland’s Warblers in Wisconsin once the first individual was documented there. The objectives ol this paper are to: ( I ) document site occupancy and nesting success in the first 2 years of colonization, and (2) evaluate the quality of the habitat patches used by the warblers by measuring vegetative parameters at the site. This information will be helpful for future conservation efforts for mis endangered species. METHODS Study Area. — We studied Kirtland’s Warblers in Adams County, Wisconsin, in commercially- owned red pine plantations. Jack pine and northern pin oak/black oak ( Quercus ellipsoida- lis/Q. vetutina: hereafter ‘ ‘oak’ ’ ) were common at the sites, while black cherry' ( Primus serntina) and bur oak ( Q . ntacrocarpa) were uncommon. Stands consisted of rows in which red pines were generally spaced ~2 ni apart and featured irregular grassy openings where pines failed to survive. Ground cover consisted of sedge (Carex pensylvanica ), grasses ( Andropogon spp. and Panicum sp.), blueberry ( Vaccinium angustifo- lium ). forbs. pine needles, mosses and lichens, and downed wood from past timber harvest. Soils of occupied stands were sandy, and conditions in neighboring stands ranged from recently clear-cut to 20-m-tafl trees. Site Occupancy. — We surveyed sites in Adams County, Wisconsin known to have been occupied by Kirtland's Warblers in previous years from mid-May to mid-July 2008 and 2009. We walked areas of suitable habitat listening and looking for Kirtland’s Warblers, starting about dawn and ending in late morning when singing subsided or the wind increased. We also used song playbacks to search apparently suitable stands within 16 km of previously occupied sites. We used mist nets and song playbacks to target-net, capture, and color-band males (Refsnider et al. 2009. Trick et al. 2009); spot-mapping (Bibby et al. 2000) was used to estimate the extent of males’ territories. Nest Monitoring. — We followed males to locate females and followed both males and females to locate nests. We systematically searched to locate nests, but this was generally less effective than follow ing birds and detecting cues from the birds. We minimized approaches to nests and generally monitored nests from a distance (4-14 m) to ascertain nest stage and verify they were active. We visited nests at estimated fledging dates to record success (fledged young). We assumed that all young present the last time we looked in the nest had fledged. Habitat Characteristics. — We collected data from 1 0 to 12 August 2009 at the stand in Adams County. Wisconsin that had most birds (6 males, 7 females, and 8 nests in 2009). We sampled 40 vegetation points spaced 30 m apart on three evenly-spaced transects in the core area of the stand used by Kirtland’s Warblers, spanning the Anich et al • KIRTLAND’S WARBLERS IN RED PINE 201 territories of six males. We obtained data that best represented the general nesting habitat at the site by placing transects in the occupied cluster. Transects were east-west to avoid sampling artifacts from north-south planted rows of red pine. Transects averaged 375 m in length and were 100 m apart with 11-15 points per transect. We used point-quarter sampling (Cottam and Curtis 1956) and measured the distance to and species of the nearest tree in each quadrant surrounding each point, allowing us to calculate tree density and relative frequency. We also measured tree height and height of the lowest green branch. We only measured trees that were ^2.5 cm in diameter at 10 cm from the ground. We also quantified ground cover below 50 cm in a I -nr quadrat centered at the point. Cover types were classified as blueberry, grasses/sedges, live woody stems, moss/lichens, bare ground, dead woody debris, forbs, pine needles, or leaf litter. We recorded grass and sedge cover separately for 26 of the 40 plots. We used tape measures across 548 m of our transects and quantified the distance (to the nearest 0.03 m) comprised by open area or canopy cover of the three major tree species. Data Analysis. — We used descriptive statistics to summarize the data. We report number of birds detected and calculate return rate of color-banded males. We report the number of nests, number successful, and estimated number of young fledged. We summarized the data for the stand vegetation measurements using means and 95% confidence intervals (Cl). We used the 95% Cl to compare stand tree heights and lowest live branch heights to previously published results from Michigan Kirtland’s Warbler breeding areas, specifically wildfire-regeneration areas and plan¬ tations (Probst and Wcinrich 1993. Bocetti 1994). RESULTS Occupancy and Nest Success. — Red pine stands occupied by Kirtland’.s Warblers in Adams County in 2008 and 2009 ranged in age from 1 1 to 13 years (since 2-year-old seedlings were planted) and ranged in size from 36 to 70 ha (T. A. Watson, pers. comm.). Eight male and five female Kirtland’s Warblers were detected in 2008. Five of seven males (71%) color-banded in 2008 returned to the site in 2009. Ten male and 10 female Kirtland’s Warblers were found in 2009. We located five nests in 2008, two of which fledged five Kirtland’.s Warbler young each. We found 10 nests in 2009. of which at least six successfully fledged an estimated 23 warbler young. Three of four stands used by Kirtland’s Warbler between 2007 and 2009 were within 3 km. We also detected a single pair in 2009 that successfully nested in a fourth stand, 10 km from the main stands. Habitat Characteristics. — Total density of trees was 1,876/ha of which 66.9% were red pine (1,254/ha), 20.6% were oak (387/ha), and 12.5% were jack pine (234/ha). Mean tree height was 3.2 m (Fig. 1 ). Jack pines in the Wisconsin stand were taller than in the Michigan stands, while heights of red pines were similar (Fig. 1). Most oaks at our site were small (mean height — 2.2 m, 95% Cl = [1.9. 2.4J. n = 33). The height of the lowest live branches of jack pine on the Wisconsin site was similar to heights reported in Michigan (Fig. 2). The lowest live branch of red pine in the Wisconsin stand was closer to the forest floor than for jack pine (Fig. 2). The canopy in the Wisconsin stand was over half open (54%) with red pine dominating the tree canopy (31% cover) followed by oak (9%) and jack pine (6%). Ground cover in the stand was dominated by sedges followed by pine needles and dead woody debris (Fig. 3). We recorded relatively few blue¬ berries, forbs, and grasses. Big blucstem (Andro- pogon gerardii) was the most common grass in our plots. The most common forb recorded was flowering spurge ( Euphorbia carol lata), which was present in 15 of 40 plots (38%). Long-branch frostweed ( Helianthemum canadense), common sheep sorrel ( Rumex acetusellu); and starry false Solomon’s seal ( Maianthemum stellatum) were each present in four plots. DISCUSSION Red pine is not a common breeding habitat for Kirtland's Warblers, but the persistent occupancy, comparable return rates to that found for birds in jack pine stands, and good nest success demon¬ strated the suitability of red pine-dominated stands for breeding Kirtland's Warblers. All four stands in Adams County selected for use by Kirtland's Warblers were red pine plantations. The return rate for our small sample of adult males is comparable to reported rates from Michigan of 53-75% (Berger and Radabaugh 1968: Mayfield 1960, 1983; Probst 1986) sug¬ gesting males survive and perceive the Adams County site as suitable habitat. Hoover (2003) suggested site fidelity is associated with site quality because birds that breed successfully are 202 THE WILSON JOURNAL OF ORNITHOLOGY • Vol. 123. No. 2. June 2011 FIG. 1. Heights of trees in stands used by Kirtland’s Warblers. White bars are means of all trees from previous studies in Michigan; Probst and Wcinrich (P & W 1993) measured 10 wildfire sites, five unbumed natural-regeneration sites, three jack pine plantations, and three plantations dominated by red pine; Bocetti (1994) measured 1 1 wildfire sites and 10 (jack pine) plantation sites. Gray bars are from 160 trees measured at a used site in Adams County, Wisconsin, and include 107 red pine. 33 northern pin oak/black oak, and 21 juck pine. Error bars are 95% confidence intervals. more likely to return. Breeding has been success¬ ful with the cowbird trapping that occurred at our site, and this population appears to be increasing. However, the long-term population dynamics in this habitat type are unknown. We recognize the limitations of results based on one stand containing the territories of six males, but our data provide important additional infor¬ mation on the lull range of habitats successfully used by Kirtland's Warblers (see also Probst and Weinrich 1993). Jack pine is thought to be a requirement for Kirtland's Warbler and natural recruitment of jack pine occurred on all occupied stands in Adams County. The density and percentage of jack pine on our Kirtland’s Warbler stand, to our knowledge, is the lowest reported in the literature. J, R. Probst (pers. comm.) observed that 2-3 red pine sites used in Lower Michigan were larger, and had fewer jack pines, than our Site. Mayfield (1960:16) reported birds nesting in 1951 in “red-pine plantations where there were few if any jack pines”, but did not elaborate further. Our measurements of pine density and total tree density are low compared to sites used for breeding in Michigan, although plantation sites typically have fewer trees than wildfire sites (Probst 1988, Probst and Weinrich 1993). Stands with fewer than 2.500 trees/ha have been considered marginal Kirtland's Warbler habitat (Probst and Hayes 1987). Houseman and Ander¬ son (2002) tound tree densities greater than ours in plantations (2.890 jack pines/ha and 3.345 total trees/ha), and on burned sites at Mack Lake (8.578 jack pines/ha and 8.950 total trees/ha). Bocetii ( 1994) tound an average of 7,000 jack pines/ha on wildfire sites; her measurement of 2.000 jack pines/ha on plantation sites was comparable to our total tree density. However, tree densities alone do not adequately define habitat suitability, because variable tree-spacing can greatly affect canopy cover in a stand, and the wider spacing of trees at Anich et al. • KIRTLAND'S WARBLERS IN RED PINE 203 FIG. 2. Height of the lowest live branch on trees in stands used by Kirtland's Warblers. White bars are means of all trees at 1 1 wildfire sites and 10 (jack pine) plantation sites in Michigan measured by Bocetti (1994). Gray bars are from 160 trees measured at a used site in Adams County, Wisconsin, and include 107 red pine, 33 northern pin oak/black oak, and 21 jack pine. Error bars are 95% confidence intervals. plantation sites provides more cover with fewer trees than in naturally regenerated sites (Probst 1988). Tree height can provide some measure of the stage of a Kirtland’s Warbler stand (Probst and Weinrich (1993). Our population was not moni¬ tored before 2007: we do not know how long birds were present at the site and whether our site is just becoming occupied, is in its prime, or is declining. Average heights of jack pines in our study have been typically associated with declining stands (Probst and Weinrich 1993) but red pine-domi¬ nated stands may have a different succession scenario. The stand in our study, based on tree canopy cover which increases with stand age. may be in its prime condition for nesting warblers (Probst and Weinrich 1993). The persistence of low live branches in our stand supports the view that low branch density is an important characteristic of suitable Kirtland's Warbler habitat; several authors (Mayfield 1960. Probst 1988. Probst and Weinrich 1993) have suggested low live branches are critical for nesting, female foraging, and nestling cover. We frequently observed females and recently fledged young using low branches for foraging and cover, and we found four nests directly beneath very low live red pine branches. The extremely low mean live green branch height shown by red pine at our site may indicate one reason for the settlement of our site by Kirtland’s Warblers. A red pine component to a stand might prolong use of that stand by Kirtland’s Warblers if loss of live green branches is a main reason for abandonment of a stand (Probst 1988). Ground cover types at our site were comparable to other sites, although our site was more dominated by sedges dian most Kirtland’s War¬ bler sites (Bocetti 1 994. Houseman and Anderson 2002. Probst and Donnerwright 2003). Some plants commonly observed in Michigan were not common at our site: bearberry ( Arctostaphylos uva-ursi) and sand cherry ( Primus putnila) were present but not common, and we observed no sweet fem ( Comptonia peregrina). The domi¬ nance of sedges and relative Jack of forbs and grasses at our site may be related to application of herbicide during site preparation, although others 204 THE WILSON JOURNAL OF ORNITHOLOGY • Vol. 123. No. 2. June 2011 FIG. 3. Ground cover measurements in I-m2 plots in a stand used by Kirtland's Warblers in Adams County. Wisconsin in 2009. Error bars are 95% confidence intervals. Means are from 40 plots, except for grasses and sedges, which are from 26 plots we separately recorded for those two cover types. The mean of grasses + sedges was recorded for all 40 plots, and was 46.1% (95% Cl = 35.7, 56.4). have reported the tendency of Care. r pensylvanica to form dense mats in jack pine stands following disturbance, which may inhibit growth of blue¬ berry and jack pine (Abrams and Dickmann 1982, Houseman and Anderson 2002, Probst and Donnerwright 2003). Probst and Donnerwright (2003) noted that ground cover does not seem to be a limiting factor for Kirtland’s Warbler nest sites or habitat suitability, as a wide range of ground cover types occurs on appropriate sites. CONSERVATION IMPLICATIONS The extensive die-off of planted red pine and substantial natural jack pine recruitment at the Adams County site provided a landscape matrix of openings and thickets that produced suitable Kirtland’s Warbler habitat. We believe that, except for these circumstances, this stand would not be suitable for occupation by Kirtland's Warblers, and that most planted red pine planta¬ tions do not create the habitat conditions required by the species. Future management mimicking the conditions at our site, featuring thickets of jack Pine complementing reduced numbers of red pine interspersed with openings (see Probst 1988) could prove fruitful. The inclusion of more- profitable red pine in this configuration might provide an incentive for timber companies to plant some stands in configurations that support Kirt¬ land’s Warblers, resulting in supplemental habitat beyond traditional jack pine stands. Understanding the characteristics of future occupied stands throughout the area of range expansion is essential if the total Kirtland's Warbler population continues to increase. The potential suitability of red pine-dominated sites could become increasingly important if jack pine continues to be converted to red pine. More study is needed on the characteristics that affect suitability ol red pine-dominated stands for Kirt- land s Warblers, especially how suitability of these sites changes over time. ACKNOWLEDGMENTS Hie Natural Resources Foundation of Wisconsin and Wisconsin Society for Ornithology provided funding for this research. Wc thank Plum Creek Timber for assistance and T. A. Watson lor providing maps and information about the stands. We are indebted to D. J. DiTommaso for finding and monitoring birds in 2007. We thank J. R. Probst for assistance in the field and many productive discussions that contributed ideas to this manuscript. J. R. Probst. R. L. Anich et at. • KIRTLAND'S WARBLERS IN RED PINE 205 Refsnider, T. J. Benson, P. A. Spaeth, the editor, and two anonymous reviewers provided helpful comments on this manuscript. B. F. Benson of USDA-APHIS Wildlife Services operated cowbird traps. J. F. Robaidek helped monitor nests. R. L. Refsnider helped capture and band birds, and N. M. Livingston provided accommodations. We thank numerous volunteers for searching for Kirtland’s Warblers in Wisconsin, especially P. C. Charland and R. \1. SamenJykc. LITERATURE CITED Abrams. M. D. avd D. I. Dickmann. 1982. Early revegetation of clear-cut and burned jack pine sites in northern lower Michigan. Canadian Journal of Botany 60:946-954. Anderson, W. L. and R. W. Stoker. 1976. Factors influencing Kirtland's Warbler nesting success. Jack- Pine Warbler 54:105-115. Berger. A. J. .and B. E. Radabaugh. 1968. Returns of Kirtland's Warblers to the hreeding grounds. Bird- Banding 39:161-186. Bibby. C. J., N. D. Burgess, D. a. Hill, and S. H. Mlstoe. 2000. Bird census techniques. Second Edition. Academic Press, London, United Kingdom. Boceiti, C. I. 1994. Density, demography, and mating success of Kirtland's Warblers in managed and natural habitats. Dissertation. Ohio State University. Colum¬ bus. USA. CorrAM, G. AND J. T. CURTIS. 1956. The use of distance measures in phytosociological sampling. Ecology 37:451-460. DONNEK, D. M.. J. R. Probst. AND C. A. RiBic. 2008. Influence of habitat amount, arrangement, and use on population trend estimates of male Kirtland's War¬ blers, Landscape Ecology 23:467-480. Hoffman, R. and R. Abernathy. 1988. Summary of the Kinland's Warbler survey in Wisconsin- 1988. Wis¬ consin Endangered Resources Report 47. Wisconsin Department of Natural Resources. Madison. USA, Hoovfr, J. P. 2003. Decision rules for site fidelity in a migratory bird, the Prothonotary Warbler. Ecology 84:416-430. Houseman. G. R. and R. C. Anderson. 2002. Effects of jack pine plantation management on barrens Bora and potential Kirtland's Warbler nest hubitat. Restoration Ecology 10:27-36. Huber. P. W.. j. a. Weinrich, and E. S. Carlson. 2001. Strategy for Kirtland's Warbler habitat management. Michigan Department of Natural Resources. USDA Forest Service, and USDI Fish and Wildlife Service. USDA Forest Service, Mio. Michigan. USA. Mayfield. H. F. 1960. The Kirtland's Warbler Bulletin Number 40. Cranbrook Institute of Science. Bloom¬ field Hills. Michigan, USA. Mayfield, H. F. 1972. Third decennial census of Kirtland’s Warbler. Auk 89:263-268. Mayfield, H. F. 1983. Kirtland’s Warbler, victim of its own rarity? Auk 100:974-976. Mayfield, 11. F. 1992. Rutland's Warbler ( Dendroica kirtlandii). The birds of North America. Number 19. PROBST. j. R. 1986. A review of factors limiting the Kirtland's Warbler on its breeding grounds. American Midland Naturalist 116:87-100. Probst, J. R. 1988. Kirtland's Warbler breeding biology and habitat management. Pages 28-35 in Integrating forest management for wildlife and fish (W- Hoek- STRA and J. C.APP, Compilers). USDA Forest Service, General Technical Report NC-122. St. Paul. Minne¬ sota, USA. PROBST. J. R. AND D. Donnkrwright. 2003. Fire and shade effects on ground cover structure in Kirtland’s Warbler habitat. American Midland Naturalist 149:320-334. Probst, J. R. and J. P. Hayes, 1987. Pairing success of Kirtland's Warblers in marginal vs. suitable habitat. Auk 104:234-241. Probst. J. R. AND J. Weinrjch. 1993. Relating Kirtland’s Warbler population to changing landscape composi¬ tion and structure. Landscape Ecology 8:257-27 1 . Probst, J. R.. D. M. Donner. C. I. Bocettl and S. SJOGREN. 2003. Population increase in Kirtland’s Warbler and summer range expansion to Wisconsin and Michigan's Upper Peninsula, USA. Oryx 37:365- 373. Refsnider, R. L., J. A. Trick, and J. L. Goyette. 2009. 2008 capture and banding of Kirtland's Warblers ( Dendroica kirtlandii) in Wisconsin. Passenger Pigeon 71:115-121. Richard, T. 2008. Conf irmed occurrence and nesting of the Kirtland's Warbler at CFB Petawawa, Ontario: a first for Canada. Ontario Birds 26:2-15. Taylor, W. 1917. Kirtland's Warbler in Madison, Wisconsin. Auk 34:343. Tilghman, N. G. 1979. The search for tho Kirtland’s Warbler in Wisconsin. Passenger Pigeon 41:16-24. Trick. J. A., K. Grveles, and J. L. Goyette. 2009. The 2008 nesting season: first documented successful nesting of Kirtland’s Warbler {.Dendroica kirtlandii) in Wisconsin. Passenger Pigeon 71:100-1 14. Trick, J. A., K. Grveles, D. DiTommaso, and J. Robaidek. 2008. The First Wisconsin nesting record of Kirtland’s Warbler ( Dendroica kirtlandii). Passen¬ ger Pigeon 70:93-102. W ALKtN’SHAW . L. H- 1983. Kirtland's Warbler: the natural history of an endangered species. Bulletin Number 58. Cranbrook Institute of Science, Bloomfield Hills, Michigan, USA. The Wilson Journal of Ornithology 123(2):206-217, 2011 AVIAN COMMUNITY AND MICROHABITAT ASSOCIATIONS OF CERULEAN WARBLERS IN ALABAMA JOHN P. CARPENTER,1 43 YONG WANG,1 CALLIE SCHWEITZER.-’ AND PAUL B. HAMEL' ABSTRACT. — Cerulean Warblers {Dendroicu cerulea) have experienced one of the highest population declines of any neotropical-Nearctic migratory species in North America. We performed point counts and habitat assessments in areas used and unused by Cendean Warblers in northern Alabama during the 2005 and 2006 breeding seasons to examine their avian associations and identify microhabitat features that best explained their occurrence. We detected on average —50 Cerulean Warbler males (total) in three disjunct populations during each breeding season. Areas used by Cerulean Warblers were characterized by avian communities with significantly higher species richness, diversity, and abundance compared to areas where they were not detected. Correspondence analysis related Cerulean Warblers to inhabitants of riparian, bottomland deciduous loresls (c.g.. Kentucky Warbler [Oporomisfonnosus], Acadian Flycatcher | Emptdonax virescens], and Northern Parula \ Panda americana]) and two edge specialists (Blue- winged Warbler | Ve minora cyanoptera ) and Indigo Bunting \ Passe rina cyaneu]) suggesting Cerulean Warblers in our study areas may be tolerant of some habitat disturbance within an otherwise largely forested landscape. Information theoretic criteria and canonical correspondence analysis indicated Cerulean Warblers preferred bottomland forests containing tall (> 29 m). large diameter, well-spaced (> 27 nr/hai deciduous trees with greater canopy cover (== 90%). closer « 20 m) canopy gaps, fewer snags < < 25/ha), and a moderately complex canopy structure. Received S March 2010. Accepted 22 December 2010. The Cerulean Warbler (Dendroica cerulea) has lost nearly 70% of its breeding population since 1966 (Rich et al. 2004) because of alterations in breeding, migratory, and wintering habitats com¬ pounded by the bird’s dependency on extensive tracts of large deciduous trees in many parts of its range (Hamel 2000a). Northern Alabama histor¬ ically represented a portion of the Cerulean Warbler's southern-most breeding range where they were described as common and even numerous in several counties throughout the state (Imhof 1976). This warbler is now rarely encountered in Alabama during the breeding season and was designated a Priority One species (highest conservation concern) by the Alabama Department of Conservation and Natural Re¬ sources (Mirarchi et al. 2004). Selection of breeding territories by landbirds is heavily influenced by structure and composition of the surrounding habitat and avian community (Mac Arthur and MacArthur 1961, Wiens 1989) Department ot Natural Resources and Environmental Sciences, Alabama A&M University, p. O Box ] 9^7 Nor mal. AL 35762, USA. 2 USDA, Forest Service. Southern Research Station. P O Box 1568, Normal, AL 35762, USA. 'USDA, Forest Service, Center lor Bottomland Hard¬ woods Research, P. O. Box 227, Sloneville. MS 38776, 5 Corresponding author; e-mail: john.carpenter@ncwildlifc.org Thus, effectiveness of management initiatives is dependent upon not only identifying the habitat requirements of the species under investigation, but also the avian community with which it associates. Recent studies of Cerulean Warblers emphasize breeding habitat requirements (Rob¬ bins et al. 1992, Jones and Robertson 2001, Weakland and Wood 2005. Barg et al. 2006b). nesting behavior (Oliarnyk and Roberston 1996. Barg et al. 2006a. Rogers 2006. Roth and Islam 2008). and habitat management (Hamel 2005, Hamel et al. 2005b, Hamel and Rosenberg 2007). while information regarding avian associations of Cerulean Warblers remains scarce (Jones et al. 2004) and anecdotal (Lynch 1981. Hamel 2000b). Recent discoveries of two small Cerulean Warbler populations in Alabama suggest habitat is available in this portion of the species range to support small breeding populations (Carpenter et al. 2005). This study was initiated in response to the Rosenberg et al. (2000) recommendation for additional Cerulean Warbler research in Alabama to provide more accurate population estimates and habitat requirements needed to effectively manage habitat for this species. Our objectives were to: (1 ) examine avian associations of the Cerulean Warbler to facilitate a better understanding of this species' habitat use and the bird community in which it breeds, and (2) identify microhabitat features that best explain Cerulean Warbler occurrence in the southern portion of its range where populations are in serious decline (Buehler et al. 2008). 206 Carpenter et al. • CERULEAN WARBLER MICROHABITAT ASSOCIATIONS 207 Lauderdale Limestone Madison Colbert Lawrence Morgan^ Marshall Franklin lerokee r.;y '7/A J \\ instiMi i • 1 Marion Cullman Blount Walker Calhoun Jefferson ® Larkin Fork © Walls of Jericho ▲ Unused locations \WA Bankhead National Forest I88S3 Sipsey Wilderness Area I | Non-deciduous/mixed forest n Deciduous/mixed forest Historic breeding range FIG. 1 . Sampling locations unused by Cerulean Warblers and Cerulean Warbler populations (Walls of Jericho, Larkin Fork, and Sipsey Wilderness) sampled in northern Alabama during the 2005 and 2006 breeding seasons. Historic range from Imhof (1976). METHODS Study Areas. — We studied Cerulean Warblers at three sites in northern Alabama during the 2005 and 2006 breeding seasons (Fig. 1). The most recently discovered Cerulean Warbler populations are in Jackson County along Hurricane Creek in the Walls of Jericho tract of Skyline Wildlife Management Area (WMA) (34 58' N. 86 6' W) and on private property along Larkin Fork (34 57'N, 86 13' W). Both Jackson County populations breed in bottomland hardwood forest of the Mid-Cumberland Plateau where vegetation is dominated by mature (80+ year-old) forest categorized as oak and oak-hickory- (Quercus spp.-Carya spp.) with mixed mesophytic commu¬ nities restricted to valleys and coves (Braun 1950). Additional canopy species include box elder (Acer negundo), elm ( Ulmus spp.). hackber- ry (Celtis occidentalis). tulip poplar (Liriodendron tuUpifera), sugar maple (Acer sacchartim), Amer¬ ican beech (Fagtts gnmdifolia). eastern sycamore ( Plaianus occidentalis), and black walnut (Ju- glans nigra). Several maintained fields averaging 208 THE WILSON JOURNAL OF ORNITHOLOGY • Vol. 123, No. 2, June 2011 2 ha in size occur throughout the floodplains of these sites. A third Cerulean population is in Lawrence County within the 71,600-ha Bankhead National Forest <34 20' N. 87 ' 22' W). Bankhead National Forest (BNF) is along the southern Cumberland Plateau and is characterized by dissected sloping ridges and rock bluffs dominat¬ ed by loblolly pine (Pinus taeda), upland hardwood, and mixed hardwood-pine with addi¬ tional canopy species similar to those at the Jackson County sites (USDA Forest Service 2004). Cerulean Warblers are concentrated in BNF along the floodplain forests of the 4,200-ha Sipsey Wilderness Area. Bird Surveys. — We surveyed Cerulean War¬ blers from May to June during the breeding seasons of 2005 and 2006 by walking the floodplains and adjacent slopes of Hurricane Creek and Larkin Fork, and along FJannigan and Borden creeks in Bankhead National Forest. We mapped male Cerulean territories on multiple visits using radiotolcmetry, repeated observations of col or- banded males, and by distinguishing song variability between neighbors (Woodward 1997). Ten-minute, fixed-radius point counts {n = 53) were performed within a territory and centered under individual, singing male Cerulean War¬ blers. All counts were conducted once at each location prior to 1030 hrs EST following Hamel et al. (1996) by a single observer to eliminate multiple surveyor bias (Sauer et al. 1994). Point counts were also performed once at 47 additional locations from May to June 2005 and 2006 in an effort to locate new breeding populations (Fig. 1 ). We concentrated our sam¬ pling effort in Skyline WMA and Bankhead NF to reduce spatial variability; however, our only requirements for these locations were that they must occur in deciduous/mixed forest and the Cerulean Warbler’s historic breeding range in Alabama (Imhof 1976). We used the ArcGIS (Version 9.1, ESRI 2005) extension Hawth’s Tools (Beyer 2004) to generate 26 random points: 12 in Skyline WMA, six in Bankhead NF. and eight in state parks and nature preserves. An additional 19 locations were selected from 122 pre-existing point count stations in Bankhead NF USDA Forest Service 1995). The remaining two locations were based on Cerulean Warbler observations from Alabama Breeding Bird Atlas surveys in 1999 and 2001 (R. L. West, pers comm.) in an effort to verify the continued existence of breeding Cerulean Warblers. Play¬ back of a conspecific song was broadcast for 5 min at the conclusion of these counts to ensure that no Cerulean Warblers were present. Microhabitat Characteristics. — We compared microhabitat front used habitat (// = 52) centered at point counts conducted under Cerulean Warbler males, and in unused habitat (n = 47) defined as point count locations where Cerulean Warblers were not detected. Habitat measurements for one used point count were not collected due to logistic constraints. The median distance between used locations in the year of sampling was 192.9 m (interquartile range = 112.4-383.6) and 2.1 km (interquartile range = 1. (1-2.8) between unused locations. Vegetation was measured by one observer within 0.04-ha (1 1.3-m radius) circular plots following James and Shugart (1970) and Noon (1981). Plot measurements included basal area, total live stems 2-3 -cm diameter at breast height (DBH). total snags >8-cm DBH. tree height, slope, aspect, understory density, and distance to and size of nearest canopy gap. Percent canopy cover was estimated from 40 ± vettical readings along transects in the cardinal directions using an ocular densitometer tube. Each reading was assigned one of four height intervals (< 5, 5-15. > 15-25. > 25 m, or no cover) to estimate canopy structure complexity. Slope was measured in degrees using a clinometer and aspect was transformed to a value ranging from 0.0 to 2.0 (Beers et al. 1966). This distinguished less productive, southwest facing slopes (value = 0.0) from more productive, mesic northeast slopes (value =■ 2.0) (van Manen et al. 2005). We assigned flat plots a neutral value of 1.0. Distance to and size of the nearest canopy gap <50 m from plot center and >10 nr were measured following Runkle (1992). Analysis of Point Counts. — All nocturnal, colonial, and raptor species including birds with restricted vocalizations (e.g., hummingbirds), were excluded from the analysis because of the difficulty of reliably detecting them during diurnal point counts (Bibby et al. 2000). Species richness was calculated as die total number of species detected during each count, and total number of individuals counted at each location was used as bird abundance. Species diversity was estimated with the Shannon-Weiner index using the Micro¬ soft ® Office Excel (Microsoft Inc. 2003) macro Biological Tools Version 0.2 (Hanks 1995). We constructed a conservation concern value using designations developed by the Alabama Nongame Carpenter et al. • CERULEAN WARBLER MICROHABITAT ASSOCIATIONS 209 Wildlife Division (Mirarchi et al. 2004), and summed the number of species designated mod¬ erate or higher detected at each count. We pooled data from both seasons to increase sample size because multivariate analysis of variance (MAN- OVA) tests suggested there was no interaction or the trend was consistent between year and type of survey (used vs. unused) lor habitat variables (Philai's Trace = 0.1 1, F = 0.51, df = 1 8 and 78. P = 0.95) and for avian community variables (e.g.. abundance, richness and diversity index, Philai's Trace = 0.08. F = 2.10, df = 4 and 93, P = 0.09). Independent sample /-tests were used to test for differences between used and unused plots in bird species richness, abundance, diver¬ sity, and conservation concern values, as well as abundance of Brown-headed Cowbirds ( Molo - thrus ater ) and three common nest predators: American Crow ( Corvus brachyrhynchos). Blue Jay (Cyanocitta cristata ), and Red-bellied Wood¬ pecker (Melaneqtes carol inns). Analysis of Avian Community Associations.— Detrended correspondence analysis (DCA) was used with bird abundance to help explain the structure of the sampled avian community (Hill and Gauch 1980). We chose nonlinear scaling and detrended the axes using second-order polynomi¬ als following Jongman et al. (1995) to avoid the limitations inherent in DCA, including distorted gradient structure and a lack of robustness (Minchin 1987). Rare species were down-weight¬ ed and ordination scores were obtained with biplot scaling focused on inter-species distances using CANOCO 4.54 (ter Braak and Smilauer 2006). We referenced Birds of North America accounts (Poole 2005) for general habitat preferences of each species to assist in interpretation of DCA axis, and excluded species detected at less than three locations to reduce the effect of transient or accidental species (Wakeley et al. 2007). Analyses of Microhabitat Characteristics. — We attempted to correct any variables w'ith non-normal distributions using Shapiro-Wilk tests and square root or logarithmic transformations. Independent sample /-tests were used to compare mean mea¬ surements of vegetation from used habitat plots with unused plots, and two-sample Mann-Whitney 17- tests for variables that violated normality or equal variance assumptions. Canopy structure complexity was estimated with the Shannon-Weiner diversity index expressed as a proportion of the maximum possible diversity using the number of readings assigned to each height interval (Zar 1999). Analysis of Microhabitat and Avian Communi¬ ty. — We used principal components analysis (PCA) to reduce the dimensionality of the original microhabitat variables. All components had var¬ iance inflation factors <1.1 and were considered to be unique contributors to the analysis (Leps and Smilaucr 2003). Canonical correspondence anal¬ ysis (CCA) was used to expose patterns of variation in avian community composition and species abundance related to PCA variables (ter Braak 1986). and to guide selection of habitat characteristics for modeling Cerulean Warbler microhabitat. The length of the longest gradient (i.e., ordination axis) was 3.68. and we considered unimodal ordination methods (e.g.. CCA) more appropriate than linear methods (e.g.. redundancy analysis) (Leps and Smilauer 2003). We used bird abundance and confined the CCA to those species detected at three or more locations within 50 m of plot center using CANOCO 4.54. This is prefer¬ able to analyzing all bird detections, which assumes vegetative measures within our plots are an adequate representation of habitats used by birds that were detected farther away where microhabitat characteristics are likely to vary. We used randomized Monte Carlo tests (n = 499) to evaluate significance of CCA axes. Analysis of Miernhabitat Models. — We used logistic regression to examine the relationship between Cerulean Warbler occurrence and habitat variables with the binary dependent variable representing used and unused habitat plots. We established 20 models a priori and compared them using the information-theoretic approach of Burnham and Anderson (2004). Variable selection was based on Cerulean Warbler literature (Hamel 2000a), as well as habitat plot comparisons, CCA, and field observations from this study. We performed a second-order bias correction (A1C(.) because n/K < 40 and calculated evidence ratios based on Akaike weights (w,) as an indication of model strength in comparison to other models considered (Burnham and Anderson 2004). We examined a variable's beta coefficient to identify its relationship (positive or negative) to Cerulean Warbler presence. Variables present in the model with the highest tv, were considered the best predictors for Cerulean Warbler occurrence. An alpha level of 0. 1 was selected for all tests ot significance due to the conservation status of the Cerulean Warbler (Asians et al. 1990). All statistical analyses, unless previously described. were performed using SPSS ® Version 15.0 (SPSS 210 THE WILSON JOURNAL OF ORNITHOLOGY • Vol. 123, No. 2, June 2011 Used {n = 53) Unused ( n = 47) FIG. 2. Mean species richness, diversity index, bird abundance, and number of species of conservation concern If?nial.PO,?t COUntS conductcd in areas llscd and unused by Cerulean Warblers in northern Alabama during the 2005 and 2006 breeding seasons. All values were significantly higher (P < 0.01 ) at used locations. Error bars are + SE. Inc. 2006). Means ± standard error (SE) are pre¬ sented unless noted elsewhere. RESULTS Bird Surveys. — Approximately 50 Cerulean Warbler males were detected in northern Alabama during each of the 2005 and 2006 breeding seasons. Cerulean Warblers were found only in Jackson County along Larkin Fork and Hurricane and Mill creeks in Walls of Jericho, and Lawrence County in Bankhead National Forest along Borden, Flannigan. and Horse creeks. No Cerule* an Warblers were encountered at unused points or during additional target searches throughout Jackson County or BNF. Walls of Jericho had the highest number of detections with 20 males followed by 15 territorial males in Bankhead National Forest and Larkin Fork. Bird species richness (r = 4.91. df = 98 P 0.01), abundance (/ = 3.85, df = 98 P < 0 0 diversity ) \ detected no difference in abundance of Brow headed Cowbird (/ = 1.06, df - 98. P < 0 > Amencan Crow (t = -0.63, df =98 P < 0 5 Blue Jay {t = -1.01, df = 98. P < 0.31), or Red- bellied Woodpecker (t = 0.85, df = 98 ,P< 0.40) between used and unused locations. Avian Community Associations— The propor¬ tion of variance explained by the DCA ordination was 23.7% with the first two axes accounting for greater than half of the variability (13.5%). Species most closely associated with Cerulean Warblers were Kentucky Warbler ( Oporomis fonnosus). Northern Parula {Parula americam). Acadian Flycatcher ( Empnionax virescens). Blue¬ winged Warbler ( Vermivora cyanoptera ), Louisi¬ ana Wated brush {Parke sia motacilia ), American Redstart (Setophuga ruticilla). Belted Kingfisher {Megaceryle alcyon), and Indigo Bunting ( Pus- serinu cyanea ) (Fig. 3). Bird community associ¬ ations revealed by the DCA suggested Axis 1 represented a gradient from xeric upland to mesic bottomlands, while Axis 2 distinguished interior deciduous forest from edge and mixed forest habitat. Microhabitat Characteristics. — Used plots. When compared to unused habitat, had signifi¬ cantly fewer live trees 2=3 cm DBH (t = -4.01. dl = 97, P < 0.01. Table 1). higher ratio of basal area to number of stems (t = 3.56. df = 97. P < 0.01 ), greater percentage of deciduous basal area (2 = -4.5, df =97 , P C 0.01), taller lower. Carpenter et al • CERULEAN WARBLER MICROHABITAT ASSOCIATIONS 211 that explained 83.8% of the total variance with the first two axes accounting for greater than half of the variability (53.9%). Cerulean Warblers displayed the strongest rela¬ tionships with the principal component represent¬ ing high percent deciduous basal area, fewer trees 212 THE WILSON JOURNAL OF ORNITHOLOGY • Vol. 123. No. 2. June 2011 TABLE 1. Microhabitat characteristic comparisons for Cerulean Warbler study plots in northern Alabama during th; 2005 and 2006 breeding seasons. Values are means (± SE) for /-tests and median (interquartile range) for Mann-Whitne (/-tests of untransformed variables. Bold type denotes significant differences. P < 0.1. Micruhabitat characteristic Variable code Variable description Used (n = 52) Unused (n - 47) BA NTREE" RBATR" NSNAG SNAGBA RBASNAG DECBA TRDBH“ LOWHT* MIDHT UPHT CCVR CSTRC'' GAPDIST GAPSZ" UNDSTRY" SLOPE ASPECT11 Basal area of live trees (nr /ha) Number of live trees (ha) BArNTREE Number of snags (ha) Basal area of snags (nr/ha) SNAGBA:NSNAG Deciduous tree BA (%) Diameter nearest tree (cm) Lower canopy height (m) Mid canopy height (m) Upper canopy height (m) Canopy cover (%) Canopy structure Distance to nearest gap Size of nearest gap Understory density (stems/ha) Slope (degree) Aspect 27.8 ± 1.5 840.4 ± 45.6 0.04 ± 0.003 25.0 (25.0-68.8) 0.6 (0.1— ],9) 0.01 (0.01-0.03) 100.0 (100.0-100.0) 22.0 ± 1.6 5.8 ± 0.2 17.0 ± 0.4 29.4 (24.9-31.6) 90.0 (83.1-95.0) 0.72 ± 0.02 2.0 (1. 0-3.0) 3.0 (1. 0-4.0) 771.6 ± 90.4 8.0 (0.0-21.4) 1.0 (1.0-1. 3) “ Logarithmic or square root Iranstormalion. Shannon-Wiener diversity index. : as r : 5 *'-»>■ • <> » ->• Transformed: A’ = cost 45 - A) + I (Beers et al. 1%6). 25.6 ± 1.2 1.305.3 ± 121.1 0.03 ± 0.003 50.0 (25.0-100.0) 1.0 (0.3-2.4) 0.02 (0.03) 96.2 (77.8-100.0) 13.5 ± 1.1 5.2 ± 0.2 15.5 ± 0.5 26.2 (22.4-31.2) 82.5 (77.5-90.0) 0.75 ± 0.01 2.0(1. 0-5.0) 1.0 (1. 0-4.0) 1.132.4 ± 92.4 8.5 (0.0-14.0) 1.0 (0.9- 1. 5) t-tesUU-ita df tfl r 97 1.13(f) 0.26 97 -4.01 (/) 0.01 97 3.56 (f) 0.01 97 -1.51 (Z) 0.13 97 — 112 (Z) 0.26 97 -0.51 (Z) 0.61 97 -4.50 (Z) 0.01 97 5.49 i/i 0.01 97 1.69(f) 0.10 97 2.58 (f) 0.01 97 -1.68 (Z) 0.09 97 -3.48 (Z) 0.01 97 -1.64 (/) 0.10 97 -0.71 (Z) 0.48 97 -1.69 (Z) 0.09 97 -3.23 (/) 0.01 97 -0.64 (Z) 0.52 97 -0.19 (Z) 0.84 TABLE 2. Principal components analysis of microhabi- tat characteristics from plots used and unused by Cerulean Warblers in northern Alabama during the 2005 and 2006 breeding seasons. Factor loadings < 0.25 not displayed. Original variables RBATR BA TRDBH UPHT LOWHT MIDHT GAPSZ GAPDIST SNAGBA RBASNAG NSNAG DECBA NTREE UNDSTRY CSTRC CCVR ASPECT SLOPE Cumulative Rotated factor loadings' l7-2 2S.9 40.4 50.3 59.1 “ Rotation ir varimax with Kaiser normalization. —3 cm diameter, and .sparse understory (Fig. 4). Positive yet weaker affiliations existed with components describing canopy cover and struc¬ ture, tree size (i.e., height, DBH, basal area) and density (i.e., basal area: number of stems), and snag density. The components derived from gap size and proximity to gaps, as well as aspect and slope, had strong negative associations with Cerulean Warbler presence. The best-supported model relating Cerulean arbler occurrence to microhabitat variables had an Akaike weight (wf) of 0.87 (Table 3). Cerulean Warblers preferred flat bottomlands containing large, well-spaced deciduous trees, a moderately complex canopy structure, closer canopy gaps, and many smaller snags. DISCUSSION The closest associates of Cerulean Warblers were neotropical migratory species that breed near streams (Louisiana Waterthrush and Northern Parula. but also Belted Kingfisher) in moist woodlands and deciduous bottomland forests (Kentucky Warbler. American Redstart, and Acadian Flycatcher). Cerulean Warblers wem not related to species that typically favor xeric Carpenter et a/. • CERULEAN WARBLER MICROHABITAT ASSOCIATIONS 213 TABLE 3. Best supported logistic regression models for predicting occurrence of Cerulean Warblers. Akaike Information Criterion (AIC) values calculated using -21og-likelihood values (L) and K (total number of parameters +1). Akaike weights (w,) derived from each model's likelihood (ML) divided by the sum of all ML values. Beta coefficients signify a variable’s relationship (+, or ±) to Cerulean Warbler presence. Model L K AIC AAIC, ML DECBA(-t-), ASPECT(-). CSTRC(-), GAPDIST(-), RBASNG(-). RBATR(+). TRDBH(-t-) 69.77 8 108.00 0.00 1.00 0.87 RBATR( -). BA(+), TRDBH( + ), L’PHT(-). LOWHT(+), MIDHTl -). DECBAH-). NTREE(- J. L'NDSTRY(±), CSTRC( - ). CCVR(+) 66.12 12 112.00 5.81 0.05 0.05 RBATRl -i. DECBAI+), CCVR(+). TRDBHI+), GAPSZI+). MIDHT(+) 78.70 7 107.00 6.65 0.04 0.03 RBATRI+). RBASXG(-). DECBA(+), GAPSZ(+). GAPDIST(-). CCVR(-), CSTRC(-). TRDBH(+), l NDSTRYi ± ). LPHTi + 1 69.47 11 111.00 6.75 0.03 0.03 BA(-). DECBAI+). CCVR(+), ASPECTt- ). TRDBH(+), UPHT(- ) 81.36 7 107.00 9.31 0.01 0.01 CCVR(+). TRDBH(-r). UNDSTRY(±), UPHT( - l. RBATR(+), DECBA(+) 81.70 7 107.00 9.65 0.01 0.01 DECBAi+1. NTREE(-). UNDSTRY(±), CSTRC(-), CCVR(+) 85.63 6 106.00 11.32 0.00 0.00 NTREE(-), DECBA(+), GAPSZI+), GAPDIST(-), CCVR(+) 86.48 6 106.00 12.17 0.00 0.00 RBATR(-). BA(+), TRDBH(+), UPHT(-), LOWHT(+), MIDHTl -). DECBA(+), NTREE(-), UNDSTRY(±) 78.98 10 110.00 13.88 0.00 0.00 DECBA(+), NTREE(-), UNDSTRY(-) 92.69 4 104.00 13.97 0.00 0.00 upland, mixed forests, and edge habitats; how¬ ever, Jndigo Buntings and Blue-winged Warblers, two species common in shrub and edge habitats, were closely associated with Cerulean Warblers. These patterns suggest Cerulean Warblers may be tolerant of small-scale disturbances within the otherwise large, contiguous forest tracts in which they are found (Hunter el al. 2001, Jones et al. 2001, Hamel et al. 2005a, Wood et al. 2005). We observed Northern Parulas and Red-eyed Vireos reacting aggressively to Cerulean Warbler playback and engage in direct physical contact with Cerulean Warbler males on several occasions (JPC. pers. obs.; Jones et al. 2007). Both of these species are common canopy-dwellers in bottom¬ land deciduous forests whose resource selection likely overlaps that of Cerulean Warblers. We detected no difference between counts of common nest predators and Brown-headed Cowbird abun¬ dance; however, the latter species was plotted near Cerulean Warblers along one axis of our ordination and may be attracted to the same edge habitat Blue-winged Warblers and Indigo Bun¬ tings are using. We did not examine these relationships in detail but acknowledge that more research is needed to learn if abundance and behavior of competing, predatory, and brood parasitic species are limiting productivity of Cerulean Warblers in Alabama. We found Cerulean Warblers breeding in communities with more individuals and species, higher species diversity, and a greater number of species of conservation concern compared to areas where they were ab.sent. Bird species richness and abundance increase as habitat patches increase in area and heterogeneity (Free- mark and Merriam 1986. Blake and Karr 1987), which is characteristic of the forested landscapes surrounding our Cerulean Warbler populations (Carpenter 2007). Cerulean Warblers were not effective bio-indicators for overall species diver¬ sity in Ontario, but were suited as an umbrella species for similar, canopy-dwelling birds (Jones et aJ. 2004). Our results also suggest managing forests for Cerulean Warbler habitat may create habitat and improve conservation prospects for several additional species. Many of our results mirror findings from similar studies throughout the Cerulean Warbler’s range and agree with the general assumptions of Cerulean Warbler selection of microhabital characteristics, including large diameter trees, less dense understo¬ ry, and taller upper canopy (Lynch 1981 . Jones and Robertson 2001 , Wood et al. 2006). However, some 214 THE WILSON JOURNAL OF ORNITHOLOGY • Vol. 123, No. 2. June 2011 differences were evident as environmental cor tions near the edge of a species* distribution , vary from those within the core of its range (Law 1993, Brown et al. 1995). Over one-third of our plots (38.5%) were in i bottomlands, and Cerulean Warblers display* strong negative relation to increasing slope : aspect. Cerulean Warblers arc cited as inhabit! ndge tops throughout Appalachia, but this tre tioT,R Tard ,hC PeriPhcries of its distril t'on (Rosenberg ct al. 2000). The appart preference for floodplain forests in Abba, may be in response to extensive logging practices of the early 20th century in the Cumberland Mountains (Smalley 1984). which typically fo¬ cused activity along ridge tops and may have forced Cerulean Warblers to lower elevations (Hamel 2000a). However, all three populations were in highly dissected areas, and the surround¬ ing topography may still have an important role in a Cerulean Warbler's hierarchical process of selecting breeding habitat in Alabama. Canopy complexity has received considerable attention in Cerulean Warbler habitat studies Carpenter et al. • CERULEAN WARBLER MICROHABITAT ASSOCIATIONS 215 (Hamel 2000b, Jones and Robertson 2001, Jones et al. 2001. Hamel 2005). Our average Shannon- Weiner index for used plots was 0.72 i 0.01 (maximum 1.0) and indicates a moderately complex canopy structure. The disparity between our used and unused plots may be due to use of crude interval measurements which did not accurately distinguish finer complexities at a significance level of 0.1. This may also clarify why Cerulean Warbler presence was negatively related to canopy structure in our modeling. A more complex canopy structure at unused plots does not necessarily indicate an abundance of suitable habitat is available elsewhere in Alabama for Cerulean Warblers. The unused plots' lack of other microhabitat characteristics (e.g., high percent deciduous basal area and fewer but well¬ spaced, large diameter trees) identified as impor¬ tant to Cerulean Warblers will likely prevent these areas from supporting future populations, if current conditions persist. The importance of canopy gaps to Cerulean Warbler territory and nest site selection has been supported by some studies (Oliarnyk and Robert¬ son 19%. Nicholson 2004) and questioned by others (Jones et al. 2001, Hamel 2005, Barg et al. 2006b). Used plots had significantly larger canopy gaps compared to unused plots, and our top model indicated Cerulean Warbler presence increased as distance to a canopy gap decreased. Cerulean Warblers in our study may be exploiting these openings as supplemental foraging areas through¬ out the breeding season and during post-breeding dispersal (Blake and Hoppes 1986, Vilz and Rodewald 2006), and to increase vocal deliver¬ ance and recognition of neighboring conspecifics (Barg et al. 2006b). Cerulean Warblers may also be using openings <10 nf created by smaller snags, another variable present in our best supported model, which may be contributing to forest heterogeneity and canopy complexity (Oliarnyk and Robertson 1996, Wood et al. 2006; but see Barg et al. 2006b). Our ordination, however, contradicts these findings by disassoci¬ ating the principal component representing cano¬ py gaps with Cerulean Warblers. A plausible explanation is the cleared fields maintained within the heavily forested landscape of the Jackson County populations possibly influenced compari¬ son with the more fragmented landscape surround¬ ing unused locations (Carpenter 2007). The appro¬ priate size, quantity, and distribution of canopy gaps and other small-scale disturbances, as well as evidence of whether or not Cerulean Warblers are using them, remains unclear in Alabama. Our results help clarify the roles of avian species assemblages and vegetative characteristics in habitat used by Cerulean Warblers. This dynamic relationship is further complicated by resource availability, predation, competition with other organisms, and habitat alteration: none of which was accounted for in our study. Future Cerulean Warbler research in Alabama and elsewhere will benefit by addressing these issues in more detail. ACKNOWLEDGMENTS Funding for this project was provided by Alabama A&M University. Alabama Department of Conservation and Natural Resources. U.S. Forest Service, and U.S. Fish and Wildlife Service. We are grateful to E. C. Soehrcn. A. A. Lcsak, C. M. Kilgore, and L. M. Gardner-Barillas for field assistance: J. A. Cochran. T. U Counts, and G. M. Lein for logistical support: R. L. West and T. M. Haggerty for historic Cerulean Warbler records and Breeding Bird Atlas data: and W. B. Tadesse and K. E. Ward for suggestions that improved the thesis on which this study is based. This manuscript benefited greatly from comments provided by Jason Jones, C. E. Braun, and two anonymous reviewers. This project would have been impossible without the cooperation of many private landowners who granted access to their property. We especially thank the Cagle and Miller families, and the Stevenson Land Company. LITERATURE CITED ASKINS, R. A., .1. F. LYNCH, AND R. Greenburg. 1990. Population declines in migratory birds in eastern North America. Current Ornithology 7:1-57. Barg, J. J.. J. Jones, M. K. Girvan, and R. J. Robertson. 2006a. Within-pair interactions and parental behavior of Cerulean Warblers breeding in eastern Ontario. Wilson Journal of Ornithology 118:316-325. Barg. .1. J.. D. M. Aiama, J. Jones, and R. J. Robertson. 2006b. 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Biostatistical analysis. Fourth Edition. Prentice Hall. Upper Saddle River, New Jersey. USA. The Wilson Journal of Ornithology 123(2):2 18-228, 2011 COURTSHIP DISPLAYS AND NATURAL HISTORY OF SCINTILLANT ( SELASPHORUS SCINTILLA) AND VOLCANO (S. FLAMMULA) HUMMINGBIRDS CHRISTOPHER J. CLARK,1 ' TERESA J. FEO,' AND IGNACIO ESCALANTE' ABSTRACT. — The natural histories of Volcano (Selasphorus flammula) and Scintillant (5. scintilla) hummingbird' ,ir. poorly known. We describe aspects of their breeding behavior with emphasis on courtship displays and sounds that male- produced for females. Males of neither species sang undirected song. Males of both species produced a display dive, in which they ascended —25 ni in the air and then dove, swooping over the female. Both species produced a pulsed sound fe was synchronized with abrupt tail spreads during the bottom of the dive. The second rectrix (R2> of both species wi- capable of generating the same sound in a wind tunnel, suggesting these sounds were made by the tail. The dive sound." ! the Volcano Hummingbird were louder than those of the Scintillant Hummingbird. Male Scintillant Hummingbirds Produced a wing trill in (light, and performed a shuttle display to females in which the wing-beat frequency readied ~10() Ilz. Males held territories in open areas during the breeding season. Not all territories included abundant floral resources, and abundant resources in closed habitat were not defended. The role of resources is unclear in the breedin-i system ot these two species. Received 6 May 2010. Accepted l December 2010. The basic natural history of most Central and South American species is poorly known, com¬ pared to North American birds. For example, of the seven species in the hummingbird elude Selasphorus , courtship displays consisting of both dives and shuttle displays have been described for Allen's (S. sasin ) (Aldrich 1938. Mitchell 2000). Rutous {S. rujus) (Calder 1993. Hurly cl al. 2001 ), and Broad-tailed (S. phtycercus) (Calder and Calder 1992) hummingbirds, as well as Calliope Hummingbird (Stellula calliope) (Tamm el al. 1989, Calder and Calder 1994). which is phylo- genetically nested within Selasphorus (McGuire et al. 2007. 2009). These four species breed in the United States and Canada. In contrast, courtship displays lor Volcano (5. flammula) and Scintillant (5. scintilla) hummingbirds of Costa Rica are only known trom the brief descriptions by Stiles (1983). and are entirely unknown for the Glow- throated Hummingbird ( S . ardens) of Panama. Members of Selasphorus and the related genera ot Ca/ypte. Archilochus, and Mellisuga perform 900^ aTd spectacular ^unship dives (Clark 2006. Clark and Feo 2008. Fco and Clark 2010). Selasphorus and Archilochus also produce shuttle displays tor females (Banks and Johnson 1961 Hamilton 1965. Hurly et al. 2001. Feo and Clark Ec^oovb0m lFUTl,m °f Na,Ural Histor>- Apartment ol Box 20810b m T™7 Bi0l°^ Yalc University, P. o, box 208106. New Haven, CT 0651 I, USA. * Escuela dc Biologia. Universjdad de Costa Rica, Ciudad Umversnana Rodrigo Facie. 2060 San Jose, Costa Rica Corresponding author; e-mail; christopher.clark ©'yale.edu 2010). The sounds produced during these displays are either vocal (Clark 2006). or mechanically produced with their wings and/or tail (Clark and Feo 2008, 2010; Fco and Clark 2010). Male Scintillant and Volcano hummingbirds have emarginated inner rectrices (Fig. 1) that may function to produce sound during displays (Stiles 1983), and male Scintillant have an emarginated PIO that may produce a wing trill (Stiles 1983) Our objectives in this paper are to: ( I ) describe the courtship displays and sounds of Volcano and Scintillant hummingbirds, and (2) provide natural history observations of their breeding biology. METHODS The Volcano Hummingbird presently has three recognized subspecies: S.f flammula, S.f. torridns. and S. f simoni (Stiles 1983). Most of our field work on this species was conducted on S.f torndus in open fields and pasture surrounded by oak (Querais spp.) forest near Estacion Biologica Cueri- cf (09' 33’ I 1.90" N, 83 40’ 18.37" W: 2,600 nt asl) and in Buenavista paramo habitat near km 89 on the Pan-American highway, east of San Jose (09 33' 20.48" N. 83 45' 1 8.63" W; 3.450 m asl). in the Cerro de la Mueite, Talamanca Mountains. San Jose Province. Costa Rica. We made additional observations and one sound recording of S. J- flammula on the summit of V’olcan Irazu. Cartage Province (09 58* 34.78" N, 83 50' 57.63" W: 3,340 m asl) on 22 October 2009. We made observations of S. scintilla and S. f. torndus at the Quetzal Education and Research Center (QERC) in San Gerardo de Dota (09 33' 1.55"N, 218 Clark el al. • SCINTILLANT AND VOLCANO HUMMINGBIRD COURTSHIP 219 Male S- flammu'a torridus Male S. scintilla FIG. I . Male Scintillant (Selasphorus scintilla) and Volcano (S. flammula torridus) hummingbirds with rectrices labeled R1-R5. R1 and R2 are emarginatcd in males (arrows). Emargination is more pronounced in the Volcano Hummingbird. Photographs courtesy Anad Varma. 83 48' 26.01" W; 2,200 m asl), San Jose Province. All observations occurred between 12 and 22 October 2009. We obtained high-speed videos of hovering and displaying hummingbirds with a hand-held mono¬ chrome high-speed camera (MIRO EX4, Vision Research. Wayne. NJ, USA) recording at 500 fps with a resolution of 800 X 600 pixels. We obtained sound recordings using a shotgun microphone (Sennheiscr MKH70, Wedemark- Wennebostel, Germany) attached to a 24-bil recorder (Sound Devices 702. Reedsburg, WI, USA), sampling al 48 kHz. Recordings were imported into Raven 1.3 (www.birds.corncll.edu/ raven) and converted into spectrograms using a 512-sample window (Hann function. 50% over¬ lap), except where otherwise indicated. Acoustic frequencies and temporal rates presented repre¬ sent the frequencies recorded by the microphone and were not corrected for Doppler shift caused by the birds" velocity. We captured hummingbirds with either mist nets (24-mm mesh) or feeder-traps. Some record¬ ed sounds were natural, and the remainder were elicited by placing a live female in a cage on a male's territory, or by releasing a recently- captured female onto a homospecific male’s territory. Volcano females were released on a male Scintillant’s territory a few times, due to a scarcity of Scintillant females, but failed to elicit a response. We collected tail feathers for laboratory experiments, and we opportunistically obtained dive recordings from one male Volcano Hum¬ mingbird both before and after plucking his entire tail. More extensive manipulations of wild birds (as in Clark and Feo 2008. 2010; Fen and Clark 2010) were unfeasible as these experiments typically take a few weeks. Tail feathers from each species were tested in a wind tunnel to ascertain if they were capable of producing sounds similar to the dive sound. This tunnel will be described in a future publication. All measures are mean ± SD. Specimens associated with this research have been deposited in the Peabody Museum. Yale University. Sound recordings have been deposited in the Museum of Vertebrate Zoology, University of California. Berkeley. USA (accession # 14752), and videos have been deposited in the Macaulay Library (accession #'s ML65124 to ML65144), Cornell University, Ithaca, New York, USA. RESULTS Volcano Hummingbird Breeding and Territorial Behavior— We saw females gathering nesting material and located two active nests with females incubating eggs at Cuerici on 15 October 2009. indicating breeding 220 THE WILSON JOURNAL OF ORNITHOLOGY • Vol. 123. No. 2. June 2011 was underway at this locality. Neither nest appeared to be on a male territory. Males at Cuerici held densely packed territories in open shrubby pastures full of cultivated blackberry ( Rubus spp.). near remnants of oak ( Quenus spp.) forest. No territories were found in closed canopy forest, although both males and females visited flowers in these areas. Males at the paramo site held small territories at the crest of a hill. Territories were small with perches of males being within a 15 X 15 m area, and central perches of neighboring territories as close as 20 m. They were tightly packed as compared to related species (CJC, pers. obs.). The males perched in 3- 10 prominent locations, such as power lines, tips of dead twigs protruding from the side of a lone tree, or the tip of the tallest cane within a bramble patch while on territory. Perches were I to 15 m from the ground, and tended to be in sunny locations. Males at times moved to shaded perches in rare periods of prolonged sun and elevated temperatures. Most interactions we observed on the territories were between males. Intruding males would frequently fly onto another's territory. The owner would leave his perch and chase the intruder. The chase would often, due to the tight packing of territories, immediately encroach on a neighboring territory, and that bird would join the chase as well; •f the chase then entered yet another male's airspace, he too would join the fray. The greatest number of birds we observed in such a chase was tour, accompanied by a tremendous twittering Males seemed most active on their territories when it was sunny, and arrived on their territories within alf an hour of sunrise. In contrast, they departed their territories up to 2 hrs before sundown. All territories had at least a few plants in flower from which we saw the birds feed. The males were seen visiting Fuchsia paniculata . cultivated Kubus spp.. Comarostaphylis arhutoides . and the tiny flowers of F. mien, phytic / on their territories oh T- h malcs und fema|cs were also bserved visitmg a dense patch of undefended fZ \°Z8T Spp- in lhe understo>'y of nearby oak defended fes fema,CS al San Ge™rdo both efended territories around small dense patches of flowering F. paniculata with both attacking other onfoZZ I' a\WC" " * scintilla intruded (2 200 m T ^ femalCS at San G<*ardo U,200 m us I ) were not observed engaging in anv g S' n=r°U,d mdiC:'K br^‘»g -h as garnering nesting material. Vocalizations. — Males uttered a ‘descending call (Fig. 2A) as well as a twittering ‘scolding call (Fig. 2B) in agonistic interactions with other Volcano Hummingbirds. The calls produced were directed towards another individual; we did " observe undirected vocalizations (i.e.. songs) from males on their territories. The descending call was also occasionally emitted towards (caged) fe¬ males. It consisted of a single tone that started ai 9.9 ± 0.41 kHz, and descended to 6.8 t 1.4 kHz over the course of 1.9 ± 0.6 sec (n = 18 calls from 7 males). Display Dives. — Males were frequently ob¬ served performing display dives throughout the day. Two of the males we observed would dive at a variety of passerine birds, if they perched prominently on the male’s territory, as well as at other hummingbirds. Most males did not seem to be so indiscriminate, and were only observed diving to other Volcano Hummingbirds. It was often not possible to ascertain the gender of the recipient of the display. It was easy to elicit dives Irotn male Volcano hummingbirds by placing a caged female on the male's territories, lhe majority of males responded to this stimulus by performing at least one dive. We obtained sound recordings of 87 dives from 13 males. The dive sound consisted of two sounds; a frequency-modulated (FM) tone and a series of sound pulses (Fig. 2C). Males began producing the FM tone early in the dive, which at its initial frequency was 4.07 ± 0.21 kHz In = 85). and it remained nearly constant pile*1 (acoustic frequency) for 0.43 ± 0.17 sec. It was then modulated up to 5.80 ± 0.34 kHz (n = S'1 over the course of 0.05 sec, then gradually descended in pitch to a final frequency ol 4.97 — 0-31 kHz. The entire sound lasted 0.92 - 0.20 sec (/i = 85), and a harmonic was present in 85 of 87 dives. The FM tone was clearly not produced by the tail, for one male lacking his tail still produced this sound when diving (Fig. 2E1- The dive sound also included 2-5 pulses of sound (indicated by p in Fig. 2C). These pulses were produced at the bottom of the display, as the male flew over the target of the display (Fig. 2C). and lasted 17 ± II ms (n = 76). The pulses were produced 46 ± 9 ms (n = 73) apart; the overall rate at which these pulses were produced was 15.2 ± 1 -2 Hz (;i = 76). Each pulse consisted of a broad-frequency swath of sound reaching up to ~ 12 kHz. A low fundamental frequency (0.82 ± 0.29 kHz, 66 Clark el al. • SCINTILLANT AND VOLCANO HUMMINGBIRD COURTSHIP 221 N X Seconds FIG. 2. Spectrograms of sounds produced t>y the Volcano Hummingbird. (A): descending call. (B): scolding call. (C): typical dive sound consisted of both the frequency modulated tone (FM) and low frequency sound pulses (p) with harmonic stack. Arrow indicates dominant frequency. (D): sound produced by a Volcano R2 in a wind tunnel set to 20 m/sec (left), and (right) tunnel control sound with same settings but no feather. Scintillant R2 produces essentially the same sound, but quieter. Spectrogram generated with a 2,048 sample window. (E): dive sound from a male missing his tail. The FM tone is present whereas the sound pulses are missing. dives from 12 males; arrow in Fig. 2C) was present in 66 of 76 recordings. The sound appeared as a stack of many closely-spaced harmonic frequencies when analyzed using a spectrogram bin size of 2.048 samples (3 dB filter bandwith: 34 Hz). The absence of the low frequency tone in 10 of the recordings may have been due to recording quality, such as recordings obtained further from the bird. Dive Kinematics. — A male Volcano Humming¬ bird began a dive by ascending steeply with a slightly undulating trajectory (Fig. 3A). After rising —25-30 m. he would turn and immediately dive, following a J or L-shaped path. After leveling out at the bottom of the dive, the male would use the accumulated speed to fly in a random direction, curving to the left or right, or up. If he performed a second dive, the male would 222 THE WILSON JOURNAL OF ORNITHOLOGY • Vol. 123. No. 2. June 2011 FIG. 3. Kinematics of display dive of the Volcano Hummingbird. (A): sketch of the dive with stages 1-3 labeled. r* f°ll0Wed.lhe same Rectory as the first dive. (B) and (C): composite images of diving birds fromhigh- VT8!5 oCCUrred 0 02 SCC apar1‘ B,rd P,acemem is approximate in both images, because the glided* nT,t T , , (B): eady in 'he dive in which ,he bird tapped its wings as it entered the frame ( 1 .). then mulfiple t mese(-SPre ) ^ -> JUS‘ “ * the frame' (C,: the bo,lom of lhe div^ i" which the male spreads his tail re-ascend to the same starting position, and follow the same trajectory as the first dive, except for the variable ending (Fig. 3A). As a result, in consec¬ utive dives the male passed over the recipient from the same direction. The direction of the dives did not seem to be specifically oriented towards the sun or another environmental feature that we could identify. We obtained high-speed videos of parts of 15 dives, from seven different males. No single video showed the entire kinematic sequence of the dive We identified stereotypical stages that appeared to e present m all of the dives by comparing the different videos. Each video was unique, thus samp e sizes for each kinematic stage vary. Males descended in stage I (Fig. 3B) on flapping wings cd-H a8 V!deOS)‘ They then ceased tapping and glided with tail shut (stage 2) for 0.17 ± 0.07 sec (n - 4 videos), before repeatedly spreading and Fig 3ri' ^eh,iUl?h,le com*nuing to glide (stage 3; rig. JL). The tail was spread for 42 ± 9 msec (n = moreP7hadS) and‘ Fr°m SCVCn videos that showed more han one spread, the tail-spread frequency <*e -ate at wh'd, the tail was spread and shut) was soundm |1 f Wh’Ch WaS 0Ot different the sound pulse frequency (f-test, P = 0.31). Male Volcano Hummingbirds during the dive had a wing-beat frequency of 58 ± 1.1 Hz (fl -5 high speed videos from 2 males). A caged male had a wing-beat frequency of 66.7 Hz. while a male hovering in the wild had a wing-bo*1 frequency of 46.9 Hz; thus, the dive wing-beat frequency is within the range observed for hovering birds. Two caged females had ahovenng wing-beat frequency of 42.7 ± 0.52 Hz. The wings did not make an audible wing trill during flight, and we did not observe any displays similar to the shuttle display of other Selasphorus. We observed one or two male 5. f flamnutla perform about four dives on 2 1 October 2009. on the summit of Volcdn Irazu, of which we obtained a sound recording from one individual. We did not detect dramatic differences in the dive trajectory trom the kinematics described for S.J- torridus (Fig. 2), nor did we detect notable differences in the dive sound. Scintillant Hummingbird Breeding and Territorial Behavior.— We heard the wing trill of Scintillant Hummingbirds near food plants at Cuerici (2,600 m asl), and one male was collected at this location. We did not make Clark et al. • SCINTILLANT AND VOLCANO HUMMINGBIRD COURTSHIP 223 any behavioral observations of this species at Cuerici. and found no evidence of breeding at this location. Scintillant Hummingbirds were breeding at San Gerardo (2.200 m asl). We observed females gathering nesting material and a female incubat¬ ing a nest in a low bush on 1 3 October 2009. The nest did not appear to be on or near a male territory. Males held territories in open areas such as the edge of an apple (Mai us spp.) orchard, in a dense stand of blooming Fuchisia paniculata. or in short trees flanking a parking lot. All territories were in open areas, and males perched in 3-5 prominent locations between 2 and 15 m above the ground, on objects such as power lines, tips of dead twigs protruding from a large tree, on the tops of banana (Musa spp.) leaves, or the upper-most branches of a heavily blooming Fuchsia. All male territories contained at least a few plants in flower, and one included a hummingbird feeder. The size of a territory varied depending on the amount of available food. Three males held densely-packed territories in a thick patch of blooming F. paniculata with all of the male’s perches in a roughly 10 x 10 m area. These territories were also immediately adjacent to feeding territories held by both male and female Volcano Hummingbirds. Four territories found elsewhere, in areas with fewer natural food resources and fewer neighboring territories, were roughly 25 X 25 m in extent. Natural dives were performed to female Scintillant Hummingbirds, or to hummingbirds of unknown gender. A female Scintillant repeat¬ edly visited flowers on a male's territory during a set of natural observations spanning ~5 min. The male performed two sets of three dives to the female, and spent the rest of the time watching her while occasionally producing a type a call, or chasing her. Male Scintillant and both male and female Volcano hummingbirds that entered the males' territories were scolded and chased. In general, the behavior of the territorial males seemed similar to that of male Rufous and Allen's hummingbirds, in terms of activity, vocalizations, and tendency to engage in aggressive interactions with other hummingbirds (CJC, pers. obs.). Vocalizations. — Males did not sing undirected song from their perches. They did produce at least three types of calls, two of which are labeled a and b (Fig. 4A). A third, apparently agonistic (scolding) call was produced, often while perched. and sounded similar to a call produced by Allen’s and Rufous hummingbirds. We did not obtain a clear recording of this call. Both males and females at times produced call a in the apparent absence of other hummingbirds, while the other two calls seemed to be produced only in agonistic interactions. Wing Sounds and Shuttle Display.— Male Scintillant Hummingbirds produced a distinctive wing trill during flight (acoustic frequency: 9 kHz; Fig. 4B) that sounded nearly identical to the wing trill of Allen’s and Rufous hummingbirds. Males also produced a shuttle display characterized by distinctive sounds and flight kinematics similar to the shuttle displays performed by Allen’s and Rufous hummingbirds. The shuttle displays had two variants, 'stationary' and 'traveling’. A male repeatedly approached a female in a cage and then produced a stationary shuttle, in which he flew back-and-forth while producing the sound. This variant was also heard emanating from inside of a bush into which a male had pursued an uniden¬ tified hummingbird. In the second variant, males (n = 2) that spotted a female crossing their territory would leave their perch and pursue the female, but not at their top speed. In this traveling shuttle, as they followed the female, the males would occasionally produce the shuttle display sound, visually appearing to decrease their forward flight speed and change their wing beat kinematics as they did so. We obtained five sound recordings from two males performing the shuttle display (Fig. 4D). Males produced similar sounds during the travel¬ ing and stationary variants of the shuttle display. The shuttle display sounds consisted of repeated sounds that appeared in alternating duplets. One pair of sounds matched the acoustic form of the male’s wing trill (i.e., sound pulses with a mean acoustic frequency of 9.4 ± 0.43 kHz and a frequency bandwith of 1.87 ± 0.28 kHz; n = 5; labeled w in Fig. 4D). The alternate duplet ( s in Fig. 4D) was a broad-band sound without a single discrete frequency. The trill rate was 93.8 ± 5.1 Hz ( /? = 5). High-speed videos of four shuttle displays from one male were recorded. The male was partially obscured behind other objects or, at times, out of frame throughout most of the videos, and sample sizes of specific events vary. The male flapped his wings at 98.1 ± 2.64 Hz (n = 4 displays) during the shuttle display, while rhythmically moving his body. We term each repeated, rhythmic move- 224 THE WILSON JOURNAL OF ORNITHOLOGY • Vol. 123, No. 2. June 2011 \ \m Seconds SpfCtr0g,rams of sounds produced by Scintillant Hummingbirds. (A): two types of vocalizations, a and b. Wing conci«L°ir,?e 'S also.Presenl- ,B); wir>g trill ("') produced by aduli males. A faint harmonic is present. (C): dive sound . . he Wmg tn (vv)' an add,t,°nal trill (T2), a harmonic of the additional trill, and a sound pulse ( p ). At least four stadon^Th,,^ TTL Thefpuls,es.are produced at the bot,om Of the dive, as the male passes over the female. (DC a wine trih tv » f, ,SP dy l° a.fe7la,e m a cage< wh,ch consis,ed of alternating duplets of sounds. One duplet comprises the wing trill (w). alternating with duplets of sound a that are broadband. ment an individual ‘shuttle motion'. Twice, tht stationary shuttle display was performed to i female in a cage: with gorget flared, the malt shuttled from side to side (laterally) in front of tht cage, over a horizontal distance of ~20 cm. Tht male would abruptly roll his body (i.e.. rotate around his longitudinal axis) while arresting his lateral motion at the end of each shuttle, flap his wings with asymmetrical motions, and sweep his tail sideways through a range of angles. The wing' did not appear to strike each other or anythin* else, during these motions. The other two high-speed videos were of the traveling shuttle display. Unlike the stationary shuttle, in which the male tended to fly side-to- side OateraHy ) repeatedly through the same space, during the traveling shuttle, the male was continually flying forward towards the fenu*Ie with little lateral motion. During this forward flight the male engaged in periodic body rotation-'*- tail rotations, and asymetrical wing kinematics similar to the stationary shuttle display (Fig 5AI- Shortly after finishing one shuttle motion, the bird would start another, rotating its body and tail in the opposite direction from the previous. The total time spent rotating the tail was 73 ± 9 msec In = 5 shuttles from 2 videos); the liming between shuttle motions was 55 ± 13 msec (n = 2 intervals). Therefore, the rate at which shuttle motions were performed was 7.8 Hz. No compo¬ nent of the shuttle sound was produced at a rale of 7.8 Hz. and this striking visual component of the display kinematics did not appear to correspond to production of a single particular sound. Clark et al. • SCINTILLANT AND VOLCANO HUMMINGBIRD COURTSHIP 225 A 7 » ” ^ ,