L I B RARY OF THE U N IVERSITY or ILLINOIS 5S0.5 PI V.3L Cop.O miUii\ SURVET NATUf^ HISTORY SURVEY I l3 FIELDIANA • ZOOLOGY Published by CHICAGO NATURAL HISTORY MUSEUM Volume 31 November 29, 1950 No. 40 REPORT ON A COLLECTION OF BIRDS FROM OAXACA, MEXICO Emmet R. Blake Associate Curator, Division of Birds The following paper is based on a collection of 542 specimens made in the vicinity of Tutla, Oaxaca, by Mario del Toro Aviles in February, March and April, 1941. Studies by contemporary ornithologists in selected approaches to the Isthmus of Tehuantepec have added much to our knowledge of the avifauna of southern Mexico but even so only the bare outlines have thus far been traced. The solution of many problems of dis- tribution, and a better understanding of faunal relationships in so complex an area, require the continued accumulation and publication of data comparable to that which has long been available elsewhere in the form of local lists or studies of speciiic collections. In Oaxaca, as in many other Mexican states, surprisingly few additions have been made to the records that were assembled by Ridgway. Innumerable birds, including many common migrants, are as yet unrecorded in these areas, although known in adjacent states. The details of distribution, local status, and population trends, as well as the areas of intergradation and, consequently, most fields of special interest to the taxonomist and zoogeographer, are largely unknown in Oaxaca except as they may be inferred from studies made elsewhere. One of the first and certainly the most important contribution to the ornithology of Oaxaca was published by Bangs and Peters in 1928. Their annotated list of 131 forms, collected by W. W. Brown in the vicinity of Chivela and Tapanatepec, included a number of birds not previously recorded in the state and presented consider- able data regarding the local distribution and relationships of others. During the past two decades there have been numerous references to Oaxaca birds in connection with studies of special groups, but there is a dearth of specific locality records supplementing those ^'°- 654 395 ,Ht UBRm Of THE DEC i 2 1950 . . .J^.'i l»MJVWHj|TY Of IIUNOIS 396 FIELDIANA: ZOOLOGY, VOLUME 31 of earlier date. In brief, our knowledge of the distribution of birds in Oaxaca is still vague, most species being represented by fewer than half a dozen records. It is not surprising that the majority (126) of the 157 forms treated in the present paper are additions to the Bangs and Peters list. Factors contributing most strongly to this high percentage of additions may be found in the geographical position of Tutla, Chivela, and Tapanatepec, and in their diverse faunistic affinities. Tutla has an avifauna most closely associated with that of lowland Vera Cruz and of Caribbean Guatemala, whereas Chivela (in a small measure) and particularly Tapanatepec, are allied to the distinct Pacific coast fauna. The 257 forms in the combined collections from these localities represent a partial cross section of Oaxaca's avifauna. Since con- siderably less than a hundred other birds have been recorded else- where in the state, it is evident that the total list is far from complete. Indicative of the need for further field work in Oaxaca — and publication of additional records that may now be submerged in various general collections — is the fact that 34 of the forms listed herein appear to constitute new records for the state. Twenty-four of these are residents, for the most part well known in adjacent areas, and the remaining ten are North American migrants. An asterisk (*) indicates the apparently new records for Oaxaca. Few elements characteristic of the Mexican Plateau, an area strongly influenced by the Temperate Zone, extend into Oaxaca. As might be expected, the fauna of southern Mexico is predominantly Central American in origin, but it also includes numerous species that are even better represented in South America. A distributional survey of the 121 resident species and subspecies in the present collection emphasizes the pronounced tropical affinities of most Oaxaca birds and reflects the extent of continuity in the avifauna of Central America and southern Mexico, as distinct from that to the northward. Of the 121 non-migratory birds listed below, only the following eight forms occupy an extensive range both in Mexico and in Central America. The distribution of each is modifled or limited by various ecological requirements, but for present purposes all may be regarded as common to both areas. Odontriorchis palliahis Speotyto cunicularia hypugaea Oreopeleia monlana montana Campylopterus hemileucurus Piaya cayana thermophila Iridoprocne albilinea albilinea Glaiicidium brasilianum ridgwayi Turdus grayi grayi i 70. V. '^1 7. V BLAKE: BIRDS FROM OAXACA, MEXICO 397 Only four birds (Columba f. flavirostris, Nyctidromiis a. yucatanen- sis, Chloroceryle americana septentrionalis and Myiarchus tyrannulus nelsoni) occupy an extended latitudinal range in Mexico, and occur southward only to northern Central America. Each of these, except Nydidromus albicollis, is represented in western Mexico by a distinct subspecies, but the basic pattern of distribution remains the same. The comparative isolation of the southern Mexican avifauna from that of the country at large is further indicated by the absence of any species (in this collection) that has wide distribution in Mexico but ranges southward only to Oaxaca. On the other hand, the preponderance of characteristically Central American birds that occur in, but not beyond, southern Mexico is noteworthy even in the present.small collection. Although only four birds (Amaurolimnas concolor castaneus, Amazilia c. Candida, Rhytipterna h. holerythra and Turdus assimilis leucauchen) of exten- sive distribution in Central America range northward only to Oaxaca, no less than 58 others occur elsewhere in, but not beyond, southern Mexico. Of the 58 Central American birds thus limited in north- ward distribution, 39 do not occur beyond southern Vera Cruz. The affinity between birds of southern Mexico and northern Central America is, of course, particularly strong. Thirty-eight of the residents collected at Tutla fall within these geographical limits and indicate the relatively homogeneous character of the bird life in this area. Southern Mexico supports proportionally a lesser number of endemic birds, of which the following were taken at Tutla. Ortalis vetula vetula Thryothorus rutilus maculipectus Colinus virginianus thayeri Nannorchilus leucogaster musicus Ar amides cajanea mexicana Granatellus sallaei sallaei Phaethornis superciliosus veraecrucis Sturnella magna mexicana Phaelhornis longuemareus adolphi Saliator maximus gigantodes Campylopterus curvipennis curvipennis Arremonops rufivirgatiis crassirostris As previously mentioned, the present collection represents an area that is little differentiated from that of the Vera Cruz lowlands, although the Yucatan influence is even less pronounced than in the latter. Only one (Leptotila verreauxi fulviventris) of the twelve characteristic Yucatan forms listed by Brodkorb (1943, p. 17) as occurring in the Tabascan Faunal District also occurs at Tutla. The pronounced Tropical Zone character of the birds from this locality is relieved by only four subtropical or highland representa- tives (Otus g. guatemalae, Campylopterus rufus, C. hemileucurus and Trogon collaris puella). 398 FIELDIANA: ZOOLOGY, VOLUME 31 Fundamental ecological differences between the Caribbean and Pacific coastal areas of Mexico and northern Central America have been discussed elsewhere and require no repetition here. Each has developed a characteristic fauna that, in Oaxaca, most nearly meets in the Isthmus of Tehuantepec, where no important topographical barrier separates the Pacific lowlands from the drainage of the Rio Coatzacoalcos. In the present collection twelve birds charac- teristic of the Caribbean lowlands are replaced on the Pacific side of Oaxaca by one or more other races as shown below. Caribbean Form Ortalis vetula vetula Colinus virginianus thayeri Leptotila verreauxi fulviventris Piaya cayana thermophila Phaethornis superciliosus veraecrucis Trogon citreolus melanocephala Pitangns sulphuratus guatimalensis Myiarchus tyrannuliis nelsoni Myiarchus tuberculifer lawrenceii Habia rubica rubicoides Sporophila torqueola morelleti Arremonops rufivirgatus crassirostris Pacific Form Ortalis vetula poliocephala Colinus virginianus atriceps Colinus virginianus coyolcos Leptotila verreauxi angelica Piaya cayana mexicana Phaethornis superciliosus mexicanus Trogon citreolus citreolus Trogon citreolus sumichrasti Pitangus sulphuratus derbianus Myiarchus tyrannulus magister Myiarchus tuberculifer querulus Habia rubica affinis Sporophila torqueola torqueola Arremonops rufivirgatus sumichrasti I am indebted to the late Boardman Conover, Research Associate in the Division of Birds, Chicago Natural History Museum, for permission to include the Tutla game birds of his collection in the present paper, and to Dr. A. L. Rand, Curator, and Mr. Melvin A. Traylor, Research Associate, for helpful suggestions. SYSTEMATIC LIST Tinamus major robustus Sclater and Salvin 2 males, 3 females, February 25-April 16. Crypturellus soui meserythrus P. L. Sclater 3 males, March 16-April 29. Crypturellus boucardi boucardi P. L. Sclater 4 males, 4 females, March 6-April 24. Odontriorchis palliatus Temminck 1 male, February 3. BLAKE: BIRDS FROM OAXACA, MEXICO 399 Accipiter striatus velox Wilson 1 male, March 1. Spizaetus ornatus vicarius Friedmann 1 male, April 20. Crax rubra rubra Linnaeus 1 male, 3 females, March 5-April 8. Penelope purpurascens purpurascens Wagler 1 male, 2 females, March 10-April 12. Ortalis vetula vetula Wagler 2 males, 3 females, February 3-April 16. The southern and western lowlands of Oaxaca are occupied by the Pacific coast race, poliocephala, which ranges into the interior of the isthmus as far as El Barrio. Colinus virginianus thayeri Bangs and Peters 1 male, April 30. Thayer's bob white appears to be limited to Oaxaca where it has been recorded previously only at Chivela. The distribution in Oaxaca of two Pacific coast races is imperfectly known. Amaurolimnas concolor castaneus Pucheran 2 males, 1 female, February 26-April 29. Tutla specimens represent the only Mexican records of this crake. There are few other examples of birds occupying an extensive area south of the Amazon and ranging northward only to the Isthmus of Tehuantepec. Aramides cajanea mexicana Bangs 4 males, March 15- April 25. Laterallus ruber tatnaulipensis Nelson 3 males, 1 female, March 28-April 17. *Heliornis fulica Boddaert 1 female, April 19. Sun-grebes range southward in suitable habitat from southern Vera Cruz, but I find no previous record for Oaxaca. 400 FIELDIANA: ZOOLOGY, VOLUME 31 Columba flavirostris flavirostris Wagler 3 females, April 8-19. Leptotila verreauxi fulviventris Lawrence 2 males, 1 female, February 1-22. Other Oaxaca records of the white-fronted dove (Amloloya, San Juan, Tehuantepec) apply to the more northern race, angelica. Leptotila plumbeiceps plumbeiceps Sclater and Salvin 2 males, February 3, 24. *Oreopeleia montana montana Linnaeus 1 male, 1 female, March 3, April 21. Pionus senilis senilis Spix 1 male, February 14. The white-crowned parrot is characteristic of numerous essentially Central American species that are represented in the lowlands of southeastern Mexico and Guatemala by a distinct race. Coccyzus erythropthalmus Wilson 2 males, 2 females, March 8-April 23. Coccyzus americanus subsp. 2 males, 2 females, February 11-April 11. Subspecific determination of these specimens is uncertain, since their measurements (Males: wing, 141, 142; tail, 137, 147. Females: wing, 144, 149; tail, 131, 147) apply equally well to the nominate race and to occidentalis. Both races winter south of Mexico and each has been recorded in Oaxaca during migration. Piaya cayana thermophila P. L. Sclater 2 males, 1 female, February 26-April 6. A very distinct race, mexicana Swainson, also occurs in Oaxaca, but it is restricted to the Pacific side. Both forms are recorded for Tehuantepec, but Ridgway's references (1916, pp. 49 and 52) are misleading in that Tehuantepec (the city) evidently applies solely to mexicana. BLAKE: BIRDS FROM OAXACA, MEXICO 401 Otus guatemalae guatemalae Sharpe 1 female, 1 male, February 27, March 7. These specimens are, respectively, in brown and semi-rufous plumage. The tail of each is less than half the length of its wing, but they agree with the nominate race otherwise and introduce a subtropical element into a fauna that is predominantly tropical. Glaucidium brasilianum ridgwayi Sharpe 1 male, March 7. Speotyto cunicularia hypugaea Bonaparte 1 male, March 26. Nyctidromus albicollis yucatanensis Nelson 6 males, 2 females, February 1-April 29. Measurements of the present series (Wing: male, 163-172; female, 155, 162. Tail: male, 147-164; female, 133, 145), as well as contradictory data published by various investigators, emphasize the absence in yucatanensis of any size differential having geo- graphical significance. Tutla specimens agree equally well in color with a fresh series of skins from Campeche and Yucatan, and I find in the latter no evidence of the paleness that has been remarked by some authors. Caprimulgus maculicaudus Lawrence 6 males, 4 females, January 1-April 22, Direct comparison of this series with 31 South American ex- amples of the species, including the type of romainei, fully establishes the monotypic status of maculicaudus. The most rufescent of the Oaxaca specimens is practically indistinguishable from the type of maculicaudus itself, and all other skins in the Mexican series can be matched individually by specimens from Colombia, Bolivia, French Guiana and Brazil (Pard, Arumanduba, Humaythd). The migratory status of this rare species is not known with certainty, but available data indicate that it is relatively sedentary. Three birds from Pard, the most southern locality for which I find specific dates, were collected April 29 and 30. Other widely scattered South American records were made in August, September, October, December and February, so there is little doubt that the Tutla specimens represent an isolated population. 402 FIELDIANA: ZOOLOGY, VOLUME 31 Discovery of an undifferentiated and apparently isolated popula- tion of maculicaudus in southern Mexico, approximately 1,000 miles north of its known range, is one of the most surprising additions to the avifauna of Mexico in recent years. A detailed discussion of these birds, and their relationship to the South American population, has been published elsewhere (Blake, 1949). Phaethornis superciliosus veraecrucis Ridgway 9 males, 6 females, February 11-April 20. The Vera Cruz hermit ranges eastward into Chiapas where it intergrades with longirostris in the vicinity of Tuxtla (Gutierrez). A female from El Ocote, Chiapas, has all of the characters of verae- crucis, whereas a male of the same locality and date is intermediate, or perhaps more closely related to longirostris. Western Oaxaca (Pluma) and Guerrero are occupied by mexicana, which is distin- guished from the Vera Cruz hermit by its larger size and darker under parts. Phaethornis longuemareus adolphi Gould 6 males, 6 females, March 5-April 30. Griscom (1932, p. 197) has commented upon the similarity be- tween fresh specimens of adolphi and old skins of saturatus. Males of the present series average somewhat darker below than the females and in duskiness of chin and upper throat are indistinguish- able from Guatemala, Nicaragua and Costa Rica examples of saturatus collected several decades earlier. Campylopterus curvipennis curvipennis Lichtenstein 1 male, April 14. ♦Campylopterus rufus Lesson 1 female, 1 male, February 2, 3. The rufous sabre-wing was previously known only from the mountains of western Chiapas, Guatemala and El Salvador. Its occurrence in northeastern Oaxaca introduces an unexpected high- land element into a fauna that is predominantly tropical. Campylopterus hemileucurus Lichtenstein 7 males, February 4-23. BLAKE: BIRDS FROM OAXACA, MEXICO 403 Measurements of Mexican and Central American specimens in Chicago Museum corroborate the conclusions of Berlioz (1931, p. 87), with whom I agree in regarding hemileucurus as a monotypic species. The species is generally regarded as essentially a subtropical form, but there is now less certainty of its zonal affinities. Todd (1942, p. 289) has theorized, on the basis of July and August records from Manatee Lagoon, British Honduras, that its visits to lower altitudes are only occasional. However, hemileucurus has also been collected in the rain forest below 2,000 feet on the Cockscomb Mountains in spring, and the present winter series further weakens the concept that it is normally limited to the Subtropical Zone. Florisuga mellivora mellivora Linnaeus 11 males, February 1-April 14. Amazilia Candida Candida Bourcier and Mulsant 2 males, 4 females, March 24-April 16. Data thus far presented fail to establish the validity of a distinct form in Vera Cruz, Puebla and Oaxaca. The northern race (genini) was separated primarily on the basis of its supposedly larger size, but comparative measurements published by Meise (1938, pp. 2-3) are inconclusive in admitting extensive overlap with Candida. The Oaxaca specimens listed above are indistinguishable from the nomi- nate race, their measurements (Male: wing, 52, 54; culmen, 15, 17. Female: wing, 50, 51, 52, 54; culmen, 18, 18, 17, 19) being duplicated by birds from Yucatan, Campeche, Chiapas and Guatemala. Amazilia tzactl tzactl De La Llave 10 males, 8 females, March 4-April 10. Trogon massena massena Gould 10 males, 4 females, February 7-April 28. Trogon citreolus melanocephala Gould 2 males, 2 females, February 21-April 18. Tutla specimens agree in every respect with the common form of the Gulf lowlands. The species is further represented in Oaxaca on the Pacific side by two closely related races which accentuate the more continuous and homogeneous nature of the eastern slope. 404 FIELDIANA: ZOOLOGY, VOLUME 31 Trogon collaris puella Gould 3 males, 2 females, March 7-April 17. Trogon violaceus braccatus Cabanis and Heine 3 males, 1 female, February 2-April 27. Chloroceryle americana septentrionalis Sharpe 2 females, April 3, 4. Chloroceryle aenea stictoptera Ridgway 4 males, February 10-April 4. *Hyloinanes momotula momotula Lichtenstein 3 males, 3 females, March 4-April 26. Tutla specimens agree with the nominate race in size of bill and differ from chiapensis Brodkorb in being generously washed with bluish on the under parts and flanks. A bird collected in Alta Vera Paz, Guatemala (momotula) in 1861 has very buffy forebreast and flanks, with a corresponding decrease of bluish wash that I judge to be a result of age. Momotus momota goldmani Nelson 2 males, 2 females, February 14-March 13. This series is not altogether characteristic of goldmani, but appears to be intermediate to lessonii of Chiapas and Central America. This relationship is expressed by the more or less distinct violet-blue posterior margin of the nuchal crescent in Tutla birds, and by the pronounced tawny wash on their under parts. In the latter respect one male (C.N.H.M. No. 119558) exceeds the average intensity of color in lessonii, and the hind neck is tawny olive-green rather than concolorous with the back as in tj^pical goldmani and exiguus. Measurements of Tutla specimens: Males: wing, 141, 144; tail, 232, 229; exposed culmen, 41, 40. Females: wing, 137, 135; tail, 220, 210; exposed culmen, 37, 35. *Galbula melanogenia Sclater 8 males, 8 females, February 6-April 25. This series, which constitutes the first Oaxaca record for the genus, agrees in every respect with 13 specimens from Central and northern South America. Black-chinned jacamars are characteristic BLAKE: BIRDS FROM OAXACA, MEXICO 405 of a large group of birds, occupying an extensive range in Central America, that range northward only to the eastern lowlands of southern Mexico. Pteroglossus torquatus torquatus Gmelin 2 females, February 2, March 3. Veniliornis oleaginus sanguinolentus Sclater 1 male, March 30. *Dendrocolaptes certhia sancti-thomae Lafresnaye 1 male, April 22. This specimen and a male collected at El Ocote, Chiapas, agree with a series from Campeche and Central America. Xiphorhynchus flavigaster eburneirostris Des Murs 2 males, 1 female, February 12-March 24. Lepidocolaptes souleyetii insignis Nelson 1 female, April 28. Sittasomus griseicapillus sylvioides Lafresnaye 2 males, 1 female, March 18- April 15. Tutla specimens and three birds from Chiapas (El Ocote, Tuxtla) agree with a Guatemala series in size, but have somewhat more greenish-olive crowns and under parts than the older skins. Dendrocincla anabatina anabatina Sclater 3 males, 1 female, February 23-April 16. The distinction between this race and typhla Oberholser is exceed- ingly fine. Three fresh specimens from Campeche (Pacaitun) are little, if any, lighter than the present series. Synallaxis erythrothorax erythrothorax Sclater 2 males, 1 female, February 8-March 2. The darker gray abdomens of two specimens may indicate some degree of intergradation with furtiva of Vera Cruz, but all have flanks tinged with reddish and are best assigned to the nominate race. 406 FIELDIANA: ZOOLOGY, VOLUME 31 Automolus ochrolaemus cervinigularis Sclater 1 male, 3 females, March 9-April 17. Tutla specimens differ slightly from a Guatemala series in having more intensely buffy throats, richer under parts and darker (less warm) crowns and backs. However, the divergence from normal appears to be too slight for nomenclatural recognition. Xenops minutus mexicanus Sclater 2 males, 2 females, March 13-April 23. The chins and throats of these specimens are slightly bufRer than in nine specimens from Campeche (Pacaitun) and Guatemala. Available comparative material is inadequate at present to judge the significance of this variation. *Taraba major transandeanus Sclater 3 males, 1 female, February 1-March 22. The crissum of one male has indistinct white apical spots, whereas that of the others is unmarked. Ridgway (1911, p. 29) has com- mented upon the variability of this character, but the frequency and prominence of the spotting in series from Costa Rica, Panama and Ecuador indicate that the status of melanocrissus Sclater requires reconsideration. Thamnophilus doliatus intermedius Ridgway 3 males, 2 females, March 4-April 9. Microrhopias quixensis boucardi Sclater 1 male, 2 females, February 13-20. Formicarius analis moniliger Sclater 4 males, 3 females, February 28-April 17. Two females from Honduras (Cotacombas and Santa Barbara, Cerro de Hiquito) in Chicago Natural History Museum have decidedly heavier (deeper) bills than other examples of analis, and may represent an undescribed race. *Rhytipterna holerythra holerythra Sclater and Salvin 2 males, 1 female, February 22-March 30. It is remarkable that this cotinga, so generally distributed in the humid tropical areas of Central America, is hitherto unrecorded in Mexico. BLAKE: BIRDS FROM OAXACA, MEXICO 407 Lipaugus unirufus unirufus Sclater 3 males, 2 females, March 2-April 23. *Pachyraniphus cinnamomeus fulvidior Griscom 1 female, February 16. Brodkorb (1943, p. 58) allocates the cinnamon becard of Tabasco (Teapa) and Chiapas (Palenque) to the larger and supposedly darker northern race described from British Honduras. Inclusion of Oaxaca birds within the range of fulvidior necessarily follows, although the present specimen hardly answers the description of that race. The dorsal parts of the Tutla specimen and of a small series of the nomi- nate race from Costa Rica and Colombia are indistinguishable, and I find no difference of diagnostic value in their under parts. Measure- ments are inconclusive, since the wing of the Tutla specimen is 78 mm., whereas two Costa Rica females are 73 and 78.5 mm. respectively. Platypsaris aglaiae sumichrasti Nelson 1 male, 1 female, March 27, 30. Tityra setnifasciata personata Jardine and Selby 4 males, 1 female, February 15-March 19. Traylor (1941, p. 213) allocated Campeche birds (Matamoros, Pacaitun) to the present form and found that Yucatan specimens (deses) are hardly, if at all, separable. I am unable to agree with Brodkorb (1943, pp. 59-60) in extending the range of so weak a race to Vera Cruz, Tabasco and northern Peten. *Pipra mentalis mentalis Sclater 5 males, 5 females, February 17-April 24. *Manacus candei Parzudaki 10 males, February 5-March 9. Four specimens collected February 20-28 are in immature plumage. *Schiffornis turdinus verae-pacis Sclater and Salvin 2 males, February 5, April 5. Muscivora forficata Gmelin 13 males, 2 females, February 1-March 2. 408 FIELDIANA: ZOOLOGY, VOLUME 31 Tyrannus tyrannus Linnaeus 1 male, 1 female, February 18, March 1. Tyrannus melancholicus chloronotus Berlepsch 5 males, 2 females, February 4-March 4. ♦Legatus leucophaius variegatus Sclater 1 male, February 13. Myiozetetes similis texensis Giraud 2 females, February 2- April 14. Pitangus sulphuratus guatimalensis Lafresnaye 1 male, April 5. Identification of this specimen is made on geographical grounds since its characters are not pronounced. According to van Rossem (1940, p. 81) the Pacific coast of Oaxaca is occupied by derbianns. Myiarchus tyrannulus nelsoni Ridgway 2 males, March 3, April 26. The Mexican crested flycatcher is essentially a bird of the Caribbean slope, being replaced in western Mexico by a distinctly larger race, magister. Both forms occur in Oaxaca, but Pacific coast records of nelsoni (Tapana, Santa Efigenia and Tehuantepec City) obviously refer to the resident western race or indicate some degree of migratory activity by nelsoni. Myiarchus tuberculifer lawrenceii Giraud 4 males, 1 female, February 3-April 6. The race is identical with connectens of Central America in color, but may be distinguished by its larger size (male: wing, 84-86; tail, 78-84). Contopus cinereus brachytarsus Sclater 1 male, April 30. * Empidonax difficilis difficilis Baird 1 male, March 6. *Myiobius sulphureipygius sulphureipygius Sclater 4 males, 2 females, March 18-April 29. BLAKE: BIRDS FROM OAXACA, MEXICO 409 Onychorhynchus mexicanus mexicanus Sclater 1 male, 1 female, February 27, April 28. Platyrinchus mystaceus cancrominus Sclater and Salvin 1 male, 1 female, April 9, 22. Tolmomyias sulphurescens cinereiceps Sclater 4 males, 2 females, February 16-April 27. One male is partially albinistic, the gray of the crown being ash- colored, the rectrices and tectrices pale brown, and the dorsal parts less richly green than in normal birds. A specimen from Pacaitun, Campeche, has conspicuous white crown feathers, and Brodkorb (1943, p. 68) refers to a bird from Tabasco with creamy white feathers in the crown. Rhynchocyclus brevirostris brevirostris Cabanis 1 male, February 17. Todirostrum sylvia schistaceiceps Sclater 1 female, March 24. Oncostoma cinereigulare cinereigulare Sclater 4 males, March 5-April 19. Elaenia flavogaster subpagana Sclater and Salvin 1 male, February 21. *Elaenia viridicata placens Sclater 1 male, March 9. Leptopogon amaurocephalus pileatus Cabanis 1 male, 1 female, March 10, 15. *Piproinorpha oleaginea assitnilis Sclater 1 male, April 6. The measurements of this specimen (wing, 72; tail, 56) slightly exceed the maximum for the race, but it is identical with a Guatemala and Costa Rica series in color. Iridoprocne albilinea albilinea Lawrence 2 males, 2 females, March 27-April 26. 410 FIELDIANA: ZOOLOGY, VOLUME 31 Xanthoura yncas vivida Ridgway 3 males, 1 female, February 7-March 8. Thryothorus rutilus maculipectus Lafresnaye 3 males, 3 females, March 16-April 12. Tutla specimens are in every respect characteristic of maculi- pectus. Oaxaca records previously assigned to umbrinus doubtless refer to the present fo'm. Henicorhina leucosticta prostheleuca Sclater 1 male, 1 female, March 15, April 9. *Nannorchilus leucogaster musicus Nelson 1 male, March 10. This skin has decidedly darker flanks and upper parts than birds from Tamaulipas, Tampico and Vera Cruz, and must therefore be assigned to the Tabasco and Chiapas form. The nominate race has been recorded in northern Oaxaca, but Playa Vicente and Tuxtepec evidently mark the extreme southern extent of its range. Dumetella carolinensis Linnaeus 3 males, 4 females, February 8-April 15. *Turdus assitnilis leucauchen Sclater 1 male, February 24. Mature and sub-adult specimens of Sclater's white-necked thrush differ so markedly as to suggest distinct species. The dark slaty- olive plumage that is characteristic of the race is found only in adult males, whereas the dorsal plumage of females and of all im- mature specimens is predominantly olive or olive brown. The Tutla specimen, which considerably extends the known range of leucauchen northward from Chiapas, is in advanced intermediate plumage but agrees satisfactorily with a skin from Los Amates, Guatemala. Available material now indicates that the range of this form must be further extended to include northeastern Honduras, an area currently supposed to be represented by parcolor of the highlands of British Honduras. A previously unreported specimen from Portillo Grande (Yoro), Honduras, is identical with an adult male collected at El Ocote, Chiapas, and three immature birds from BLAKE: BIRDS FROM OAXACA, MEXICO 411 the same locality agree with a series in comparable plumage from eastern Guatemala (Izabal). 1 see no reason to confuse parcolor with leucauchen, and even less cause for regarding the former as most closely related to ohlitus (Austin, 1929, p. 386) of Costa Rica. On the contrary, three topo- tjrpical specimens of parcolor most nearly resemble adult male leucauchen, but they are readily distinguished by their even darker slate (less olive) upper parts and decidedly smaller size (males: wing, 114, 117; tail, 90, 89). A series of ohlitls collected at Peralta, Costa Rica, is strikingly similar to female and immature specimens of leucav£hen. Turdus grayi grayi Bonaparte 4 males, 1 female, February 7-April 26. The range of variation in this series not only bridges the gap between the nominate race and umhrinus, but also introduces a plumage variant that I have not found duplicated in either popula- tion. Only one specimen agrees with the nominate race, and that only with several of the more richly colored (rufescent buff) birds from eastern Guatemala (Los Amates, Izabal and El Rancho, Zacapa), which, although decidedly darker than the average, are readily separable from umhrinus of western Guatemala. A second male is indistinguishable from seven representative examples of umhrinus. Griscom (1930, pp. 5-6) restricts the range of the latter to the Pacific lowlands of Guatemala, but a series from Solola (Lake Atitlan) and Amatitlan (Lake Amatitlan) in the adjacent highlands is identical with specimens of umhrinus collected at Escuintla and Suchitepequez. It is probable, therefore, that the records from San Lucas, Panajachel and Antigua, which have been referred to the nominate race, actually apply to the distinct race of western Guatemala. Three other Tutla specimens are intensely rufescent buff, and considerably surpass in richness even the most extreme examples in a series of 31 skins from various localities. These birds equal umhrinus in darkness, but they are much more rufescent (less brown- ish) and evidently represent an unusual degree of individual variation. *Hylocichla tnustelina Gmelin 5 males, February 8-March 22. *HyIocichla ustulata swainsoni Tschudi 2 males, February 1-March 1. 412 FIELDIANA: ZOOLOGY, VOLUME 31 These skins agree with the average of swainsoni but can be matched by individual specimens of the nominate race. *Polioptila caerulea caerulea Linnaeus 1 male, February 25. Ramphocaenus rufiventris rufiventris Bonaparte 1 male, 1 female, February 27, March 28. *Sniaragdolanius pulchellus pulchellus Sclater and Salvin 5 males, March 10-April 15. Tutla specimens and birds from El Ocote and Ocosingo, Chiapas, are identical with a Guatemala series and considerably extend the known range of this rare greenlet. Vireo griseus griseus Boddaert 1 male, March 12. *Vireo gilvus gilvus Vieillot 1 female, March 19. Hylophilus ochraceiceps ochraceiceps Sclater 3 males, 2 females, March 20-April 26. Cyanerpes cyaneus carneipes Sclater 3 males, 1 female, February 3-April 26. Coereba flaveola mexicana Sclater 2 males, 3 females, March 25-April 25. Mniotilta varia Linnaeus 1 female, March 29. *HeIinitheros vennivorus Gmelin 1 male, April 2. Evidently a spring migrant, since the species ordinarily winters south of Oaxaca. *Dendroica aestiva sonorana Brewster 1 male, February 5. BLAKE: BIRDS FROM OAXACA, MEXICO 413 Dendroica magnolia Wilson 1 female, February 6. Dendroica auduboni auduboni 1 male, March 1, Dendroica fusca Miiller 4 males, February 4-21. *Dendroica pensylvanica Linnaeus 1 female, February 23. *Seiurus aurocapillus aurocapillus Linnaeus 4 males, 1 female, March 4-April 21. Seiurus motacilla Vieillot 1 female, April 13. A very late date for southern Mexico. I am unable to account for the extremely worn plumage of this specimen. Oporornis formosus Wilson 3 males, 2 females, March 4-April 8. *Chamaethlypis poliocephalus palpebralis Ridgway 1 male, February 20. Icteria virens virens Linnaeus 3 males, 1 female, March 13-April 25. Icteria virens auricollis Bonaparte 1 male, February 4. Hellmayr (1935, p. 447) extends the winter range of auricollis to Oaxaca, but I find no specific reference to its occurrence so far south. Granatellus sallaei sallaei Bonaparte 1 male, April 27. *Wilsonia citrina Boddaert 4 males, 1 female, March 10-April 23. 414 FIELDIANA: ZOOLOGY, VOLUME 31 ♦Wilsonia pusilla pusilla Wilson 3 females, March 7-28. Wilsonia pusilla pileolata Pallas 1 male, 1 female, March 13, 22. Wilsonia canadensis Linnaeus 1 male, February 28. Setophaga ruticilla Linnaeus 1 male, 1 female, March 20, 21. Basileuterus culicivorus culicivorus Lichtenstein 1 female, February 10. Basileuterus rufifrons rufifrons Swainson 2 males, 1 female, February 18-25. Gymnostinops montezuma Lesson 1 male, March 18. Amblycercus holosericeus holosericeus Lichtenstein 1 female, February 13. Psomocolax oryzivorus impacificus Peters 1 male, March 3. Icterus galbula Linnaeus 3 males, February 14-27. Icterus spurius Linnaeus 4 males, March 3-April 10. Orchard orioles have been recorded in southeastern Mexico in May, June and July (Ridgway, 1902, p. 276) but definite breeding records from the area are unavailable. Icterus prosthemelas prosthemelas Strickland 1 male, 1 female, April 4-16. Icterus mesomelas mesomelas Wagler 1 female, February 10. BLAKE: BIRDS FROM OAXACA, MEXICO 416 Sturnella magna mexicana Sclater 3 males, February 10-25. Allocation of Tutla meadowlarks is uncertain, since these speci- mens are intermediate between mexicana and alticola. They re- semble the former in size (wing, 103-109; tail, 65-70), but the greatly increased extent of white on the four outer rectrices (immaculate in one bird) indicates some admixture with the larger race of the adjacent highlands. Tanagra aflfinis affinis Lesson 3 males, 2 females, March 7-April 20. Tanagra lauta lauta Bangs and Penard 1 male, February 12. The plumage of this specimen agrees with Ridgway's detailed description (1902, p. 27) of immature males, and is matched by birds collected in November (Chiapas), December (Guatemala), and April (El Salvador). *Tangara nigro-cincta larvata Du Bus 1 male, 1 female, February 24, April 15. *Thraupis episcopus diaconus Lesson 1 male, 1 female, February 10, 20. Thraupis abbas Lichtenstein 4 males, 2 females, February 13-April 20. Phlogothraupis sanguinolenta sanguinolenta Lesson 3 males, 4 females, February 10-April 30. Piranga rubra rubra Linnaeus 1 male, 1 female, March 28. *Piranga leucoptera leucoptera Trudeau 1 female, February 4. Piranga ludoviciana Wilson 1 male, February 15. 416 FIELDIANA: ZOOLOGY, VOLUME 31 Habia rubica rubicoides Lafresnaye 7 males, 8 females, February 2-April 30. A distinctly paler race, affinis Nelson, occupies the Pacific slope of Oaxaca (Pinotepa) and possibly parts of Guerrero. Although this widespread species is characteristically a bird of the tropical lowlands, rubicoides is replaced in the Subtropical Zone of Vera Cruz by holobrunnea Griscom. Habia gutturalis salvini Berlepsch 8 males, 5 females, February 5-April 21. Lanio aurantius aurantius Lafresnaye 1 male, 2 females, February 5, March 5. Saltator atriceps atriceps Lesson 1 male, March 30. Saltator maximus gigantodes Cabanis 2 males, February 11, March 25. Influence of magnoides on Tutla specimens is reflected in the prominent olive-green margins of their black crown feathers. The high percentage of specimens of this intermediate type occurring at random in both populations, as well as in geographically remote localities, is evidence that gigantodes and magnoides are closely related by genetic ties and that their geographical isolation is recent, or as yet incomplete. Six specimens of magnoides, in a series of 18 birds from Guate- mala, Nicaragua and Costa Rica, exhibit the crown character of gigantodes in varying degrees. It is noteworthy that two of the most extreme examples are almost identical with gigantodes, although collected at Limon, Costa Rica, near the southern limits of the range occupied by magnoides. Similarly, both Tutla birds are intermediate in appearance, as might be expected, whereas the sole additional specimen of this series, an adult from Teapa, Tabasco, is indistinguishable from characteristic examples of the Central American race. Caryothraustes poliogaster poliogaster Du Bus 1 male, March 16. This specimen and four males from El Ocote, Chiapas, are de- cidedly larger than birds from Guatemala, whereas a series from BLAKE: BIRDS FROM OAXACA, MEXICO 417 Campeche (Pacaitun) is intermediate in size, but nearer the latter. All, however, are identical in color and evidently constitute a cline from south to north. Hedymeles ludovicianus Linnaeus 1 male, April 30. A very late record for southern Mexico, since the species ordi- narily leaves Guatemala by the first of the month and has been reported in northern Illinois by the twenty- third. Cyanocompsa cyanoides concreta Du Bus 2 males, 1 female, February 6-14. Passerina cyanea Linnaeus 3 males, February 6-March 30. Passerina ciris Linnaeus 7 males, 1 female, February 1-April 9. Sporophila torqueola morelleti Bonaparte 1 male, February 21. Morellet's seed-eater is typical of the very numerous Tropical Zone birds widely distributed in Central America and ranging northward into southeastern Mexico. In the present collection only two other species with somewhat similar patterns of distribution (Trogon citreolus, Pitangus sulphuratus) are also represented in western Mexico by a form that occurs on the Pacific slope of Oaxaca. The nominate race replaces morelleti in southwestern Mexico and has been recorded in the interior of Oaxaca at Oaxaca de Judrez (Salvin, 1858, p. 303), and also adjacent to the known range of the Central American form at Capulalpam. The Tutla specimen is in partial molt, but agrees in every respect with morelleti (wing, 49; tail, 42). Arremon aurantiirostris saturatus Cherrie 3 females, February 8-27. Arremonops rufivirgatus crassirostris Ridgway 1 male, 1 female, February 16-April 27. The distribution of this sparrow in southern Mexico is of par- ticular interest in that it represents one of the few instances in 418 FIELDIANA: ZOOLOGY, VOLUME 31 which three races of a single species converge in the Isthmus of Tehuantepec. The present form ranges from Pueblo and Vera Cruz to Tutla, in Oaxaca, whereas the Pacific lowlands from Colima to Huamelula (Oaxaca) are occupied by sumichrasti. Birds from the valley of the Chiapas River (Rio Mexcalapa), southward in the interior of Chiapas, constitute a distinct race that appears to be most closely related to the Pacific coast form. *Melospiza lincolnii lincolnii Audubon 1 male, February 19. Mexican and Guatemala records of the nominate race have been questioned since the separation of alticola Miller and McCabe, which is granted a winter range extending southward to Guatemala. Nevertheless, the Tutla specimen is indistinguishable from a large series of Lincoln's sparrow, as are three birds from Chilpancingo, Guerrero, in Chicago Museum (Blake, 1950, p. 392). REFERENCES Austin, Oliver L., Jr. 1929. Birds of the Cayo District, British Honduras. Bull. Mus. Comp. Zool., 69, pp. 363-394. Bangs, Outram and Peters, James 1928. A collection of birds from Oaxaca. Bull. Mus. Comp. Zool., 68, pp. 385-404. Berlioz, J. 1931. Revision des Trochilides du groupe "Campyloptere." Bull. Mus. d'Hist. Nat. Paris, (2), 3, pp. 82-90. Blake, Emmet R. 1949. The distribution and variation of Caprimulgus maculicaudus. Fieldiana, Zool., 31, No. 26, pp. 207-213. 1950. Report on a collection of birds from Guerrero, Mexico. Fieldiana, Zool., 31, No. 39, pp. 375-393. Brodkorb, Pierce 1943. Birds from the Gulf lowlands of southern Mexico. Misc. Pub. Mus. Zool., Univ. Mich., 55, pp. 1-88. Griscom, Ludlow 1930. Studies from the Dwight collection of Guatemala birds. IIL Amer. Mus. Nov., No. 438, pp. 1-18. 1932. The distribution of birdlife in Guatemala. Bull. Amer. Mus. Nat. Hist., 64, ix+439 pp. Hellmayr, Charles E. 1935. Catalogue of birds of the Americas. Field Mus. Nat. Hist., Zool. Ser., 13, pt. 8, vi+541 pp. BLAKE: BIRDS FROM OAXACA, MEXICO 419 Meise, Wilhelm 1938. Ueber einige Kolibris der Gattung Agyrtrina Chubb. Bull. Mus. Roy. Hist. Nat. Belgium, 14, pp. 1-6. RiDGWAY, Robert 1902. The birds of North and Middle America Bull. U. S. Nat. Mus., 50, pt. 2, xx+834 pp. 1911. The birds of North and Middle America Bull. U. S. Nat. Mus., 50, pt. 5, xxiii+859 pp. 1916. The birds of North and Middle America Bull. U. S. Nat. Mus., 50, pt. 7, xiii+543 pp. Salvin, Philip L. 1858. On a collection of birds received by M. Auguste Sall6 from Oaxaca in southern Mexico. Proc. Zool. Soc. London, 26, pp. 294-305. Todd, W. E. Clyde 1942. List of the hummingbirds in the collection of the Carnegie Museum. Ann. Carnegie Mus., 29, pp. 271-370. Traylor, Melvin a. 1941. Birds from the Yucatan Peninsula. Field Mus. Nat. Hist., Zool. Ser., 24, pp. 195-225. Van Rossem, A. J. 1940. Notes on some North American birds of the Genera Myiodynastes, Pitangus, and Myiochanes. Trans. San Diego Soc. Nat. Hist., 9, pp. 79-86.