Kmtynjjm'd Birds in Riparian Ecosystems ■ WESTERN BIRDS Quarterly Journal of Western Field Ornithologists President: Tim Manolis, 808 El Encino Way, Sacramento, CA 95864 Vice-President: Narca A. Moore-Craig, P.O. Box 254, Lakeview, CA 92353 Treasurer /Membership Secretary: Art Cupples, 3924 Murrieta Ave., Sherman Oaks, CA 91423 Recording Secretary: Jean-Marie Spoelman, 4629 Diaz Drive, Fremont, CA 94536 Circulation Manager: Jerry R. Oldenettel, 4368 37th Street, San Diego, CA 92105 Directors: Peter Gent, Virginia P. Johnson, John S. Luther, Guy McCaskie, Timothy Manolis, Robert McKeman, Narca Moore-Craig, Joseph Morlan, Janet Witzeman Editor: Philip Unitt, 3411 Felton Street, San Diego, CA 92104 Associate Editors: Cameron Barrows, Tim Manolis, Narca A. Moore-Craig, Thomas W. Keeney Layout Artist: Virginia P. Johnson Photo Editor: Bruce Webb, 5657 Cazadero, Sacramento, CA 95822 Review Editor: Richard E, Webster, P.O. 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Send membership dues, changes of address, correspondence regarding missing issues, and orders for back issues and special publications to the Treasurer. Make checks payable to Western Field Ornithologists. Back issues of California Birds/ Western Birds: $15 per volume, $4.00 for single issues. Xerox copies of out of print issues (Voi. 1, No. 1; Vol. 2, Nos. 1 and 4; Vol. 6, No. 2): $4.50 each. Checklist of the Birds of California: $2.00 each, 10 or more $1.50 each. PelagicBirds of Monterey Bay, California: $2.50 each, 10 or more $2.00 each, 40 or more $1.50 each. All postpaid. Published October 15, 1987 WESTERN BIRDS ADVERTISING RATES AND SPECIFICATIONS Full page 4 x 6 3 A inches $60 per issue $200 per year Half Page 4x3% inches $40 per issue $130 per year Quarter Page 4 x \ u / lf> inches $30 per issue $1 10 per year Offset printing, one column per page, 4 inches wide. Glossy, black and white photos are ac- ceptable; half-tone screen size: 133 line. Photo-ready copy is requested. If this is not possible, extra charges for typesetting will be made as follows; $15 full page, $10 half page, $5 quarter page. Send copy with remittance to the Treasurer. Make checks payable to Western Field Ornithologists. A 15% commission is allowed for agencies. WESTERN BIRDS Volume 18, Number 1, 1987 MANAGEMENT AND PRESERVATION OF ENDANGERED BIRDS IN RIPARIAN ECOSYSTEMS: A SYMPOSIUM PRESENTED IN CONJUNCTION WITH THE COOPER ORNITHOLOGICAL SOCIETY ANNUAL MEETING, 10 SEPTEMBER 1986 STEPHEN A. LAYMON, Department of Forestry and Resource Management, 145 Mulford Hall, University of California, Berkeley, California 94720 When the Cooper Ornithological Society announced its annual meeting to be held in Davis, California, in the fall of 1986, the organizers requested topics for mini-symposia. Because one of the major management issues and conservation problems concerning birds in California and the arid West is the preservation and management of riparian ecosystems and their accompany- ing bird communities, I organized a steering committee to explore the possibility of conducting a symposium on this topic. This steering committee consisted of Edward Beedy of Jones and Stokes Associates, Kathleen Franzreb of the U.S. Fish and Wildlife Service Endangered Species Office, and John Gustaf- son of California Department of Fish and Game Nongame Bird and Mammal Section. The format we chose emphasized the management and preserva- tion of endangered birds in riparian habitats. The call for papers met with enthusiasm and the final program consisted of 17 papers ranging from reports of original scientific research to papers reviewing issues of management importance. The symposium concluded with a panel discussion involving members of the academic, land management, and environmental communities. This was an opportunity to explore the views, concerns, and management plans of the participating organizations. Special thanks go to Felix Smith of the U.S. Fish and Wildlife Service, who acted as the moderator, and to the panel members, David Busch of the Bureau of Reclamation, Earle Cummings of the California Department of Fish and Game, Steven Johnson of The Nature Conservancy, William Laudenslayer of the U.S. Forest Service, Robert Ohmart of Arizona State University, Richard Spotts of Defenders of Wildlife, and Daniel Taylor of the National Audubon Society, for making it a success. Western Birds 18:1-2,1987 1 The steering committee is grateful to the Cooper Ornithological Society and Daniel Anderson, chairman of the local arrangements committee, for pro- viding logistical support during the symposium. Special recognition must be extended to the Western Field Ornithologists for publishing the proceedings. Many organizations and individuals have provided funding for these pro- ceedings, including Biosystems Analysis, Davis Audubon Society, EIP Associates, Environmental Science Associates, Harvey and Stanley Associates, Inc., Jones and Stokes Associates, Inc., Kern Audubon Society, Kerncrest Audubon Society, Richard Kust, Marin Audubon Society, Mt. Diablo Audubon Society, Morro Coast Audubon Society, Riparian Systems, Mr. and Mrs. David Rorick, Sacramento Audubon Society, Sea and Sage Audubon Society, David D. Smith & Associates, and Westec Services, Inc. It is our hope that this volume will contribute to the management of en- dangered species inhabiting riparian ecosystems. We trust that the following papers will not be viewed as containing the ultimate answers, but rather, that they will provide grains of knowledge that will stimulate a new round of research and management activites and promote the reestablishment of viable riparian ecosystems throughout the West. 2 PERSPECTIVES ON MANAGING RIPARIAN ECOSYSTEMS FOR ENDANGERED BIRD SPECIES KATHLEEN E. FRANZREB, U S. Fish and Wildlife Service, Endangered Species Of- fice, 2800 Cottage Way, Room E-1823, Sacramento, California 95825 The emphasis of this symposium is the management of endangered, threatened, and other sensitive bird species in western riparian habitats. Riparian areas are limited in their extent, yet are extremely productive and have well documented wildlife values (Gaines 1977, Johnson and Jones 1977, Stevens et al. 1977, Warner and Hendrix 1984). This paper examines the nature of riparian systems from historical and current perspectives, describes the importance of riparian habitats to sensitive bird species, and briefly ex- plores the laws, policies, and regulations designed to protect these habitats. DEFINITION OF RIPARIAN HABITATS Located primarily along major rivers and tributaries, riparian forests are usually associated with abundant water supplies, have coarse textured and well-drained soils, and contain high levels of nutrients (Roberts et al. 1977). Riparian habitats may be defined as streamside, riverside, or lakeside com- munities, extending from high forest to low desert (Pase and Layser 1977). Soil moisture is seldom limiting although surface water may be lacking at times (Pase and Layser 1977). GENERAL DESCRIPTION Within riparian forests the density and diversity of vegetation tend to be greater than in adjacent upland habitats because of edge effects. Western riparian forests are complex and structually diverse ecosytems, often having dense understories of shrubs or young trees with canopy layers of more mature trees. In many western riparian systems early successional stages are pure cotton wood -willow (Populus spp. -Salix spp.), whereas mid- and late suc- cessional stages frequently have cottonwood -willow overstory with an occa- sional oak ( Quercus spp.) or sycamore (Platanus spp.) . Box elder ( Acer negun- do subsp. californicum) , black walnut ( Juglans hindsii), and ash (Fraxinus spp.) often constitute the second canopy layer in these older stands (Strahan 1984) . Should flood-induced scouring of the forest be absent for many years, cottonwood -willow habitats may be replaced by these second canopy (as defin- ed above) species (Strahan 1984). Reproduction is usually by seed, but willows such as sandbar willow ( Salix hindsiana ) also use vegetative means. For a more complete description of riparian habitats, please refer to Johnson and Jones (1977), Johnson and McCormack (1978), and Warner and Hendrix (1984). Western Birds 18:3-9,1987 3 MANAGING RIPARIAN ECOSYSTEMS HISTORICAL PERSPECTIVE Historical accounts suggest that along both sides of large, lowland rivers, belts of riparian trees averaged from 3.2 to 6.4 km (2-4 mi.) in width (Thomp- son 1961). Such conditions prevailed especially in the Central Valley in Califor- nia, which provides a typical example of modifications that have occurred in riparian areas. Farmers, noting that the soil in riparian areas was very fertile, cleared riparian vegetation so they could grow crops. The expansion of farming and concur- rent increase in the demand for water and flood control prompted large-scale water development and reclamation projects that had far-reaching, adverse effects on riparian systems. Much of the water diverted for crop irrigation was no longer available to support riparian habitats. Towns developed in conjunction with the rapidly expanding agricultural industry. Seasonal flooding became a major concern because many of these valley towns were built in floodplains. As levees were built higher and higher, water levels rose and water that would have previously overflowed into the natural floodplain basins was now confined within the levees. Extensive, controversial water projects have been constructed throughout the Central Valley. The once vast riparian forests have been decimated by dam building, river channelization (riprapping, concrete lining, etc.), ground- water pumping, land clearing (for urban and agricultural development), ar- tificial levees, water diversion (irrigation canals), bank protection systems, graz- ing, road construction, and pooling of water (to water stock and for water diversion) (Carothers 1977, Johnson 1978, Katibah 1984, Katibah et al. 1984). DECLINE IN DISTRIBUTION AND QUANTITY OF RIPARIAN HABITAT Bottomland riparian forests are the most highly modified of natural land- scapes in California. Most of the riparian forest along the water courses of the Central Valley was rapidly eliminated or greatly reduced in size. Using a map by J. Greg Howe, Katibah (1984) conservatively estimated the pre- settlement riparian vegetation for the entire Central Valley at more than 373,000 ha (924,000 ac). In 1979 it was estimated that about 41,300 ha (102,000 ac) of riparian forest remained in the Central Valley and 85% of it was in a disturbed or degraded condition (Katiban et al. 1984) (Table 1). Similar losses are evident throughout much of the U.S. (Korte and Fredrickson 1977). BIRD USE OF RIPARIAN HABITATS According to Miller (1951), the “ . . . number of species of birds associated with riparian woodlands is larger than that of any other formation.” Several factors contribute to the avian diversity of riparian habitats, including ecotone and edge effects, as the aquatic stream ecosystem interfaces with the adja- cent terrestrial habitat (Odum 1978). 4 MANAGING RIPARIAN ECOSYSTEMS Table 1 Current Sample Site 8 Condition of Riparian Systems in the Central Valley b Condition Amount (ha) Percentage Apparently unaltered 1,239 3 Good 4,956 12 Disturbed 10,325 25 Degraded 12,803 31 Severely degraded 11,977 29 Total 41,300 100 *For definition of sample site, see Katibah et al. (1984), pp. 316-317. ‘From Katibah (1984) and Katibah et al. (1984). Avian use of riparian systems is well documented (Table 2). Although most of the studies concentrated on breeding birds, similar trends are evident with migrants; both Rappole and Warner (1976) and Stevens et al. (1977) reported that migrants preferred riparian habitat over adjacent upland areas. This is particularly significant because the loss of riparian habitat affects not only nesting birds, but may adversely affect migrating individuals by influencing migration routes, reducing cover, eliminating resting areas, and reducing food supplies (Rappole and Warner 1976, Stevens et al. 1977, Johnson 1978). Riparian habitat also serves as an essential link for long-distance migrants and as winter- ing grounds (Laymon 1984) . Table 2 Examples of Avian Use of Riparian Areas Habitat State Estimated no. per 40 ha Source Mixed broadleaf AZ 332 pairs Carothers et al. (1974) Cottonwood AZ 847 pairs Carothers et al. (1974) Cottonwood - willow TX 475 birds Engel-Wilson and Cottonwood-willow AZ/CA 84-298" birds Ohmart (1978) Anderson et al. (1983) Desert riparian AZ 336* birds Szaro and Jakle (1985) Willow-tamarisk AZ 445* birds Szaro and Jakle (1985) Honey mesquite AZ 178-200" birds Anderson et al. (1983) Salt Cedar AZ 23-146" birds Anderson et al. (1983) Arrow weed AZ 111" birds Anderson et al. (1983) Screwbean mesquite AZ 92-202" birds Anderson et al. (1983) Mesquite bosque AZ 476 pairs Gavin and Sowls (1975) ‘Densities varied depending on year and interior/edge area of riparian. "Densities values for spring season; all plots along the Colorado River. 5 MANAGING RIPARIAN ECOSYSTEMS Avian densities and species richness in riparian systems demonstrate the importance of these habitats to birds. For example, riparian forests support more species of breeding birds in California than any other habitat type and at least 100 species use it for food and cover (Gaines 1977) . In analyzing data from American Birds for various habitat types, Laymon (1984) noted that riparian areas had the highest density (birds/km 2 ) and greatest species richness of all habitats studied in both the breeding and winter seasons. During the last 100 years, 83 species are known to have nested in riparian habitats in the Sacramento Valley, and 20 of the regularly occurring species are believed to have their highest densities in riparian systems (Laymon 1984). Several species, such as the Willow Flycatcher ( Empidonax traillii) and Least Bell’s Vireo (Vireo bellii pusillus), are no longer known to nest anywhere in the interior lowland areas of California. Riparian avifaunas also increase the avian diversity of nearby and adjacent communities. For example, it was found that the avian community in a riparian area increased the nearby desert bird community in both species composi- tion and density (Szaro and Jakle 1985) . In this south-central Arizona study, contributions from the riparian avifauna ranged from 23 to 33% of the birds along the adjacent desert washes and 7 to 15% within the desert uplands (Szaro and Jakle 1985). This contrasts with a contribution of only 1 to 15% from the desert areas to the riparian community (Szaro and Jakle 1985). Likewise, riparian birds exert a stong influence over the bird communities in adjacent agricultural and second-growth fields and pastures (Carothers et al. 1974, Conine et al. 1978). Along the Sacramento River, agricultural land devoid of adjacent riparian areas supported 95% fewer individuals and 32% fewer species than similar agricultural lands bordering riparian habitat (Henke and Stone 1978). MANAGEMENT CONCERNS AND ADVERSE IMPACTS A number of activities either modify or have the potential to adversely af- fect riparian habitats and their avian populations. These include water storage projects that inundate riparian areas, erosion, excessive groundwater pump- ing (and declining water tables), human recreation (camping, hunting, trap- ping, etc.), pesticide buildup resulting from drainage and erosion from near- by agricultural fields, flood control projects, and bank protection projects (Johnson 1978, Katibah 1984, Katibah et al. 1984). Invasions by exotic plants such as salt cedar ( Tamarix spp.) and giant reed ( Arundo donax) present insidious threats because the exotics gradually replace cottonwood-willow and other native riparian species. Floodplain manage- ment is designed to protect against loss of human life and property, but fre- quently moves the potential problem downstream by channelizing the water from one locale to another (Johnson 1978). These conditions all serve to reduce native riparian vegetation and portend either the elimination or reduc- tion in avian populations and other wildlife. Management of riparian areas requires that the natural periodicity of the river flow be sustained to allow the functioning of riparian systems. Depen- ding on its frequency, duration, and intensity, flooding can be beneficial or stressful to a riparian system (Odum 1978) . Projects that reduce or eliminate 6 MANAGING RIPARIAN ECOSYSTEMS normal seasonal flooding retard riparian productivity (Odum 1978). Too fre- quent flooding knocks down vegetation and may prevent it from becoming reestablished. If flooding (and attendant scouring of vegetation) is too infre- quent, succession will proceed to climax, to the detriment of species that rely on early successional stages, such as the Least Bell's Vireo. If the flood is too intense or long in duration, extensive scouring and erosion may result, adversely modifying the stream bed. As a conservation policy, any structures that alter river flow so as to cause a substantial negative effect on the riparian ecosystem should be discouraged. A balance must be maintained between riparian and fluvial systems. We must recognize that flooding is a natural process and should consider chan- nel and floodplain as complementary if we are to maintain the integrity of riverine systems. In some areas natural flooding is no longer feasible and ar- tificial means of duplicating the effects of natural flooding should be considered. The public must be involved in the management of riparian systems; such involvement could include education, legislation, preservation, and restoration. A number of laws and regulations are available to manage and protect riparian habitat. These include the Clean Water Act, National Environmental Policy Act of 1969, Endangered Species Act of 1973, Fish and Wildlife Coor- dination Act, National Wild and Scenic Rivers Act of 1968, and others. In California, several state laws apply, such as the California Environmental Quali- ty Act of 1970, State Wild and Scenic Rivers Act of 1972, and Surface Min- ing and Reclamation Act of 1975. A prime example of how laws can be used to manage sensitive species is provided by the Endangered Species Act of 1973, as amended. Federally listed species and the ecosystems on which they depend are protected under the Endangered Species Act through implementation of two of its provisions. Section 9 prohibits “take” (defined as harass, harm, pursue, hunt, shoot, wound, kill, trap, capture, or collect, or to attempt to engage in any such conduct) and states the penalties for violations. Section 7 requires that all federal agencies insure that actions they authorize, fund, or carry out are not likely to jeopardize the continued existence of any endangered or threatened species or result in destruction or adverse modification of any designated critical habitat. According to the Endangered Species Act, for federally listed species the term “endangered” means “any species (this includes subspecies of vertebrate fish or wildlife or plants and any distinct population segment of any species of vertebrate fish or wildlife which interbreeds when mature) which is in danger of extinction throughout all or a significant portion of its range.” The reference to a population segment is pertinent because it enables a distinct portion of a vertebrate species to be listed even though the entire species may not war- rant protected status. A federally “threatened” species is one which is likely to become endangered should factors currently reducing the population per- sist throughout all or a significant portion of its range. The Secretary of the Interior bases the decision to list a species as endangered or threatened on whether it meets at least one of the following criteria: (a) the present or threatened destruction, modification, or curtailment of its habitat or range; (b) overutilization for commercial, recreational, scientific, or educational pur- poses; (c) disease or predation; (d) the inadequacy of existing regulatory 7 MANAGING RIPARIAN ECOSYSTEMS mechanisms; and (e) other natural or man-made factors affecting its continued existence. Various states maintain lists of endangered, threatened, or rare species with their own standards that a species must meet to qualify for state listing. To protect riparian habitat all applicable laws and regulations must be ag- gressively implemented and stringently enforced. A far-reaching monitoring program to assess and evaluate the status of riparian systems should be established by a consortium of federal, state, and local agencies. Only through dynamic, diligent, and innovative actions to manage riparian areas appropriate- ly will this sensitive, valuable, and irreplaceable habitat persist. LITERATURE CITED Anderson, B., Ohmart, R., and Rice, J. 1983. Avian and vegetation community struc- ture and their seasonal relationships in the Lower Colorado River Valley. Con- dor 82:392-405. Carothers, S. W., Johnson, R. R., and Aitchison, S. W. 1974. Population structure and social organization in southwestern riparian birds. Am. Zool. 14:97-108. Carothers, S. W. 1977. Importance, preservation, and management of riparian habitats: an overview. Pp. 2-4 in R. Johnson and D. Jones, eds., op. cit. Conine, K. H., Anderson, B. W,, Ohmart, R. D., and Drake, J. F. 1978. Responses of riparian species to agricultural conversions. Pp. 248-262 in R. Johnson and J. McCormack, tech, coords., op. cit. Engel-Wilson, R. W., and Ohmart, R. D. 1978. Floral and attendant faunal changes on the Lower Rio Grande between Fort Quitman and Presidio, Texas. Pp. 139- 147 in R. Johnson and J. McCormack, tech, coords., op. cit. Gaines, D. 1977. The valley riparian forests of California: their importance to bird popula- tions. Pp. 57-85 in A. Sands, ed., Riparian forests in California: their ecology and conservation. Inst. Ecol. Publ. 15, Univ. Calif., Davis. Gavin, T. A., and Sowls, L. K. 1975. Avian fauna of a San Pedro Valley mesquite forest. J. Ariz. Acad. Sci. 10:33-41. Henke, M., and Stone, C. 1978. Value of riparian vegetation to avian populations along the Sacramento river system. Pp. 228-235 in R. Johnson and J. McCor- mack, tech, coords., op. cit. Johnson. R. 1978. The Lower Colorado River: a western system. Pp. 41-45 in R. Johnson and J. McCormack, tech, coords., op. cit. Johnson, R., and Jones, D., eds. 1977. Importance, preservation, and management of riparian habitats. U.S. Forest Service GTR-Rm-43, Rocky Mt. Forest and Range Exp. Sta., Ft. Collins, CO. Johnson, R. and McCormack, J., tech, coords. 1978. Strategies for protection and management of floodplain wetlands and other riparian ecosystems. U.S. Forest Service GTR-WO-12, Washington, D.C. Katibah, E. F. 1984. A brief history of riparian forests in the Central Valley of Califor- nia. Pp. 23-29 in R. E. Warner and K. M. Hendrix, eds., op. cit. Katibah, E. F., Dummer, K. J., and Nedeff, N. E. 1984. Current condition of riparian resources in the Central Valley of California. Pp. 314-321 in R. E. Warner and K. Hendrix, eds., op. cit. 8 MANAGING RIPARIAN ECOSYSTEMS Korte, P., and Fredrickson, L. 1977. Loss of Missouri’s lowland hardwood ecosystem. Trans. 42nd N. Am. Wildlife & Nat. Res. Conf., Wildlife Mgt. Inst, Washington, D C., Pp. 31-41. Laymon, S. 1984. Riparian bird community structure and dynamics: Dog Island, Red Bluff, California. Pp. 587-597 in R. E. Warner and K. Hendrix, eds., op. cit. Miller, A. H. 1951. An analysis of the distribution of the birds of California. Univ. Calif. Publ. Zool. 50:531-643. Odum, E. 1978. Opening address: ecological importance of the birds of the riparian zone. Pp. 2-4 in R. Johnson and J. McCormack, tech, coords., op. cit. Pase, C., and Layser, E. 1977. Classification of riparian habitat in the Southwest. Pp. 5-9 in R. Johnson and D. Jones, eds., op. cit. Rappole, J. H., and Warner, D. W. 1976. Relationships between behavior, physiology, and weather in avian transients at a migratory stopover site. Oecologia 26: 193-212. Roberts, W., Howe, J. , and Major, J. 1977. A survey of riparian forest flora and fauna in California. Pp. 3-19 in A. Sands, ed., Riparian forests in California: their ecology and conservation. Inst. Ecol. Publ. 15, Univ. Calif., Davis. Stevens, L. E., Brown, B. T., Simpson, J. M., and Johnson, R. R. 1977. The impor- tance of riparian habitat to migrating birds. Pp. 156-164 in R. Johnson and D. Jones, eds., op. cit. Strahan, J. 1984. Regeneration of riparian forests of the Central Valley. Pp. 58-66 in R. E. Warner and K. Hendrix, eds., op. cit. Szaro, R. C. , and Jakle, M. D. 1985. Avian use of a desert riparian island and its adja- cent scrub habitat. Condor 87:511-519. Thompson, K. 1961. Riparian forests in the Sacramento Valley, California. Ann. Assoc. Am. Geog. 51:294-315. Warner, R. E. and Hendrix, K., eds. 1984. California riparian systems: ecology, con- servation, and productive management. Univ. Calif. Press, Berkeley. 9 STATUS OF BREEDING RIPARIAN-OBLIGATE BIRDS IN SOUTHWESTERN RIVERINE SYSTEMS WILLIAM C. HUNTER, ROBERT D. OHMART, and BERTIN W. ANDERSON, Center for Environmental Studies, Arizona State University, Tempe, Arizona 85287-1201 Ecological values of riparian habitats have received much attention over the past decade. One issue confronting management agencies is the effect of intensive water management on riparian vegetation in the Southwest (e.g., the decline of native vegetation and the increase of exotic Salt Cedar [Tamarix chinensis]; Table 1). Many bird species have declined in number or suffered extirpation along these riparian systems as habitat changes have occurred (Table 2). We ex- amine breeding birds obligated to riparian habitats and draw qualitative con- clusions on their status throughout their range below 1524 m elevation (Phillips et al. 1964, Ohmart 1982, Ohmart and Anderson 1982). Trends are also described for species that are breeding riparian obligates in one or more riparian systems but use nonriparian habitats elsewhere. Species are reviewed with respect to historical status and present status, as well as to riparian habitat use within and among riparian systems. We compare Salt Cedar as breeding habitat with native habitats, both within and among riparian systems, present possible explanations for existing patterns, and review management implications. METHODS Data on breeding birds in riparian habitats are from our studies and from other published information. Sites of studies include the upper Verde River (1969-1972, Carothers et al. 1974), the lower Colorado River (1972-1984, Anderson and Ohmart 1984), the Rio Grande near Presidio, Texas (1977-1978, Engel-Wilson and Ohmart 1978), the lower Verde River (1980, Higgins and Ohmart 1981), the middle Pecos River (1979-1981, Hildebrandt and Ohmart 1982), the middle Rio Grande (1981-1983, Hink and Ohmart 1984), the lower Virgin River (1982-1983, Kasprzyk 1984), the upper Gila River (1978-1979 in mixed broadleaf habitats only, Clark 1984), the lower and upper Gila River (1985-1986, Hunter 1987), the lower San Pedro River (1985-1986, Hunter 1987), and the upper San Pedro River (1986, Krueper and Corman unpubl.), the lower Salt, lower Santa Cruz, and middle Gila rivers (Rea 1983), the Colorado River through the Grand Canyon (Brown et al. 1981), and the upper Santa Cruz River (Arnold 1940). Climatic dif- ferences among riparian systems may have an important effect on a species’ use of riparian habitat. We divided study sites into low-elevation (below 427 m) and high-elevation (427 m-1524 m) groups to investigate climatic effects on habitat use. Bird species were grouped by four criteria: (1) dependence on broadleaf habitats (obligate, partial obligate, generalist); (2) type of nest (open, covered, cavity); (3) residency (permanent resident or summer visitor); and (4) period of peak egg laying (spring-early summer or midsummer). Western Birds 18:10-18,1987 10 RIPARIAN-OBLIGATE BIRDS Dependence on broadleaf riparian was determined from field studies. Nest type and residency status are drawn from the literature or personal observa- tions. Peak egg-laying periods are primarily from Bent (1963-1968). RESULTS Broadleaf Obligates Seventeen of the 32 riparian-dependent species are broadleaf obligates (Table 3). Two major groups within the 17 species are large raptors (seven species) and cavity nesters (seven species). Broadfleaf- obligate raptors require tall, large trees for nest placement. Mature broadleaf trees constitute the most important raptor nest sites in riparian systems. Honey Mesquite ( Prosopis glandulosa) and Salt Cedar are rarely used for nest platforms. The Mississippi Kite ( Ictinia mississippiensis) requires Table 1 Area Encompassed by Riparian Habitats along Each River Reach* ' Elevation/river reach Hectares/habitat type 6 Total ha CW SM HM SC SH MB Low (<427 m) Colorado 3,417 9,799 5,652 15,638 3,826 38,382 Gila 330 4,985 22,493 2,162 29,970 Salt 228 49 277 Santa Cruz 18 1,665 46 1,729 Subtotal 3,993 9,799 12,302 38,276 5,988 70,358 Percentage 5.7 13.9 17.5 54.4 8.5 High (427-1524 m) Virgin 70 3,211 3,281 Grand Canyon 109 600 901 1,610 Gila 442 5,771 7,281 462 13,956 Salt 388 1,278 542 123 54 2,385 Santa Cruz 270 4,033 4,303 Lower San Pedro 490 2,976 715 4,181 Upper San Pedro 804 4,728 307 5,839 Lower Verde 2,309 2,426 4,735 Upper Verde 1,244 1,105 505 1,610 Lower Rio Grande 60 25 3,029 5,600 8,714 Middle Pecos 834 215 11,295 12,344 Subtotal 6,950 25 26,161 26,641 585 559 62,958 Percentage 10.9 0.0 40.7 46.5 0.9 0.9 'From Ohmart (1982) except for the Pecos River (Hildebrandt and Ohmart 1982) and the lower Rio Grande (Engel-Wilson and Ohmart 1978). "GW, cottonwood-willow; SM, Screwbean Mesquite; HM, Honey Mesquite; SC, Salt Cedar; SH, Salt Cedar- Honey Mesquite; MB, mixed broadleaf. 11 Table 2 Riparian Birds That Have Declined or Been Extirpated in the Southwest since 1900* j= u (O 0) ha T3 C <0 E 0) -h* (/) £ 10 a— , r\ 8 7 7 8 CM cm t-h H OOCOOOMHCO o t- 1 Ua rH rH rH rH rH r- 1 i— 1 rH rH rH UJ to "3 +J o C 3 1 3 4 <0* 4 6 1 rH ro^o^tin^coco t- 10 rH a "3 V) O * T3 AJ c (H 2 Da Da Da Da Q Da Da Da o 00 *V 1m o o j Da Da Da UJ Da UJ Da Da Da CM t-'a £ Q> D Da Da Da Da Da Da Da Da Da UJ Da Da Da Da Da rH r"H ”3 ha w a. > X P P P P Da P E P Da Da Da UJ Da Da Da Da Da CM 1/3 rH o ha T3 W Da D P P E P Da Da Da Da DaDaQD.DaD.DaDa CM rH c 10 X P P P P Da P P P Da (X Da D, Da Da D. Da Da o f'a C/3 rH o P P P P Da P E P Da DaDaUJDaDaDaDaDa CM 1/3 -a-* a — 1 10 C/3 D E P UJ -J UJ UJ Q Da UJUJUJ'UJUJUJQ co CM Q t— 1 N 1m u X P P E P Da Cl Cl Cl Da DaDaUJDaDaDaDaDa CM 1/3 10 +-• C ID -I UJ UJ Q D E P Da UJ UJ UJ UJ UJ UJ UJ CM CM C/3 rH JO D Da Da Da Da P E P Da DaDaDaDaDaDaDaD. rH in a-H O X UJ UJ Q D E P Da UJ UJ Q UJ UJ UJ Q CM CM rH c "Si ha Da Da Da Da DaD.UJD.DaDaD.Da rH a“H > a-H o *3 (0 GC A Da (X Da Da Da Da Da Da o 00 o CM rH CO o U UJ UJ UJ Q Q Q a DaQUjQUjQDaDa (A g> '0 v a c/3 || o « * 3 - ^ X -O CQ C js o 2 g. r E o § E O o o U N U o o o 3 5 O M— Ul) 5 0 3a G ^ cr .C cu to <» ha O 5 Ua ■S C ^ J c o = 5 E Otla >53 oa > 0? 10 _C ha u u o> a* ta s ^ £ o 13 U-. > 3 > 5 o _"> o 0) %a 10 JZ h, U I « "8 UJ cot" (0 u ns w f- O g s b h- (- 12 'D, declining; E, extirpated; F, still present in stable numbers; L, lower reach; M, middle teach; U, upper reach; GC, Grand Canyon. ’Status unclear. RIPARIAN-OBLIGATE BIRDS an understory of Salt Cedar to provide one of its primary foods, the cicada ( Diceroprocta apache; Glinski and Ohmart 1983). Besides this special case, no raptor extensively uses Salt Cedar anywhere in the Southwest. Breeding Cooper’s Hawks ( Accipiter cooperii ) and Harris’ Hawks [Parabuteo unicinc- tu$) have been extirpated from the lower Colorado River and adjacent tributaries, while the Common Black-Hawk ( Buteogallus anthracinus) has disappeared from the upper Santa Cruz and upper San Pedro rivers (Table 2) . Cavity-nesting species are locally obligated to riparian vegetation, and when so, are also obligated to broadleaf trees. In areas where Saguaro cacti ( Carnegiea gigantea ) do not occur, the Elf Owl ( Micrathene whitrteyi), Gila Woodpecker ( Meianerpes uropygialis) , Northern (Gilded) Flicker ( Colaptes auratus), and Brown-crested Flycatcher ( Myiarchus tyrannulus ) are broadleaf obligates. The Elf Owl has declined to very low population levels along the lower Colorado River (Cardiff 1978); declines have also been noted on the lower Gila, lower Salt, and lower Santa Cruz rivers (Rea 1983). The status of the Ferruginous Pygmy-Owl ( Glaucidium brasilianum ) remains an enigma as this species has declined significantly since the late 1800s (Rea 1983). Cavity-nesting species are not known to occur in or regularly use Salt Cedar anywhere in the Southwest. Remaining broadleaf obligates are the Rose-throated Becard ( Pachyram - phus aglaiae ), Thick-billed Kingbird (Tyrannus crassirostris) , and Northern Beardless Tyrannulet ( Camptostoma imberbe). All are primarily tropical in distribution and occur locally along riparian systems in southeastern Arizona at the northern edge of their range. In summary, all but two broadleaf obligate species (Thick-billed Kingbird and Northern Beardless Tyrannulet), require tall and mature broadleaf trees for nest sites whether for huge basket, large platform, or cavity nests. Honey Mesquite and Salt Cedar rarely grow tall enough to become suitable nest sites for these species. Partial Broadleaf Obligates Nine of the 32 species are broadleaf obligates in some areas but not in others (Table 3) . All are broadleaf obligates in low-elevation river systems but nest in Salt Cedar and/ or Honey Mesquite along high-elevation riparian systems. The seven summer-visiting, midsummer-breeding builders of open nests were all found to nest in Salt Cedar in higher-elevation riparian systems but not at lower elevations. Four species— Yellow-billed Cuckoo ( Coccyzus americanus) , Bell’s Vireo (Vireo beliii) , Yellow-breasted Chat (lcteria uirens), and Summer Tanager ( Piranga rubra) — also use Honey Mesquite habitats along high-elevation river systems. Willow Flycatcher ( Empidonax traillii) and Yellow Warbler ( Dendroica petechia) have been extirpated from all low- elevation sites and some high-elevation sites. Broadleaf habitats are required for the existence of all these species in low- elevation river systems. In high-elevation river systems, all of these species use Salt Cedar and/ or Honey Mesquite as well as broadleaf habitats. All species in this category have declined at lower elevations but retain healthier popula- tions at high elevations. 13 RIPARIAN-OBLIGATE BIRDS Riparian Generalists Six of the 32 riparian -obligate species are riparian generalists throughout the Southwest (Table 3). These species use most, if not all, riparian habitats in all river systems. The Northern Cardinal ( Cardinalis cardinalis ) is very rare on the lower Colorado River but occurs in all riparian habitats from Gila Bend, Arizona, eastward. Blue Grosbeak (Guiraca caerulea) is the only midsummer- breeding riparian-obligate species to occur in Salt Cedar throughout the Southwest. Broadleaf habitats are not required for the occurrence of any of these species in the Southwest, nor are any declining within their range. Characteristics of Broadleaf Obligates and Salt Cedar Users All riparian-obligated raptors and cavity nesters at both low and high eleva- tions are broadleaf obligates. However, more raptor and cavity-nesting species are found on high-elevation river systems. Differences in species composi- tion of the broadlead riparian obligates between low and high elevations are in the number of raptor and cavity-nesting species vs. the number of partial broadleaf obligates (Table 4). The number of species using Salt Cedar at low vs. high elevations differs only in the number of midsummer-breeding sum- mer visitors that build open nests. Six of the eight species in this category use Salt Cedar at high elevations but are broadleaf obligates at low elevations. DISCUSSION The Importance of Broadleaf Riparian Vegetation Broadleaf trees within riparian systems provide secure, suitable nest plat- forms for raptors. Woodpeckers excavate the large dead, softwood limbs, and these cavities are subsequently used by other species. Where Saguaro cacti are absent, broadleaf trees are apparently vital to these species. Dependence of midsummer breeders on broadleaf riparian is more difficult to explain. Some species may be adversely affected by the extremely high summer temperatures at low elevations outside the structurally complex mature broadleaf forests. Temperature stress may affect survival of eggs during mid- summer, The upper physiological limit for embryo life is 43°C (Walsberg and Voss-Roberts 1983). This limit is exceeded on over 25% of all days at eleva- tions below 427 m (Hunter 1987) . This stress rarely exists above 427 m eleva- tion, where all midsummer breeders expand into habitats other than broadleaf riparian. Thus, nest-site selection appears to be a very important determinant in the breadth of habitat use among these species in southwestern riparian systems. Management of Riparian Obligate Species Management of southwestern riparian birds has often centered on the few Federally and state listed endangered and threatened species. The only ter- restrial bird in the Southwest that is Federally listed as an endangered species is the Bald Eagle (Haliaeetus leucocephalus) . The Arizona race of the Bell’s Vireo ( V.b . arizonae) is no longer being considered for listing while the western population of the Yellow-billed Cuckoo (C.a. occidentalis ) is presently being considered. California considers 16 of the riparian obligates as endangered, 14 RIPARIAN-OBLIGATE BIRDS Table 3 Riparian-Obligate Species and Their Life-History Characteristics Broadleaf dependency/ species Nest type Residency status' Peak egg laying 6 Locations of Salt Cedar use' Habitats other than broadleaf used" LE HE Obligate Bald Eagle Open PR Sp -early Su No No None Mississippi Kite Open SV Mid-Su No No None Cooper’s Hawk' Open PR Sp -early Su No No None Gray Hawk Open SV Sp -early Su No No None Zone-tailed Hawk' Open SV Sp -early Su No No None Common Black-Hawk Open SV Sp- early Su No No None Harris’ Hawk' Open PR Sp -early Su No No None Elf Owl' ' Cavity SV Sp -early Su No No None Ferruginous Pygmy-Owl ' ! Cavity PR Sp -early Su No No None Gila Woodpecker ' 1 Cavity PR Sp- early Su No No None Northern (Gilded) Flicker' ‘ Cavity PR Sp -early Su No No None Thick-billed Kingbird Open SV Mid-Su No No None Brown-crested Flycatcher ' ' Cavity SV Mid-Su No No None Rose-throated Becard Covered SV Mid-Su No No None Northern Beardless Tyrannulet Covered PR Mid-Su No No None Bridled Titmouse' Cavity PR Sp-early Su No No None White-breasted Nuthatch' Cavity PR Sp -early Su No No None Partial Obligate Yellow-billed Cuckoo Open SV Mid-Su No Yes SC, HM Tropical Kingbird Open SV Mid-Su No Yes SC Vermilion Flycatcher' Open PR Sp-early Su No No HM Willow Flycatcher Open SV Mid-Su No Yes SC Bell’s Vireo Open SV Mid-Su No Yes SC, HM Yellow Warbler Open SV Mid-Su No Yes SC Yellow-breasted Chat Open SV Mid-Su No Yes SC, HM Hooded Oriole Covered SV Mid-Su No No HM Summer Tanager Open SV Mid-Su No Yes SC, HM Generalists Crissal Thrasher' Open PR Sp-early Su Yes Yes SM,SC,HM Lucy’s Warbler Covered SV Sp-early Su Yes Yes SM,SC,HM Northern Cardinal Open PR Mid-Su Yes Yes HM,SC Blue Grosbeak Open SV Mid-Su Yes Yes SM,SC,HM Abert’s Towhee Open PR Sp-early Su Yes Yes SM,SC.HM Northern Oriole Covered SV Sp-early Su Yes Yes SM,SC,HM *PR, permanent resident; SV, summer visitor. *Sp, spring; Su, summer. 'LE, low elevation (<427 m); HE, high elevation (427-1524 m). ‘Vegetation abbreviations as in Table 1. •Locally obligated to riparian. These species may construct or use cavities in very large mesquites, but primarily use soft-wood riparian trees. Table 4 Numbers of Broadleaf Obligates and Salt-Cedar-Using Species Compared by Life-History Characteristics between Low (L) and High (H) Elevations <0 £ t. 3 O CO i - ■ 6 .2 32 >2 CO CD c 3 C & CO ro -rj ' E .is 13 if) ~ »« © y CL 3 fc. CO p o II? CO Q, CO -t— 3 C ^ CO 2> c -* C Q) -i 1 2:2 !3 C W) Q) *- a) T £ ^ a co a> a (A V Z 5^ Co 00 VO CM 1-H CM CO CO o CO in Tt CM VO CM h h ^ 00 \0 1 - _< T— ^ 00 00 o o CO CO o CO CO CM CM CM CM to co in co Tt CM co 00 CO VO CM CM CM CM if) CD - 4—1 a cn X) O «+» > p. is o O U U ~T3 - 0) 3% *— ■ C q> 5 > , a <0 o -3 O U U -2 TO O CO f- <0 T3 0) U in <0 +-* O -t-* J= "O CD T3 J3 O c co 0) ‘5 CD a a to -O E 3 C c CD a CD 0) C 0) <0 a c X V X) E 3 Z 16 RIPARIAN-OBLIGATE BIRDS threatened, or species of special concern. New Mexico lists four species of special concern along the upper Gila River. Arizona lists seven species as threatened native wildlife. An additional seven species have declined from at least half of their historical range in Arizona. Finally, the Ferruginous Pygmy- Owl and Willow Flycatcher are not listed, though they have disappeared from most of their historical range in Arizona. Despite the Federal listing of the Bald Eagle, this species does not greatly influence riparian habitat management where many bird species have declined or been extirpated. The greatest problem afflicting effective riparian manage- ment throughout the Southwest, especially at lower elevations, is the atten- tion given to single species at the expense of an entire community of species that is in trouble. The change in status of any single species is insufficient to indicate the loss of native riparian habitat regionwide. The Arizona Bell’s Vireo has declined tremendously at lower elevations but remains common and has even spread at higher elevations (Brown et al. 1983). Listing throughout its range is therefore inappropriate, while listing of declining populations at lower eleva- tions is needed. The same problem may apply to western populations of the Yellow-billed Cuckoo. The listing of Yellow-billed Cuckoo populations at low elevations, where they are declining, will not protect populations of cuckoos or other riparian birds at high elevations. Listing of any one species will not protect all other declining species of riparian birds in the Southwest. A radical change in orientation is needed, from the piecemeal approach of protecting single species (which is still essential) to protecting habitats. Native riparian systems must be protected for what they are — endangered ecosystems. Only by river system management can we effectively stem the decline of our riparian avifauna. The priority should be the return of healthy stands of broadleaf trees. To maximize the growth of broadleaf trees, natural regeneration should be encouraged, large-scale revegetation efforts should be initiated, and Salt Cedar should be controlled. The need for mature broadleaf trees as nesting platforms and for cavity excavation is unequivocal; in addition, mature and structurally complex stands of broadleaf trees may also provide the thermal cover necessary for successful nesting of midsummer breeders at low eleva- tions. The most effective management for riparian-obligate breeding species is to return the breeding habitat they require. ACKNOWLEDGMENTS We wish to thank the many field biologists who have been instrumental in collecting the inventory data. Editing by Kathleen Franzreb, John Gustafson, and Stephen Laymon greatly enhanced the manuscript. We also thank Cindy D. Zisner for typing and editing the manuscript. LITERATURE CITED Anderson, B.W., and Ohmart, R.D. 1984. A vegetation management study for the enhancement of wildlife along the lower Colorado River. U.S. Bureau of Reclamation, Boulder City, NV. Arnold, L. W. 1940. An ecological study of the vertebrate animals of the mesquite forest. Unpubl. M.S. Thesis, Univ. Arizona, Tucson, AZ. 17 RIPARIAN-OBLIGATE BIRDS Bent, A.C. 1963-1968. Life histories of North American birds. Dover, New York. Brown, B.T., Carothers, S.W., Haight, L.T., Johnson, R.R., and Riffey, M.M. 1981. Checklist of the birds of the Grand Canyon area. Grand Canyon Nat. Hist. Assoc., Grand Canyon National Park, A Z. Brown, B.T., Carothers, S.W., and Johnson, R.R. 1983. Breeding range expansion of Bell’s Vireo in Grand Canyon, Arizona. Condor 85:499-500. Cardiff, S. 1978. Status of the Elf Owl in California. Nongame Wildlife Invest., Job III-1.0, Calif. Dept. Fish and Game, Sacramento, CA. Carothers, S.W., Johnson, R.R., and Aitchison, S.W. 1974. Population structure and social organization of southwestern riparian birds. Am. Zool. 14:97-108. Clark, T.O. 1984. Avifaunal studies in the Gila River complex, eastern Arizona. Unpubl. M.S. Thesis, Arizona State Univ., Tempe, AZ. Engel-Wilson, R.W., and Ohmart, R.D. 1978. Floral and attendant faunal changes on the lower Rio Grande between Fort Quitman and Presidio, Texas. USDA Forest Serv. Gen. Tech. Rep. WO-12:139-147. Glinski, R.L., and Ohmart, R.D. 1983. Breeding ecology of the Mississippi Kite in Arizona. Condor 85:200-207. Higgins, A,, and Ohmart, R.D. 1981. Riparian habitat analysis: Tonto National Forest. USDA Forest Service, Albuquerque, NM. Hildebrandt, T.D., and Ohmart, R.D. 1982. Biological resource inventory (vegetation and wildlife)— Pecos River Basin, New Mexico and Texas. U.S. Bureau of Reclamation, Amarillo, TX. Hink, V., and Ohmart, R.D. 1984. Middle Rio Grande biological survey final report. U.S. Army Corps of Engineers, Albuquerque, NM. Hunter, W.C. 1987. Response to an exotic habitat by arid riparian breeding birds along an elevational gradient. U.S. Bureau of Reclamation, Boulder City, NV. Kasprzyk, M.J. 1984. Results of biological investigations: lower Virgin River vegetation management study. U.S. Bureau of Reclamation, Boulder City, NV. Ohmart, R.D. 1982. Past and present biotic communities of the lower Colorado River mainstem and selected tributaries. U.S. Bureau of Reclamation, Boulder City, NV. Ohmart, R.D., and Anderson, B.W. 1982. North American desert riparian ecosystems, in Reference Handbook on the Deserts of North America (G.L. Bender, ed.), pp. 433-479. Greenwood Press, Westport, CT. Phillips, A., Marshall, J,, and Monson, G. 1964. The Birds of Arizona. Univ. Arizona Press, Tucson, AZ. Rea, A.M. 1983. Once a River. Univ. Arizona Press, Tucson, AZ. Walsberg, G., and Voss-Roberts, K.A. 1983. Incubation in desert-nesting doves: mechanisms for egg cooling. Physiol. Zool. 56:88-93. 18 CAN THE WESTERN SUBSPECIES OF THE YELLOW-BILLED CUCKOO BE SAVED FROM EXTINCTION? STEPHEN A. LAYMON, Department of Forestry and Resource Management, 145 Mulford Hall, University of California, Berkeley, California 94720 MARY D. HALTERMAN, 10508 Malaga Way, Rancho Cordova, California 95670 Historically, the California Yellow-billed Cuckoo {Cocc\;zu s americanus oc- cidentalis ) was considered common in river bottoms throughout western United States and southern British Columbia (Gaines and Laymon 1984). It began a drastic decline in numbers as the riparian forests on which it depended were removed for fuel and to make way for agriculture and grazing. Along with local declines, there was an overall range contraction; the last known breeding birds were in British Columbia in the 1920s, in Washington in the 1930s, in Oregon in the 1940s, and in California north of the Sacramento Valley in the 1950s (Roberson 1980, Gaines and Laymon 1984, Figure 1). Clearing for agriculture, flood control, and urbanization has resulted in the loss of hundreds of thousands of hectares of riparian habitat throughout the West. Examples of this massive habitat destruction include (1) the Los Angeles basin, which supported hundreds of cuckoos prior to 1900, no longer sup- ports any riparian habitat (Gaines and Laymon 1984); (2) the Buena Vista Lake area of Kern County, where ornithologists collected 17 cuckoos in three weeks in 1921, has been converted to a seemingly endless sea of cotton fields (Gaines and Laymon 1984); and (3) the Sacramento Valley, where the species was once common, now has less than 1% of the original habitat and sup- ports fewer than 50 pairs of breeding cuckoos (Gaines and Laymon 1984). Remnant fragments of riparian habitat throughout the West are still en- dangered by degradation, clearing, and inundation. For these reasons the future of the California Yellow-billed Cuckoos appears uncertain. In this paper we present the results of field surveys from California that further document this species’ decline. We also discuss causes for these recent declines and pro- spects for the future. METHODS Our conclusions are based on research done on the Sacramento River, Butte and Tehama counties, during 1978 and 1979; along the South Fork Kern River, Kern County, during 1985 and 1986; and throughout southern Califor- nia in 1986. Methods included field surveys, nest monitoring, foraging obser- vations, radiotelemetry, and measuring eggshell thickness. Our standard survey method involved stopping every 200 m in suitable habitat and playing a tape- recorded Yellow-billed Cuckoos call 10 times, or until a response was elicited. The tape recording could be heard to approximately 300 m under field con- ditions. Unmated cuckoos were distinguished from paired ones by their coo- ing or cawing vocalizations and their high level of interest in the tape-recorded calls. While surveying and locating nests, we recorded data, including tree Western Birds 18:19-25,1987 19 WESTERN YELLOW-BILLED CUCKOO species and foraging height, on the cuckoos’ foraging activity. Radio-telemetry data were gathered on two female cuckoos at the Kern River site and includ- ed both constant monitoring of foraging behavior and delineation of home range. RESULTS Gaines (1974) defined Yellow-billed Cuckoo habitat as willow ( Salix spp.)- cottonwood (Populus fremontii) forests below 1300 m elevation, >10 ha in extent, and wider than 100 m. Using radio-telemetry and intensive observa- tion we refined this definition of the species’ habitat. We determined that cuckoos used larger areas, averaging 17 ha, and foraged predominantly in cottonwoods rather than willows, as expected from previous observations. Nests were placed almost entirely in willows, making a mix of cottonwoods and willows essential (for more data see Laymon and Halterman 1985). We defined a tract of riparian woodland as suitable for cuckoos if it was larger than 15 ha and included a minimum of 3 ha of closed-canopy, broad-leafed forest. We defined as unsuitable tracts smaller than 4 ha and all tracts con- taining no closed-canopy, broad-leafed forest, regardless of their extent. In 1986 we surveyed all habitat meeting this definition of suitability in southern California from Inyo and Kern counties south to the Mexican border and in Arizona along the Colorado River. The only population (defined as more than 5 pairs) found in California was 9 pairs on the South Fork of the Kern River. In the Prado Flood Control Basin on the Santa Ana River, River- side County, we found one breeding pair and two additional adults; a third adult was found by R.L. Zembal (pers. comm.). The single birds may also represent mated birds, giving a total of 4 pairs for the Prado area. The only other pair away from the Colorado River was on the Amargosa River near Tecopa, Inyo County. Single unmated birds were found in the Owens Valley and on the Mojave River. Seemingly suitable habitat for several pairs is pre- sent on the Mojave, Santa Clara, and Owens rivers, but no cuckoos were found there. We located 2 pairs of cuckoos on the California side of the Col- orado River, 3 pairs on the Arizona side, and an additional 3 unmated birds, 2 in California and one in Arizona. We estimate the total population for the Colorado River from Davis Dam to the Mexican border to be 5-10 pairs, representing a 92-96% decline from the 122 pairs estimated in 1977 (Gaines and Laymon 1984). The only area where we found a substantial population of cuckoos was on the Bill Williams River between Lake Havasu and Planet Ranch, Mohave and La Paz counties, Arizona. At this site we found paired cuckoos at 17 locations and an additional 4 unmated birds. We estimated that 25-30 pairs were breeding there in 1986, a decline from an estimated 57 pairs in 1977 (Gaines and Laymon 1984). In 1979 we collected two eggs and analyzed them for pesticides. The eggs contained an average of only 0.1 parts per million of DDE, suggesting that chlorinated hydrocarbons are present in low concentrations (Laymon 1980) . However, in 1985 we collected from three nests on the South Fork of the Kern River eggshell fragments that averaged 0.115 mm thick, an average of 20 WESTERN YELLOW-BILLED CUCKOO 19% and range of 17 to 24% thinner than eggshells (average thickness 0.143 mm) collected before the DDT era. Figure 1. Historic and current range of the California Yellow-billed Cuckoo. 21 WESTERN YELLOW-BILLED CUCKOO DISCUSSION What relationship do drastic population declines, restrictive habitat re- quirements, and possible pesticide contamination have on the western subspecies of the Yellow-billed Cuckoos? There has, of course, been massive riparian loss throughout the West. Since cuckoos need large expanses of closed-canopy cottonwood -willow riparian forest, their numbers have drop- ped as habitat has been removed and degraded. The recent decline of 92-96% along the Colorado River between 1977 and 1986 is cause for great con- cern; this area was the stronghold of the species in the northwestern 70% of its original range (Figure 1). Although there has been some clearing for agriculture along the Colorado River since 1977, most of the habitat loss since that time was due to un- sually high water flows from May 1983 to the present. Heavy precipitation and the filling of Glen Canyon Dam have resulted in extensive floods that immersed the roots of willows and cottonwoods for prolonged periods of time, drowning as much as 99% of the existing habitat (B.W. Anderson pers. comm.). Areas occupied by several pairs of cuckoos in 1977 are now monotypic stands of salt cedar (Tamarix pentandra) and uninhabited by cuckoos. For example, above Laguna Dam in 1977 at least 3 pairs of cuckoos occupied a 12-ha site that was approximately 40% willow (Gaines and Laymon 1984) . The dominant vegetation is now salt cedar and less than 1% willow cover remains; our 1986 survey revealed no cuckoos at this site. Another example is the vicinity of Picacho State Recreation Area, where in 1977 21 pairs of cuckoos were breeding in 120 ha of 70-m wide willow forest (Gaines and Laymon 1984). Salt cedar and aquatic vegetation now dominate this site and in 1986 we found no cuckoos in the 5 ha of scattered willow -cottonwood habitat that remains. The sites on the Colorado River where we did locate cuckoos cannot be considered suitable habitat for the species. They are marginal locations at best, lacking sufficient extent, breadth, and structural diversity. Habitat for several pairs on the Amargosa River at Tecopa was eradicated by flash floods in 1983 that scoured out the river bed (J. Tarble pers. comm.) . Only one pair remains at this site where four were found in 1977. We also noted declines in areas where habitat has remained constant or improved. Gaines and Laymon (1984) found 3 pairs in the Owens Valley where we found only a single unmated female. The habitat was unchanged at this site. Unoccupied habitat was also found on the Santa Clara, Mojave, Amargosa, and Sants Ana rivers. The Amargosa site is especially interesting since it has been surveyed yearly since 1977 (J. Tarble pers. comm ). Since 1977, when 4 pairs were found at the site, cuckoos have nested only in 1979 (1 pair), 1982 (2 pairs), and 1986 (1 pair), illustrating a very unstable popula- tion. A possible explanation is that with the population decline along the Col- orado River, fewer recruits are available to colonize and sustain outlying areas. With small populations, under 25 pairs, stochastic events could cause chance extinctions (Soule and Wilcox 1980) . At this time we do not know if any population in California is safe from these effects. 22 WESTERN YELLOW-BILLED CUCKOO Comparison with early ornithological records shows that the western subspecies of the Yellow-billed Cuckoo now uses a narrower range of habitats than it did historically. Yellow-billed Cuckoos once bred in spruce bogs in Washington, along city streets in Sacramento, and in prune orchards in Marysville, all non-riparian habitats (Gaines and Laymon 1984). Two hypotheses that might explain these differences include (1) cuckoos were forced into marginal areas by saturation of suitable habitat and (2) cuckoos actually had a wider range of suitable habitats then they do today. If the latter is cor- rect, this narrowing of habitat preference could have come from a physical inability to reproduce in the more open, arid habitats because of moisture loss caused by eggshell thinning induced by pesticides. Water loss in eggs is caused by a relationship between the thickness and porosity of the eggshell and environmental factors such as temperature and humidity. Higher temperature, lower humidity, and thinner eggs all could cause excess water loss and reduced hatchability (Rahn and Ar 1974). Arizona cuckoos breed in dry, open salt cedar habitats at elevations above 500 m, but are confined to moist willow-cottonwood habitats below 500 m (Hunter et al. 1987) . Sum- mer rains in eastern Arizona and lower temperatures at the higher elevations could mitigate the effects of eggshell thinning. Since DDT was banned in the United States in the mid-1970s, birds are exposed to persistent pesticides primarily on their wintering grounds and in migration . The wintering grounds of the western subspecies are unknown but suspected to be in South America, where the eastern subspecies winters. Exposure to other pesticides and agricultural chemicals can be either direct or indirect. We observed direct exposure in the Sacramento Valley when ac- tive nests in walnut orchards were sprayed with Zolone, causing sub-lethal poisoning of the young (Laymon 1980) . Cuckoos could be exposed indirect- ly when a favored food, such as the Pacific tree frog (Hy/a regilla), occurs in pesticide-laden runoff from adjoining agricultural lands. Sphinx moth lar- vae (Sphingidae) , another favored prey, could be poisoned by pesticides, thus reducing the prey population. This reduction of prey would be another in- direct effect on cuckoos. The western Yellow-billed Cuckoo has declined dramatically in geographic range as well as number. Eastern Arizona, New Mexico, western Texas, and Sonora and Chihuahua in Mexico are currently the only areas where cuckoos are believed still to have populations of which extinction is not an immediate concern. Even in these areas, much riparian habitat has been removed for agriculture or river channelization, displaced by salt cedar, and degraded by grazing. No surveys of cuckoos have been done in these areas so the current populations there are unknown. However, on the basis of estimates of cur- rent habitat (Hunter et al. 1987) , the numbers of the subspecies must be very low. In California, 50-75 pairs of cuckoos probably still breed (Gaines and Laymon 1984) . It is likely that fewer than 200 pairs breed in Arizona, 100-200 pairs breed in New Mexico, and 100-200 pairs breed in western Texas. Numbers in Mexico are unknown, but are believed to be low because of habitat degradation in at least the northern two-thirds of Sonora (S. Howell pers. comm.). These estimates yield a total of 475-675 pairs in North America north of Mexico; the Mexican population is unknown, but probably does not exceed this figure. The U.S. Fish and Wildlife Service lists as endangered 23 WESTERN YELLOW-BILLED CUCKOO species and subspecies of birds that have larger populations than that of the California Yellow-billed Cuckoo (e.g., Red-cockaded Woodpecker Picoides borealis ) . The California Yellow-billed Cuckoo’s range is approximately 30% of its historical extent. Wilcove and Terborgh (1984) categorized the patterns by which birds decline; the Yellow-billed Cuckoo most closely fits a pattern of retraction from the peripheral parts of its range combined with retraction from marginal habitats. This pattern characterizes the northwestern 70% of the historic range. Wilcove and Terborgh (1984) cited no examples of this pat- tern and listed it only as a theoretical possibility. MANAGEMENT CONSIDERATIONS What can be done to ensure the future of the California Yellow-billed Cuckoo? The first priority is a survey to determine numbers and locations of cuckoos, especially in the center of the remaining population’s range. Such information would permit management agencies to direct efforts at habitat preservation and restoration to the areas where they would best benefit the cuckoos. Acquisition and improvement of both actual and potential cuckoo habitat should be the primary aim of efforts to save the western subspecies. One step to improve areas for cuckoos is removal of grazing to allow natural regeneration and encourage increased density of willows and cottonwoods. In treeless areas that have been severely overgrazed for a long time, or where natural flooding does not occur, other steps need to be taken. The most ef- fective way to reforest an area is through sapling plantings. This has been done, with varying degrees of success, on the Colorado River over the past 15 years (B.W. Anderson pers. comm). The Nature Conservancy at the Kern River Preserve has initiated reforestation at suitable sites by using California Department of Fish and Game tax check-off funds. In 1986 11 ha of willow and cottonwood forest were replanted to replace the original forest that had been removed in the late 1800s to fuel a local flour mill. The success on this site is phenomenal, with some trees reaching a height of 3 m during the first growing season (B.W. Anderson pers. comm ). This area will be a valuable addition to the existing 120 ha of forest currently on the preserve. In 1987 two additional sites totaling 27 ha are scheduled to be replanted. Captive propagation and reintroduction into areas, such as the Willamette Valley of Oregon, where much seemingly suitable habitat persists but cuckoos have been extirpated, is also a management tool that merits investigation. Studies should be initiated to determine the habitat and food resource base of potential reintroduction sites and the feasibility of captive breeding of cuckoos. Further research is needed to determine effective population size and site tenacity in the cuckoo. In addition, almost all life-history variables such as mortality and longevity are still poorly known. The location of the wintering grounds has not yet been located; this needs to be determined before threats to wintering cuckoos can be addressed. We feel that the western subspecies of the Yellow-billed Cuckoos can be saved from extinction, but not without the concerted efforts of researchers, resource management agencies, and conservation organizations. 24 WESTERN YELLOW-BILLED CUCKOO ACKNOWLEDGMENTS Guillaume Labeyrie, Zev Labinger, Duncan McNiven, and Virginia Norris provided extensive field assistance. Numerous others helped on a short-term basis. We gained valuable insight from conversations with Bertin Anderson and Chuck Hunter, Arizona State University, Tempe, AZ. Dick Zembal, U.S. Fish and Wildlife Service, Laguna Niguel, CA, provided information on cuckoos in Prado Flood Control Basin. Jan Tar- ble, Shoshone, CA, provided valuable information on the cuckoo population on the Amargosa River. Steve Howell, Point Reyes Bird Observatory, Stinson Beach, CA, shared his knowledge of cuckoos and habitats in Mexico. Rick Hewitt and The Nature Conservancy provided funding, housing, and other moral and physical support. John Gustafson, Alan Craig, and the California Department of Fish and Game Non-game Bird and Mammal Section provided funding through contracts E-W-3 1979 and 85/86 C-1393. Ted Beedy, Kay Franzreb, and John Gustafson provided valuable comments which improved the manuscript. Above all, David Gaines provided the inspiration without which this work would never have been undertaken. LITERATURE CITED Gaines, D. 1974. Review of the status of the Yellow-billed Cuckoo in California: Sacramento Valley populations. Condor 76:204-209, Gaines, D., and Laymon, S.A. 1984. Decline, status and preservation of the Yellow- billed Cuckoo in California. W. Birds 15:49-80. Hunter, W.C., Ohmart, R.D., and Anderson, B.W. 1987. Status of breeding riparian- obligate birds in southwestern riverine systems. W. Birds 18:10-18. Laymon, S.A. 1980. Feeding and nesting behavior of the Yellow-billed Cuckoo in the Sacramento Valley. Wildlife Mgt. Branch Admin. Rep. 80-2. Calif. Dept. Fish and Game, Sacramento. Laymon, S.A., and Halterman, M.D. 1985. Yellow-billed Cuckoo in the Kern River Valley: 1985 population, habitat use and management recommendations. The Nature Conservancy, Kern River Preserve, P.O. Box 1662, Weldon, CA 93283. Rahn, H., and At, A. 1974. The avian egg: incubation time and water loss. Condor 76:147-152. Roberson, D. 1980. Rare Birds of the West Coast. Woodcock Publ., Pacific Grove, CA. Soule, M.E., and Wilcox, B.A. 1980. Conservation biology: An evolutionary-ecological perspective. Sinauer Assoc., Sunderland, MA. Wilcove, D.S., and Terborgh, J.W. 1984. Patterns of population decline in birds. Am. Birds 38:10-13. 25 Yellow-billed Cuckoo Sketch by Narca Moore-Craig 26 WILLOW FLYCATCHER SURVEYS IN THE SIERRA NEVADA JOHN H. HARRIS, Department of Biology, Mills College, Oakland, California 94613 SUSAN D. SANDERS, 133 North St., Woodland, California 95695 MARY ANNE FLETT, 1764 Newell Ave., Walnut Creek, California 94595 The Willow Flycatcher ( Empidonax traillii) was formerly a common sum- mer resident in California, breeding in riparian willow thickets. It has been extirpated from most of its California range, and is currently under considera- tion for state Threatened or Endangered status (R. Schlorff pers. comm.). Most of the remaining populations occur in isolated mountain meadows of the Sierra Nevada and along the Kern, Santa Margarita, and San Luis Rey rivers (Remsen 1978, Serena 1982, Unitt 1987). The California Department of Fish and Game conducted a survey for Willow Flycatchers in six Sierra Nevada national forests and Yosemite National Park in 1982 (Serena 1982). This paper describes the results of the 1986 Willow Flycatcher survey in the Sierra Nevada and summarizes information about the species’ status in Califor- nia. The purposes of our study were to survey sites at which Willow Flycatchers had been previously seen, search for new sites, and attempt to refine our knowledge of the species’ habitat requirements, METHODS We conducted our surveys between 23 June and 31 July 1986 in order to minimize the likelihood of counting migrant birds. Studies at Dinkey, Poison, and Long meadows in the Sierra National Forest (Stafford and Valentine 1985) suggest that Willow Flycatchers frequently arrive at their breeding location as late as mid-June, occasionally as late as early July. In the same area, Willow Flycatchers depart at any time from the end of July to late August, with a peak in mid-August. During the 1982 survey some sites were visited in the first week of June. Birds observed at this time could have been migrants. We conducted our surveys early in the morning, generally from sunrise until 1000. Spontaneous singing declines after 1000 (King 1955, Flett and Sanders 1987), although individuals can be heard at any time of day. A second, less intense, period of singing generally occurs before dusk. At each site, we walked along the perimeter of all willow habitat, listening and play- ing taped songs and calls of Willow Flycatchers. We recorded the number of singing male Willow Flycatchers at each site and mapped the locations of all Willow Flycatchers on sketched maps of the sites. A significant fraction of the singing males may remain unpaired through the breeding season, as current studies on the Little Truckee River and Shaver Lake area indicate (Flett and Sanders 1987, Stafford and Valentine 1985). The assumption that singing males represent pairs may thus lead to an overestimate of the number of breeding birds. On the other hand, song frequency declines after pairing (Stafford and Valentine 1985) ; thus successfully paired males may be missed in a song survey. Western Birds 18:27-36.1987 27 WILLOW FLYCATCHER SURVEYS During 1982 the Inyo, Sierra, Stanislaus, Tahoe, Plumas, and Lassen national forests were surveyed (Serena 1982) . Other areas surveyed includ- ed The Nature Conservancy’s Kern River Preserve and Yosemite National Park. We visited most of the sites of the 1982 survey, including all locations which had Willow Flycatchers in 1982 or subsequent years. New areas of coverage included portions of the El Dorado, Toiyabe, and Sequoia national forests, Sequoia National Park, and Kings Canyon National Park. We also visited new sites in the Lassen, Plumas, Inyo, Sierra, and Tahoe national forests. RESULTS We visited 125 sites during the 1986 survey, recording 110 singing male Willow Flycatchers at 30 sites. In addition, we have received reports of an additional 6 birds in the Sierra/Cascades region, for a total thus far of 116 singing males. Fifty-six of the sites visited were not surveyed in 1982. These sites were added to the survey on the basis of suggestions by biologists and sightings of Willow Flycatchers between 1982 and 1986. Visits to these new sites resulted in sighting of 1 1 singing males at 6 of the sites. Areas with more than 2 singing males are shown in Table 1. The Nature Conservancy’s Kern River Preserve had the largest number of singing males (39). The preserve contains several miles of riparian cottonwood -willow forest (Populus fremontii, Salix laevigata, and S. gooddingii) . The Little Truckee River drainage, which had the largest number of singing males in 1982, had 25 in 1986. This area Table 1 Willow Flycatcher Concentrations in the Sierra Nevada 1982-1986' Location 1982 1983 1984 1985 1986 Perazzo Meadow (Tahoe N.F.) 11 17 12 8 11 Lacey Valley (Tahoe N.F.) 13 14 10 12 7 Little Truckee R. Total (Tahoe N.F.) 39 — — — 25 Kern River Preserve (Nat. Conserv.) 26 — 23 29 39 Shaver Lake Area (Sierra N.F.) 10 — 15 8 9 Beasore Meadow (Sierra N.F.) 2 — — — 4 Hodgdon Meadow (Yosemite N.P.) 2 — — 3 1 Ackerson Meadow (Stanislaus N.F.) 5 — — — 2 b Westwood Meadow (Lassen N.F.) 4 — — — 6 Gurnsey Meadow (Lassen N.F.) 0 — — — 3 Faith, Charity Valleys (Toiyabe N.F.) — — — — 5 Klamath River (Siskiyou Co.) — — — 3' — ‘For each site the number of singing male Willow Flycatchers is indicated for years in which surveys have been conducted. The table includes all sites that had more than 2 singing male Willow Flycat- chers at some time during the study period. Only sites in the Sierra Nevada and Cascade ranges are included. A total is given for the Little Truckee River drainage, which includes Perazzo Meadow and Lacey Valley. ^Reports indicate that there may have been 3 singing males (J. Winter pers. comm.). ‘Reported by M. Robbins. 28 WILLOW FLYCATCHER SURVEYS includes extensive meadows near Webber Lake, Perazzo Meadow, and ad- ditional meadows along the Little Truckee River west of Highway 89. The Shaver Lake area, Sierra National Forest, had 9 singing males. This area in- cludes Dinkey, Long, and Poison meadows. Dinkey Meadow had 6 singing males in 1982 and 3 singing males in 1986. The Little Truckee River, Kern River, and Shaver Lake areas together account for 67% of the Willow Flycat- cher sightings in the Sierra during 1986. These three areas accounted for 73% of the Sierra Nevada sightings during 1982. Roughly the same number of birds was seen at the sites surveyed in both 1986 and 1982 (99 in 1986, 103 in 1982). Seven sites that had Willow Flycat- chers in 1982 had none in 1986. Six of these sites had only one bird in 1982. Six additional sites decreased in number. Most important among this group were Lacey Valley (declined from 13 to 7), Little Truckee River (one site de- clined from 8 to 2) , and Dinkey Meadow (declined from 6 to 3) . Three sites that had no Willow Flycatchers in 1982 had birds in 1986. In two cases three birds were present in 1986, in the other case two birds were present. Seven additional sites increased in numbers of Willow Flycatchers. Most important among these were Westwood (increased from 4 to 6), Beasore Meadow (in- creased from 2 to 4), Long Meadow (increased from 1 to 3), and the South Fork of the Kern River (increased from 26 to 39) . The three most numerous Sierran populations have been surveyed during at least 4 of the last 5 years. Perazzo Meadow and Lacey Valley are two Little Truckee River sites that have been consistently surveyed over the last five years. The Perazzo Meadow population has fluctuated, but there were the same number of singing males in 1986 and 1982. The Lacey Valley popula- tion appears to be declining, and accounts in part for the overall decline along the Little Truckee River. The Shaver Lake area (9 sites) has been studied intensively since 1983. The population during 1985 and 1986 was smaller than that in 1982. Dinkey Meadow had 6 singing males in 1982 (this may have been an overestimate, B. Valentine pers. comm.), but has had 3 in all subsequent years except 1985, when there were only 2 singing males. Long Meadow, which had only 1 singing male in 1982, has had 3 in every year since 1984. The Kern River population apears to have increased steadily since 1984. The increase is distributed fairly evenly over the area. Grazing has been eliminated in several of the areas of concentration within the preserve since 1981 or 1982. Prince Pond, which has had as many as 13 birds, was ac- quired by the Nature Conservancy in 1982 and has been ungrazed since 1983. Mariposa Marsh, ungrazed since 1981, has increased from 7 to 12 birds in the last three years. Prince Pond had fewer birds (7) in 1986 than in the last two years, but the birds may have moved to adjoining flooded habitat. Flooded areas west of Prince Pond had at least 6 singing males where none had been sighted previously. These areas are not flooded every year. Willow Flycat- cher distribution on the Kern River floodplain may be related to the distribu- tion of flooded areas in a given year. Grazed areas adjoining the preserve, such as Onyx and Bloomfield Ranches, had no birds this year. Among the new sites visited, 6 sites had Willow Flycatchers. A site on the Feather River near Clio had 1 Willow Flycatcher. Other new sites included one on the Little Truckee River (3 birds) , Summit Meadow 2 (Shaver Lake area, 1 bird), Faith Valley and Charity Valley (Toiyabe National Forest, 3 29 WILLOW FLYCATCHER SURVEYS and 2 birds, respectively), and Troy Meadow (Sequoia N.F., 1 bird; 1 has been seen in previous years) . The Faith Valley and Charity Valley sites are only a few miles apart, and there is some apparently suitable habitat nearby in Hope Valley, although we did not locate singing males there during the 1986 survey. DISCUSSION The Willow Flycatcher was formerly considered common and widely distributed in the state wherever suitable habitat existed (Grinnell and Miller 1944). Areas where it was most common included the Central Valley, the southern coastal region, and central California in general. Specific areas men- tioned in which Willow Flycatchers were common or abundant include the Kings River (Goldman 1908), the vicinity of Buena Vista Lake (Linton 1908), the south coast (Willet 1912, 1933), swampy thickets near Los Angeles and the valley rivers of central California (Belding 1890), the San Francisco Bay region (Barlow 1900), and Yosemite Valley (Grinnell and Storer 1924). Ridgway considered it to be the most abundant and generally distributed Em- pidonax species (cited in Belding 1890). In the Sierra Nevada, Willow Fly- catchers were felt to be common along willow-lined streams, especially in broad river bottomlands (Grinnell and Storer 1924, Grinnell et al. 1930, Sumner and Dixon 1953) . Nesting sites were found from sea level to about 2500 m (8000 ft) (Grinnell and Miller 1944) . As a breeding species, the Willow Flycatcher has been extirpated from most of its former range, surviving only in mountain meadows of the Serra Nevada, and along the south fork of the Kern River, the Santa Margarjta River, and the San Luis Rey River (Remsen 1978, Garrett and Dunn 198 J; Serena 1982, Unitt 1987). As a spring and fall transient, the Willow Flycatcher is still fairly common in riparian willow habitat throughout the state (McCaskie et al. 1979, Garrett and Dunn 1981). Willow Flycatchers no longer breed in the Central Valley (McCaskie et al. 1979), and records from the southern coast and cen- tral coast have been sporadic (Stallcup and Greenberg 1974, Garrett and Dunn 1981, Roberson 1985, Unitt 1984). Extensive searches in the Sacramento River Valley (Gaines 1974) have revealed no breeding Willow Flycatchers. Careful search of riparian habitat in southern California in the summer of 1978 revealed only two singing males (Garrett and Dunn 1981), although subse- quent surveys have revealed populations on the Santa Margarita and San Luis Rey rivers in San Diego County (L. Salata pers. comm., Unitt 1987). Even in the Sierra Nevada, the species has apparently declined (Gaines 1977, Serena 1982), having become alarmingly scarce in the Yosemite region. Our survey results indicate that the majority of Sierra Nevada Willow Fly- catchers are located in three general areas. Between the Little Truckee River (Tahoe National Forest) and Westwood Meadow (Lassen National Forest), we found 43 singing males, most of which were along the Little Truckee River (Table 1). Nineteen singing males were found in the central Sierra, from Acker- son Meadow (Stanislaus National Forest) to the Shaver Lake area (Sierra National Forest) . The south fork of the Kern River had the largest popula- tion, with 39 singing males. In addition to these major areas, small numbers of singing males were located on the east side of the Sierra, near Mono Lake 30 WILLOW FLYCATCHER SURVEYS (3 singing males) and in the vicinity of Carson Pass (5 singing males) . There is a large gap in the distribution of sightings between the central Sierra and the Kern River. There have been a few reports in recent years of Willow Flycat- chers in the Sequoia and Kings Canyon National Parks (L, Norris pers. comm, to R. Schlorff) but no birds were found during this year’s survey, and there seems to be insufficient habitat to support large populations. Portions of northern California, particularly the area north of Lassen National Forest, from the Nevada border to the coast, should be surveyed in the future. During our survey, a singing male was located along the Feather River, near Clio. This site was visited briefly, and there appears to be more suitable habitat that should be surveyed in the future. Singing males have been reported in recent years from the forks of the Salmon (1), the vicinity of Mt. Shasta (1), and Lower Klamath Lake (3 nests) (M. Robbins pers. comm.). Singing males have been reported from Humboldt County in the vicinity of Garberville (R. LeValley pers. comm.) and from Willow Creek (Serena 1982). These sightings may have been of migrants (R. LeValley pers. comm.). Recent Breeding Bird Surveys have produced a few sightings in the northern tier of counties (S. Droge pers. comm.). There are 29 survey routes in Humboldt, Trinity, Del Norte, Siskiyou, Shasta, and Modoc counties. Seven of these routes have recorded Willow Flycatchers during the period from 1982 to 1985 (4, 3, 3, and 6 birds in the four years) . A single male was observed at the Modoc Na- tional Wildlife Refuge for the first time in 1985, and a pair fledged a single young there in 1986 (W. Radke pers. comm,). This successful nesting may have resulted from protection of riparian habitat over the last 6 years. Fur- ther surveys in northern California will likely produce more sightings, but there is no indication that large populations occur in this region. The subspecific identity of California Willow Flycatcher populations pro- vides further reason for concern about the species status in the state. Three subspecies occur in California (Unitt 1987). Empidonax traillii brewsteri breeds from Fresno County north, from the coast to the Sierra Nevada crest. Em- pidonas traillii adastus breeds east of the Sierra/Cascade axis. The type locality for this taxon is in southern Oregon, and it is known to range into Modoc County (Phillips 1948) and perhaps south to northern Inyo county (Unitt 1987). Willow Flycatchers in northern California may represent a zone of in- tergradation between E.i. brewsteri and E.t. adastus (Phillips 1948). Southern California populations of Willow Flycatchers have recently been shown (Unitt 1987) to belong to the subspecies E.t. extimus Phillips (1948). The northern limits of breeding for this taxon are Independence in the Owens Valley, the south fork of the Kern River, and the Los Angeles basin. It has also suffered serious declines in the portions of its range outside of California (Unitt 1987) . Thus the small number of breeding Willow Flycatchers in California is further divided among three subspecies, each of which has declined to very low numbers within the state. Remsen (1978) listed the Willow Flycatcher as a species of highest priori- ty, facing extirpation if current trends continue. In 1980, reports from the Pacific coast and southwest regions led to the species being added to the Audubon Blue List (Arbib 1979). The Blue List for 1981 included Utah, Arizona, and New Mexico as areas of concern (Tate 1981) . In 1983, the Kings River Con- servation District began studies of Willow Flycatchers at Dinkey Meadow and 31 WILLOW FLYCATCHER SURVEYS other nearby meadows in the vicinity of Shaver Lake (Stafford and Valentine 1985). Dinkey Meadow, known to harbor breeding Willow Flycatchers, is due to be inundated by the Dinkey Creek Hydroelectric Project. In 1984, the Willow Flycatcher was added to the U.S. Forest Service Region 5 Sensitive Species list. The U.S. Fish and Wildlife Service has also designated the Willow Flycat- cher as a Sensitive Species for Region 1 (Washington, Idaho, Oregon, Califor- nia, and Nevada) on the basis of significant declines in this region (Sharp 1986) . The Willow Flycatcher is currently under review for possible listing as a state Threatened or Endangered Species (R. Schlorff pers. comm.). Many authors agree that alteration and loss of riparian habitat, especially in the Central Valley, had a role in the decline of Willow Flycatchers (Remsen 1978, Garrett and Dunn 1981). However, the absence of Willow Flycatchers in apparently suitable habitat suggests that other factors are also at work. Brown-headed Cowbird ( Molothrus ater) nest parasitism has been suggested as a cause of the Willow Flycatcher’s decline (Gaines 1974) . Studies at low elevations in southern California suggested that the Willow Flycatcher is suscep- tible to cowbird parasitism (Hanna 1928, Rowley 1930). Friedmann (1963) reported 150 instances of Brown-headed Cowbird parasitism of Willow Fly- catchers, 41 of which were reports from southern California. Gaines (1974) concluded that 9 of 12 species (including the Willow Flycatcher) known to have declined along the Sacramento River are highly susceptible to cowbird parasitism. Decline of Willow Flycatchers in central and coastal California coin- cides with the spread of cowbirds in the 1920s and 1930s (Gaines 1974, Gar- rett and Dunn 1981) . The lack of overlap in breeding seasons between Brown- headed Cowbirds and Willow Flycatchers in the Shaver Lake area and the lack of observed parasitism (Stafford and Valentine 1985) suggest that cowbird parasitism may be less important in the Sierra Nevada than at lower eleva- tions (but see Flett and Sanders 1987). Grazing in riparian habitats has been suggested as a possible factor in decline of the Willow Flycatcher in the Sierra Nevada and elsewhere (Serena 1982, Stafford and Valentine 1985, Taylor 1986, Flett and Sanders 1987). Cattle can adversely affect Willow Flycatchers by disturbing nests (Stafford and Valen- tine 1985, Flett and Sanders 1987) and by changing the structural features of riparian habitat such as meadow wetness (drying of meadows by soil com- paction and gullying) , willow foliage height, and willow foliage volume (Serena 1982, Taylor 1986). At the Malheur Wildlife Refuge in Oregon, ungrazed transects had higher willow foliage density and volume and had more Willow Flycatchers than grazed transects (Taylor and Littlefield 1986). These authors also present data indicating a correlation between increases in Willow Fly- catcher numbers and decreases in grazing. Other factors that might be involved in the decline of Willow Flycatchers in the Sierra Nevada include loss of meadow habitat due to reservoir and hydroelectric development, fires set by grazers, Lodgepole Pine (Pinus contorta) encroachment on meadows, and events on the wintering grounds (Serena 1982). The habitat relationships of Willow Flycatchers in the Sierra Nevada were studied by Serena (1982). Complete analysis of our habitat data will be reported elsewhere (Harris et al. 1987) , but we present here a few brief com- ments on the habitat preferences of Willow Flycatchers. In agreement with Serena (1982), we found that most birds (104 of 110) were in meadows larger 32 WILLOW FLYCATCHER SURVEYS than 8 ha. Broad, flat areas seem to be preferred, as suggested by Grinnell and Storer (1924) and Gaines (1977). Serena reported no association bet- ween occurrence of Willow Flycatchers and the wetness of meadows. During our survey, Willow Flycatchers appeared to prefer wet meadows (see also Flett and Sanders 1987; Stafford and Valentine pers. comm.). Virtually all of the sites with more than one singing male had standing water. Willow Fly- catchers were only found where the willow cover was at least 2 m high. The total amount of willow cover, obviously correlated with meadow size and per- cent cover of willow, is also important, though the percentage cover of willow alone may show no association with Willow Flycatcher presence or absence (Serena 1982) . Most of the sites with Willow Flycatchers had high foliage den- sity. Meadows in which the willows were very arborescent, or in which willows had been severely “high-lined” by cattle, generally did not support Willow Flycatchers. Meadows with clumps of willow separated by openings were preferred over solid masses of willow, as suggested by Serena (1982), although Willow Flycatchers were sometimes found at the edge of such masses of willow. SUMMARY AND MANAGEMENT RECOMMENDATIONS The 1982 survey resulted in the observation of 103 singing males in the Sierra Nevada. Nineteen sightings were reported in addition, giving a statewide total of 122 singing males for 1982. Our surveys resulted in sightings of 110 singing males. We have also received reports of an additional 6 birds in the Sierra/ Cascades region, for a total thus far of 116 singing males. Unitt (1987) and L. Salata (pers. comm.) suggest breeding populations of about 15 pairs on the Santa Margarita River and about 12 pairs on the San Luis Rey River (both in San Diego County). This gives a statewide total for 1986 of about 143 singing males. It appears that in California the species has been reduced to a small number of marginal populations. These belong to three subspecies, one of which (E.t. extimus) has declined dramatically in most of its range. Three relatively small areas account for about two thirds of the known Sierra Nevada population. With the two San Diego County populations, these ac- count for 70 percent of the known statewide population of Willow Flycatchers. We believe that our results and the results of past surveys justify the follow- ing management recommendations: 1. The Willow Flycatcher should receive Threatened or Endangered status because of its small population size, evidence of severe decline in numbers, and the concentration of the majority of the state’s breeding Willow Flycatchers in five areas. This situation is critical because the Little Truckee River popula- tion appears to be declining, the Shaver Lake population is threatened by hydroelectric development, and two dams, which would flood much of the existing riparian habitat, have been proposed for the Santa Margarita River. Management planning should recognize the plight of all three of the recognized subspecies of Willow Flycatcher occurring in California and should address the preservation of genetic variation in this species. 2 . Future surveys should attempt to clarify the status of the species in areas not previously surveyed, including north coastal California, the Klamath Moun- 33 WILLOW FLYCATCHER SURVEYS tains and Cascades, and northeastern California in general. Areas of con- centration should continue to be surveyed. 3 . Existing meadow sites should be protected from habitat loss (as from hydroelectric projects or housing developments) . Acquisition of private parcels or purchase of conservation easements by public agencies or conservation organizations may be appropriate in some situations. 4 . Planning for the species should recognize that a site that is unoccupied during a given year should not be considered to be unsuitable, as it may be reoccupied. This is likely to be important especially for small sites. 5. Riparian vegetation should be protected from grazing wherever possible, particularly where grazing is reducing foliage density or drying meadow sites by soil compaction and gullying. Furthermore, grazing in riparian zones should be curtailed during June and July, when Willow Flycatchers are breeding. More studies are needed to clarify the effects of grazing on riparian birds. 6 . Further studies are needed on the responses of Willow Flycatchers to Brown- headed Cowbird nest parasitism, particularly at lower elevations. Experiments in cowbird removal would provide useful data and might enhance Willow Flycatcher populations. 7 . Response of Willow Flycatchers to revegetation and meadow restoration should studied, as a possible means of increasing the amount of available habitat and of attracting Willow Flycatchers to otherwise suitable meadows. Restoration of Willow Creek, Modoc County, provides an encouraging model for meadow restoration (Clay 1984). ACKNOWLEDGMENTS This study was funded by the California Department of Fish and Game (contract 1986-1529). Ronald W. Schlorff initiated the study and provided background data, advice, and encouragement. Many people provided suggestions for survey techniques and sites to visit, observations of Willow Flycatchers, or assistance in the field, including Dan Airola, Bob Barnes, Ted Beedy, Sam Droge, David Gaines, Mary Halterman, Stan Harris, Rick Hewe.tt, Tom Lambert, William Laudenslayer, Steve Laymon, Ron LeValley, Zev Labinger, Larry Norris, Mike Prather, William Radke, Mike Robbins, Larry Salata, Michael Stafford, Philip Unitt, Bradley Valentine, and Jon Winter. The following individuals reviewed the manuscript and made many helpful suggestions: Ted Beedy, Kay Franzreb, David Gaines, John Gustafson, Steve Laymon, Ron Schlorff, Philip Unitt, and Bradley Valentine. LITERATURE CITED Arbib, R. 1979. The Blue List for 1980. Am Birds 33:830-835. Barlow, C. 1900. Some additions to Van Denburgh’s list of land birds of Santa Clara Co., California. Condor 2:131-133. Belding, L. 1890. Land birds of the Pacific district. Occ. Pap. Calif. Acad. Sci. 2. Clay, D.H. 1984. High mountain meadow restoration, in California Riparian Systems (R.E. Warner and K.M. Hendrix, eds.), pp. 477-481. Univ. Calif. Press, Berkeley. Flett, M.A., and Sanders, S.D., 1987. Ecology of the Sierra Nevada population of Willow Flycatchers. Western Birds 18:37-42. Friedmann, H. 1963. Host relations of the parasitic cowbirds. U.S. Natl. Mus. Bull, 233. 34 WILLOW FLYCATCHER SURVEYS Gaines, D. 1974. A new look at the nesting riparian avifauna of the Sacramento Valley, California. W. Birds 5:61-80. Gaines, D. 1977. Birds of the Yosemite Sierra. Cal-Syl Press, Oakland. Garrett, K., and Dunn, J. 1981. Birds of Southern California: Status and Distribution. Los Angeles Audubon Soc., Los Angeles. Goldman, E.A. 1908. Summer birds of the Tulare Lake region. Condor 10:200-205. Grinnell, J., Dixon, J., and Linsdale, J.M. 1930. Vertebrate natural history of a sec- tion of northern California through Lassen Peak. Univ. Calif. Publ. Zool. 10:197-406 Grinnell, J., and Miller, A.H. 1944. The distribution of the birds of California. Pac. Coast Avifauna 27. Grinnell, J., and Storer, T.I. 1924. Animal life in the Yosemite. Univ. Calif. Press, Berkeley. Hanna, W.C. 1928. Notes on the Dwarf Cowbird in southern California. Condor 30:161-162. Harris, J.H., Sanders, S.D. and Flett, M.A. 1987. The status and distribution of the Willow Flycatcher (Empidonax traillii) in the Sierra Nevada. Calif. Dept, of Fish and Game Wildlife Mgt. Branch Admin. Rep. 87-2. King, J.R. 1955. Notes on the life history of Traill’s Flycatcher ( Empidonax traillii) in southeastern Washington. Auk 72:148-173. Linton, C.B. 1908. Notes from Buena Vista Lake, May 20 to June 16, 1907. Condor 10:196-198. McCaskie, G., De Benedicts, P., Erickson, R., and Morlan, J. 1979. Birds of Nor- thern California: An Annotated Field List. Golden Gate Audubon Soc., Berkeley. Phillips, A.R. 1948. Geographic variation in Empidonax traillii. Auk 65:507-514. Remsen, J.V., Jr. 1978. Bird species of special concern in California. Calif. Dept. Fish and Game, Nongame Wildlife Invest. Rep. 78-1. Roberson, D. 1985. Monterey Birds. Monterey Peninsula Audubon Soc., Carmel, CA. Rowley, J.S. 1930. Observations on the Dwarf Cowbird. Condor 32:130. Serena, M. 1982. The status and distribution of the Willow Flycatcher ( Empidonax traillii) in selected portions of the Sierra Nevada, 1982. Wildlife Mgt. Branch Ad- min. Rep. 82-5, Calif. Dept. Fish and Game. Sharp, B. 1986. Management guidelines for the Willow Flycatcher. U.S. Fish and Wildlife Service, Portland, OR. Stafford, M.D., and Valentine, B.E. 1985. A preliminary report on the biology of the Willow Flycatcher in the central Sierra Nevada. Cal-Neva Wildlife Trans, pp. 66-77. Stallcup, R , and Greenberg, R. 1974. The nesting season. Middle Pacific Coast region. Am. Birds 28:943-947. Sumner, L., and Dixon, J.S. 1953. Birds and Mammals of the Sierra Nevada. Univ. Calif. Press, Berkeley. Tate, J. 1981. The Blue List for 1981. Am. Birds 35:3-10. Taylor, D.M. 1986. Effects of cattle grazing on passerine birds nesting in riparian habitat. J. Range Mgt. 39:254-258. Taylor, D.M., and Littlefield, C.D. 1987. The influence of cattle grazing on Willow Flycatchers and Yellow Warblers. Am. Birds 40:1169-1173. Unitt, P. 1984. The birds of San Diego County. San Diego Soc. Nat. Hist. Memoir 13. 35 WILLOW FLYCATCHER SURVEYS Unitt, P. 1987. Empidonax traillii extimus: An endangered subspecies. W. Birds 18: in press. Willett, G. 1912. Birds of the Pacific slope of southern California. Pac. Coast Avifauna 7. Willett, G. 1933. A revised list of the birds of southwestern California. Pac. Coast Avi- fauna 21. Willow Flycatcher Sketch by Keith Hansen 36 ECOLOGY OF A SIERRA NEVADA POPULATION OF WILLOW FLYCATCHERS MARY ANNE FLETT, 1764 Newell Avenue, Walnut Creek, California 94595 SUSAN D. SANDERS 133 North Street, Woodland, California 95695 Willow Flycatchers ( Empidonax traillii ) have declined in California, and much of the state’s population is now restricted to meadows in the Sierra Nevada (Harris et al. 1987, Serena 1982). To understand the factors contributing to their decline and to develop recommendations to protect and enhance the flycatchers’ habitat, we studied a Sierra Nevada population of Willow Fly- catchers in the late spring and summer of 1986. In this paper, we present preliminary information on Willow Flycatcher nesting success, territory and habitat characteristics, and effects of livestock grazing. We conclude with some management recommendations based on this study and the results of a distributional survey also conducted in the summer of 1986 (see Harris et al. 1987). STUDY SITES Perazzo Meadows and Lacey Valley are in the Little Truckee River drainage approximately 32 km northwest of the town of Truckee, Sierra County, Califor- nia. These meadows are at an elevation of 2010 m on the east slope of the Sierra Nevada in Tahoe National Forest. Both are wet meadows with peren- nial streams running through them and are surrounded by lodgepole pine (Pinus murra^ana) forest. Willow clumps ( Salix sp.) are scattered in patches throughout the meadows. Perazzo Meadows is over 350 ha in size. We confined our study to the eastern 60 ha of this extensive meadow system. Lacey Valley, approximate- ly 3 km east of Perazzo Meadows, extends over 90 ha. These two meadows support the largest population of breeding Willow Flycatchers in northern California (Serena 1982). METHODS Our field work extended from early June to late August 1986. We observed 13 pairs of Willow Flycatchers and 6 additional singing males, at least 2 of which were unpaired. Birds were observed from dawn to mid-morning, and the location and behavior of Willow Flycatcher individuals, pairs, or families were recorded. These observations were the basis for determining the breeding status of individuals, nest locations, habitat use, and territorial boundaries. We spent 186 hours observing the birds. To facilitate observations and iden- tify individuals, we captured 16 Willow Flycatchers in mist nets and banded them with unique color combinations. We regularly checked nests to follow the fate of eggs and nestlings. Recorded characteristics of nests included height, location in willow clumps, and foliage density at the nest. We assessed foliage density by placing aim square board behind the nest, pacing back about 5 m, and estimating the percentage of Western Birds 18:37-42,1987 37 WILLOW FLYCATCHER ECOLOGY the board obscured by willow twigs and leaves. Because nests were placed near the outer edge of willow clumps and the clumps were impenetrable, we made foliage density measurements at the nests from the outside of the clumps. To determine the boundaries of the territories of paired males, we recorded the locations of perches from which males repeatedly sang and measured the distances between those perches. We considered the area enclosed by the outermost singing perches to be the male’s territory. Since territories shifted during the different phases of the breeding season , we mapped and measured territorial boundaries only when a nest containing eggs or nestlings was within the territory. We measured 8 territories in the two study sites. To assess habitat characteristics of Willow Flycatcher territories, we estimated the percentage of each territory covered by willows, standing or running water, and trees. Using the technique described above, we measured willow foliage density at 0-1 m and 1-2 m above the ground at 10 sites throughout the territory. Since foliage on shrubby willows normally extends to the ground, measurements taken at 0-1 m were intended to document the effects of livestock browsing on the lower portions of the willows. Because Willow Flycat- chers at our study sites place their nests approximately 1.5 m from the ground, measurements at 1 - 2 m were taken to assess the vigor and amount of foliage at heights appropriate for nesting. These measurements were taken every 5 m for 50 m along the outer edge of the longest willow clump in the territory. Circumference of the willow clumps generally did not exceed 50 m. On 31 separate days we observed the cattle in Perazzo Meadows by walk- ing through the study area and recording the number of cows in the open and in willows. We made similar observations of sheep at Lacey Valley, but because of the late arrival of the flock and its habit of traveling as a unit, we were able to observe it on only 4 of 13 days spent searching for it. We noted associations of Brown-headed Cowbirds (Molothrus ater) with the livestock. RESULTS AND DISCUSSION Breeding Chronology Willow Flycatchers arrived by early to mid-June and established territories by late June. The first eggs were laid by mid- June and the young hatched by 30 June. The first young fledged on 15 July. Clutches were still being laid in mid- to late July, and the last young fledged on 13 August. Territories began breaking down the week of 28 July, and the last breeding Willow Flycatchers departed by the end of August. Nest and Egg Success Table 1 summarizes data from 11 Willow Flycatcher nests at Perazzo Meadows and Lacey Valley. The average number of fledglings per nest was 1.3 (n = 11, s.d. = 1.3). The total number of young fledged was 14 or 15 (we are uncertain whether 3 or 4 young fledged from nest number 5). For 5 of the 11 nests, we had complete egg-to-fledgling data. The total egg- to-fledgling success rate for these 5 nests was 29% . There was little difference in success rates between Perazzo Meadows and Lacey Valley. Willow Fly- catchers at Perazzo Meadows produced an average of 1 .6 fledglings per nest 38 WILLOW FLYCATCHER ECOLOGY Table 1 Numbers of Willow Flycatcher Eggs, Nestlings, and Fledglings Pro- duced from 11 Nests at Perazzo Meadows and Lacey Valley, 1986 Nest Location No. eggs No. nestlings No. fledglings 1 Lacey 3 0 0 1A Lacey ? 1 0 2 Perazzo 3 3 0 3 Lacey ? 4 3 5 Perazzo ? 4 3-4 6 Perazzo 2 1 8 Perazzo 3 1 1 9 Perazzo 2 1 1 10 Lacey ? 3 0 11 Lacey 3 2 2 13 Perazzo ? 3 3 Total 31? 24 14-15 Mean no ■. of fledglings per nest: 1.35 Egg-to-fledgling success: 29% Perazzo Meadows: 25% Lacey Valley: 33% (n = 6, s.d. = 1.4) and had an egg-to-fledgling success rate of 25%. At Lacey Valley the flycatchers produced an average of 1.0 fledglings per nest (n = 5, s.d. = 1.4), resulting in an egg-to-fledgling success rate of 33%. Stafford and Valentine (1985) followed 8 Willow Flycatcher nests over 2 years in the southern Sierra Nevada and found a range of egg-to-fledgling success rates between 25% and 38% . Stafford and Valentine’s estimated success rates and ours are low compared to Nice’s (1957) estimate of 45% for open-cup nesters. The cause of nest failure is known for 4 of the 11 nests. Nest 1 at Lacey Valley was precariously placed at the outermost edge of a willow clump. We found it tipped over and the eggs in fragments on the ground below it. The nest was destroyed either by heavy gusts of wind or by a predator; there were no livestock present then to account for the nest upset. Nestlings in nests 1A and 10 were found dead after a severe hailstorm on 25 July. Nest 2 was parasitized by a Brown-headed Cowbird. The only other published observa- tion of parasitism of a Willow Flycatcher nest by the cowbird in the Sierra Nevada occurred in 1960 (Gaines 1977). The single cowbird in nest 2 fledged successfully, but its 3 Willow Flycatcher nestmates died within several days of hatching. These 3 Willow Flycatchers represented more than 10% of the total number of nestlings produced in the two sites in 1986. If all three nest- lings had fledged, the egg-to-fledgling success rate in the two sites would have been 50% instead of 29%. 39 WILLOW FLYCATCHER ECOLOGY Nest Characteristics All Willow Flycatcher nests were in willows, even though lodgepole pines were present in some territories. The birds placed their open-cup nests at a mean of 1.3 m above the ground (n =11, range = 0.90-1.75 m, s.d. = 0.28 m) and at a mean of 1.0 m from the top of the willow shrub (n = 11, range = 0.50-1.50 m, s.d. = 0.27 m). Willow foliage density in the vicinity of the nest averaged 63% (n = 11, range = 10-90%, s.d. = 29%). Nine of the 11 nests were placed at a mean distance of 1.68 m from the edge of a willow clump (n = 9, range = 0.60-2.40 m, s.d. = 0.57 m). Two of the 11 nests were deeper within a willow clump, but even these nests were close to livestock trails that tunneled through the willows. The distances of these nests from the outer edge of the willow clumps were 6.75 and 7.0 m, but the distances to the nearest livestock trails were only 1.5 and 2.5 m. Territory Size and Characteristics The average territory size for a paired Willow Flycatcher male was about 3000 m 2 (n = 8, range = 800-7000 m 2 , s.d. = 2000 m 2 ). Males spent most of their time singing or foraging from a few high perches on their ter- ritories. The average number of singing perches per territory was 6 {n = 8, range = 5-9, s.d. = 2.5). If tall lodgepole pines or snags were available within the territories, males used them more often than willows for singing and foraging perches. Males and females did most of their flycatching from perches within the territory, although they occasionally foraged beyond ter- ritorial boundaries. The average percentage of the territory covered by willow clumps was 46% (n = 8, range = 16-80%, s.d. = 23%). Foilage density was 64% at 0-1 m (range = 44-78%, s.d. = 13%) and 80% at 1-2 m (n = 8, range = 74-96%, s.d. = 7%) . These measurments and those taken at the nests show that foliage was fairly dense where Willow Flycatchers bred in these study sites. Standing and/or running water was present on all ter- ritories early in the season and remained on some through the end of the summer. Other studies (Harris et al. 1987, Stafford and Valentine 1985) con- firm that the presence of free water is an important aspect of Willow Flycatcher habitat. Effects of Livestock Approximately 150 cattle arrived at Perazzo Meadows in late June. Cattle foraged mainly in the open meadow, but a small percentage were usually observed in or near willow clumps. An average of 3.8% (n = 31, range = 0-6%, s.d. = 4.4%) of the cattle were typically found in willow clumps, creating trails within the clumps in their search for shade and forage. Stafford and Valentine (1985) report that 3 out of 8 Willow Flycatcher nests in their study sites were probably destroyed by cattle. We have no data suggesting nest upsets by livestock, but the placement of nests in willow clumps made them all potentially vulnerable to disturbance because they were built near the edge of willow clumps and low enough to be knocked over by cattle. One thousand sheep arrived at Lacey Valley in mid-July, after most Willow Flycatchers had finished nesting. During 4 observations of the flock, we noted that sheep were always accompanied by flocks of 5-50 Brown-headed 40 WILLOW FLYCATCHER ECOLOGY Cowbirds that foraged in the immediate vicinity of the flock and even perch- ed on the backs of the sheep. These data suggest that the arrival of sheep and their cowbird associates could cause an increase in Willow Flycatcher nest parasitism if the flock’s presence coincided with the peak of egg-laying. MANAGEMENT RECOMMENDATIONS Designate the Willow Flycatcher as a Threatened or Endangered Species in California Willow Flycatchers need the legal protection that state Threatened or En- dangered status would provide. In California, the range and numbers have been dramatically reduced and the population shows no sign of recovery {Har- ris et al. 1987). Acquire and Manage Existing Willow Flycatcher Habitat Most Sierra Nevada meadows that support breeding Willow Flycatchers are managed for livestock grazing rather than for wildlife resources. Sierra Nevada meadows are vulnerable to inundation by hydroelectric projects, to housing or recreational development, and to livestock grazing. Montane meadows that support Willow Flycatchers should be protected by conservation easements with landowners or by land purchases or exchanges. In particular, efforts should be made to acquire and protect the meadow system along the Little Truckee River. These meadows support the second largest population of Willow Flycat- chers in the state, and the population in them is declining. Reduce or Eliminate Grazing in Willow Flycatcher Habitat Livestock grazing can adversely affect willows and other shrubs (Taylor 1986). Duff (1979) found that exclusion of grazers yielded an increase in the middle story of willows, the favored nesting height of Willow Flycatchers. Streambank trampling and soil compaction associated with overgrazed riparian areas could affect the water table and reduce free water, an important aspect of Willow Flycatcher habitat in California. Definitive guidelines that would establish the appropriate level, timing, and duration of livestock grazing on meadows or riparian areas supporting Willow Flycatchers do not exist. A single set of specific guidelines would not be applicable to all meadow and riparian habitat because of differences in elevation, vegetation, soils, slopes, and hydrology. Further studies are needed to determine grazing levels and to create monitoring and management plans suitable for protection and enhancement of Willow Flycatcher habitat. Until such plans are available, land managers should implement a general policy of reducing grazing on meadows and riparian areas that support Willow Flycatchers, especially during the nesting season in June and July. Effective enforcement of this policy will require im- plementation of the first two recommendations made above. Reduce or Eliminate Brown-headed Cowbirds in Willow Flycatcher Habitat Because Willow Flycatchers in California are so few, single incidents of nest parasitism can have significant impacts on Willow Flycatcher populations. 41 WILLOW FLYCATCHER ECOLOGY Because of the close association of Brown-headed Cowbirds with livestock, eliminating grazing in Willow Flycatcher habitat could alleviate nest parasitism by cowbirds. Studies to document further the effects of cowbird nest parasitism on Willow Flycatchers are necessary. ACKNOWLEDGMENTS We are grateful to Ken Corey, Anna Grace, and Mary Whitfield for their invaluable assistance with field work. Ron Schlorff deserves special thanks for initiating this reasearch and providing logistical support. We are also grateful to Laura Colton, Doug and Jodie Garton, Tom Lambert, Stephen Laymon, Bill Laudenslayer, Dick Mewaldt, Michael Stafford, and Brad Valentine for assistance with this study. We appreciate the help given to us by John Gustafson, Ted Beedy, Kay Franzreb, and Stephen Laymon in editing this paper. This project was supported by endangered species tax check-off funds from the Nongame Bird and Mammal Section, California Department of Fish and Game. LITERATURE CITED Duff, G.D. 1979. Riparian habitat recovery on Big Creek, Rich County, Utah, in Forum— Grazing and Riparian/Stream Ecosystems, pp. 91-92. Trout Unlimited, Denver. Gaines, D. 1977. Birds of the Yosemite Sierra: A Distributional Survey. Calif. Syllabus, Oakland. Harris, J.H., Sanders, S.D., and Flett, M.A. 1987. Willow Flycatcher surveys in the Sierra Nevada. W. Birds 18:27-36. Nice, M.M. 1957. Nesting success in altricial birds. Auk 74:305-321. Serena, M. 1982. The status and distribution of the Willow Flycatcher ( Empidonax traillii) in selected portions of the Sierra Nevada. Wildlife Mgt. Branch Admin. Rep. 82-5, Calif. Dept. Fish and Game. Stafford, M.D., and Valentine, B.E. 1985. A preliminary report on the biology of the Willow Flycatcher in the central Sierra Nevada. Cal-Neva Wildlife Trans, pp. 66-77. Taylor, D.M. 1986. Effects of cattle grazing on passerine birds nesting in riparian habitat. J. Range Mgt. 39:254-258. 42 ENDANGERED STATUS AND STRATEGIES FOR CONSERVATION OF THE LEAST BELL’S VIREO (VIREO BELLI! PUSILLUS ) IN CALIFORNIA KATHLEEN E. FRANZREB, U.S. Fish and Wildlife Service, Sacramento Endangered Species Office, 2800 Cottage Way, Room E-1823, Sacramento, California 95825 The Least Bell’s Vireo (Vireo bellii pusillus) is a small, gray, migratory passerine that feeds mainly on insects. The normal clutch of four eggs is in- cubated about 14 days The young remain in the nest approximately 10-12 days. The Least Bell’s Vireo arrives in its breeding habitat from mid-March to early April, and departs in late August or September for its wintering range in Baja California, Mexico. The Least Bell’s Vireo usually constructs its nest low to the ground, primarily in willow-dominated riparian habitats, but also uses a variety of shrubs, trees, and vines. Nesting is now largely restricted to small, remnant segments of willow-dominated habitats. Its precarious status prompted the U.S. Fish and Wildlife Service (FWS) (1986a) to designate it officially as an endangered species on May 2, 1986. The state of California classified the vireo as an en- dangered species in 1980. HISTORICAL AND PRESENT DISTRIBUTION, POPULATION SIZE, AND DENSITY Once widespread and abundant throughout the Central Valley and other low-elevation riverine valleys, the Least Bell’s Vireo maintained an historical breeding range that extended from interior northern California (near Red Bluff, Tehama County) to northwestern Baja California, Mexico. In the last several decades, the subspecies apparently has been extirpated from the Sacramen- to and San Joaquin valleys, which once were the center of its breeding range. Several intensive surveys of virtually all potential breeding habitat in Califor- nia have been conducted (Gaines 1977, Goldwasser 1978, Goldwasser et al. 1980, unpublished FWS data). In total, Least Bell’s Vireos have been reported from only 47 of over 150 former localities (some Iocatities cover several miles of a water course) surveyed in the U.S. from 1977 through 1985 (Table 1). The data indicate the presence of approximately 300 territorial males. This is considered a maximum estimate because roughly 20% of ter- ritorial male vireos are believed to be unpaired. Results from a comprehensive survey in 1986 indicate there are approx- imately 395 territorial males (319 pairs) in the United States (RECON 1986). Preliminary field examinations in Baja California, Mexico, resulted in the locating of a number of small populations, but suitable habitat is declining and limited (Wilbur 1980a, P. Fromer, pers. comm. 1986, Franzreb, pers. obs.). There are probably several hundred pairs in Baja California (Wilbur 1980b) . Relative density data (Table 2) indicate that from 1 to a maximum of 20 males per kilometer of habitat were located during recent surveys. This com- pares to the historical figure of 11-29 males/km estimated by Grinnell and Storer (1924). Western Birds 18:43-49,1987 43 ENDANGERED STATUS OF LEAST BELL’S VIREO Table 1 Location and Number of Territorial Male Least Bell’s Vireos in 1985 County Sites 1 Males 6 San Benito 1 1 Monterey" 0 0 Inyo" 0 0 San Bernardino" 0 0 Santa Barbara 3 26 Ventura 1 5 Los Angeies 3 7 Orange 1 1 Riverside 8 29 San Diego 30 223 Total 47 292 ■Number of different known breeding localities. "Number of known territorial males. c No known breeding in 1985. The average number of fledglings produced per nesting pair has varied from a low of 0.17 in 1984 along the San Diego River (Jones 1985) to a high of 2.85 in 1983 along the Santa Margarita River (Salata 1983b). Fledging rates have been substantially higher in the least degraded habitats such as the Santa Margarita River on Camp Pendleton (40-59%) and Gilbraltar Reser- voir (35-36%) (Table 3). Table 2 Population Densities of the Least Bell’s Vireo Region Estimated males/km Source Historical Sierra Nevada foothills 11-29* Grinnell and Storer (1924) Current Santa Margarita River (Camp Pendleton) 3-7 Salata (1981) 1-8 Salata (1983a) 1-13 Salata (1983b) 1-19 Salata (1984) 8 sites in southern California 3-5 Goldwasser et al. (1980) Northwestern Baja California 8-20 Wilbur (1980a) ■Historical density data are based on extrapolation and are not direct counts. 44 Table 3 Fledging Rate and Reproductive Success of the Least Bell’s Vireo ENDANGERED STATUS OF LEAST BELL’S VIREO o h* 3 O c/) a cn <5 CO - a c .is «1£3 to 3 CO a 'ts ~o 1/3 Ji) g 1 3 ou W) 2 s s k cn > t- © 0) Q. a < x> c to cn tig iui — UU c o '■H 10 u o 10 J3 CO CO 00 00 Os ON <0 (0 -*-< 4-. jg jg 10 (0 co m 0) a> > ;> (0 to too S "O -a c c _ to eg eg eg oq eg cd eg cd evi in o q eg t— t oo Csi ooLOoooocor^o ooqNOONocNji-tin (NiNt-it-ir-iood OC'^OnDlOvOlOnO rt* LD lO CO CO H c o 4-M _g> T3 C H) c o -c c c o 4-. c 9 (X o, a. a a a £E£ to id (0 uuu 0> > > > 2 2 2 *g <0 «3 «3 > +-* ■*-< H •c C *C to i #fi K k. .2 fl3 g (0 *— 1 Im _t X) c to o on Q ■*=- 5 <0 a a) c CD c CD O O O CD a cn c cn -o 0.080, p>0,05). The sex ratio of Brown-headed Cowbirds trapped in this study (Figure 1) does not appear to be representative of other wild populations. The plumage of 4316 first-year birds in west-central Kansas indicated a sex ratio of 1: 1 (Hill 1976) . Darley (1971) observed a ratio of 1.5 adult males to 1.0 adult females in western Ontario. Rothstein et al. (1986) reported the same ratio for parts of the U.S. In contrast, along the Sweetwater River 163 males and 46 females DATE Figure 1. Total number of cowbirds trapped on the Sweetwater River, San Diego Co., 1986. 56 VIREO MANAGEMENT BY COWBIRD TRAPPING were trapped, a ratio of 3.5 to 1.0. This ratio of males to females deviates significantly from the 1.5: 1.0 ratio (x 2 = 28.2, p < 0.001). The sex ratio of all the 562 cowbirds trapped in San Diego County 1984-1986, 2.3: 1.0, also differs significantly from the 1.5: 1.0 ratio (x 2 = 20.7, p < 0.001) (Table 1 ). A two-way G test of independence indicates that the sex of the cowbirds trapped was independent of the type of area in which the trapping was done (x 2 = 3,00< 3.841, p>0. 05). Along the Sweetwater River more males than females were trapped per trap day both in riparian woodland and around stables (Table 2). Significantly more birds per trap day were trapped in the foraging area than in the riparian area (U = 60.5>57, p<0.05). In this study trapping yield of female Brown-headed Cowbirds was highest in April. The cowbirds donated to the San Diego Natural History Museum from Camp Pendleton in 1983 and 1984 showed a similar trend, but the sub- sample that was donated may not be representative of the trapped population. A plot of ovary size versus time indicates that ovary recrudescence begins by April (Figure 2). The first burst follicles appear in late April, indicating that egg laying has begun by that time. The decline in numbers of cowbirds trapped appears to coincide with the onset of breeding. DISCUSSION Lower-than-expected numbers of females trapped in both areas suggest trap bias— the probability of trapping a female being lower than the fraction of females in the population— or that the local populations have a larger percentage of males than those reported by Darley (1971) and others. Roth- DATE Figure 2. Cowbird ovarian development at Camp Pendleton, San Diego Co., 1983 and 1984. Error bars represent the standard error of the mean. 57 Table 1 Ratios of Male to Female Brown-headed Cowbirds Trapped in San Diego County. VIREO MANAGEMENT BY COWBIRD TRAPPING 3 3 3 3 a a a a 0) CJ c c c c 3 3 3 3 >- - - - ~ 3 TO ra VO CO on lO tT s t-H in X) ra .£ CJS 0> rH \£) O ■§ o ^ m oo *2 1 CM »-h U }m 0) i-i i-. > (0 0) ^ t* 0) si > cu 0) > DC tO EsnCt > K K cd CO c s-. a-. fZ* ® O O a a ra cn To in 3 £ ^ 3 3 tO tN oj Q Q o) •— i H §> c c s c 3 ra ra 3 ra co co oo co oo Vi io in in io to 00 00 00 00 00 Q> n ON ON ON ON ON > rH i-H rH rH t-H o co 0) ■c (0 CO 0) > dc i-i 0) ra "S CD CO to i-i <0 CO c ’5) (0 >-i o UL TD C (0 e .2 ‘E (0 cx £ c -a 0) a a (0 in ~o >-> 2 Z o U '■o 00 ON r*H cj , o> 3 § (0 o H U W „ TD 10 .*= o-§ t- ! u :>v (O »- -a 0) a a ra in 10 o) i- *o — CD >2 a a 2 ro .£ - c co- ra ra ra .£■00 DC PU H 58 VIREO MANAGEMENT BY COWBIRD TRAPPING stein et al. (1980) reported higher ratios of males to females (3:1 to 6:1) in the Sierra Nevada. Sex ratios in San Diego County cowbird populations have not been determined so bias cannot be demonstrated conclusively. Traps that rely on decoys, however, have been shown to catch a biased ratio of icterines in Quebec (Weatherhead and Greenwood 1981). The sex of trapped cow'birds has important implications for the effectiveness of trapping as a management tool. Females are the brood parasites, so their removal would reduce the rate of parasitism more than the removal of males. A reduction in numbers of males is essentially unimportant as long as suffi- cient numbers remain to fertilize the available females. Cowbirds in central California appear to have a monogamous mating system with the dominant males guarding their mates from other males (Rothstein et al. 1986), but this system does not preclude a female’s remating in the event of the loss of her mate. Bias may be related to cowbird behavior in the breeding range, or it may be inherent in the trapping scheme. Cowbirds typically maintain two ranges. The roosting area is separate from the foraging area, requiring that the birds commute daily. Cowbirds roost in riparian habitats during the night and females parasitize nests in the morning. During the afternoon the birds forage in communal groups. Rothstein et al. (1984) reported commuting distances of up to 7 km during the breeding season in the Sierra Nevada of California. Radiotelemetry of cowbirds showed that males returned to riparian areas much less consistently than did the females. Only four of the eight males equipped with radio transmitters by Rothstein et al. (1984) returned to the egg-laying sites in the evening, whereas all five of the marked females return- ed every evening. Because of this behavior, female cowbirds might be ex- pected to be more abundant than males in riparian traps. However, while laying eggs, females forage very little; Rothstein et al. (1980) rarely observed cowbirds on the ground in the breeding sites. Mate guarding by the males may keep the dominant males away from the traps in the areas where their mates are laying eggs. If this is so, subordinate males are more likely to forage in the morning in either breeding or foraging areas than the females or the dominant males. If in southern California cowbirds behave as they do in the Sierra Nevada, trapping in the riparian areas would be less effective at removing females than trapping in the foraging area. In this study the lower numbers of females per trap day in both areas suggests trap bias. The breeding season may not be the optimal time for trapping, especially if trapping is conducted in the riparian (breeding) areas. The ovaries of the female cowbirds dissected at the San Diego Natural History Museum were only beginning to recrudesce at the time of year when the Sweetwater River traps were most successful. Following the onset of egg laying, indicated by the first appearance of burst follicles, the numbers of both sexes trapped de- clined. The population may have decreased as a result of the trapping effort; alternatively, the cowbirds may be less attracted to the traps while they are concentrating on egg laying. If the latter hypothesis is true, deployment of traps prior to the breeding season would be more effective in reducing numbers of cowbirds. 59 VIREO MANAGEMENT BY COWBIRD TRAPPING Cowbirds show marked regional variation in mating, territorial, and host- selection behavior (P. Mason, pers. comm.). Without some knowledge of their local habits, designing a program for management would be difficult. In areas where cowbird trapping has been pursued, the cowbirds’ foraging areas and commuting patterns remain unknown. More information on sex- ual differences in cowbird behavior could help improve the efficiency of a management program, but no studies of cowbird biology have been conducted in southern California. CONCLUSIONS AND MANAGEMENT RECOMMENDATIONS Along the Sweetwater River, trapping in the foraging area yielded more cowbirds of both sexes per trap day than did trapping in the riparian area. The highest trapping success was in April just after the cowbirds arrived and before they began intensive breeding. The apparent sex bias in the trapping results may be the consequence of the trap design. A trap baited with a single male bird may be insufficient to attract females. Providing a lek-like situation of several males might give females more incentive to enter the trap. Conversely, females forage together before the breeding season (personal observation). If traps are deployed at that time female decoys might be more effective than males in attracting other females. We recommend that 1. Brown-headed Cowbird population size, site fidelity, and host selection be studied in an area where a trapping scheme is proposed before the trap- ping is begun. 2. Cowbirds be trapped in areas and at times when the probability of reduc- ing numbers of females is greatest; traps should be placed in foraging areas and should be operating well in advance of the breeding season. 3. Alternative cowbird trapping or removal methods be tested. A Potter trap may bias trapping in favor of females (Darley 1971). ACKNOWLEDGMENTS We thank Gerald Collier and his staff at San Diego State University for providing trap data and Amadeo Rea and Stephen Gustafson of the San Diego Natural History Museum for providing the ovarian measurements. Stephen Rothstein and Paul Mason of the University of California, Santa Barbara, provided invaluable insights. Collier, Paul Fromer, Barbara Kus, Abby White, John Griffith, and especially Ted Beedy re- viewed the manuscript and provided useful suggestions. Funding for the Sweetwater River trapping was provided by the California Department of Transportation. LITERATURE CITED Darley, J.A. 1971. Sex ratio and mortality in Brown-headed Cowbirds. Auk 88:560-566. Hill, R.A. 1976. Sex ratio and sex determination of immature Brown-headed Cowbirds. Bird-Banding 47:112-114. 60 VIREO MANAGEMENT BY COWBIRD TRAPPING Rothstein, S.I., Vemer, 375 burrows ( N = 19). Thirty-two colonies (11 each from the small and medium groups and 10 from the large group) were randomly selected for intensive study. At the selected colonies, we made three vertical transects of unequal length at equally spaced locations across the bank and recorded colony and bank length, height of the bank and burrow column, distance from bank to water, and aspect and slope of the bank. These measurements were averaged for each colony. We took soil samples from areas adjacent to transects by using seamless sample tins and determined soil type from bulk density measurements (Hausenbuiller 1978) and U.S. Soil Conservation Service County Soil Surveys. We assessed detrimental impacts to swallow populations and habitats by reviewing proposed erosion control projects and recording land use practices around swallow colonies. RESULTS AND DISCUSSION Population Size and Distribution We located 60 colonies ranging in size from 12 to 1784 breeding pairs (Figure 1); the average was 269 (± a standard error (SE) of 47.9) pairs per colony. Thirty-five (58.3%) colonies had <150 pairs, 13 (21.7%) colonies had 151-450 pairs, and 12 (20.0%) colonies had >525 pairs. We estimate the total breeding population for the Sacramento River as 16,149 pairs (95% confidence interval = 14,597-17,700). Burrow occupancy was 55.9% (± 2.7% SE) on the basis of 1330 burrows checked at 26 colonies. The number of young per nest averaged 2.84 (± 0.07 SE) on the basis of 211 burrows checked at 14 colonies. We found 43 (71.7%) colonies between River Mile (RM) 140 and RM 240, 10 (16.7%) colonies downstream from RM 140, beneath which the river is channelized by levee systems, and 7 (11.7%) col- onies upstream from RM 240, an area of hard sandstone banks and bluffs (Figure 2). Approximately 11,300 (70.0%) pairs were located between RM 150 and RM 220. The largest concentration of 3860 (23,9%) pairs was found between Chico Landing and Woodson Bridge State Recreation Area (RM 200 to RM 220). Habitat Measurements Colony banks (N = 32) averaged 3.3 ( ± 0.3 SE) m tall (range = 1.3-7. 3) with a slope of 83.3° (± 0.9° SE, range = 68.3°-96.7°). Bank length averaged 454.6 ( ± 77.9 SE) m (range = 13-1900). There were 2.2 (± 0.2 SE) burrows per transect (range = 0.0 -5. 3) for a density of 0.8 (± 0.1 SE) burrows/m (range = 0.0- 1.9). Burrow columns were 0.5 (±0.1 SE) m tall (range = 0.0- 1.7), and colony banks were 4.1 (± 0.8 SE) m (range = 0.0-21.8) from water. The length of the colony averaged 66.4 (± 12.4 SE) m (range = 2-366). Most colonies (56 of 99 transects) were adjacent 72 BANK SWALLOW DISTRIBUTION to open grass fields. Approximately 25% of the transects were associated with agricultural lands, either row crops (N = 11) or orchards (N = 16). The re- maining transects (N = 16) were under riparian and oak forests. Bank Swallow colonies generally occur in soft soils. Of the 86 soil samples collected, most were taken from fine sandy loam (N = 19, 22.1%), loam (N = 33, 38.4%), and silt loam (N = 7, 8.1%) soils, while the remainder were in sand (N = 3, 3.5%), sandy loam { N = 6, 7.0%), clay loam (N = 2, 2.3%), clay (N = 8, 9.3%), and aggregated clay (N = 8, 9.3%) soils. Spencer (1964) reported a preference for loamy soils by Bank Swallows in Pennsylvania and Vermont. Most colonies (N = 99) faced north (35%) and east (32%) . West exposures accounted for 24% , whereas southern exposures were only 8% . Soil moisture and/or presence of suitable banks may be fac- tors in colony orientation. Detrimental Impacts Proposed bank stabilization and flood and erosion control projects repre- sent the largest single threat to Bank Swallow colonies and habitat on the Sacramento River. Existing colonies will be destroyed, as will potential habitat. Such construction activity also may adversely affect swallow behavior. A minimum of 32 (53.3%) colonies are threatened by proposed projects, and an additional 3 (5.0%) colonies also may be affected by construction (Figure 2) . Construction activities with the greatest potential impact are planned from Figure 1. Frequency distribution of Bank Swallow colonies by colony size, Sacramento River, California, 1986. 73 NUMBER OF BREEDING PAIRS BANK SWALLOW DISTRIBUTION RM 143 to RM 243 (Army Corps of Engineers 1983, The Reclamation Board, 1986). Coincidentally, this is the region of greatest Bank Swallow abundance. 4000 - 3500 - 3000 - 2500 - 2000 - 1500 - 1000 - 500 - 0 - - 43 283 RIVER MILE Figure 2. (a) Frequency distribution of Bank Swallow colonies by 20-river-mile sections that are threatened, affected, or unaffected by proposed erosion control projects. (b) Number of breeding pairs of Bank Swallows by 20-river-mile sections that are threatened, affected, or unaffected by proposed erosion control projects, Sacramento River, California, 1986. 74 BANK SWALLOW DISTRIBUTION A minimum of 9280 (57.5%) pairs are threatened, and an additional 416 (2.6%) pairs may be affected by construction (Figure 2). These declines will likely occur within the next 5-10 years if all proposed projects are carried out. The colony at Woodson Bridge State Recreation Area (RM 218.6) is one of the two largest. An experimental bank protection method known as palisading was implemented there in August 1986. The integrity of the bank face was retained, and the colony site was not destroyed. The full impact of this bank protection method on Bank Swallows cannot be evaluated fully for several years. If bank erosion at Woodson Bridge is curtailed, the suitability of the bank for swallow nesting will decline through time as the bank face becomes less vertical because of sluffing. Blem (1979) has demonstrated that when this happens, predation increases and Bank Swallow colonies decline and are eventually abandoned. CONCLUSIONS Proposed erosion control projects threaten over 50% of the Sacramento River Bank Swallow population. On the basis of our findings, Threatened status for the Bank Swallow in California may be appropriate. Further research on the statewide distribution of Bank Swallows is scheduled for 1987. Efforts should be made to protect existing colonies and develop mitigation techni- ques. Alternative means of bank protection that have minimal impact on bank- nesting avifauna and riparian vegetation should be developed and tested. Above all, resource management agencies must realize that a river free from erosion is not compatible with the maintenance of healthy populations of bank- nesting birds. ACKNOWLEDGMENTS We gratefully acknowledge the funding by the California Department of Fish and Game, California Department of Water Resources, and Army Corps of Engineers. Ronald W. Schlorff, California Department of Fish and Game, deserves special thanks for his continued interest and support of this project, and we thank Frank J. Michny, U.S. Fish and Wildlife Service, for field assistance. Carol B. Calza and Lloyd Hess, Army Corps of Engineers, deserve appreciation for their help and interest. Dr. Reginald H. Barrett, Department of Forestry and Resource Management, University of Califor- nia, Berkeley, supervised the contract. LITERATURE CITED Army Corps of Engineers. 1983. Draft Comprehensive Erosion Control Plan for the Sacramento River. Sacramento District, Army Corps of Engineers, Sacramento, CA. Blem, C.R. 1979, Predation of black rat snakes on a Bank Swallow colony. Wilson Bull. 91:135-137. Freer, V.M. 1979. Factors affecting site tenacity in New York Bank Swallows. Bird- Banding 50:349-357. Grinnell, J., and Miller, A.H. 1944. The distribution of the birds of California. Pac. Coast Avifauna 27. Hausenbuiller, R.L. 1978. Soil Science Principles and Practices. Brown, Dubuque, IA. 75 BANK SWALLOW DISTRIBUTION MacBriar, W.N., Jr., and Stevenson, D.E. 1976. Dispersal and survival in the Bank Swallow ( Riparia riparia) in southeastern Wisconsin. Milwaukee Public Mus. Con- trib. Biol. Geol. 10. Mead, C.J. 1979. Colony fidelity and interchange in the Sand Martin. Bird Study 26:99-106. Remsen, J.V., Jr. 1978. Bird species of special concern in California. Calif. Dept. Fish and Game, Wildlife Mgt. Branch Admin. Rep. 78-1. Spencer, S.E, 1964. A study of the physical characteristics of nesting sites used by Bank Swallows. Diss. Abstr. Int. 23:4034-4035. The Reclamation Board. 1986. Final Environmental Impact Report for the Butte Basin Overflow Area. Calif. Dept. Water Resources, Sacramento, CA. Bank Swallows Sketch by Tim Manolis 76 BIRDS OF REMNANT RIPARIAN FORESTS IN NORTHEASTERN WISCONSIN NORMAN E. FOWLER, Environmental Science 317, University of Wisconsin -Green Bay, Green Bay, Wisconsin 54301 ROBERT W. HOW'E, College of Environmental Sciences, University of Wisconsin - Green Bay, Green Bay, Wisconsin 54301 Recently much research has been focused on the effect of forest fragmen- tation on so-called “forest interior” bird species. Forest interior birds are depen- dent for breeding habitat on the central portions of large forest tracts; a decline in these species has been associated with a reduction in size and quality of remnant forests (Robbins 1979, Whitcomb et al. 1981, and others). Fragmen- tation creates a greater proportion of edge habitat, resulting in increased nest predation (Wilcove 1985) and brood parasitism (Brittingham and Temple 1983). Ranney et al. (1981) have described edge-related changes in forest vegetation. Our study considers forest birds of Brown and Kewaunee counties in nor- theastern Wisconsin, where forested landscapes have been drastically altered over the last two hundred years. A few remnants of the original vegetation type occur in lands considered marginal for agriculture. We focus on those remnant forests that may be considered riparian because they adjoin a stream, river, or wetland. Brown and Kewaunee counties once were covered entirely by northern mesic forest (Stearns and Kobringer 1975) and scattered areas of lowland black ash ( Fraxinus nigra ) or conifer swamps (Link and Frings 1980). Less than 16% of the original forest remains in Kewaunee County, while only 11% remains in Brown County (Wisconsin Department of Natural Resources 1968). Deforestation undoubtedly has altered the original forest bird assemblages. The great reduction and fragmentation of forests, in light of observations elsewhere in eastern North America, suggest that forest interior bird species in Brown and Kewaunee counties must be greatly reduced in numbers if they persist at all. We ask: “Which forest interior birds, if any, remain today in these riparian remnants?” If forest interior birds are found, we then ask: “Can those sites with forest interior species be distinguished consistently from sites in which these species are absent?” METHODS We identified remnant riparian forests from aerial photos and topographic maps. In these forests, we selected 38 survey points in Brown County (Table 1) and 20 points in Kewaunee County (within tracts of 100, 157, 178, 217 and 229 ha). For comparison, we chose 17 additional points in a larger forest (867 ha) in Kewaunee County. The Brown County riparian remnants reflect a gradient from early successional to moderately mature stands of northern mesic forest. The Kewaunee remnants represent lowland conifer (cedar) swamps or mixed coniferous-hardwood swamps. With the exception of the 867-ha site in Kewaunee County, none of our sites is part of a contiguous Western Birds 18:77-83,1987 77 REMNANT RIPARIAN FORESTS forest larger than 250 ha; the Brown County sites, in particular, are con- siderably smaller. Each site was visited at least once during the peak avian breeding season (June through mid-July) of 1985. All visits were completed during calm, non -rainy weather between sunrise and 0900. We recorded all birds seen or heard from a central point during two consecutive 10-minute censuses. We surveyed 30 sites in Brown County and 16 in Kewaunee County (including sites in the larger forest) repeatedly during 1985 and 1986. Details of these extended studies will be reported elsewhere. Table 1 Environmental Variables and Discriminant-Analysis F Ratios for Survey Points in Riparian Remnants of Brown County F Ratio (initial step) Ovenbird Environmental variable Mean (± std. dev.) Ovenbird Wood Thrush and/ or Wood Thrush Percent forested area within 1000 m 16.3± 7.4 8.0 11.4 21.0 500 m 55.2 ±19.4 20.1 5.5 18.1 250 m 29. 3± 13.8 10.4 14.2 28.7 150 m 74.0 ±20.4 12.2 0.6 5.3 Area of remnant (ha) 35.8±26,7 5.0 9.7 16.1 Contiguous area (ha) 56.3 ±39.6 3.7 8.3 10.9 Nonagricultural area (ha) 68.1 ±43.7 1.8 7.6 7.5 Elevation above river (m) 4.4±4.5 8.6 0.2 0.7 Distance to the edge (m) 100 ±37 2.3 0.8 1.7 Forest length (m) 1153 ±684 7.8 6.0 15.6 Forest width (m) 225 ±100 3.8 1.5 3.5 Canopy closure (%) 81.7 ± 17.6 5.4 0.6 2.7 Ground cover (%) 46. 2± 19,2 0.8 0.8 2.4 Heterogeneity (Roth 1976) Canopy 54.4 ±13.1 1.7 0.2 0.9 Understory 56,1 ± 13.5 1.7 1.1 1.9 Shrub 74. 3± 13.5 3.4 3.9 5.1 Height (m) Canopy 11.1±2.8 1.1 0.6 2.3 Understory 3.7 ±1.1 0.3 0.1 0.04 Shrub 10±0.2 0.7 0.3 1.4 Basal area (m 2 ) Canopy 0.61 ±0.31 0.2 1.7 0.03 Understory 0.0044 ±0.006 0.4 0.7 0.02 Shrub 0.0039 ±0.0023 0.3 1.7 1.0 Density (stem/m 2 ) Canopy 0.016±0.077 0.1 0.2 0.02 Understory 0.044 ±0.032 5.1 1.4 1.5 Shrub 0.150±0.110 0.4 3.7 10.2 78 REMNANT RIPARIAN FORESTS Vegetation was analyzed in detail for the Brown County sites; analysis of the Kewaunee sites is in progress. Five sample quadrats were evaluated near each Brown County survey point. At each quadrat we recorded data on canopy trees, understory trees (less than two-thirds the height of canopy but at least 2 m tall) and woody shrubs (<2 rn tall) by using a modified point- centered quarter method (Cottam and Curtis 1956, James and Shugart 1970). Percentage ground cover and percentage canopy cover were also estimated (Hays et al. 1981) . These data, in addition to a review of aerial photos, allowed us to estimate 27 environmental variables (Table 1). We used discriminant analysis to compare these habitat characteristics to the bird census results (Rice et al. 1983). RESULTS We found significant numbers of forest interior birds (Whitcomb et al. 1981) even in unexpectedly small riparian remnants. For example, a narrow (< 120 m wide) riparian strip in Kewaunee County (not included in Table 2) was occupied by singing Ovenbirds and Black-and-white Warblers, two species considered by Whitcomb et al. (1981) to be sensitive to forest extent. Larger sites in Kewaunee County were inhabited by Winter Wren, Pileated Woodpecker, Veery, Wood Thrush, Brown Creeper, and other forest interior species (Table 2). Width of these riparian areas rarely exceeds 500 m, even though the total area of contiguous forest is greater than 100 ha. Forest birds of Kewaunee County riparian fragments did not precisely reflect bird assemblages in the larger forest tract (Table 2), yet only two species characteristic of lowland forests in Kewaunee County (Red-breasted Nuthatch and Broad-winged Hawk) were absent in the isolated fragments. The Red- shouldered Hawk ( Buteo lineatus) and several other species probably inhabited many of these areas before settlement but today they are absent even in the 867-ha site. Fewer forest bird species were recorded in the drier riparian forests of Brown County, but several species sensitive to forest extent, such as the Ovenbird, Hairy Woodpecker, and Wood Thrush, were found consistently (Table 2). A detailed study of remnant riparian forests in Brown County focused on the Ovenbird and the Wood Thrush, two forest interior species from the same foraging guild (ground-feeders). These birds were the species most commonly encountered in Brown County that are widely considered to be sensitive to forest extent. The 38 census points were grouped according to the presence or absence of these two species. Stepwise discriminant analysis identified habitat characteristics that are significantly associated with the presence or absence of either bird. Percentage forest within 500 m of the census point was most significant in distinguishing sites inhabited by the Ovenbird. This single habitat characteristic provided enough information to classify 76.3% of the points correctly. Discriminant analysis based on presence or absence of the Wood Thrush provided similar results, although in this case the most important discriminating variable was the percentage forest within 250 m. From this variable alone, 72% of the cases could be classified correctly. These results, 79 REMNANT RIPARIAN FORESTS Table 2 Forest Interior Birds of Riparian Fragments (<250 ha) and a Larger Forest (867 ha) in Northeastern Wisconsin in 1985 Percentage occurrence Kewaunee County Brown County Species 867 ha (17 points) 100-229 ha (20 points) <100 ha (38 points) Ovenbird (Serurus aurocapillus) 88 75 26 Black-capped Chickadee (Parus atricapillus ) 65 65 36 Hairy Woodpecker (Picoides uillosus) 53 55 47 Winter Wren ( Troglodytes troglodytes ) 47 50 0 Red-eyed Vireo ( Vireo olivaceus) 41 10 47 Pileated Woodpecker ( Dryocopus pileatus ) 29 25 0 Red-breasted Nuthatch {Sitta canadensis) 29 0 0 Black-and-white Warbler ( Mniotilta varia ) 29 40 0 Veery ( Catharus fuscescens) 24 30 0 Wood Thrush ( Hylocichla mustelina ) 24 30 42 Scarlet Tanager ( Piranga oliuacea) 24 5 7 Brown Creeper (Certhia americana ) 18 15 0 Eastern Wood Pewee ( Contopus virens) 18 15 71 Broad-winged Hawk ( Buteo platypterus ) 12 0 0 White-breasted Nuthatch ( Sitta carolinensis ) 0 20 60 coupled with the species’ less frequent occurrence overall, suggest that Oven- birds are more sensitive than Wood Thrushes to forest fragmentation. We also performed a discriminant analysis based on the presence /absence of either the Wood Thrush or the Ovenbird. If neither bird was present the point was grouped in the “absent” category and if one or both species were present the point was grouped in the “present” category. Percentage forested area within 250 m of the census point was selected by this analysis as the most important discriminating variable. Other significant variables included shrub density, shrub heterogeneity, average understory height, and forest type 80 REMNANT RIPARIAN FORESTS (based on varimax factor analysis of tree species importance values) . The lat- ter variable differentiates mature forests from stands in earlier stages of suc- cession. The discriminant function with all five variables correctly classifies the samples (those with one or both species versus those with neither species) in 94.7% of the cases. DISCUSSION Forest interior birds do indeed exist in riparian forest remnants of these highly modified landscapes. The Ovenbird, Winter Wren, and Pileated Woodpecker bred successfully in Kewaunee County remnants. More intensive studies (in progress) will be needed to determine the status of birds we observed, yet 11 of the 15 forest interior species in Kewaunee County (Table 2) were only slightly less frequent in outlying forest remnants than they were in the larger (867-ha) forest. The Brown-headed Cowbird ( Molothrus ater ) has been implicated in decreased fledging success of forest interior birds in Wisconsin (Brittingham and Temple 1983). In Kewaunee County, Brown-headed Cowbirds were pre- sent in 20% of the smaller sites but were not recorded at all in the 867-ha site. The increased frequency of cowbirds in smaller forests may reduce the breeding success of birds in the smaller remnants. Robbins (1979) suggested that contiguous forest areas of at least 2650 ha might be necessary to support a population of Ovenbirds and that at least 100 ha are needed for a viable Wood Thrush population. Brown and Ke- waunee counties have no forest remnants larger than 2500 ha and few larger than 100 ha, yet, as we have shown, both species (and other sensitive species) are present. Perhaps the extensive forested areas remaining northwest and west of Brown and Kewaunee counties provide a regular source of colonists for populations in our riparian remnants. In other words, the local popula- tions that we have studied might not be self-sustaining. Current studies of the Kewaunee County sites are attempting to resolve this uncertainty. Another possibility, first implied by Bond (1957), is that moister sites are better able to sustain populations of forest interior birds than are drier upland sites. Whitcomb et al. (1981) observed that forest interior bird species often are more abundant in bottomlands or mesic habitats than they are in drier uplands. Upland sites are more prone to the inevitable drying effects of sun and wind following forest fragmentation. Riparian forest fragments, on the other hand, have a source of moisture and often sheltered slopes to counteract these effects. Thus, riparian remnants might better retain the mesic nature of original forests. Forest interior birds species may, therefore, persist in smaller tracts if the tracts are riparian. Isolation may be another important element contributing to the decline of habitat-island populations (Whitcomb et al. 1981, Lynch and Whigham 1984). Because riparian forests tend to form corridors that promote movement be- tween local populations, they may be important in maintaining genetic or demographic integrity of regional populations (Noss and Harris 1986). The “interconnectedness” of riparian forests in our study areas, despite relatively small forest sizes and high proportions of edge habitat, may be another ex- planation for the presence of species sensitive to forest extent. 81 REMNANT RIPARIAN FORESTS Results from our investigations illustrate the complexity of the relationships between habitat extent, habitat quality, and bird distributions. Many species, like Ovenbirds, occur in a variety of forest habitats, yet their abundance varies locally. Ovenbirds and several other species seem to be more successful in the moister forests of Kewaunee County, for example, than they are in riparian forests of Brown County (Table 2) . The opposite seems to be true for the Wood Thrush, Eastern Wood Pewee, and Red-eyed Vireo. Small areas of highly favorable habitat might be equivalent to larger areas of less favorable habitat. We suggest that riparian or lowland forests are indeed highly favorable for certain forest interior bird species. Hence, these birds might be able to persist in riparian areas that are smaller than their minimum habitable areas in upland forest types. Changes in forest size may affect the quality of forest vegetation. Red- breasted Nuthatches are fairly common in the large (867-ha) lowland forest of Kewaunee County, yet they are replaced by White-breasted Nuthatches in smaller, more isolated tracts of otherwise similar habitat (Table 2). Red- breasted Nuthatches in northeastern Wisconsin typically occur in shady con- iferous forests, whereas White-breasted Nuthatches seem to favor deciduous forests, which for much of the year are considerably more open than con- iferous woods. In other words, fragmentation of lowland coniferous forests may create a relatively open forest environment, more suitable for species like the White-breasted Nuthatch. Perhaps other, more subtle interactions be- tween habitat quality and habitat size will be revealed as more types of “habitat islands” are evaluated. The fact that significant numbers of forest interior specialists still occur in riparian forest remnants of our study area suggests that it is not too late to preserve at least a part of the original forest interior avifauna in this region. Riparian forests, because of their relatively high levels of available moisture and perhaps because of their interconnectedness, might play a crucial role in preservation efforts. The preservation of maximum bird species diversity in these two counties and many like them requires protection of the regional variation in forest habitats. Riparian forests provide a significant system of these forest refugia and thus are vital to regional bird species diversity. ACKNOWLEDGMENTS We thank CEIP, Inc., through EIP Great Lakes Student-Initiated Projects, and the Institute for Land and Water Studies at the University of Wisconsin -Green Bay for fun- ding portions of this study. Special thanks go to Hallett Harris and Keith White for their advice and criticism. We sincerely appreciate the cooperation of private landowners in Brown and Kewaunee Counties and the Wisconsin Department of Natural Resources, who graciously allowed us to conduct this study on their lands. LITERATURE CITED Bond, R.R. 1957. Ecological distribution of breeding birds in the upland forests of southern Wisconsin. Ecol. Monogr, 27:253-284. Brittingham, M.C., and Temple, S.A. 1983. Have cowbirds caused forest songbirds to decline? Bioscience 33:31-35. 82 REMNANT RIPARIAN FORESTS Cottam, G., and Curtis, J.T. 1956. The use of distance measures in phytosociological sampling. Ecology 37:451-460. Hays, R.L., Summers, C., and Seitz, W. 1981. Estimating wildlife habitat variables. FWS/OBS-81/47, Fish and Wildlife Serv., U S. Dept. Interior. James, F.C., and Shugart, H.H. 1970. A quantitative method of habitat description. Aud. Field Notes 24:727-736. Link, E.G., andFrings, S.W. 1980. Soil survey of Kewaunee County, Wisconsin. Soil Conserv. Serv., U.S. Dept. Agric. Lynch, J.F., and Whigham, R.F. 1984. Effects of forest fragmentation on breeding bird communities in Maryland, USA. Biol. Conserv. 28:287-324. Noss, R.F., and Harris, L.D. 1986, Nodes, networdsand MUMS: preserving diversity at all scales. Environ. Mgt. 10:in press. Ranney, J.W., Bruner, M.C., and Levenson, J.B. 1981. The importance of edge in the structure and dynamics of forest islands, in Forest Island Dynamics in Man- Dominated Landscapes (R.L. Burgess and D.M. Sharpe, eds,), pp. 67-95. Springer- Verlag, New York. Rice, J., Omhart, R.D., and Anderson, B.W. 1983. Habitat selection attributes of an avian community: a discriminant analysis investigation. Ecol. Monogr. 53:263-290. Robbins, C.S. 1979. Effect of forest fragmentation on bird populations, in Management of North Central and Northeastern forests for nongame birds. U.S. Forest Serv. Gen Tech. Rep. NC-51:198-212. Roth, R.R. 1976. Spatial heterogeneity and bird species diversity. Ecology 57:773-782. Stearns, F., and Kobringer, N. 1975. Environmental status of the Lake Michigan drainage basin. Argonne National Laboratory, Argonne, IL. Whitcomb, R.F., Robbins, C.S., Lynch, J.F., Whitcomb, B.L., Klimkiewicz, M.K., and Bystrak, D. 1981. Effect of forest fragmentation on avifauna of the eastern deciduous forest, in Forest Island Dynamics in Man-dominated Landscapes (R.L. Burgess and D.M. Sharpe, eds.), pp. 123-205. Springer- Verlag, New York. Wilcove, D.S. 1985. Nest predation in forest tracts and the decline of migratory songbirds. Ecology 66:1211-1214. Wisconsin Department of Natural Resources. 1968. Wisconsin forest resource statistics, Lake Michigan survey report. Wis. Dept. Nat. Res. Bull. 83 Ovenbird and Wood Thrush Sketch by Narca Moore-Craig 84 THE CALIFORNIA NATURAL DIVERSITY DATA BASE AND RIPARIAN ECOSYSTEM CONSERVATION CARRIE ANNE SHAW, Nongame-Heritage Program, California Department of Fish and Game, 1416 Ninth Street, Sacramento, California 95814 The California Natural Diversity Data Base (Data Base) is an ongoing pro- ject of the Department of Fish and Game’s Nongame -Heritage Program. This paper presents background information on the Data Base, briefly describes the types of riparian-associated data collected and computerized in it, and explains the importance and usefulness of the Data Base for riparian ecosystem conservation. THE NATURAL DIVERSITY DATA BASE IN A NUTSHELL California is well known for the diversity of its natural resources and for the rapid pace at which its lands have been developed. Because of this unhesitating and extensive land development, many species of plants, animals, and some natural communities are threatened with extinction. Others, though not currently endangered, are rare and unique to California. The California Department of Fish and Game recognizes the need to identify these special species and natural communities and to develop plans for their conservation and management. To this end, the Department, in cooperation with The Nature Conservancy, established the California Natural Diversity Data Base. The Data Base was patterned after heritage inventories developed by The Nature Conservancy in the eastern United States. Currently, there are more than forty similar state and several similar international inventories. The Data Base is an ongoing computerized inventory of the locations and condition of endangered, threatened, and rare animal and plant taxa, as well as of terrestrial and aquatic natural communities. The Data Base staff con- tinually expands, updates, and analyzes the Data Base in order to keep the inventory current and to identify research and conservation needs for a par- ticular site or taxon. The animals and plants included are (1) those on or pro- posed for governmental lists of endangered or threatened taxa, (2) taxa that are sensitive, fully protected, or of special concern, (3) taxa that are biologically rare, very restricted in distribution, declining throughout their range, or are peripheral to California, and (4) taxa closely associated with ecosystems that are declining in California at an alarming rate (e.g., wetlands, desert aquatic systems, native grasslands, and riparian ecosystems) . Current lists of the plants, animals and natural communities inventoried by the Data Base are available on request to the Nongame-Heritage Program, California Department of Fish and Game. Members of the Data Base science staff (zoologists, botanists, and vegeta- tion ecologists) rarely do original field work. Instead, they rely on data gathered by others and made available to the Data Base. The staff encourages profes- sional, student, and lay biologists to contribute data to the project by submit- ting field survey forms (available from the Data Base), theses, status reports, Western Birds 18:85-88,1987 85 NATURAL DIVERSITY DATA BASE articles, and environmental documents, or by communicating personally with the staff. Currently, Data Base scientists collect information on about 50 riparian- associated animals and plants. Many are riparian obligates such as the Western Yellow-billed Cuckoo ( Coccyzus americanus occidentalis ) or Valley Elderberry Longhorn Beetle ( Desmocerus californicus dimorphus). Others, such as salmonid fishes, require microhabitats that are influenced by the quality of riparian vegetation. Surprisingly, less than one dozen rare plants are associated with riparian ecosystems in California, One example is the California Hibiscus ( Hibiscus californicus) , which grows on moist, freshwater-soaked banks along the lower Sacramento and San Joaquin rivers. About three dozen riparian plant communities have been described in California. A draft riparian classification groups the communities into three broad types. These are riparian forests, such as the gallery forests along the lower Sacramento River, riparian woodlands, such as the sycamore alluvial woodland along Los Banos Creek in Merced County, and scrub communities, such as the southern riparian scrub along the Santa Margarita River. The riparian communities of the Sacramento and San Joaquin valleys and along the lower Colorado River are the best documented and inventoried by the Data Base at the present time . The riparian vegetation of southern California and the California deserts will be the next areas of research and data acquisi- tion by Data Base vegetation ecologists. THE IMPORTANCE AND USEFULNESS OF THE DATA BASE The Data Base is unique and important for several reasons. It is a com- puterized synthesis of information from many unrelated sources, such as museum or herbarium collections, status reports, field surveys, environmen- tal documents, published articles, and personal communications with research- ers. Nowhere else in California is data-gathering and synthesis on sensitive species being done on a statewide scale. The information in the Data Base is provided, on a cost-reimbursement basis, to a large number of interested parties in a variety of formats, principally map overlays and computer reports. An average of 51 requests for data was filled each month during the first 6 months of 1987. The Data Base is not simply a static, computerized inventory of data on sensitive species; it is an extremetly useful conservation tool. The Data Base is used to select the best sites for land-based conservation projects such as the setting aside of ecological reserves or other natural areas. It is also used in the environmental review of land management plans and development proj- ects. In addition, it is used to provide a statewide perspective on the distribu- tion patterns and population trends of sensitive taxa, and to pinpoint gaps in our knowledge of these taxa and natural communities. THE DATA BASE AND RIPARIAN ECOSYSTEM CONSERVATION The Department of Fish and Game’s Lands and Natural Areas Project and The Nature Conservancy use the Data Base as a foundation for their conser- vation efforts in California. For example, much of the best remaining riparian 86 NATURAL DIVERSITY DATA BASE habitat in the Central Valley of California is privately owned. If purchasing a piece of property is not desirable or financially feasible, the site could be a candidate for The Nature Conservancy’s Landowner Contact Program. The Nature Conservancy may be able to educate a property owner and help the owner protect or enhance land supporting riparian forest and associated wildlife. On the other hand, many of the most diverse desert riparian areas in California are wholly or partially under the jurisdiction of the U.S. Bureau of Land Management (BLM) . A new interagency committee composed of state, federal, and private agencies, the Interagency Natural Areas Coor- dinating Committee, has been organized by the Department of Fish and Game’s Land and Natural Areas Project. The purpose of the committee is to coordinate the protection of natural areas throughout the state. As a member of the committee, the BLM can use the Data Base to help establish a priority for its riparian ecosystem conservation projects. In the enviromental review process, the Data Base is used extensively in both the project development and document review stages. Recently, the Sacramento District of the U.S. Army Corps of Engineers requested detailed reports and map overlays showing where sensitive species and riparian com- munities are known to occur in the entire district. The Corps intends to use these data to evaluate the impacts of its bank stabilization projects. The En- vironmental Services staff of the Department of Fish and Game also has these data. The Department also uses the Data Base to fulfill its trust agency respon- sibilites under the California Environmental Quality Act, through review of the Corps’ environmental documents for projects. The Department urges the Corps and other developers to address, assess, and mitigate adequately the impacts that their projects have on wildlife and natural diversity. Occasionally the Department of Fish and Game uses the Data Base to fulfill its mandates under special legislation. Recently, Chapter 885 of Senate Bill 1086 appropriated $150,000 for the Wildlife Conservation Board to survey critical wildlife habitat and natural areas along the upper Sacramento River between the mouth of the Feather River and Keswick Dam near Redding. The Data Base will be one of several sources of information used by the Depart- ment to identify these important areas and rank them for possible acquisition. These are just a few examples of how the Data Base is used as a conserva- tion and management tool for riparian ecosystems. As human development puts more and more pressure on California’s remaining natural areas, there will be an even greater need for a central, computerized, up-to-date inven- tory of the state’s natural diversity. FUTURE PLANS FOR THE DATA BASE The Data Base currently has over 16,000 records— with more being add- ed every day— and the demand for information is increasing rapidly. In the first 6 months of 1987, requests for data increased 41 % over the same period in 1986. In order to accommodate more data and fulfill user needs, the Data Base will be converted to a Geographic Information System (GIS) during 1988 and 1989. The new GIS will make data input, storage, retrieval, and analysis much easier, more reliable, and much more flexible. The Data Base will become a more versatile and powerful conservation tool, better suited to serve 87 NATURAL DIVERSITY DATA BASE those people working to protect and manage California’s remaining sensitive riparian ecosystems. ACKNOWLEDGMENTS I thank John Gustafson, Kathleen Franzreb, Stephen Laymon and Edward Beedy for their review and comments on the draft manuscript. My appreciation also goes to all the concerned and committed biologists who have contributed their knowledge and hard work to the Natural Diversity Data Base so that the information can be used toward the conservation of California’s natural heritage. 88 ENDANGERED HABITATS VERSUS ENDANGERED SPECIES: A MANAGEMENT CHALLENEGE R. ROY JOHNSON and LOIS T. HAIGHT, National Park Service, School of Renewable Natural Resources, University of Arizona, Tucson, Arizona 85721 JAMES M. SIMPSON, 4249 N. 34th Street, Phoenix, Arizona 85018 Riparian ecosystems are the most productive and possibly the most sen- sitive of the various bird habitats in the arid and semiarid North American Southwest, The highest population densities of noncolonial nesting birds for North America were reported from riparian cottonwood (Populus fremontii) forests in central Arizona by Johnson (1971) and Carothers at al. (1974). Most avian studies in southwestern riparian ecosystems have been conducted along perennial and intermittent streams where both species richness (Hub- bard 1970) and population densities are extremely high (Johnson et al. 1977, Johnson 1979) . Factors contributing to this high avian species richness and density have not been well studied but apparently include (1) high temperatures and soil moisture availability, which contibute to high primary productivity, high insect biomass, and, consequently, many insectivorous birds (Carothers et al. 1974), (2) a diversity of vegetation resulting from well-developed herbs, shrubs, and trees and leading to a large number of foraging layers and available nest sites, and (3) ready access to water during the nesting season. Manage- ment schemes, species recovery plans, etc., that concentrate on the conser- vation of individual species without also emphasizing conservation of the associated critical habitat and ecological processes are inadequate. METHODS In 1977 we analyzed the nesting birds of the Southwest lowlands in rela- tion to their use of riparianlands as breeding habitat (Johnson et al. 1977). That analysis included several tropical species that occur in the United States only in the lower Rio Grande Valley of southwestern Texas. Here we have excluded riparian breeding species of the Tamaulipan thorn scrub in the lower Rio Grande Valley (Brown et al. 1979) because that region’s biological af- finities differ appreciably from those of the desert scrub and desert grasslands of the North American Southwest lowlands. Additionally, we have divided our 1977 “nonriparian” category into “facultative riparian” and “nonriparian” since some species show no nesting preference for either riparian or upland ecosystems while others actually select nonriparian breeding sites (Table 1). Although only three species have been extirpated, 69% of the 161 nesting species of the arid lowlands of the Southwest have apparently suffered popula- tion reductions due to loss of riparian and associated aquatic habitats. For nesting birds as for humans, the more arid the region, the more valuable water and its attendant habitats. This new analysis is based on our combined 84 years of collecting field data in the Southwest and data from literature (Table 1). Papers currently in the literature have dealt almost entirely with hydroriparian (accompaning peren- Western Birds 18:89-96,1987 89 ENDANGERED HABITATS nial water) and mesoriparian habitats (associated with intermittent streams) , thus limiting our analysis to those (wet) riparian types. The importance of xeroriparian (dry riparian) habitats is addressed elsewhere (Johnson and Haight 1985 and in press). RESULTS Although numerous papers have demonstrated the importance of riparian habitats to nesting birds in the Southwest, the reasons for high riparian pro- ductivity and species richness are not well understood. Available soil moisture is presumably the key factor. To this, add temperature, since higher temperatures result in greater physiochemical activity such as respiration, photosynthesis, and evapotranspiration (van Hylckama 1980). This combina- tion apparently results in higher primary productivity and hence a high avian biomass. Although no studies have tested this hypothesis directly, numerous studies have documented that populations of birds in the higher, colder areas of the western United States (Beidleman 1978) are generally lower than those in the southwestern lowlands (Carothers et al. 1974). Additionally, accord- ing to at least one study, “the most diverse avifauna occurs in riparian zones at lower elevations” (Knopf 1985) where foraging niches for insectivores should be expected to be more numerous because of the greater variety of insects. Categories of Riparian Dependency Riparian-nesting species can be divided into several categories based on their dependence on riparian habitats. Riparian and Other Wetlands: Species that nest either along a river’s or lake’s edge or in the aquatic habitats of the river or lake itself. Obligate Riparian: Species that nest almost exclusively in riparian habitats. Preferential Riparian: Species that nest in numbers in both upland and riparian habitats but whose population densities are greater in riparian habitats. Facultative Riparian: Species that nest indiscriminately in either riparian or nonriparian habitats; often nesting in desert trees or subtrees, e.g., mesquites and paloverdes, regardless of whether these plants are in a wet riparian, dry riparian, or upland site. Others, such as the Canyon Wren, select canyon walls or other factors that may or may not be associated with a stream. Nonriparian: Species that select dry habitats, especially grasslands, that are different structurally from most riparian habitats. Habitat Selection and Distributional Categories Since birds have long been the subject of behavioral and other studies because of their colorful and, for the most part, diurnal activity, their life histories are better known than those of most other animal groups. Some avian species exhibit relatively consistent patterns of habitat and nesting-site selec- tion from one geographic region to another or from one habitat type to another. Other species vary greatly in some aspect of their natural history from one locality to another. In studies in saltcedar ( Tamarix chirtensis ) along three 90 ENDANGERED HABITATS lowland rivers of the Southwest (the Colorado, Rio Grande, and Pecos) Hunter et al. (1985) found certain species of birds acting differently along each river. Factors determining such behavioral differences often go undetected by even the most knowledgeable riparian ecologist, making the categorizing of species difficult. In establishing riparian dependence (Table 1) the following groupings of southwestern riparian nesting species were considered: 1. Peripheral species: Those at the periphery of their ranges, usually the north- ern limit, with the bulk of their population in Mexico (e.g., Common Black Hawk, Gray Hawk, and Ferruginous Pygmy-Owl). The major rivers of north- western Mexico, as well as those of the southwestern United States, have been dammed and diverted for agricultural and urban use, so a large percen- tage of riparian habitats, and thus the avifauna of the entire North American Southwest, have been greatly affected. 2 . Species whose highland as well as lowland populations are riparian (e.g., Bald Eagle, Yellow Warbler, and Blue Grosbeak). 3 . Species which, because of their affinity for more mesic vegetation such as deciduous trees, are riparian only at lower elevations (e.g., Cooper’s Hawk, Cassin’s and Western kingbirds, and White-breasted Nuthatch) and become facultatively riparian or even nonriparian at higher elevations. 4 . Species that prefer riparian habitats but adapt to indigenous nonriparian habitats such as saguaros, the only trees in much of the desert Southwest uplands (e.g., Harris’ Hawk, Gila Woodpecker, and Screech Owl) and species that adapt to agricultural and/or urban landscapes (e.g., Screech Owl, Black- chinned Hummingbird, and Western Kingbird). 5 . Riparian specialists which do not adapt to nonriparian habitats, either natural or man-made (e.g., Yellow-billed Cuckoo, Lucy’s Warbler, and Summer Tanager). 6 . Site-specific species, such as those showing different preferences between Phoenix and Tucson, Arizona, cities separated by only 100 miles of Lower Sonoran Desert. Ladder-backed Woodpeckers have adapted to urban trees in Tucson but are still restricted to riparian habitats in the Phoenix area. Abert’s and Brown towhees have “reversed roles” in Tucson and Phoenix: the Brown Towhee is a common bird around Tucson foothill residences, while the Abert’s Towhee occurs only in remote, densely vegetated riparian areas. Converse- ly, in Phoenix the Abert’s Towhee nests commonly in suburban yards, while the Brown Towhee’s sparse populations are confined to the arid foothills. MANAGEMENT IMPLICATIONS Variation in habitat selection and other aspects of avian behavior should affect the management strategies for different riparian areas. Birds of the same species, occupying the same habitat type along two different segments of the same river or along two lowland rivers in the same geographic region, often exhibit different behavior. Thus, although some generalities can be applied, the manager must be aware of the dangers involved in extrapolating from 91 Table 1 Breeding Bird Dependence for Lowland Wet Riparian Habitats of the Warm Deserts and Grasslands in the Southwestern United States* eP r>> a a in CM 0 ) 3 — -¥-• 3 (J (0 UL ZC 3 X <0 ^ , T3 05 05 >H a c a 05 x u i- Ti r a: i 21 Si (0 — 05 O W cn V ~<2 C SE . CO £ 00 10 o U _ ) 05 E c 3 CD 3 o >-i k* (0 a 3 co o — <0 a co to 0 * 05 u> T3 -C •2 3o J— 4—* •-*_ (0 0 3 > CQ DC Jp o CM a a w CM CO c "C <0 a "C c o 2 X 2 ! | 3 I - 4 — < ”3 .« > § S'! 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Jj = a < ■a }- ^5 3 o O T3 0) N c o Vi CQ x u c X x -a -5.S o O Q2« ° 0) u £ O 22 v X 0) +4 m K *n O cu z a c 0) v 3 10 i— I 6P dJ 2 X 1-1 -4—1 O || "O c (0 c .2 v 10 a m v -o o) E 44 10 (0 X DO 0) X ^ a a in CO 10 o V X +4 3 o _ 3 0) ^ v _, ^ 8 X E £ £ <2 o 2 U (0 X U TJ 2 3 Sn O (0 v o> 5 x a 3^ o cn == c » o > co Js u CQ JS _ CQ ^ T5 ’ 1 ° I s c ^ II 0) 0) a > 93 ■Excludes accidental nesters. Modified from Johnson et al. 1977. "Extirpated as a nesting species in the Southwest lowlands. ENDANGERED HABITATS one riparian management area to another even if conditions in the two areas are similar. One such example pertains to Brown-headed Cowbird control, designed to prevent extirpation of the Least Bell's Vireo ( Vireo bellii pusillus ) in California (discussed by several papers in this volume). By contrast, our studies during the past 35 years in the heavily dammed Salt- Verde River system of central Arizona show that habitat loss, not cowbirds, is the major problem for the Arizona Bell’s Vireo (V. b. arizonae). Research Needs for Management of Riparian Birds Although a sizable body of knowledge is now available, additional scien- tific information needs to be gathered before effective riparian management techniques can be instituted. One of the earlier lists of research needs (Carothers and Johnson 1975) is still largely appropriate. We here repeat some of those continuing needs, along with additional needs that are particularly important for “sensitive species,” i.e., endangered, threatened, and rare species. 1. Establish “endangered habitat recovery plans,” not just endangered species recovery plans. For example, a “San Pedro River Recovery Plan” would ad- dress the problems of numerous species instead of those of a single species, as in the “Least Bell’s Vireo Recovery Plan.” 2 . Determine the minimal area and configuration of a particular habitat type necessary to maintain healthy populations of all avian species. These needs differ greatly between species. Lucy’s Warbler maintains territories of 30 meters square in optimum mesquite habitat, and Yellow Warblers maintain popula- tions in a narrow fringe of willow-tamarisk along the water’s edge. Bald Eagles and Common Black Hawks may need territories of tens of hectares in a con- figuration that is at least 100 meters or more wide and hundreds of meters long. Size of the bird is not always a good clue. The 60-gram Yellow-billed Cuckoo uses territories, even in optimum cottonwood -willow habitat, of up to 20 hectares or more (S.A. Laymon, pers. comm.). 3 . Determine the maximum distance separating “islands” of a given habitat type before the loss of certain species (especially migrants) occurs. 4 . Determine both minimal and optimal requirements for each species within a given habitat type for factors such as ground cover, canopy, number of trees or shrubs per unit area, and foliage volume, density, and configuration. Knowledge of these requirements is particularly important for sensitive species. 5 . Examine the interrelationships between recreation and riparian birds. With increasing urbanization, “nonconsumptive uses” of riparian resources, such as birdwatching, camping, and picnicking, have grown more rapidly than “con- sumptive uses,” such as hunting, fishing, and logging. Research in this im- portant area has not kept pace with recreational demands. Questions about the compatibility of various recreational activities, such as off-road vehicular usage, with a given avian species remain unanswered. In addition to these research needs, better methods must be established for applying the information already available. Resource management agen- cies need “clearing houses” so they can coordinate existing information, identify 94 ENDANGERED HABITATS areas where their policies are weak, and establish sound, uniform guidelines for riparian management. Resource management agencies need to establish a sound riparian management policy. If further elimination of critical riparian resources is to be prevented, scientists, managers, and conservationists must work more closely together to collect new information and to apply better what is already known. LITERATURE CITED Beidleman, R.G. 1978. The cottonwood -willow riparian ecosystem as a vertebrate habitat, with particular reference to birds, in Lowland River and Stream Habitat in Colorado: A Symposium (W.D. Graul and S.J. Biseil, tech, coords.), pp. 192-195. Colo. Chapter Wildlife Soc. and Colo. Audubon Council, Denver. Brown, D.E., Lowe, C.H., and Pase, C.P. 1979. A digitized classification system for the biotic communities of North America, with community (Series) and associa- tion examples for the Southwest. J. Ariz.-Nev. Acad. Sci. 14 (Suppl. 1) : 1 - 16. Carothers, S.W., and Johnson, R.R. 1975. Water management practices and their effects on nongame birds in range habitats, in Proceedings of Symposium on Management of Forest and Range Habitats for Nongame Birds, pp. 210-222. Dept. Agric. Forest Serv. Gen. Tech. Rep. WO-1, Washington, D.C. Carothers, S.W., Johnson, R.R., and Aitchison, S.W. 1974. Population structure and social organization of southwestern riparian birds. Am. Zool. 14:97-108. Hubbard, J.P. 1970. Checklist of the birds of New Mexico. N.M. Ornithol. Soc. Pubi. 3. Hunter, W.C., Anderson, B.W / ., and Ohmart, R.D. 1985. Summer avian community composition of Tamarix habitats in three southwestern desert riparian systems, in Riparian Ecosystems and Their Management: Reconciling Conflicting Uses. First North American Riparian Conference (R.R. Johnson, C.D. Ziebell, D.R. Patton, P.F, Ffolliott, and R.H. Hamre, tech, coords.), pp. 128-134. Gen. Tech. Rep. RM-120, U.S. Dept. Agric. Forest Serv., Rocky Mtn. Forest and Range Exp. Stn., Fort Collins, CO. Johnson, R.R. 1971, Tree removal along southwestern rivers and effects on associated organisms, in Am. Philos. Soc., Yearbook 1970, pp. 321-322. Johnson, R.R. 1979. The lower Colorado River: a western system, in Strategies for Protection and Management of Floodplain Wetlands and Other Riparian Ecosystems (R.R. Johnson and J.F. McCormick, tech, coords ), pp. 41-55. U.S. Dept. Agric. Forest Serv. Gen. Tech. Rep, WO- 12, Washington, D.C. Johnson, R.R., and Haight, L.T. 1985. Avian use of xeroriparian ecosystems in the North American warm deserts, in Riparian Ecosystems and Their Management: Reconciling Conflicting Uses. First North American Riparian Conference (R.R. Johnson, C.D. Ziebell, D.R. Patton, P.F. Ffolliott, and R.H. Hamre, tech, coords.), pp. 156-160. Gen. Tech. Rep. RM-120, U.S. Dept. Agric. Forest Serv., Rocky Mtn. Forest and Range Exp. Stn., Fort Collins, CO. Johnson, R.R., and Haight, L.T. In press. Avian use of xeroriparian systems in the Big Bend region, Texas. Proc. 2nd Symp. Chihuahuan Desert. Chihuahuan Desert Res. Inst., Alpine, TX. Johnson, R.R., Haight, L.T., and Simpson, J.M. 1977. Endangered species vs. en- dangered habitats: a concept, in Importance, Preservation and Management of Riparian Habitat: A Symposium (R.R. Johnson and D.A. Jones, tech, coords.), pp. 68-79. Dept. Agric. Forest Serv. Gen. Tech. Rep. RM-43, Rocky Mtn. Forest and Range Exp. Stn,, Fort Collins, CO. 95 ENDANGERED HABITATS Knopf, F.L. 1985, Significance of riparian vegetation to breeding birds across an altitudinal cline, in Riparian Ecosystems and Their Management: Reconciling Con- flicting Uses. First North American Riparian Conference (R.R. Johnson, C.D. Ziebell, D.R. Patton, P.F. Folliott, and R.H. Hamre, tech, coords ), pp. 105-111. Gen. Tech. Rep. RM-120, U. S. Dept. Agric. Forest Serv., Rocky Mtn. Forest and Range Exp. Stn., Fort Collins, CO. Van Hylckama, T.E.A. 1980. Weather and evapotranspiration studies in a saltcedar thicket, Arizona. U.S. Geol. Surv. Prof. Pap. 491-F., Washington, D.C. Western Birds solicits papers that are both useful to and understandable by amateur field ornithologists and also contribute significantly to scientific litera- ture, The journal welcomes contributions from both professionals and amateurs. Appropriate topics include distribution, migration, status, identifi- cation, geographic variation, conservation, behavior, ecology, population dynamics, habitat requirements, the effects of pollution, and techniques for censusing, sound recording, and photographing birds in the field. Papers of general interest will be considered regardless of their geographic origin, but particularly desired are reports of studies done in or bearing on the Rocky Mountain and Pacific states and provinces, including Alaska and Hawaii, western Texas, northwestern Mexico, and the northeastern Pacific Ocean. Send manuscripts to Philip Unitt, 3411 Felton Street, San Diego, CA 92104. For matter of style consult the Suggestions to Contributors to Western Birds (8 pages available at no cost from the editor) and the Council of Biology Editors Style Manual (available for $24 from the Council of Biology Editors, Inc., 9650 Rockville Pike, Bethesda, MD 20814. Reprints can be ordered at author’s expense from the Editor when proof is returned or earlier. Good photographs of rare and unusual birds, unaccompanied by an article but with caption including species, date, locality and other pertinent informa- tion, are wanted for publication in Western Birds. Submit photos and captions to Photo Editor. 96 Volume 18, Number 1, 1987 Introduction Stephen A. Laymon 1 Perspectives on Managing Riparian Ecosystems for Endangered Bird Species Kathleen E. Franzreb 3 Status of Breeding Riparian-obligate Birds in Southwestern Riverine Systems William C. Hunter , Robert D. Ohmart, and Bertin W. Anderson 10 Can the Western Subspecies of the Yellow-billed Cuckoo Be Saved from Extinction? Stephen A. Laymon and Mary D. Halterman 19 Willow Flycatcher Surveys in the Sierra Nevada John H. Harris, Susan D. Sanders, and Mary Anne Flett 27 Ecology of a Sierra Nevada Population of Willow Flycatchers Mary Anne Flett and Susan D. Sanders 37 Endangered Status and Strategies for Conservation of the Least Bell’s Vireo { Vireo bellii pusillus) in California Kathleen E. Franzreb 43 Nest-site Tenacity of Least Bell’s Vireos James M. Greaves 50 Least Bell’s Vireo Management by Cowbird Trapping John A. Beezley and John P. Rieger 55 Brown-headed Cowbirds in California: Historical Perspectives and Management Opportunities in Riparian Habitats Stephen A. Laymon 63 Bank Swallow Distribution and Nesting Ecology on the Sacramento River, California Barrett A. Garrison, Joan M. Humphrey, and Stephen A. Laymon 71 Birds of Remnant Riparian Forests in Northeastern Wisconsin Norman E. Fowler and Robert W, Howe 77 The California Natural Diversity Data Base and Riparian Ecosystem Conservation Carrie Anne Shaw 85 Endangered Habitats Versus Endangered Species: A Management Challenge R. Roy Johnson, Lois T. Haight, and James M. Simpson 89 Cover photo by James M. Greaves, Santa Barbara, California: Least Bell’s Vireo (Vireo bellii pusillus ) at nest site, Gibraltar Reservoir, near Santa Ynez River, Santa Barbara County, California, May 1980. Vol. 18, No. 2, 1987 WESTERN BIRDS Quarterly Journal of Western Field Ornithologists President: Tim Manolis, 808 El Encino Way, Sacramento, CA 95864 Vice-President: Narca A. Moore-Craig, P.O. Box 254, Lakeview, CA 92353 Treasurer/ Membership Secretary: Art Cupples, 3924 Murrieta Ave., Sherman Oaks, CA 91423 Recording Secretary: Jean-Marie Spoelman, 4629 Diaz Drive, Fremont, CA 94536 Grculation Manager: Jeny R. Oldenettel, 4368 37th Street, San Diego, CA 92105 Directors: Peter Gent, Virginia P. Johnson, John S. Luther, Guy McCaskie, Timothy Manolis, Robert McKeman, Narca Moore-Craig, Joseph Morlan, Janet Witzeman Editor: Philip Unitt, 3411 Felton Street, San Diego, CA 92104 Associate Editors: Cameron Barrows, Tim Manolis, Narca A. Moore-Craig, Thomas W. Keeney Layout Artist: Virginia P. Johnson Photo Editor: Bruce Webb, 5657 Cazadero, Sacramento, CA 95822 Review Editor: Richard E. Webster, P.O. Box 6318, San Diego, CA 92106 Secretary, California Bird Records Committee: Don Roberson, 282 Grove Acre Ave., Pacific Grove, CA 93950 Editorial Board: Robert Andrews, Alan Baldridge, Andrew J. Berger, Laurence C. Binford, David F. DeSante, Jon L. Dunn, Richard Erickson, Kimball L. Garrett, Joseph R. Jehi, Jr., Ned K. Johnson, Virginia P. Johnson, Kenn Kaufman, Brina Kessel, Stephen A. Laymon, Paul Lehman, John S. Luther, Guy McCaskie, Joseph Morlan, Harry B. Nehls, Dennis R. Paulson, Stephen M. Russell, Oliver K. Scott, Ella Sorensen, Richard W. Stallcup, Charles Trost, Terence R. Wahl, Roland H. Wauer, Bruce Webb, Wayne C. Weber, Richard E. Webster Membership dues, for individuals and institutions, including subscription to Western Birds: Patron, $1000; Life, $250; Supporting, $50 annually; Contributing, $25 annually; Regular, $14 U S. ($17 outside U.S.) annually. Dues and contributions are tax-deductible to the ex- tent allowed by law. Send membership dues, changes of address, correspondence regarding missing issues, and orders for back issues and special publications to the Treasurer. Make checks payable to Western Field Ornithologists. Back issues of California Birds/Westem Birds: $15 per volume, $4.00 for single issues. Xerox copies of out of print issues (Vol. 1, No. 1; Vol. 2, Nos. 1 and 4; Vol. 6, No. 2): $4.50 each Checklist of the Birds of California: $2. 00 each , 10 or more $1 .50 each . Pelagic Birds of Monterey Bay, California: $2.50 each, 10 or more $2.00 each, 40 or more $1 .50 each. All postpaid. WESTERN BIRDS ADVERTISING RATES AND SPECIFICATIONS Full page 4 x 6 3 A inches $60 per issue $200 per year Half Page 4x3% inches $40 per issue $130 per year Quarter Page 4 x l 1 /,* inches $30 per issue $110 per year Offset printing, one column per page, 4 inches wide. Glossy, black and white photos are ac- ceptable ; half-tone screen size; 133 line , Photo-ready copy is requested . If this is not possible, extra charges for typesetting will be made as follows: $15 full page, $10 half page, $5 quarter page. Send copy with remittance to the Treasurer. Make checks payable to Western Field Ornithologists. A 15% commission is allowed for agencies. WESTERN BIRDS Volume 18, Number 2, 1987 COLORADO FIELD ORNITHOLOGISTS’ RECORDS COMMITTEE REPORT FOR 1978- 1985 PETER R. GENT, 55 South 35th St., Boulder, Colorado 80303 The last Colorado Field Ornithologists (CFO) Records Committee report in Western Birds is for 1976-1977 (Andrews 1979). The time elapsed since the last report precludes discussion of all records handled by the Records Committee (RC) in this period, so this report covers only first, second, and third state records and new or very unusual definite breeding records for Col- orado from 1978 throuqh 1985. The full reports of the RC for this period can be found in Chase (1981, 1982, 1983) and Gent (1984; 1985a, b; 1986). This report discusses 21 additions to and 8 deletions from the CFO state list, resulting in a net gain of 13 species from the 427 mentioned by Andrews (1979) . Thus, the CFO state list for Colorado currently stands at 440 species, 5 of which are introduced. Andrews (1980) summarized the state list in 1980, and the present list is summarized by Gent (1987). The RC has had three chairmen during the period covered by this report: Robert Andrews 1978-1980, Charles Chase 1980-1983, and Peter Gent 1983- 1985. The members of the committee during this period were Winston William Brockner, Richard Bunn, Daniel Casey, Kevin Cook, David Griffiths, Edward Hollowed, Mark Holmgren, Harold Holt, Mark Janos, Ron Lambeth, Steve Larson, Tim Manolis, Peter Moulton, Ronald Ryder, James Sedgewick, and Richard Stransky. The following list is of those species seen in Colorado fewer than 10 times. The RC desires reports if these species, or any unrecorded from the state, are seen or heard in Colorado. The RC also desires reports of new breeding records in the state, species significantly changing their breeding range in the state, and very unusual occurrences of other species. Reports should be sent to Chairman CFO Records Committee, c/o Dept, of Zoological Collections, Denver Museum of Natural History, City Park, Denver, Colorado 80205. A CFO checklist of Colorado birds is available from the above address or the author upon request. Please send reports of Red-throated and Yellow-billed loons, Brown Pelican, Olivaceous Cormorant, Anhinga, Magnificent Frigatebird, Reddish Egret, White Ibis, Roseate Spoonbill, Wood Stork, Western Birds 18:97-108, 1987 97 COLORADO RECORDS REPORT Black-bellied Whistling-Duck, Trumpeter Swan, Brant, Harlequin Duck, American Swallow-tailed Kite, Common Black-Hawk, Gyrfalcon, Yellow, Black, and King rails, Purple Gallinule, Common Moorhen, Eskimo Curlew, Sharp-tailed Sandpiper, Ruff, Long-tailed Jaeger, Little, Mew, Lesser Black-backed, Glaucous- winged, Great Black-backed, Ross’, and Ivory gulls, Arctic Tern, Marbled and Ancient murrelets, Groove-billed Ani, Barred Owl, Lesser Nighthawk, Whip-poor-will, Blue-throated and Anna’s humm- ingbirds, Black Phoebe, Dusky-capped Flycatcher, Long-billed and Bendire’s thrashers, Phainopepla, White-eyed Vireo, Lucy’s, Hermit, Prairie, Cerulean and Swainson’s warblers, Louisiana Waterthrush, Connec- ticut and Mourning warblers, Painted Redstart, Hepatic Tanager, Henslow’s, LeConte’s, and Sharp-tailed sparrows, and Brambling. In the following sections, reports are identified by a three-part number (A-B-C). A is a code number from 1 to 56 for the bird family (numbers have not been altered despite the recent changes in the AOU taxonomic order) , B is the year of the report, and C is the sequence number in which the report was received during the year. PART 1. ADDITIONS AND DELETIONS DUE TO AOU TAXONOMIC CHANGES ARCTIC LOON (Gauia arctica). Deleted from the state list by decision of AOU (1985). No Colorado records are known to pertain to this species. PACIFIC LOON ( Gauia pacifica ). Added by decision of AOU (1985). The Pacific Loon is an uncommon fall migrant in Colorado. CLARK’S GREBE ( Aechmophorus clarkii). Added by decision of AOU (1985). Clark’s Grebe is an uncommon breeder mainly in the southern part of the state, whereas the Western Grebe (A. occidentalis ) is a common breeder throughout the state . WESTERN SCREECH-OWL (Otus kennicottii) . Added by decision of AOU (1983). The Western Screech-Owl is a fairly common breeder throughout the state except in the eastern and northeastern plains. Here the Eastern Screech-Owl (O. asio) is an un- common breeder. RED-NAPED SAPSUCKER ( Sphyrapicus nuchalis). Added by decision of AOU (1985). The Red-naped Sapsucker is a common breeder in the mountains of Col- orado. The Yellow-bellied Sapsucker (S. uarius) is an uncommon migrant throughout the eastern plains and is not known to have bred, nor is it expected to breed, in the state . GRAY- HEADED JUNCO (Junco caniceps) . Deleted by decision of AOU (1983). The Dark-eyed Junco ( J . hyemalis) is a common resident and breeder in the mountains of Colorado. ROSY FINCH (Leucosticte arctoa ). Added by decision of AOU (1983). The Rosy Finch is a common resident and breeder in the mountains of Colorado. GRAY-CROWNED ROSY-FINCH ( Leucosticte tephrocotis) . Deleted by decision of AOU (1983). BLACK ROSY-FINCH ( Leucosticte atrata). Deleted by decision of AOU (1983). BROWN-CAPPED ROSY-FINCH ( Leucosticte australis ). Deleted by decision of AOU (1983). 98 COLORADO RECORDS REPORT PART 2. SPECIES DELETED FROM THE STATE LIST GLOSSY IBIS ( Plegadis falcineUus). The only reported specimen of this species for Colorado, collected in El Paso Co. on 22 May 1916, is in the Denver Museum of Natural History (DMNH 39079) . The specimen was examined by Mark Holmgren and Joe Strauch and found to be a White-faced Ibis (P, chihi). COMMON EIDER ( Somaterici mollissima) . The single sight report from Marston Reservoir, Jefferson Co., on 25 Feb 1932 contains no details. The RC thought that this report does not justify the inclusion of Common Eider on the state list. SMITH’S LONGSPUR [Calcariu s pictus). The reason for removing this species is that the main field mark used to identify it in submitted reports has been the white shoulder patches. This field mark does not eliminate Chestnut-collared Longspur (C. ornatus ) in fall, and most reports are for September. PART 3. ACCEPTED FIRST, SECOND AND THIRD STATE RECORDS YELLOW-BILLED LOON { Gauia adamsii ). One male collected in Jan 1944 at Sterl- ing, Logan Co., by K.C. Morse and now in the Denver Museum of Natural History (DMNH 23974). The specimen was identified by Allan R. Phillips. One (1-82-2) observed on the Denver Christmas Bird Count, 19 Dec 1981, at Chatfield State Recreation Area, Jefferson Co. (Robert Andrews, Mark Holmgren, and Jack Reddall). One (1-83-1) seen at the same location on the same event the following year. 18 Dec 1982 (Mark Holmgren and Don Johnson; photo on file). First, second, and third records. OLIVACEOUS CORMORANT (Phalacrocorax oliuaceus) . One (4-78-42) at Barr Lake State Park, Adams Co., on 15 Jun 1978 (Robert Andrews). One adult (4-81-25) at Red Lion State Wildlife Area, Logan Co., on 29 Jun 1981 (Peter Gent). Second and third records. This species is being observed in Colorado with increasing frequency and there is a recent first report from western Colorado near Delta (4-85-52. Mark Janos). MAGNIFICENT FRIGATEBIRD ( Fregata magnificens) . One adult female (N-85-35) seen in southwest Denver on 14 Sep 1985 and killed at Green Mountain Reservoir, near Kremmling, Summit Co., 2 days later (Hans Feddern and Betsy Webb; see also Webb 1985) . This bird is now in the Denver Museum of Natural History (DMNH 39020) , and was killed because of its persistent attacks on a windsurfer! First state record, although there are records from all states surrounding Colorado except Utah and Wyoming. WHITE IBIS ( Eudocimus albus ). One immature (7-85-15) seen at Nee Noshe Reser- voir, Kiowa Co., from 20 Jul through Aug 1985 (Dan Bridges and Peter Gent; see also Bridges 1985). This bird associated with White-faced Ibises (Plegadis chihi). First state record, although again there are records from all states surrounding Colorado except Utah. BLACK-BELLIED WHISTLING-DUCK (Dendrocygna autumnalis). One adult (8-80-84) at Chatfield State Recreation Area. Jefferson Co., on 21 Sep 1980 (Robert Andrews and Mike Fitzpatrick). First state record. The CFO RC decided to add this species to the state list once the possibility that the bird had escaped from known local waterfowl collections had been eliminated. The RC decided to accept species that are known to wander even when the possibility of an individual being an escapee cannot be totally eliminated. This policy differs from that of the California RC, which prefers to wait until a clear pattern of vagrancy is established; see Binford (1985). 99 COLORADO RECORDS REPORT TRUMPETER SWAN (Cygnus buccinator) . Seven adults and one immature (8-78-19) between early Dec 1977 and 12 Feb 1978 at Lake DeWeese, Custer Co. (Robert Andrews, Dave Griffiths, Peter Moulton, and Bruce Webb). Third state record. There are several more recent records including one from Mack, Mesa Co., of a bird banded at Red Rock Lakes NWR, Lakeview, Montana (8-84-50, Van Graham). COMMON BLACK-HAWK (Buteogallus anthracinus) . One adult (10-80-83) observed 20 and 21 Jun 1980 at Chatfield State Recreation Area, Jefferson Co. (Robert Andrews and Cate Kittleman). First state record. BLACK RAIL ( Laterallus jamaicensis) . One (17-76-59) tape-recorded at Fort Lyon, Bent Co., on 11, 18, and 25 Jun 1975 (John Griese). One (17-82-11) briefly seen on 30 Apr 1982 at Fort Collins, Larimer Co. (David Palmer). First and second records. The RC decided to accept diagnostic sound recordings as documenting first state records. KING RAIL (Ralius elegans). One adult (17-85-12) from 12 May to 2 Jun 1985 at Lower Latham Reservoir, Weld Co. (Jerry Cairo and Peter Gent; see also Cairo 1985). Second state record. PURPLE GALLINULE (Porphprula martinica) . One adult (17-78-55) observed near Durango, La Plata Co., on 6 and 7 Aug 1978 (Elva Fox and Howard Winkler; photos on file). First state record. This species is known to wander far from its usual range, although again the possibility of an escapee cannot be totally eliminated; see the discussion under Black -bellied Whistling -Duck above. LITTLE GULL (Larus minutus). One subadult (23-80-68) at Barr Lake, Adams Co., on 13 Sep 1980 (Robert Andrews and Peter Moulton). Third state record. MEW GULL (Larus canus). One (23-80-17) in first winter plumage observed on 7 Mar 1980 at Sloans Lake, Denver Co. (Robert Andrews, Charles Chase, Mark Holmgren, and Robert Rozinski; Figure 1; photos on file). One adult (23-81-7) on 28 Apr 1981 at Union Reservoir, Longmont, Weld Co. (Timms Fowler, Mark Holmgren, and Mike Middleton) . One adult (23-82-71) again at Sloans Lake, Denver Co., on 22 Mar 1982 (B.J. Rose; Figure 2; photo on file). First, second, and third records. GLAUCOUS -WINGED GULL (Larus glaucescens) . One first-summer bird (23-82-72) at Antero Reservoir, Park Co., on 24 and 25 Jul 1981 (Charles Chase and Peter Gent; photos on file). First state record. GREAT BLACK-BACKED GULL (Larus marinus) . One immature (23-80-14) at Centennial Park, Arapahoe Co., from 1 to 30 Jan 1980 (Tim Manolis and Bruce Webb; Figures 3 and 4; photos on file). First state record. ROSS’ GULL ( Rhodostethia rosea). One immature (23-83-32) observed between 28 Apr and 7 May 1983 on Jumbo Reservoir, Sedgwick Co. (Robert Andrews, Barry Knapp, and Inez and Bill Prather; Figures 5 and 6; photos on file; see also Knapp 1983). First state record, and only the fourth in the contiguous 48 states. CASPIAN TERN ( Sterna caspia). One (23-78-40) at Cherry Creek Reservoir, Arapahoe Co., between 22 and 29 May 1978 (Robert Andrews and William Lybarger). Third state record; this species is being seen with increasing frequency in Colorado. ARCTIC TERN ( Sterna paradisaea) . One immature collected on 16 Sep 1912 near Windsor, Weld Co., by G.E. Osterhaut is in the Denver Museum of Natural History (DMNH 39080). This bird was previously identified as a Common Tern (S. hirundo ); see Conry and Webb (1982). One adult (23-80-2) at Union Reservoir, Weld Co., on 11 and 12 Sep 1979 (Charles Chase, Peter Gent, and Peter Moulton). First and sec- ond records. 100 COLORADO RECORDS REPORT Figure 1. Mew Guli (23-80-17) in first winter plumage. Sloans Lake. Denver Co.. Colorado. 7 Mar 1980. Photo by Robert Rozinski Figure 2. Adult Mew Gull (23-82-71), Sloans Lake. Denver Co.. Colorado. 22 Mar 1982. Photo by B.J. Rose 101 COLORADO RECORDS REPORT Figures 3 and 4. Great Black-backed Gull (23-80- 14} in first winter plumage. Centen- nial Park. Arapahoe Co , Colorado, 3 Jan 1980. Note white background of tail with black barring and spotting: heavy barring is strongest subterminally and medially. 102 Photos by Bruce Webb COLORADO RECORDS REPORT Figures 5 and 6. Immature Ross’ Gull (23-83-32). Jumbo Reservoir. Sedgwick Co.. Colorado, between 28 Apr and 7 May 1983. Photos by Inez Prather (aboue) and William R. Maynard (below) 103 COLORADO RECORDS REPORT MARBLED MURRELET ( Brachyramphus marmoratus). One of the Asiatic race ( B.m . perdix) found in Aspen. Pitkin Co., on 22 Aug 1982. The bird died and is now in the Denver Museum of Natural History (DMNH 37691); see also Kingery (1983). First state record. This race was also recorded in Indiana in Dec. 1981 (Peterjohn 1982) and in Massachusetts in Sep 1982 (Forster 1983). GROOVE-BILLED AN! (Crotophaga sulcirostris) , One (26-80-5) on 15 Oct 1975 at CF and 1 Reservoir, Pueblo, Pueblo Co. (Eddie Blatnick). Second state record chronologically; the first and third records were discussed by Andrews (1979). ANNA’S HUMMINGBIRD ( Calppte anna). One male (31-79-2) at Grand Junction, Mesa Co., from 19 Nov to 6 Dec 1978 (Helen Traylor). Third state record. ALDER FLYCATCHER ( Empidonax alnorum). One male collected on 28 May 1904 in Arvada, Jefferson Co., by H.G. Smith and now in the Denver Museum of Natural History (DMNH 36457). The specimen was identified by Allan R. Phillips. First state record chronologically; the second and third records were discussed by Andrews (1979). HERMIT WARBLER ( Dendroica occidentals) . One female (52-78-39) at Red Rocks Park, Jefferson Co. , from 7 to 9 May 1978 (Robert Andrews) . One male (52-79-9) in Lakewood, Jefferson Co., from 27 to 29 Apr 1979 (Robert Andrews, Joyce and John Cooper; photos on file). Second and third records. MOURNING WARBLER ( Oporornis Philadelphia). One immature collected by Mildred Snyder at Sedalia, Douglas Co., on 18 Oct 1964 and now in the Denver Museum of Natural History (DMNH 34586). The specimen was identified by Allan R. Phillips. One male (52-80-26) on 18 May 1975 at the U.S, Air Force Academy, El Paso Co, (Camille Cummings, David Griffiths, and David Thomas). One female col- lected north of Boulder, Boulder Co., on 25 Sep 1979 by Craig Williams and now in the Denver Museum of Natural History (DMNH 37882). First, second, and third records. HENSLOW’S SPARROW ( Ammodrarnus henslowii) . One adult (56-85-55) at Jackson Reservoir, Morgan Co., on 10 Sep 1985 (Larry Halsey and Wade Leitner). First state record. BRAMBLING ( Fringilla montifringilla) . One female (56-83-59) in Colorado Springs. El Paso Co , between 30 Oct and 4 Nov 1983 (Martha and Ed Curry, Larry Halsey, Barry Knapp and William Maynard; photos on file; see also Curry and Curry 1984). One female (56-83-60) in Boulder, Boulder Co., between 17 Dec 1983 and 15 Mar 1984 (Marjorie Foland and Robert Jickling; Figures 7 and 8; photos on file; see also Jiekling 1984). First and second records. There were several other North American records in the same winter, which were summarized by Lehman (1984). PART 4. CONFIRMED FIRST STATE BREEDING RECORDS This section updates the breeding status given by Andrews (1980) in the 1980 state list. In that list, Ovenbird (Se/urus aurocapillus ) should be a con- firmed breeder. YELLOW-CROWNED NIGHT-HERON ( Nycticorax uiolaceus). A pair bred suc- cessfully on an island at the Denver Zoo, Denver Co., in 1983 (Charles Chase), and returned in 1984 and 1985. BARROW’S GOLDENEYE ( Bucephala islandica) . A pair (8-82-64) bred 2 miles west of Walden, Jackson Co., in 1982, producing five young (Jos Grzybowski and Michael Szymczak; photo on file). This is the first confirmed breeding in Colorado for nearly a century. 104 COLORADO RECORDS REPORT BROAD-WINGED HAWK ( Buteo platypterus) . A pair bred successfully in a Fort Col- lins cemetery, Larimer Co., in 1978 (Daniel Casey and Charles Chase). MARBLED GODWIT ( Limosa fedoa). One pair (19-84-44) found on nest with two eggs on 26 May 1984 at Grover, Weld Co. (Lois Webster). Four eggs were in the nest on 10 Jun, but only eggshells remained on 24 Jun, so a predator may have destroyed the eggs. LEAST TERN ( Sterna albifrons). The first breeding records (23-78-76) since 1949 were of pairs in 1978 at Adobe Creek Reservoir, Kiowa Co., and Horse Creek Reser- voir, Otero Co., in southeast Colorado (Charles Chase; see also Chase 1979). BOREAL OWL (Aegolius funereus ). A pair (28-81-48) bred at Corral Park, Larimer Co,, in 1981 (David Palmer and Ronald Ryder; Figure 9; photo on file). The breeding attempt failed, and the eggs are in the Denver Museum of Natural History collection. In 1982 a pair (28-82-33) bred successfully in the same location (David Palmer; Figure 10; photo on file; see also Palmer and Ryder 1984) . This species has now been found in Hinsdale Co. in southwestern Colorado (28-85-45, John Rawinski; photo on file) and in Delta Co. in western Colorado (28-85-47, Mark Janos). VERMILION FLYCATCHER ( Pyrocephalus rubinus). One pair (34-81-18) bred near Akron, Washington Co., in 1981 (Helen Downing and Larry Halsey; photos on file). The female and two young were killed in a hailstorm 13 Jun 1981 and are now in the Denver Museum of Natural History (DMNH 37401). BAY-BREASTED WARBLER (Dendroica castanea ), A pair (52-78-56) bred at Westcreek, Douglas Co., in 1978 (Charles Campbell). HEPATIC TANAGER (Piranga flava). Breeding was confirmed in 1980 on Mesa de Maya, near Kim, Las Animas Co. (Charles Chase). Observations since 1980 show that there is a small, but stable, breeding population of this species on Mesa de Maya. NORTHERN CARDINAL ( Cardinalis cardinalts) . A pair bred just south of Wray, Yuma Co., in 1982 (Bruce Bosley). This is the first known Colorado nesting since 1926. GREAT-TAILED GRACKLE ( Quiscalus mexicanus) . This species was first found breeding in the state at Monte Vista, Rio Grande Co., in 1973. It has recently been found breeding on the eastern plains at Fountain, El Paso Co. (54-82-31, Richard Bunn) and at Buena Vista, Chaffee Co. (54-84-28, Peter Gent). These records in- dicate a rapid expansion of this species’ breeding range east and north in Colorado. SCOTT’S ORIOLE ( Icterus parisorum) . Breeding was first confirmed at Rangely, Rio Blanco Co., in 1979 (54-80-45 and 54-80-48, Austin Johnson). In 1981 breeding was confirmed at Pleasantview, Montezuma Co. (54-81-17, Clair Button) and at Mormon Gap, Rio Blanco Co. (54-81-57, Edward Hollowed). This species now breeds in most northwest Colorado counties south to Grand Junction, Mesa Co., and in Montezuma Co. in the southwest. These records indicate a recent expansion of the breeding range. ACKNOWLEDGMENT I thank Robert Andrews and Charles Chase for their careful comments on the first draft of this report. LITERATURE CITED AOU 1983. Check list of North American Birds, 6th ed. Am. Ornithol. Union, [Washington, D C.] 105 COLORADO RECORDS REPORT Figures 7 and 8. Brambling (56-83-60) in female plumage. Boulder, Boulder Co.. Colorado, 22 Dec 1983. Photos by Stephen Vaughan 106 COLORADO RECORDS REPORT Figure 9. Adult Boreal Owl (28-81-48), Corral Park, Larimer Co., Colorado, 1 May 1981. Figure 10. Young Boreal Owls (28-82-33), Conral Park, Larimer Co., Colorado, 31 Jul 1982. Photos by David Palmer 107 COLORADO RECORDS REPORT AOU 1985. Thirty-fifth supplement to the AOU check-list of North American birds. Auk 102:680-686. Andrews. R. 1979. CFO Records Committee report 1976-1977. W. Birds 10:57-70. Andrews, R. 1980. The CFO Checklist of Colorado birds. CFO Journal 14:82-87. Binford. L.C. 1985. Seventh report of the California Bird Records Committee. W. Birds 16:29-48. Bridges, L.W.D. 1985. White Ibis— first Colorado record . CFO Journal 19:75-76. Cairo. J. 1985. King Rail— second Colorado record. CFO Journal 19:38. Chase, C.A. 1979. Breeding shorebirds in the Arkansas Valley. CFO Journal 13:31-34. Chase. C.A. 1981. CFO Records Committee report 1977-1980. CFO Journal 15:24-30, 54-59. Chase. C.A. 1982. CFO Records Committee report 1980-1981. CFO Journal 16:46-51. Chase, C.A. 1983. CFO Records Committee report for 1981. CFO Journal 17:75-82. Conry, J.A., and Webb, B.E. 1982. An extant specimen of Arctic Tern from Col- orado. W. Birds 13:37-38. Curry, E., and Curry, M. 1984. A Brambling in Colorado. CFO Journal 18:3. Forster, R. 1983. Northeastern Maritime region. Am. Birds 37:155-158. Gent, P R. 1984 The CFO Records Committee report for 1982. CFO Journal 18.51-57. Gent, P R. 1985a The CFO Records Committee report for 1983. CFO Journal 19:28-33, Gent, P.R. 1985b. The CFO Records Committee report for 1984. CFO Journal 19:82-87. Gent, P.R. 1986. The CFO Records Committee report for 1985. CFO Journal 20:44-50. Jickling, R. 1984. The Boulder Brambling. CFO Journal 18:3-4. Kingery, H.E. 1983. Mountain West region. Am. Birds 37:205-208. Knapp, B. 1983. An immature Ross’ Gull in eastern Colorado. CFO Journal 17.16-17. Lehman, P. 1984. The changing seasons. Winter 1983-1984. Am. Birds 38:287-292. Palmer, D.A., and Ryder, R.A., 1984. The first documented breeding of the Boreal Owl in Colorado. Condor 86:215-217. Peterjohn, B. 1982. Middlewestern Prairie region. Am. Birds 36:298-302. Webb, B. 1985. Against all odds: first record of a Magnificent Frigatebird in Colorado. CFO Journal 19:94-96. Accepted 24 October 1986 108 IMPACTS ON WATERBIRDS FROM THE 1984 COLUMBIA RIVER AND WHIDBEY ISLAND, WASHINGTON, OIL SPILLS STEVEN M. SPEICH, 4817 Sucia Drive, Ferndale, Washington 98248 STEVEN P. THOMPSON, Nisqually National Wildlife Refuge, 100 Brown Farm Road, Olympia, Washington 98506 (present address: Stillwater Wildlife Management Area, P.O. Box 1236, Fallon, Nevada 89406) Two major oil pollution events in Washington in 1984 resulted in signifi- cant oiling of waterbirds. The first occurred 19 March 1984 when a tanker ran aground near St, Helens, Oregon, releasing oil into the Columbia River. The second occurred 21 December 1984 when a vessel released oil into southern Admiralty Inlet off the south end of Whidbey Island in Puget Sound, Washington. During both spills many waterbirds were found dead, and many others were found incapacitated. This paper documents the species of waterbirds oiled in each event. Although some impacts of oil spills on waterbirds on the Pacific Coast of North America have been documented (Aldrich 1938, Moffitt and Orr 1938, Richardson 1956, Smail et al. 1972, Vermeer and Vermeer 1975, PRBO 1985), many others are undocumented and doubtless will remain so (Vermeer and Vermeer 1975, Speich unpubl. data) . THE OIL SPILLS The Columbia River Spill The tanker Mobiloil ran aground in the Columbia River near St. Helens, Oregon, on Warrior Rock (river mile 88,2) on 19 March 1984 (Figure 1). Its tanks ruptured, releasing an estimated 170,000 to 233,000 gallons of heavy residual oil, number six fuel oil, and an industrial fuel oil into the river (Ken- nedy and Baca 1984) . A portion of the released oil sank but the rest floated downstream, reaching the mouth of the Columbia River 21 March 1984. It was then carried north by ocean currents, reaching Ocean Shores, Washington, by 25 March 1984. Oil was deposited on much of the Washington shoreline of the Columbia River, and lesser amounts were found on ocean beaches. Small amounts of oil were observed in Grays Harbor and in Willapa Bay. Later, a small number of oil globs and tar balls were reported on ocean beaches north to Cape Flattery, at the entrance to the Strait of Juan de Fuca. Small amounts of oil were also reported as far south as Cannon Beach, Oregon. The Whidbey Island Spill An unidentified vessel released about 5000 gallons of number six fuel oil into Puget Sound near Whidbey Island on 21 December 1984 (Figure 1). When first reported that day a slick extended about 10 miles from Seattle north to Possession Sound. About 1500 gallons came ashore on south Whidbey Island on 22 December 1984, and large amounts appeared on shore there over the next 5 days. The majority of the oil covered shorelines Western Birds 18:109-116, 1987 109 WASHINGTON OIL SPILLS from Columbia Beach to Scatchet Head on the southern end of Whidbey Island. Additional small amounts were found on other beaches on south Whidbey Island and on beaches of other land areas such as Marrowstone Island, Bainbridge Island, and the Kitsap Peninsula. EFFECTS ON WATERBIRDS Columbia River Impacts Part of the response to both spills was the cleaning of oil from shorelines and from shoreline and marsh vegetation. For the Columbia River spill this process started 24 March 1984 and continued daily through 16 April 1984, with crews, hired by Mobil Oil Co., working along the Columbia River and on the Washington ocean beaches, especially of the Long Beach Peninsula, just north of the mouth of the Columbia River. The crews disposed of many dead oiled birds without recording their identity, numbers, sex, age, etc. Altogether, 450 oiled live birds were retrieved and taken to the cleaning center set up at the Columbia White-tailed Deer National Wildlife Refuge (A. Berkner pers. comm., Table 1). The center opened 23 March 1984 and operated until 23 April 1984, although no new birds were accepted after 9 April 1984. The most numerous species were Western Grebe (50%), White- winged Scoter (17%), and Common Murre (26%). The birds were released as soon as possible after treatment. In total, 284 (68%) birds were released, but the species’ identities were not recorded, the birds were released un- banded, and no data were collected on the survival rates of the released birds. Birds found oiled and alive after the center ceased accepting birds on 9 April 1984 were cared for by concerned citizens and a rehabilitation center in Tillamook, Oregon. Unfortunately, no data on the species involved, their numbers, or their fate are available. In addition, at least 200 lightly oiled, free-roaming waterbirds were observed, including Western Grebes, uniden- tified scaups, unidentified mergansers, and gulls. Table 1 Numbers and Percentages of Bird Species Oiled, Captured, and Brought to the Cleaning Station for Treatment after the Columbia River Oil Spill Species Number Percentage Red-throated Loon ( Gavia stellata) 4 <1% Common Loon (G. immer ) 2 <1 Western Grebe (Aechmophorus occidentalis ) 227 50 Goose (domestic, species unknown) 1 <1 Mallard (Anas platyrhynchos) 3 1 Greater Scaup (Aythya marila) 1 <1 Common Scoter ( Melanitta nigra) 9 2 Surf Scoter (M. perspicillata ) 8 2 White-winged Scoter (M. fusca ) 77 17 Common Murre ( Uria aalge ) 118 26 Total 450 110 WASHINGTON OIL SPILLS Figure 1, Approximate areas of water and shoreline oiled following the Columbia River and Whidbey Island. Washington, spills. 1984. 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CD C — >- C= >_ CD J3 c/> CD CO C r o o Cu T3 J IS CD -9 CD ^ 5% use) during 1984 shifted (by 0.4 to 0.5 km) to the west of those used during 1983 (Figure 1) . In both years, lengths of dispersal flights were typically 0.5 to 0.8 km. The longest flights recorded in 1983 and 1984 were 2.1 and 1.9 km, respec- tively. These data are comparable to those of other investigators. Carr (1967) reported that males had a maximum cruising radius of 1.4 to 1.8 km from the lek -at his study area. Wallestad and Schladweiler (1974) reported that movements of males of up to 1.3 km from a lek were common and that 82% of all movements were greater than 0.3 km Rothenmaier (1979) found that 64% and 86% of the radio locations of males using the “section 17 strutting ground” were within a 1.0- and 1.2-km radius, respectively. Emmons (1980) stated that dispersal distances to day-use areas of 0.2 km were com- mon and that 67% of all day-use areas were over 0.5 km from the lek. Schoenberg (1982) found that daily movements of males to day- use areas averaged 0.9 km (range 0.03 to 2.4 km). After arriving at feeding and loafing sites, birds remained fairly sedentary. Observations coupled with radio locations revealed that, if not disturbed, 118 1983 l 1984 BREEDING MALE SAGE GROUSE '/A t 1 ■ Is s .. y A I 2 V/. '/■ V . fa fa //. /Z '6 w DC LLi III i o LO CO o 119 Figure 1. Distribution of radio-tagged Sage Grouse near Duchesne, Utah, in 1983 and 1984. BREEDING MALE SAGE GROUSE birds seldom moved more than 0.2 km between 0900 and 1500. Birds often moved back toward the lek 2 hours before sunset. If disturbed while in day- use areas birds would flush and commonly fly beyond 0.8 km. Similar behavior was reported by Emmons (1980), Radio-tagged grouse were com- monly with 15 to 30 other grouse when flushed. The nonrandom dispersal patterns of breeding male Sage Grouse to day- use areas reported here are similar to those found by Rothenmaier (1979) in Wyoming, and by Emmons (1980) and Schoenberg (1982) in Colorado. These patterns are most likely the result of habitat selection for certain sagebrush characteristics (Schoenberg 1982, Ellis et al. unpubl.). None of these studies, however, intensively monitored the same lek from year to year to see if similar patterns persisted. On the basis of similar dispersal distances and distribution patterns, we believe that breeding male Sage Grouse in other areas most likely continue to select the same day-use areas year after year. Such areas, once identified, should be protected to the greatest extent possible. Alteration of these areas may cause abandonment of a lek. ACKNOWLEDGMENTS Financial support for this study was provided by Deseret Generation and Transmis- sion Cooperative through a contract to Clayton M. White. Utah Division of Wildlife Resources and Department of Zoology at Brigham Young University. Our apprecia- tion extends also to Clayton M. White, Barbara Ellis, Chris Ellis. Marcia Richins, Jay A. Roberson and Lee K. Swenson for their assistance and encouragement during the study. Alan M. Craig and W.H. Behle provided comments that improved the manuscript. LITERATURE CITED Amstrup, S.D. 1980. A radio collar for game birds. J. Wildlife Mgt. 44:214-217. Carr, H.D. 1967. Effects of sagebrush control on abundance, distribution, and movements of Sage Grouse. Colorado Game, Fish, Parks Dept. Job Compl. Rep. W-37-R-20. Job 8a Ellis, K.L. 1984. Behavior of lekking Sage Grouse in response to a perched Golden Eagle. W. Birds 15:37-38. Emmons, S.R. 1980. Lek attendance of male Sage Grouse in North Park. Colorado. M.S. thesis, Colorado State Univ., Fort Collins. Giesen, K.M., Schoenberg, T.J., and Braun, C.E. 1982. Methods for trapping Sage Grouse in Colorado. Wildlife Soc. Bull. 10:224-231. Klenbenow, D A, 1969. Sage Grouse nesting and brood habitat in Idaho. J. Range Mgt. 33:649-662. Patterson, R.L. 1952. The Sage Grouse in Wyoming. Sage Books. Denver. Peterson, J.G. 1970. Gone with the sage. Montana Outdoors 5:1-3. Rogers, G.E. 1964. Sage Grouse investigations in Colorado. Colorado Game. Fish & Parks Dept. Tech. Rep. 16. Rothenmaier. D. 1979. Sage Grouse reproductive ecology: breeding season movements, strutting ground attendance and nesting. M.S. thesis. Univ. Wyom- ing, Laramie. 120 BREEDING MALE SAGE GROUSE Schoenberg, T.J. 1982. Sage Grouse movements and habitat selection in North Park, Colorado. M.S. thesis, Colorado State Univ., Fort Collins. Springer, J.T. 1979. Some sources of bias and sampling error in radio triangulation. J. Wildlife Mgt. 43:926-935. Tate, J., Jr., Boyce, M.S. and Smith, T.R. 1979. Responses of Sage Grouse to ar- tificially created display ground. Proc. Mitigation Symp., Colo, State Univ., Fort Collins, pp. 459-463. Wallestad, R.O. 1975. Male Sage Grouse responses to sagebrush treatment. J. Wildlife Mgt. 39:482-484. Wallestad, R.O. , and Pyrah, D. 1974. Movement and nesting of Sage Grouse hens in central Montana. J. Wildlife Mgt. 38:630-633. Wallestad, R.O., and Schladweiler, P. 1974. Breeding season movements and habitat selection of male Sage Grouse. J. Wildlife Mgt. 38:634-637. Accepted 6 February 1987 121 122 Sage Grouse Photo courtesy of California Department of Fish and Game NOTES A NORTHERN JACANA IN TRANS-PECOS TEXAS SARTOR O. WILLIAMS III, Route 10, Box 476, Glenwood, New Mexico 88039 At 0945 on 7 October 1982, Melissa J. Renfro and I found a single Northern Jacana ( Jacana spinosa) on a pond at a site known as “The Post” (elev. 1200 m), located at the end of a county road about 8 km south-southwest of Marathon, Brewster County, Texas. We watched the bird, which was in typical immature plum- mage, for about 45 minutes, then we left the area. We returned that afternoon (1430-1900) and obtained a series of 27 color slides of the bird; representative slides were subsequently verified and deposited in the Texas Photo-Record File as No. 404, a-d (Texas Cooperative Wildlife Collections, Texas A&M University, College Station, TX 77843). The jacana was still present at the site on 11 October 1982, when it was seen by Geth and Edmund White of Alpine, Texas. 1 do not know if the bird was seen after that date; it was not present when I next visited the site on 18 October 1982. The small (90 m x 13 m) pond was the result of a low dam across Pena Creek and seemed to be several decades old. Cattails ( Typha ) bordered the open water, which was almost completely choked with a dense stand of pondweed ( Potomogeton ) , the pondweed forming a solid mat just below the surface. The jacana spent most of its time walking about on the vegetation mat and feeding actively, presumably on aquatic insects. At one point, however, it captured, dispatched, and consumed a large dragonfly. The bird was wary and alert and would fly to the center of the pond, calling loudly, if approached too closely or otherwise disturbed. There it would remain, watchful for a while, before resuming its feeding. Marathon lies about equidistant (some 800 km) from resident Northern Jacana populations on the west coast in Sinoloa and on the east coast in southern Texas and Tamaulipas; it is less than half again as far from resident populations on the Mexican Plateau due south in Guanajuato. Jalisco, and Michoacan. There are scattered inland Texas records, presumably from the eastern population, in Real (Am. Birds 34:177, 1980), Kerr (Am. Birds 40:492 and 1223, 1986), Uvalde, Bexar, Webb, and Victoria counties (Oberholser, H.C., The Bird Life of Texas, Vol. 1:306, 1974; Univ. Tex. Press, Austin) (but not Mitchell County: see below), and an immature jacana was noted upriver in the Rio Grande valley at Santa Ana National Wildlife Refuge. Hidalgo County, 10-30 November 1982 (Am. Birds 37:200, 1983). Of interest, however, is a Pacific storm, Hurricane Paul, that crossed the Sinaloa coast in late September and tracked northeastward through the Trans-Pecos region of Texas on 30 September 1982. one week before 1 discovered the Brewster County bird. Also of interest are the many impoundments that now stretch northward across the Mexican Plateau, from central Mexico through Durango and Chihuahua to the United States border: these impoundments, typically recharged during the summer-fall rainy season, appear to be providing a northward avenue for several other waterbirds that are similarly common in the central highlands (S.O. Williams, unpubl. data). Because the Brewster County jacana could conceivably have arrived from any one of these three geographic areas. 1 believe it is incorrect to assume automatically that it originated from the east coast population. The recent (7 June 1985-3 January 1986) appearance of an adult jacana near Nogales. Arizona (Am. Birds 39:946, 1985: 40:311, 1986) which, after the Brewster County bird, represents only the second record for the southwestern United States, is of similar uncertain origin, there being but one record for adjacent Sonora, a specimen labeled only “Sonora, 1961“ (S.M, Russell, pers. comm.). Western Birds 18:123-124. 1987 123 NOTES Contrary to the 5th and 6th editions of the American Ornithologists’ Union’s Check- list of North American Birds (1957:163, 1983: 176) , there is no record, valid or other- wise, of a Northern Jacana in Mitchell County in north-central Texas. The error ap- parently resulted from confusion of Mitchell Lake in Bexar County, site of a valid 1922 record, with Mitchell County. I thank Keith A. Arnold, Stephen M. Russell, Dale A. Zimmerman, and reviewer Roland H. Wauer for helpful comments on the manuscript. Accepted 22 January 1987 Immature Northern Jacana Sketch by Narca Moore-Craig 124 NOTES GREAT HORNED OWL PREDATION ON CAVE SWALLOWS STEVE WEST, Box 2489, Carlsbad, New Mexico 88220 Both Great Horned Owls ( Bubo uirginianus ) and Cave Swallows ( Hirundo fulva ) occur in the caves of southeastern New Mexico, but no interaction between the two species has been recorded. On 1 June 1984, Tom and Bobbie Bemis, Ron Kerbo, and I visited Ogle Cave, Slaughter Canyon, Carlsbad Caverns National Park, Eddy County. New Mexico, to check on the approximately 100 Cave Swallows nesting there. As we rappelled into the cave, we flushed a Great Horned Owl, which was mobbed by Cave Swallows as it left the cave. Beneath a Great Horned Owl nest I found a pellet containing bird bones and a U.S. Fish and Wildlife Service band. The band (number 970-75444) was from a Cave Swallow that had been banded in the en- trance of Carlsbad Cavern, about 13 km northeast of Ogle Cave, on 3 August 1983. Our banding studies suggest that Cave Swallows move among the caves after their nesting season. The pellet contained 313 bones representing at least four individual swallows, as well as insect parts. It is now in the collection of the Carlsbad Caverns Na- tional Park museum. On several occasions since 1978 1 have banded Cave Swallows at Swallow Sinkhole, Glass Mountains, Brewster County, Texas; usually Great Horned Owls are present at this site too. On 9 June 1984, when Orlando Ornelas and I visited Swallow Sinkhole, we flushed from its nest a Great Horned Owl, which was then vigorously mobbed by Cave Swallows. An owl pellet found in the sinkhole entrance also contain- ed bones the size of a Cave Swallow’s. 1 thank Jim Walters for providing helpful advice on an earlier draft of the manuscript. Accepted 10 April 1987 Western Birds 18:125. 1987 125 NOTES FIRST RECORD OF LONG-TOED STINT IN OREGON JEFF GILLIGAN, 26 N.E. 32nd Avenue, Portland, Oregon 97232 OWEN SCHMIDT, 3007 N.E. 32nd Avenue. Portland. Oregon 97212 HARRY NEHLS, 2736 S.E. 20th Avenue, Portland, Oregon 97202 DAVID IRONS, 1535 S.E. Rhine, Portland, Oregon 97202 The Long-toed Stint (Calidris subminuta) breeds in northeast Asia and migrates through southeast Asia to India and Australia (King et al. 1978). In Alaska it is a rare spring and fall visitant to the western Aleutian Islands. There are spring records for the Pribilof Islands, St. Lawrence Island, and the Seward Peninsula (Kessel and Gibson 1978). The first Long-toed Stint for North America outside of Alaska was photographed and tape recorded at the base of the South Jetty of the Columbia River, Clatsop County, Oregon, on 5 September 1981. On that day, Gilligan, Schmidt, Irons, Mike Houck, Jake Redlinger, and Mark Smith flushed a small Calidris from thick Salicornia near the tidal pools. When flushed, the bird rose rapidly and gave repeated calls that suggested a soft version of the familiar Pectoral Sandpiper (C. melanotos ) call. Gilligan based his original identification as C. subminuta on the bird’s small size, habitat choice, and calls. We had ample opportunity to confirm the identification during extraordinary views as close as 3 m for the next 4 hours. Other observers in- cluded Nehls, Richard Smith, Matt Hunter, Steve Heinl. Alan Contreras, Richard Palmer. David Hofmann, John Gatchet, Durrell Kapan, and many others. The bird was last seen on 12 September 1981. Final identification of the bird as a juvenile Long-toed Stint was based on its field marks, behavior, and voice. Field Marks. The bird was larger and more chestnut colored than a typical juvenile Least Sandpiper (C. minutilla). The upperparts were mostly dark, with the crown feathers, scapulars, and tertials edged in bright chestnut. The dark crown extended to the bill and lores. There was a very conspicuous whitish “V” on the back, similar to that of juvenile Least Sandpiper. The wing coverts were rich brown and broadly edged in buff to whitish-buff; the tertials were dark with very noticeable bright chestnut fringes. The supercilium was nearly clear white, broadening over the eye and flaring onto the nape over a chestnut ear patch. The underparts were whitish with the breast smudged gray-brown and prominently streaked through the center, The bill tapered to a fine point and was slightly decurved near the tip. The upper mandible and tip were black, but the base of the lower mandible was tan, which distinguishes the Long-toed Stint from other small Calidris sandpipers (Wallace 1974) . The legs were yellow, appearing brighter than a Least Sandpiper’s. The toes ap- peared exceptionally long, the middle about as long as the tarsus, giving the bird a big- footed appearance as it walked on the flats. Prater et al. (1977) suggest that long toes may be a useful field mark. When the bird stood on one leg, the toes on the raised leg projected from the belly feathers, accenting their length. Behavior. The Long-toed Stint seemed to run faster than the Least and Western Sandpipers (C. mauri ) that were nearby, and it had an unusual forward-leaning posture. It took long, loping strides, quite unlike the more scurrying footsteps of the other species. When alarmed it erected its posture and craned its neck, giving it an elegant, tall, thin appearance. Kitson (1978) observes that this neck-stretching and generally elongated appearance are more typical of Long-toed Stint than of other small sandpipers. In our opinion, however, a Least Sandpiper can appear nearly equally upright, long-necked, and elongated when alarmed. The most notable behavioral characteristic of the Long-toed Stint was its preference for cover On several occasions it was flushed from the mudflats, flew back over the 126 Western Birds 18:126-128, 1987 NOTES Figure 1. The juvenal Long-toed Stint had a bright chestnut crown with its supercilium flaring behind the eye, chestnut ear coverts, streaked breast, very bright chestnut edges on the scapulars and tertials, and particularly long toes. Photo by Owen Schmidt Figure 2. The juvena! Long-toed Stint (right) is larger than the juvenal Least Sand- piper (left) and shows much brighter chestnut on the crown, ear coverts, and back, and also has longer and brighter yellow legs. Photo by Owen Schmidt 127 NOTES observers, descended steeply, and disappeared into thick Salicornia taller than itself. This behavior was somewhat reminiscent of the manner in which a Common Snipe (Ga/linago gallinago) plunges into vegetation. On one occasion a Least Sandpiper descended with the Long-toed Stint, but at the last instant, as the Long-toed Stint dropped into the vegetation, the Least Sandpiper hovered for a moment just above the vegetation and then rose again and flew off. On the flats the Long-toed Stint tended to remain close to grass and driftwood, often crouching in a depression near cover. Voice. We noticed immediately that the Long-toed Stint’s calls differed from those of the other small Calidris familiar to us. The bird usually called in sets of 2 or 3 notes as it flew. We interpreted the calls as dry, low-pitched, muted “preep,” “prr rrp,” or “treeet” notes. Several observers described the call as more of a 2-syllable “churr-up,” “prr-up,” or “tirr-et.” One observer reported that the Long-toed Stint gave a weak, mellow “chert” call when flushed, similar to the Pectoral Sandpiper’s sharper “cherk.” Viet and Jonsson (1984) say the call is a softly rolling “chrrup,” which is perhaps the same sound. The bird was silent except when flushed. The Least Sandpiper’s typical calls are a harsher, more shrill “kreeet” or “breeep.” Since the sighting of the Long-toed Stint, Irons and Gilligan have on rare occasions heard Least Sandpipers give calls somewhat similar to those of the Long-toed Stint, but higher in pitch. The calls of the Long-toed Stint were recorded on a cassette recorder with the aid of a parabolic reflector. A copy of the recording is filed with the Oregon Bird Records Committee, P.O. Box 10373, Eugene, OR 97440. The record has been accepted by the Oregon Bird Records Committee. Theodore Tobish, Dan Gibson, and Richard Veit have examined several of the photographs of the bird and agree with this identification. LITERATURE CITED Kessel, B. and Gibson, D., 1978. Status and distribution of Alaska birds. Studies Avian Biol. 1. King, B., Woodcock, M., and Dickinson, E., 1978. A Field Guide to the Birds of South-East Asia. Houghton-Mifflin, Boston. Kitson, A. 1978. Identification of Long-toed Stint, Pintail Snipe and Asiatic Dowitcher. Br. Birds 71:558. Prater, A., Marchant, J., and Vuorinen, J. 1977, Guide to the Identification and Ageing of Holarctic Waders. British Trust for Ornithology, Tring. Veit. R. and Jonsson, L.. 1984. Field identification of smaller sandpipers within the genus Calidris. Am. Birds 38:852. Wallace, D. 1974. Field identification of small species in the genus Calidris. Br. Birds 67:1. Accepted 20 November 1986 128 NOTES A BREEDING RECORD OF THE DARK-EYED JUNCO ON SANTA CATALINA ISLAND, CALIFORNIA CHARLES T. COLLINS, Department of Biology, California State University, Long Beach, California 90840. A total of 56 species of land birds has been recorded breeding on the eight Channel Islands off the coast of southern California (Diamond and Jones 1980) . Many are per- manent resident species breeding every year, while others are migrants or immigrants that only infrequently or briefly establish breeding populations. This dynamic equilibrium of the breeding birds of the Channel Islands has been addressed by several authors (Lynch and Johnson 1974, Jones 1975, Jones and Diamond 1976, Dia- mond and Jones 1980) and predicts that from time to time additions will be made to the list of breeding species (see Haemig 1986). This report documents a successful breeding of the Dark-eyed Junco (Junco hyemalis ) on Santa Catalina Island and the first record of this species breeding on any of the Channel Islands. On 14 April 1986, I observed an adult Dark-eyed Junco accompanied by two juvenal-plumaged fledglings in a small gully in Renton Mine Canyon, located on the southeastern side of the island. Much of the vegetation on Santa Catalina Island has been greatly altered by man. However, the vegetation in Renton Mine Canyon con- sists of some of the best-recovered native island plant communities. On the south slope there is an island version of sage scrub with Eriogonum giganteum and a chapar- ral dominated by Ceanothus arboreus. The north slope is mostly an oak woodland made up of a variety of hybrid oaks. The canyon bottom is dominated by Prunus lyonii and Quercus x macdonaldii. There are some scattered introduced Eucalyptus on the edge of a road high on the north slope. Others present who also saw the birds were T. Martin. S. Critchfield, C. Boardman, and G. Hoffman. The two young birds were giving fledgling location notes and begging vocalizations and were attended and periodically fed by the adult. Although they appeared capable of flight, it is improbable that they were strong enough to have made an over- water flight to the island. It is most likely that they were hatched near the point of observation in Renton Mine Can- yon. The attending adult had the coloration of a female of one of the races of Oregon Junco. The mainland breeding populations closest to Santa Catalina Island have been assigned to Junco hyemalis thurberi (Grinnell and Miller 1944). Dark-eyed Juncos have been recorded as winter visitors on several of the Channel Islands (Garrett and Dunn 1981, pers. obs,). A single early summer observation sug- gested they might have bred on Santa Cruz Island but convincing evidence was lacking (Diamond and Jones 1980, H.L. Jones pers. comm.). This species has recently expanded its breeding range in coastal southern California, particularly in the Santa Monica Mountains (H.L. Jones pers. comm.); its appearance as a breeder in the Channel Islands is perhaps not unexpected. It remains to be seen, of course, if this is an isolated occurrence or the establishment of a new breeding population, I am indebted to Terry Martin and the Catalina Conservancy for transportation on the island and for providing the vegetative description of Renton Mine Canyon. LITERATURE CITED Diamond, J.M . . and Jones. H.L. 1980 Breeding landbirds of the Channel Islands, in The California Islands: Proceedings of a Multidisciplinary Symposium (D.M. Power, ed ). pp. 597-612. Santa Barbara Mus. Nat. Hist,. Santa Barbara. Garrett, K. , and Dunn, J. 1981. Birds of Southern California; Status and Distribution. Los Angeles Audubon Soc.. Los Angeles. Western Birds 18:129-130, 1987 129 NOTES Grinnell, J., and Miller, A.H. 1944. The distribution of the birds of California. Pac. Coast Avifauna 27. Haemig, P.D. 1986. Nesting of the Phainopepla on Santa Cruz Island. California. W. Birds 17:48. Jones, H.L. 1975. Studies in avian turnover, dispersal, and colonization of the California Channel Islands. Ph.D, thesis, Univ. Calif., Los Angeles. Jones, H.L., and Diamond, J.M. 1976. Short- time -base studies of turnover in breeding birds of the California Channel Islands. Condor 76:526-547. Lynch, J.F., and Johnson, N.K. 1974. Turnover and equilibria in insular avifaunas, with special reference to the California Channel Islands. Condor 76:370-384. Accepted 10 April 1987 130 NOTES THE FIRST RECORD OF A FOUR-EGG CLUTCH FOR SANDHILL CRANES CARROLL D. LITTLEFIELD and GAYLIN D. HOLLOWAY, Malheur Field Station, Box 260-E, Princeton, Oregon 97721 We determined clutch sizes in 815 Greater Sandhill Crane (Grus canadensis tabida) nests in Oregon from 1966 through 1984. Of these, 744 (91.3%) nests contained two eggs 67 (8.2%) one egg, 3 (0,4%) three eggs, and 1 (0.1%), which we report on here, contained four eggs. Average clutch size was 1.92. Three-egg clutches from Sandhill Cranes are rare, but there are records from Florida (Walkinshaw 1973), Idaho (Drewien 1973), Michigan (Walkinshaw 1973), Oregon (Littlefield 1981), and Wisconsin (Gluesing 1974), There is no previous record of a wild Sandhill Crane pro- ducing a four-egg clutch. Furthermore, there are no such records for other members of the family Gruidae, except for the Common Crane (G. grus) (cf. Johnsgard 1983) and South African Crowned Crane (Balearica regulorum regulorum). Four-egg clutches are not uncommon for the latter (Walkinshaw 1973) . On 18 April 1983, we located a crane nest about 8.0 km WNW of Diamond, Harney Co., Oregon, on Malheur National Wildlife Refuge (NWR). When discovered, the nest contained two eggs that measured 95.6 x 61.5 mm and 98.7 x 61.4 mm, respectively. On 21 May, after the normal 30-day incubation period, the pair was still incubating. Assuming the eggs were infertile, we flushed the male off the nest. Surpris- ingly, the nest contained four eggs. The two additional eggs measured 95.8 x 61.1 mm and 95.0 x 61,5 mm. Two eggs were in the nest bowl, but the other two were near the nest’s edge. By Westerskov’s (1950) method for incubational stages, one egg was at stage 5, one at stage 4, and two at stage 3, indicating that all four eggs were not being incubated simultaneously. On 28 May, all eggs were together in the nest bowl and were being tended by an adult. The pair abandoned the nest on the morning of 29 May after incubating at least 43 days. The nest was adjacent to Kiger Creek, which flooded during the afternoon of 29 May, washing away the nest and eggs. The pair (Pair 216) occupy a large territory and receive no disturbance from other Sandhill Crane pairs, eliminating the possibility of another female dumping eggs into the nest. In addition, all four eggs were very similar in size and coloration: whitish tan with a few small reddish spots on the blunt end. The nearest neighbors (Pair 186) nest about 0.8 km south of the site and lay olive-brown eggs. Furthermore, territorial Sandhill Crane pairs are intolerant of other cranes in spring and it is highly unlikely another female would be permitted on Pair 216’s territory long enough to deposit two eggs, particularly since the nest was not concealed and could be seen from a great distance. Pair 216 has had an interesting history since establishing the territory in 1971. The pair’s nests were examined in 1974, 1982, and 1983. In 1974, their clutch consisted of three eggs and represented the first three -egg clutch located on Malheur NWR. They laid a normal two-egg clutch in mid-April 1982; however, one egg was infertile. The fertile egg hatched on 16 May. After hatching, one adult tended the young crane while the other adult continued to incubate the infertile egg at least through 22 May. Eggs laid in 1974 and 1982 were similar in size and coloration to those laid in 1983, indicating the same female has occupied this territory since at least 1974. Another in- teresting behavior is the pair’s tolerance of human disturbance. The nest was on the same site in 1982 and 1983, adjacent to a corral within 75 m of a well-traveled county road. In 1974, the nest was within the corral. A ranch house was within 50 m of the nests and refuge vehicles passed daily within 5 m of the site without excessively distur- bing the incubating bird. Western Birds 18:131-132. 1987 131 NOTES The circumstance involved in the female’s laying four eggs is unclear. Up to seven- teen eggs per year have been laid by captive Greater Sandhill Cranes, with six eggs be- ing the average number produced (Erickson 1976). However, eggs from these birds were removed shortly after being laid, thus stimulating females to produce additional eggs. Perhaps the first eggs of Pair 216 were displaced from the nest bowl, resulting in the female’s laying two additional eggs. Because the female had laid a three-egg clutch in the past, however, it is likely she is unique both behaviorally and physiologically, and her future nesting efforts will be interesting to monitor. We thank Brad Ehlers, Gary Ivey, Dean Knauer, and David Paullin for reviewing an earlier draft of this report. In addition, we thank Tim Manolis and David Winkler for their reviews, which were most helpful. We also thank Arlene Miller for typing assistance. Funds for Sandhill Crane studies on Malheur NWR in 1983 were provided by Oregon Department of Fish and Wildlife and the U.S. Fish and Wildlife Service. LITERATURE CITED Drewien, R.C. 1973. Ecology of Rocky Mountain Greater Sandhill Cranes. Ph.D. dissertation, Univ. Idaho, Moscow. Erickson, R.C. 1976. Whooping Crane studies at the Patuxent Wildlife Research Center. Proc. Int. Crane Workshop 1:166-176. Gluesing, E.A. 1974. Distribution and status of the Greater Sandhill Crane in Wiscon- sin. M.S. Thesis, Univ. Wisconsin, Stevens Point. Johnsgard, P.A. 1983. Cranes of the World. Indiana Univ. Press. Bloomington. Littlefield, C.D. 1981. A probable record of intraspecific egg dumping for Sandhill Cranes. Auk 98:631. Walkinshaw, L.H. 1973. Cranes of the World. Winchester Press. New York. Westerskov, K. 1950. Methods for determining the age of game bird eggs. J. Wildlife Mgt. 14:56-67. Accepted 22 April 1987 132 NOTES LOGGERHEAD SHRIKE FEEDS ON A DEAD AMERICAN COOT FLOYD E. HAYES, Department of Biology, Loma Linda University, Riverside, California 92515 (Present Address: Ministerio de Agricultura y Ganaderia, Inventario Biologico Nacional, Casilla de Correo 3303, Asuncion, Paraguay) WILLIAM S. BAKER, 270 White Cottage Road, Angwin, California 94506 In the early afternoon of 8 December 1984, we observed a Loggerhead Shrike (Lanius ludouicianus ) feeding on the carcass of an American Coot (Fulica americana ) along the shore of a marsh at Chula Vista, San Diego County, California. For about 2.5 min the shrike tore off and swallowed at least a dozen pieces of meat before flying away. After waiting 30 min for the shrike to return, we examined the carcass. The head of the coot was missing; the shrike had been feeding on the blood-clotted meat in the neck area. No mammal tracks, scattered feathers, talon on tooth punctures, or maggots were evident. The coot was lying under the high-voltage power lines, sug- gesting that it died after colliding with the power lines. Either the shrike found the coot dead or it successfully attacked and killed an unusually large item of prey. Both the Northern Shrike (L. excubitor) and Loggerhead Shrike are well known for their predatory habits, but they seldom feed on carrion. Bent (1950:117) reported a Northern Shrike feeding on a dead cow, Lloyd (1887) observed a Loggerhead Shrike feeding on a dead sheep, Anderson (1976) noted Log- gerhead Shrikes eating the remains of prey left by Northern Harriers ( Circus cyaneus ) and a Rough-legged Hawk ( Buteo lagopus ), and Reid and Fulbright (1981) found the impaled remains of two coots presumably cached by Loggerhead Shrikes. Lloyd (1887) speculated that shrikes may resort to carrion more often during the winter when normal food items are scarce. In support of this, Craig (1979) found that in cen- tral California in December the density of Loggerhead Shrike prey was low and that shrikes were apparently stressed, as evidenced by two collected individuals that were well below mean weight. Perhaps our Loggerhead Shrike was similarly stressed and opportunistically fed on the coot carcass. Since the shrike was feeding on the neck, where shrikes typically attack prey (Miller 1931, Smith 1973), it may have killed the coot. Although Cade (1962) gave 80-100 g as the weight of the largest prey the slightly larger Northern Shrike (average weight ca. 60 g) can handle. White (1963) observed a Northern Shrike unsuccessfully attack a Sharp-tailed Grouse (Tympanuc t hus phasianellus; ca. 675 g), Ellison (1971) saw a Northern Shrike unsuccessfully attack a Spruce Grouse ( Dendragapus canadensis; ca. 600 g) , and Baida (1965) witnessed a Loggerhead Shrike successfully attack a Mourn- ing Dove ( Zenaida macroura; ca 130 g). Slack (1975) demonstrated that shrikes normally select smaller, easier-to-catch prey rather than larger prey that once captured provides more food He suggested that shrikes attack unusually large prey only when motivated by severe hunger. Although our shrike may have been exceptionally hungry, because Loggerhead Shrikes are not known to kill prey larger than the ca. 130-g dove, we suspect the shrike discovered the coot as carrion. Shrikes probably feed on carrion more frequently than the literature suggests. We thank L.C. Binford and E.R. Schwabb for reviewing the manuscript. LITERATURE CITED Anderson, R.M. 1976. Shrikes feed on prey remains left by hawks. Condor 78:269. Baida, R.P. 1965. Loggerhead Shrike (Lanius ludouicianus ) kills Mourning Dove ( Zenaidura macroura ). Condor 67:359. Western Birds 18:133-134, 1987 133 NOTES Bent, A.C. 1950. Life histories of North American wagtails, shrikes, vireos, and their allies. U S, Natl. Mus. Bull. 197. Cade, T.J. 1962, Wing movements, hunting, and displays of the Northern Shrike. Wilson Bull. 74:386-408. Craig, R.B. 1978. An analysis of the predatory behavior of the Loggerhead Shrike. Auk 95:221-234. Ellison, L.N. 1971. Spruce Grouse attacked by a Northern Shrike. Wilson Bull. 83:99-100. Lloyd, W. 1887. Birds of Tom Green and Concho Counties, Texas. Auk 4:289-299. Miller, A.H. 1931. Systematic revision and natural history of the American shrikes (Lanius). Univ. Calif. Publ. Zool. 38:11-242. Reid, W.H., and Fulbright, H.J. 1981. Impaled prey of the Loggerhead Shrike in the northern Chihuahuan Desert. Southwest. Nat, 26:204-205. Slack, R.S. 1975. Effects of prey size on Loggerhead Shrike predation. Auk 92:812-814 Smith. S.M. 1973. A study of prey-attack behavior in young Loggerhead Shrikes. Lanius ludouicianus L. Behaviour 44:113-141. White, C.M. 1963. Unusual behavior of the Northern Shrike. Wilson Bull. 75:459-460 Accepted 6 June 1987 134 NOTES SONG IN A FEMALE PLAIN TITMOUSE L. SCOTT JOHNSON, Department of Biological Sciences, Northern Arizona Univer- sity, Flagstaff, Arizona 86011 (Present Address: 8 High Road, Inver Grove Heights, Minnesota 55075-3821) Although females of some temperate-zone species sing regularly, in most species females do not sing, There have, however, been numerous reports of singing by females that are normally non-singers (reviewed by G. Ritchison, Auk 100:105-116, 1983). In the titmouse family (Paridae), female song is common in some species and absent in others. Males of the three species of North American crested titmice, the Tufted. Plain, and Bridled titmice ( P . bicolor, P. inornatus, P. wollweberi ) , do sing well-developed true songs, but consistent female singing of maie-like songs has been reported in only some populations of the Tufted Titmouse (H. Brackbill, Auk 87:552-536, 1970; P.K. Gaddis, OrnisScand. 14:16-23; D.J. Schroeder and R.H. Wiley, Anim. Behav. 31:1128-1138, 1983). 1 report here oh an occurrence of song in a female Plain Titmouse. On 20 March 1983, 22 km N of Flagstaff, Arizona. 1 recaptured a banded female Plain Titmouse on her territory in a drop-door wire mesh Potter-type trap. Prior to release, she appeared abnormally agitated, moving rapidly and often from side to side in the trap even before I approached closely. This was possibly the result of her being trapped for a time much longer than normal, as I was unable to check the trap for ap- proximately 45 min after it was set. Upon release, she flew to a branch 2 m away and sang one song similar to some of the 18 song types 1 have recorded from males in the same population (L.S. Johnson. Ornis Scand. 18:24-32, 1987). This female was paired with a male who sang regularly in the same territory. This incident was the only occurrence of female song I observed, although 1 trapped females more than 50 times during a 2-year study of Plain Titmice, This observation suggests that female Plain Titmice have the capacity to sing but do not normally do so. A closer comparison of the natural history of the three North American crested titmice may reveal why females sing regularly in only one of these three congeners. I thank Daniel J. Albrecht, Russell P. Baida, Jeff D. Braun, Keith L. Dixon, L. Henry Kermott. Millicent S. Ficken. and Nalani A. McCutcheon for commentary and discussion. Accepted 27 June 1987 Western Birds 18:135. 1987 135 Volume 18, Number 2, 1987 Colorado Field Ornithologists’ Records Committee Report for 1978-1985 Peter R. Gent 97 Impacts on Waterbirds from the 1984 Columbia River and Whidbey Island, Washington, Oil Spills Steven M. Speich and Steven P. Thompson 109 Distribution of Breeding Male Sage Grouse in Northeastern Utah Kevin L. Ellis, Joseph R. Murphy, and Gary H. Richins 117 NOTES A Northern Jacana in Trans-Pecos Texas Sartor O. Williams III 123 Great Horned Owl Predation on Cave Swallows Steve West 125 First Record of Long-toed Stint in Oregon Jeff Gilligan, Owen Schmidt, Harry Nehls, and David Irons 126 A Breeding Record of the Dark-eyed Junco on Santa Catalina Island, California Charles T. Collins 129 The First Record of a Four-egg Clutch for Sandhill Cranes Carroll D. Littlefield and Gaylin D. Holloway 131 Loggerhead Shrike Feeds on Dead American Coot Floyd E. Hayes and William S. Baker 133 Song in a Female Plain Titmouse L. Scott Johnson 135 BULLETIN BOARD 136 Cover photo by Alan S. Hopkins, San Francisco, California: Buff-breasted Sandpiper ( Tringytes subruficollis) , Abbott’s Lagoon, Marin County, California, 30 September 1984 Western Birds solicits papers that are both useful to and understandable by amateur field ornithologists and also contribute significantly to scientific litera- ture. The journal welcomes contributions from both professionals and amateurs. Appropriate topics include distribution, migration, status, identifi- cation, geographic variation, conservation, behavior, ecology, population dynamics, habitat requirements, the effects of pollution, and techniques for censusing, sound recording, and photographing birds in the field. Papers of general interest will be considered regardless of their geographic origin, but particularly desired are reports of studies done in or bearing on the Rocky Mountain and Pacific states and provinces, including Alaska and Hawaii, western Texas, northwestern Mexico, and the northeastern Pacific Ocean. Send manuscripts to Philip Unitt, 3411 Felton Street, San Diego, CA 92104. 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WESTERN BIRDS Volume 18, Number 3, 1987 EMPIDONAX TRAlLLll EXTIMUS: AN ENDANGERED SUBSPECIES PHILIP UNITT, 3411 Felton Street, San Diego, California 92104 The Willow Flycatcher ( Empidonax traillii ) is a widely distributed species with a breeding range extending from southern British Columbia south to north- ern Baja California and east to the Atlantic coast. Small passerines with such wide ranges usually show some geographic variation, and several subspecies of £. traillii have been described by Oberholser (1918, 1932, 1947), Phillips (1948), and Aldrich (1951). But proof that the former “Traill’s Flycatcher” is composed actually of two sibling species (Stein 1958, 1963), now known as the Willow and Alder (£. alnorum) flycatchers, disrupted the study of in- traspecific variation in this pair. Mayr and Short (1970) wrote “we consider these species monotypic in view of their variability and difficulties in deter- mining the specific, let alone subspecies, status of individual birds,” Traylor (1979) likewise recognized no subspecies of £. traillii, but wrote “both species are almost certainly polytypic, but the subspecies cannot be worked out without long series of fresh material of known song type.” The problem of intraspecific variation in £. traillii is especially acute in view of the precarious status of the populations breeding in the southwestern United States, where the birds are restricted to riparian woodland. Although the species remains common east of the Mississippi, Garrett and Dunn (1981) considered the breeding population of southern California “virtually extirpated.” In Arizona, Monson and Phillips (1981) noted that no nests were found be- tween 1970 and 1981. My purpose in this paper is to integrate the intimately related problems of the taxonomy, distribution, current status, reproductive biology, and conser- vation of the southwestern populations of £. traillii , with an emphasis on those in southern and Baja California. TAXONOMIC PROCEDURES Specimen Resources To study geographic variation and migration of £. traillii in southern and Baja California, I examined 305 study skins: 60 in the San Diego Natural History Museum (SD), 126 in the Museum of Vertebrate Zoology, Berkeley (MVZ), 20 in the San Bernardino County Museum (SBCM), 15 from the Western Birds 18:137-162. 1987 137 EMPIDONAX TRAILLII EXTIMUS University of California, Los Angeles (UCLA), 16 from the Los Angeles Coun- ty Museum (LACM) , 10 from the University of Arizona (UA) , 5 from the New York State Museum (NYSM), 50 from the United States National Museum (US), and one from the collection of Amadeo M. Rea (AMR). Specimen Analysis The first step necessary in analyzing geographic variation in breeding popula- tions of £. traillii is to segregate specimens that were on their breeding ter- ritories when collected from those taken in migration. Ideally, this segrega- tion should be made on the basis of a specimen label providing data on gonad development, fat condition, habitat, behavior, and song. Unfortunately, however, few labels on Willow Flycatchers bear this information; scientific col- lecting of birds declined about the time most ornithologists realized the im- portance of preserving such data with specimens. Therefore, I assumed that specimens collected from 24 June to 17 July, when Willow Flycatchers have not been reported migrating through the southwestern United States, also were on their breeding territories. In samples of specimens collected near the northern limit of the Willow Flycatcher’s range, the likelihood of encounter- ing birds far from their breeding range is low, so I assumed that all specimens from Oregon, Washington, and Idaho represented the breeding populations of the sites where they were collected. In the central and eastern United States the Alder Flycatcher migrates throughout the Willow Flycatcher’s range, so from this area I used only specimens known to be traillii on the basis ofkong or that had been identified as such by R. C. Stein. I examined these specimens for evidence of geographic variation in measurements, wing structure, and color. Measurements I took were wing chord, tail length from insertion of central rectrices, bill length from nostril, and bill width at base. From these data I calculated for each specimen wing length minus tail length, the ratio of wing length to tail length, and the ratio of bill length to bill width. I measured only adults, excluded measurements of structures that were badly worn or damaged by shot, and compared the sexes separately. I measured only the specimens in the SD, AMR, UA, NYSM, and US collections. Phillips (1944) and Snyder (1953) reported that the eastern and western populations of £. traillii differ in wing formula, that the tenth primary is equal to or shorter than the fifth in western populations, longer in eastern. I ex- amined the relative lengths of the fifth and tenth primaries in the same sam- ple of specimens that I measured. Again, I compared the sexes separately, because I observed that within each population the wings of males average slightly more pointed than those of females. Evaluation of Willow Flycatcher coloration requires more careful analysis than evaluation of size and structure. Age, length of time since collection, and degree of plumage wear are additional complicating factors contributing to color variation. Not all specimens suitable for measuring were suitable for color comparison. An understanding of the species’ molt schedule is essential to an under- standing of the effects of age and wear on the birds’ coloration . Willow Fly- catchers have a single annual molt, which takes place in their winter range, after the birds have migrated south of the United States. Therefore, they are 138 EMPIDONAX TRA1LLII EXTIMUS in their freshest plumage when they arrive in the spring, wear during the breeding season, and are badly worn when they depart in the fall. Young birds migrate while still in their juvenal plumage, and return the following spring in a plumage identical to that of older adults. That is, the first basic plumage is definitive. Juvenal Willow Flycatchers differ from adults by their buff wing bars and flimsy-textured plumage, which wears and fades much faster than the adult plumage. Foxing, the change in plumage color that affects aging study skins, occurs in £. traillii. Foxing is manifested in £. traillii as a buff-brown tint to the greenish- gray parts of the plumage. It is usually slight, but I have noticed it in specimens collected as recently as the 1950s. The skins prepared by some collectors, particularly Frank Stephens, have foxed more than others. Therefore, the possibility of foxing must be considered when recently collected specimens are compared with older ones. Plumage wear also affects the birds’ appearance, particularly on the crown, where in extremely worn individuals the greenish distal portion of the feathers may be completely lost, leaving only the dark gray bases. Therefore, it is essen- tial that worn birds not be compared with fresh ones and that conclusions be drawn from the least worn specimens possible. Phillips (1948) reported that in £. t. brewsteri males average darker than females, and that in £. t. extimus males average more olive than females, but sexual differences are negligible in the specimens I examined. I therefore combined the sexes when comparing colors. A Standard for Definition of the Subspecies One definition of subspecies that ornithologists traditionally have used is the “75% rule”: For population A to be considered a subspecies distinct from population B, 75% of the individuals of population A should overlap with no more that 3% of the individuals of population B (Mayr 1969). I have selected this purely morphological definition for characterizing the subspecies of £. traillii because it is more restrictive than the statistical significance of dif- ferences between population means, also used in some taxonomic studies. The 75% rule allows more individual specimens to be assigned to subspecies and is more easily applied to the characters in which the populations of £. traillii show the most external difference. Genetic definitions of subspecies have been introduced recently (Zink 1986) but genetic techniques were not available to me and would require the collection of more additional specimens than is currently practical. If the variation in a mensural character is normally distributed, the 75% criterion can be expressed mathematically by x A + 0 . 675 s A > x B — 1 . 88 s b where x represents the mean, s the standard deviation, and x A < x B . The factors 0.675 and 1 .88 derive from the table of z values of the normal distribu- tion. If the standard deviations of the two populations are different, this test may not give the same results when B is compared to A as when A is com- pared to B. I therefore performed the test in both directions between each pair of subspecies in each character. 139 EMPIDONAX TRAILLII EXTIMUS TAXONOMIC RESULTS The most comprehensive study of geographic variation in E. traillii was by Aldrich (1951), who recognized five subspecies: E. t. brewsteri Oberholser (1918), breeding from the Pacific Ocean east to the Cascade Range and Sierra Nevada, E. t. adastus Oberholser (1932), breeding between the Cascades and the Rocky Mountains, E. t. extimus Phillips (1948), breeding in the desert Southwest, southern Great Basin, and “the southern Great Plains” (though breeding Willow Flycatchers are very rare to absent in that region) , E. t. traillii (Audubon 1828) , breeding from Alaska through the boreal forest of Canada to the northeastern United States, and E. t. campestris Aldrich (1951), breeding from the Great Plains east through the Great Lakes states. Subsequently, Stein (1958, 1963) demonstrated that Aldrich’s nominate traillii is the separate species now known as the Alder Flycatcher, and Snyder (1953) and the A. O. U. Committee on Classification and Nomenclature (A. O. U. 1973) sug- gested that Audubon’s name traillii is better applied to the Willow Flycatcher. Measurements and Proportions Measurements and proportions of the four subspecies of E. traillii are listed in Tables 1 and 2. The sharpest distinctions in size or proportion among the subspecies of E. traillii are the functions of wing and tail lengths. In males, the greatest difference is in the wing - tail difference between extimus and traillii, but in even that character the 75% rule is satisfied in only one direc- tion of comparison. In females, traillii might be distinguishable from the three western subspecies in both wing - tail difference and wing/tail ratio. The 75% criterion is met in both directions when traillii is compared to brewsteri, and in one direction when traillii is compared to extimus or adastus. However, the sample of female traillii is so small (n * 4) that any conclusion drawn from it can be considered only tentative. Therefore if subspecies exist in E. traillii they must be defined on a basis other than size. Color My results with respect to plumage color and wing structure, however, ac- cord for the most part with those of Aldrich (1951) and Snyder (1953) . The back color in specimens 40 to 80 years old (the great majority of those available) of all four subspecies is close to Olive (color 30) of Smithe (1975) but somewhat greener. In brewsteri the green is in the direction of Olive Green (color 48) , in adastus in the direction of Greenish Olive (color 49) , and in extimus and traillii in the direction of Grayish Olive (color 43). That is, brewsteri is a dark brownish olive, adastus a dark grayish green, and extimus and traillii a pale grayish green. In less worn individuals the contrast between a paler cap and darker back often noticeable in brewsteri and adastus is usually lack- ing in extimus and traillii. In extimus and traillii the underparts as well are often paler than in brewsteri and adastus, and the grayish breast band is less distinct, but these differences are less constant than those on the upperparts. I saw no consistent differences in color between extimus and traillii and can- not confirm Aldrich’s (1951) statement that u campestris ,, (i. e., traillii) is “somewhat more greenish” than extimus. The sample of u traillii" with which 140 EMPIDONAX TRAILLII EXTIMUS Table 1 Measurements and Proportions of Male Empidonax traillii extimus' traillii b adastus c brewsteri d Wing chord n 9 10 25 22 Mean 68.7 70.8 70.4 68.0 Range 65.7-72.5 68.8-74.2 66.8-73.9 65.9-71.2 SD' 2.04 1.73 1.68 1.35 Tail length n 9 9 25 22 Mean 59.3 59.1 59.7 58.1 Range 56.8-62.5 56.3-62.6 56.4-62.7 54.8-60.7 SD 1.91 1.96 1.57 1.61 Wing minus tail n 9 9 25 22 Mean 9.4 11.9 10.6 9.9 Range 7.9-11.6 10.6-12.8 8.4-13.4 7.5-12.5 SD 1.26 0.71 1.04 1.14 Wing/tail ratio n 9 9 25 22 Mean 1.16 1.20 1.18 1.17 Range 1.13-1.20 1.18-1.22 1.14-1.23 1.13-1.22 SD 0.023 0.016 0.019 0.023 Bill length from nostril n 9 10 24 21 Mean 9.7 9.2 9.5 9.5 Range 9.2-10.2 8.9-9. 7 8.6-10.2 8.5-10.0 SD 0.32 0.25 0.37 0.36 Bill width at base n 9 10 25 22 Mean 7.1 7.2 7.2 7.3 Range 6. 7-7. 5 6. 7-7.8 6.5-8. 1 6. 8-8.0 SD 0.26 0.36 0.41 0.34 Bill length/width n ratio 9 10 24 21 Mean 1.37 1.27 1.32 1.31 Range 1.29-1.50 1.18-1.39 1.14-1.48 1.18-1.44 SD 0.069 0.060 0.085 0.063 •Localities represented : Calif., Imperial Co., Potholes (4); Baja Calif. Norte, Las Cabras (2); Ariz., Navajo Co., Vi mi E Fort Apache (1); Pinal Co., 9 mi. S Mammoth (1); Pima Co., Tucson (1). "Localities represented: N. Dak., Ward Co., Kenmare (1); Kidder Co., Dawson (1); Dickey Co., Oakes (2); S. Dak., Miner Co. (1); N. Y., Monroe Co., Hilton (1); Tompkins Co., Ithaca (4). 'Localities represented: Wash., Okanagan Co., Riverside (1); Lincoln Co., Sylvan Lake (1), Sprague Lake (1), 6 mi. S Sprague (1); Spokane Co., Spokane (1); Whitman Co., Pullman (1), Union- town (2); Asotin Co., Anatone (1), Grande Ronde River (1); Ore., Umatilla Co., Pendleton (1); Wallowa Co., Swamp Creek (1); Baker Co., Homestead (1); Hamey Co., Stinking Water Mt. (1); Malheur Co., Beulah (1), 3 mi. W Juntura (2), Rockville (1); Nev., Washoe Co., Reno (1); Pershing Co., Winnemucca Lake (1); Ida., Boundary Co., Porthill (1); Butte Co., Big Lost River (1); Utah, Davis Co., Antelope Island (1); Carbon Co., Clear Creek (1); Mont., Flathead Co., Java (1). "Localities represented: Wash., Clallam Co., Forks (1); Ore., Multnomah Co., Portland (6); Marion Co., Salem (1), Scotts Mills (1); Calif., San Diego Co., La Jolla (1), Bonita (1), Ballena (1); Imperial Co., Potholes (5), Bard (2); Baja Calif. Norte, Ojos Negros (1); Ariz., Yuma Co., Yuma (1); Sonora, Isla Tiburon (1). •SD, standard deviation. 141 EMPIDONAX TRA1LLII EXTIMUS Table 2 Measurements and Proportions of Female Empidonax traillii extimus* traillii * adastus c brewsteri d Wing chord n 15 4 16 12 Mean 65.7 66.9 67.0 64.8 Range 62.7-70.1 65.8-68.2 64.4-69.4 61.3-69.3 SD 1.98 1.00 1.25 2.09 Tail length n 15 4 16 12 Mean 57.3 54.8 57.5 56.5 Range 54.5-60.2 53.1-56.7 55.7-59.5 55.0-59.8 SD 2.04 1.49 1.20 1.43 Wing minus tail n 15 4 16 12 Mean 8.4 12.1 9.5 8.2 Range 4.5-11.9 11.3-13.5 8.0-11.2 4.0-10.0 SD 1.90 0.99 1.05 1.58 Wing/tail ratio n 15 4 16 12 Mean 1.15 1.22 1.16 1.15 Range 1.08-1.20 1.20-1.25 1.14-1.20 1.07-1.18 SD 0.035 0.023 0.020 0.028 Bill length from nostril n 13 4 16 11 Mean 9.5 9.4 9.1 9.3 Range 8.7-10.1 9. 0-9. 6 8.5-10.0 8.8-9.8 SD 0.47 0.29 0.46 0.35 Bill width at base n 15 4 15 12 Mean 7.4 7.3 7.2 7.4 Range 6. 8-7. 9 7. 2-7.4 6. 7-7.6 6. 8-8.0 SD 0.33 0.08 0.29 0.35 Bill length/width n ratio 13 4 15 11 Mean 1.30 1.29 1.27 1.25 Range 1.20-1.45 1.25-1.32 1.13-1.46 1.14-1.40 SD 0.075 0.031 0.088 0.071 ‘Localities represented: Calif,, San Diego Co., Doane Valley (1), 3.6 km NW Lake Henshaw Dam (1), National City (1); Imperial Co. , Potholes (2), Bard (2); Ariz., La Paz Co., Bill Williams Delta (1); Yuma Co., Yuma (6); Pima Co., Tucson (1). ‘Localities represented: N. Dak., Kidder Co., Dawson (2); Richland Co., Lidgerwood (1); Illinois, Fulton Co., Canton (1). ‘Localities represented: Wash., Lincoln Co., Sylvan Lake (1) , 6 mi. S Sprague (1); Whitman Co., Palouse (1), Pullman (1); Ore., Wallowa Co., Enterprise (1), Swamp Creek (1); Baker Co., Homestead (1); Crook Co., 20 mi. S Paulina (1); Klamath Co., head of Whiskey Creek (1); Ida., Latah Co., Potlatch (1), Harvard (1), Moscow (1); Power Co., American Falls (1); Utah, Box Elder Co., Bear River mouth (1); Wyo., Stanley (not located; possibly Stansbury, Sweet- water Co., Wyo., or Stanley, Custer Co., Ida.) (1); N. Mex., Guadalupe Co., Santa Rosa (1). ‘'Localities represented: Wash., King Co., Seattle (1); Ore., Multnomah Co., Portland (4); Calif., Yolo Co., Grafton (1); San Diego Co., La Jolla (1); Imperial Co., Potholes (2), Bard (2); Baja Calif. Norte, Las Cabras (1). 142 EMPIDONAX TRAILUI EXTIMUS Phillips (1948) compared extimus consisted largely if not entirely (A. R. Phillips pers. comm.) of alnorum, which is usually if not always darker and greener than even adastus (pers. obs. of specimens in NYSM and US). One hundred percent of specimens of extimus from the lower Colorado River and Arizona are paler and grayer on the back than all specimens of brewsteri. For specimens from southwestern California and northwestern Baja California, the figure drops to 82% . Eighteen of 20 specimens (90%) from Arizona, southern California, and northern Baja California that should have been extimus on the basis of range are paler-backed than adastus, while 26 of 28 specimens (93%) from eastern Washington, eastern Oregon, northern Nevada, Idaho, northern Utah, and Wyoming are darker than extimus. Twenty-five of 28 adastus (89%) are grayer or purer green than brewsteri, while 15 of 18 brewsteri (83%) are browner or more olive than adastus. Wing Formula Phillips (1944) and Snyder (1953) reported that the eastern and western populations of £. traiHii, as then considered, differ in wing formula, that in eastern birds, the tenth primary is longer than the fifth, while in the western birds, the tenth is equal to or shorter than the fifth. My results (Table 3) sup- port this conclusion. The wing formula thus distinguishes 93% of the extimus and traillii in my sample, 88% of the adastus and traillii, and 89% of the brewsteri and traillii. It is more reliable for females than for males; the western Table 3 Relative Lengths of Primaries 10 and 5 in the Four Subspecies of Empidonax traillii * 10 > 5 10 = 5 10 < 5 n % n % n % Males traiHii 20 95 1 5 extimus 3 18 4 24 10 59 adastus 9 20 19 41 18 39 brewsteri 7 17 18 45 15 38 Females traillii 6 86 1* 14 extimus 3 11 24 89 adastus 1 4 8 31 17 65 brewsteri 2 8 22 92 'Each individual wing scored separately; wings with primaries 10 or 5 broken or badly worn not scored. Of 93 specimens with primaries 5 and 10 intact on both sides, 1 1 were sufficiently asymmetrical that the two wings fell into different categories. All cases of asymmetry, however, included the 10 = 5 category; that is, in no case was 10 > 5 in one wing and 10 < 5 on the other. Asymmetry was most frequent in adastus (7 of 34 specimens). ‘Specimen poorly prepared, with wings apparently tied to body, so primary formula possibly disrupted. 143 EMPIDONAX TRAILLII EXTIMUS birds in which the tenth primary is longer than the fifth are mostly long-winged males (wing chord > 70 mm). Summary I conclude that the four races of £. traillii recognized by Aldrich (1951) are valid by the criterion of the 75% rule and may be distinguished from each other by color, wing formula, or both. Figure 1 shows the approximate original breeding ranges of all four subspecies of £. traillii plus that of £. alnorum. The morphological differences among the races of £. traillii are minor, but differ little in magnitude from those distinguishing the species traillii from alnorum. In Empidonax, small differences in morphology may mask large differences in biology. My concern in this study is the Willow Flycatchers of the southwestern United States and therefore with £. t. extimus. Although £. t. extimus was omitted from the 1957 edition of the A. O. U. Check-List of North American Birds, it has been recognized in all taxonomic studies of £ traillii since its original description. Its existence has been generally unappreciated probably because migrants of other subspecies occur commonly in its range during most of its breeding season, because of the dearth of original research on subspecies dur- ing the last 30 years, and because of fear of confusion of £. traillii with the sibling species £. alnorum, which does not occur in the southwestern states. During this period of neglect, extimus has dwindled nearly to extinction as the habitat on which it depends has been degraded and decimated. Empidonax traillii extimus in California Phillips (1948) and Aldrich (1951) included southern California in the breeding range of brewsteri, but my study shows that instead extimus occupies this area. All southern and Baja California specimens that either were labeled as breeding or were collected from 20 June to 15 July are listed in Table 4. These data indicate that only race extimus breeds in southern and Baja Califor- nia and that intergradation with the subspecies to the north begins around Independence and Los Angeles. All specimens from Mono and northern In- yo counties are adastus or migrant brewsteri, so I suggest that Independence represents the northern limit of the range of extimus in eastern California. Three probably breeding specimens (MVZ) from the Sierra Nevada of Fresno County were all brewsteri, so it seems reasonable to regard Weldon as the northern limit of extimus along the axis of the Sierra Nevada. A single specimen (US 264166) collected at Tulare Lake 9 miles south of Lemoore, Kings Coun- ty, on 20 June 1907 is too worn and poorly prepared to identify. I could find no specimens that unquestionably represent the population of coastal central California, so the northern limit of extimus along the coast is uncer- tain. However, no specimens of extimus have been collected in coastal Califor- nia north of the San Fernando Valley. New Specimen Table 4 makes it obvious that the number of specimens of breeding Willow Flycatchers from southern California is small. Because only a small sample, or even a single individual, is preserved from most localities, further specimens 144 EMPIDONAX TRAILUI EXTIMUS would be desirable to support the conclusion that extimus is the subspecies breeding in southern California. Since the populations remaining in southern California are now so small and few, such collecting must be done judicious- ly, preferably from the largest remaining colonies. The only suitable site where I was able to collect is along the San Luis Rey River 3.6 km northwest of the Lake Henshaw dam in the Cleveland National Forest, San Diego Coun- ty, where I obtained one female on 21 May 1984. The specimen, my original number 375, is now SD 44653. Its ovary was beginning to enlarge (7.5 x 4 mm, largest ovum 1.5 mm diameter) and it had only slight fat, indicating that it was on its breeding territory but had not yet begun to nest. This specimen is clearly extimus, on the basis of comparison with other unfoxed specimens, as it matches closely one collected at Fort Apache, Arizona, on 29 May 1972 (AMR 3915) but is much paler than a migrant brewsteri found dead at Bor- rego Springs, San Diego County, on 1 June 1980 (SD 42124). Although the concept of the occurrence of extimus in California rests on a small number of specimens, there is little likelihood that this base can be added to soon. Therefore, the range of the subspecies must be estimated on Figure 1. Breeding ranges of the subspecies of £. traillii and of £. alnorum. 145 Table 4 Southern and Baja California Specimens of Willow Flycatcher Labeled as Breeding or Collected from 20 June to 15 July EMPIDONAX TRAILLIl EXTIMUS in CD U CD a !/> ■O 3 c n to 3 X CD CD ^-1 .S 'c CD CD c O CD O T3 ET CO «0 CO ^«0 « E i- « 0) ^ to CO -*a 3 3 3 3 | 2 C 3 3 V) 3 E E E .1 .s t; o E E $> S X X X S CD T3 a X -*3 X -O CD CD CD CD m 0) CD C o <9 "cn "cn c c t 3 -o CD c c c c Q = 3 3 f 0 D 3 3 3 •“3 o "3 "3 s -3 "3 -3 CJ 00 00 LO vO T— 1 o O o On CM CM CM CM CM CM CM CD 0) CJ u c c CD ID d -o c -o c U ID 0) o o 15 a ID a ID U c V o -o c -o jc c 0) Si ~ (CJ CD c ii a: c -o c i<2 o o !2 ° s E £ E £ "5 2 $ (N CM £ 6 1 0) $ r-~ NO CO On CO E -o !>• On On m i i ON r- ON o CM CM r > > > 2 2 2 2 o U U) jd o tO CD O O cn U c in JD jd c < H - CD ID CD to ■In JD CD cn 05 O) cn o (0 O) CD~ +4 c C < CD S C < CD S c ^ <0 o in o <2 O 2 «3 c CD c < 2 O 2.3 Si 9) > U u3 w UJ 2 m CM CO r-~ o He i—t i—i H s-H CO VO CO o o o o t-~ r-~ 2 2 2 2 H u u u u N < < < < > ij ij ij 2 146 LACM 22295 Los Cerritos, 12 Jun 1908 “breeding” extimus Los Angeles Co. LACM 22296 Los Cerritos, 12 Jun 1908 “breeding” specimen too poorly Los Angeles Co. prepared to identify Indication of Specimen Date breeding on number Locality collected specimen label EMPIDONAX TRAILLII EXTIMUS >< CD to i+2 5 X ia C O CD •-4— i CD D* u o -a -#-* c CD CO -O \ 05 CD ** CO CD E — CD +-* C E 33 p ^ B -C u ~ CD T3 3 £ 33 3 £ 33 a CO 3 £ 33 3 £ 33 3 E -M X X a X X X X X v U o CD J2 z M— i o U to II o U to ■U II o U d CD CO 33 (0 E o M— c ('"V t-i CD CQ c o c CO l-i -1—* CD ai c CO o c CO ti CD CO C 10 u 15 c CD s C o Si To 'n CD a V) JD o *2 c CD a i/j JD o s CD a jo 3 ■>- s o w T3 To U •2, o (0 to a fd i— O a <0 i-i O o 15 CO cO mi E -C +-* o £ J3 1 o E O (P! CD a io (23 O U U Z co CL a. >v -1 H VO vO CM r—i T— 1 t— 1 H r — i i-H 1— ( vO VO VO co lD CO VO vO so CO co CM CO oo CM 00 o s 2 S T i 2 co as o U u CO u 1 — 1 T— 1 OS CQ < < Q CQ Q Q Q JO _1 to to co to co 147 EMPIDONAX TRAILLII EXTIMUS the basis of the currently available specimens. All identifiable southern Califor- nia specimens labeled as breeding or collected between 13 June and 17 July are extimus except for the two intermediates from El Monte and Colton listed in Table 4. Table 5 Additional Southern and Baja California Specimens of Empidortax traillii extimus (No Indication of Breeding on Specimen Label) Specimen number Locality Date Age MVZ 27965 LACM 7011 MVZ 33378 LACM 7016 MVZ 33375 UCLA 23810 MVZ 33381 MVZ 3187 MVZ 3182 MVZ 11753 MVZ 11755 MVZ 3078 SD 19184 UCLA E128 MVZ 3615 SBCM 36114 SBCM 36115 SBCM 36117 SBCM 36118 SBCM 36119 UCLA 31873 SD 13037 SD 13038 SD 13200 SD 13222 SD 19164 SD 10019 SD 13204 MVZ 12910 SD 8714 MVZ 52932 MVZ 52933 MVZ 52934 MVZ 52935 Wild Rose Canyon, Panamint Mts., Inyo Co. 12 Jun San Fernando, Los Angeles Co. 13 Jun San Fernando Valley, Los Angeles Co. 13 Sep Cienaga (= West Los Angeles), Los Angeles Co. 28 Jul El Monte, Los Angeles Co. 12 Aug Long Beach, Los Angeles Co. 10 May Seven Oaks, San Bernardino Co. 13 Jun Santa Ana R. near Colton, San Bernardino Co. 20 Jul Santa Ana R. near Colton, San Bernardino Co. 25 Jul Riverside, Riverside Co. 26 Jul Riverside, Riverside Co. 26 Jul Palm Canyon, San Jacinto Mts., Riverside Co. 12 Jun Doane Valley, Palomar Mts., San Diego Co. 12 Jun Sunnyside, Sweetwater R., San Diego Co. 6 Jun Campo, San Diego Co. 13 May 3 mi. W of Niland, Imperial Co. 5 Oct 3 mi. W of Niland, Imperial Co. 13 Jun 3 mi. W of Niland, Imperial Co. 4 Sep 3 mi. W of Niland, Imperial Co. 4 Sep 3 mi. W of Niland, Imperial Co. 4 Sep Salton Sea, Imperial Co. 26 May Potholes (= Laguna Dam), Imperial Co. 5 May Potholes ( = Laguna Dam), Imperial Co. 5 May 1 mi. N of Potholes (= Laguna Dam), 30 May Imperial Co. 1 mi. N of Potholes (= Laguna Dam), 10 Jun Imperial Co. Bard, Imperial Co. 3 Jun 2 mi. N of Bard, Imperial Co. 28 Sep 3 mi. N of Bard, Imperial Co. 31 May Colorado River 5 mi. NE of Yuma, Imperial Co. 4 May Las Cabras, Rio San Telmo, Baja California 4 Jun 7 mi. E of Cerro Prieto, Colorado delta 5 Jun 7 mi. E of Cerro Prieto, Colorado delta 6 Jun 7 mi. E of Cerro Prieto, Colorado delta 11 Jun 7 mi. E of Cerro Prieto, Colorado delta 11 Jun 1917 1899 1903 1888 1897 1913 1905 1908 1908 1892 1892 1908 1945 1917 1908 1952 1953 1953 1953 1953 1934 1930 1930 1930 1930 1945 1925 1930 1910 1923 1928 1928 1928 1928 ad. juv. juv. juv. juv. ad. ad. ad. juv. juv. juv. ad. ad. ad. ad. juv. ad. juv. juv. juv. ad. ad. ad. ad. ad. ad. juv. ad. ad. ad. ad. ad. ad. ad. 148 EMPIDONAX TRA1LLII EXTIMUS DISTRIBUTION OF EMPIDONAX TRAILLII EXTIMUS In addition to the museum study skins listed in Tables 4 and 5, I used the data cards accompanying the egg collections of SBCM and the Western Foun- dation for Vertebrate Zoology, Los Angeles (WFVZ), as my sources of infor- mation on the subspecies’ original range in southern California. Literature reports of Empidonax species may be questioned in this genus of difficult-to- identify birds unless the identifications are supported by specimens still available for reexamination. Fortunately, however, published accounts of Willow Fly- catchers in southern California do not deviate much from the evidence verifiable through preserved specimens. My primary sources of information on the range of extimus east of Califor- nia were Behle (1985) and a list of specimens identified and supplied by A. R. Phillips. I used published literature as a supplementary source for addi- tional breeding localities within the range delineated by these sources. Egg collections, though a major information resource for coastal southern Califor- nia, are nearly lacking from the region east of the Colorado River. Breeding or probable breeding localities for the entire range of extimus are plotted in Figure 2, where crosses indicate localities where Willow Flycatchers were found before 1970 but have not been reported since. California Willett (1912, 1933) stated that Willow Flycatchers bred commonly in coastal southern California, and the large numbers of egg sets collected before 1940 in the Los Angeles basin (67) , the San Bernardino/Riverside area (34) , and San Diego County (42) bear this out. I have plotted egg records from the Santa Clara River in Ventura County also in Figure 2, although I have seen no unquestionably breeding specimens that would indicate the subspecific iden- tity of that population. In southeastern California, substantial Willow Flycatcher populations probably existed only along the Colorado River, as indicated by 37 nests collected by Herbert Brown near Yuma in 1902, 33 of which are now in the University of Arizona (J. Bates and T. R. Huels, pers. comm.). Baja California The six specimens from the three Baja California localities listed in Tables 4 and 5 constitute all available information on the summer range of Willow Flycatcher in that region. Previously, the species’ status in the peninsula had not been determined precisely. The specimen from La Grulla is the only evidence indicating that the Willow Flycatcher has ever nested in Baja Califor- nia. The “almost certain” E. traillii reported from various locations in northern Baja California between 5 and 24 April 1967 (Short and Crossin 1967) were almost certainly misidentified because the species is unknown in southern California earlier than 28 April and does not normally winter north of southern Mexico. Arizona In the other parts of its range, which are largely desert, extimus was always localized and usually uncommon. It is known to have occurred at a few 149 EMPIDONAX TRA1LLII EXT1MUS localities along the San Pedro River, and one of these, Feldman, is its type locality. Other areas of known occurrence in Arizona were the Santa Cruz River near Tucson, Camp Verde, the Colorado River (Lee’s Ferry and junc- tion of Little Colorado River as well as along the California border), and the White Mountain region (Whiteriver, Springerville, and Alpine) (Phillips 1948 and pers. comm.; Phillips et al. 1964). Nevada £. t. extimus has been recorded at only three Nevada localities: Indian Springs (three nesting pairs in 1932, two specimens collected on 8 and 11 July, Linsdale 1936), Corn Creek (one specimen on 16 May 1962), and Co- lorado River at the southern tip of the state (one specimen on 9 May 1953, A. R. Phillips, pers. comm.). Utah The northern limits of extimus in the eastern part of its range have been subject to widely different interpretations. Snyder (1953) ascribed the subspecies to northeastern Utah, Burleigh (1972) to southern Idaho, and Aldrich (in Bailey and Niedrach 1965) to Colorado. Aldrich (1951) outlined its range rather vaguely as including the southern Great Basin and the southern Great Plains. The reason for these varying concepts is that the intergradation between extimus and adastus in the Great Basin/Rocky Mountain area is much more gradual than that between extimus and brewsteri in California, where the intermediate population, if any, in central California was never collected and is now extinct. Behle (1985) addressed the problem of intergradation between extimus and adastus explicitly. He found that in Utah there is a fair- Figure 2. Past and present breeding distribution of £. t, extimus. Crosses, localities where breeding or probably breeding extimus were recorded before 1970 but not since; dots, localities where definitely or possibly breeding extimus have been recorded since 1970. 1, South Fork of Kern River at Weldon; 2, South Fork of Kern River 18 km E of Onyx Ranch; 3, Big Morongo Wildlife Preserve; 4, Prado Basin; 5, Santa Margarita River, Camp Pendleton; 6, Santa Margarita River, 3 km NE of Fallbrook; 7, San Luis Rey River, 3 km NE of Bonsall; 8, San Luis Rey River, Lake Henshaw to La Jolla Indian Reservation; 9, Cuyamaca Lake; 10, Sweetwater Reservoir; 11, Lower Otay Lake; 12, Tijuana River Valley; 13, Rio Santo Tomas, 5 km NW of Santo Tomas; 14, Colorado River, Grand Canyon, River Miles 47 to 54; 15, Colorado River, Grand Canyon, River Mile 71; 16, 1 km E of Fort Apache; 17, South Fork of Little Colorado River near Springerville; 18, Greer; 19, Black River, White Mountains; 20, Blue River, White Mountains; 21, San Pedro River at Dudleyville; 22, Cook’s Lake; 23, San Pedro River near San Manuel; 24, Gila River at Fort Thomas; 25, Gila River at Redrock; 26, Gila River at Cliff; 27, Pleasanton, San Francisco River; 28, Glenwood, San Fran- cisco River; 29, Reserve, San Francisco River; 30, Zuni; 31, Kirtland, San Juan River; 32, Rio Chama at Chama; 33, Rio Chama at Los Ojos/Park View; 34, Canjilon, San Juan Mountains; 35, Rio Grande at Alameda; 36, Rio Grande at Albuquerque; 37, Rio Grande at Isleta; 38, Rio Grande at Los Lunas; 39, Rio Grande at Bernardo; 40, Rio Grande at La Joya; 41, Rio Grande at Bosque del Apache National Wildlife Refuge; 42, Rio Grande at Elephant Butte Marsh; 43, Rio Grande at Caballo Lake. ~* 150 Nevada X r i i i i i i i i x i i 151 EMPIDONAX TRAILLII EXTIMUS ly smooth cline from darker birds in the north to paler birds in the south, but that specimens from only the southern tier of Utah counties are closer to ex- timus than to adastus. In Utah the subspecies occurred along the Virgin River in the St. George and Springdale areas, 3 miles south of Kanab (Behle et al. 1958), along the San Juan River, and along the Colorado River in Glen Canyon (now under Lake Powell), where the species was found nesting in 1958 (Behle 1960). New Mexico The taxonomy of £. traillii in north-central New Mexico and Colorado has not been studied in detail and probably cannot be determined without further collecting. A. R. Phillips (pers. comm.) has identified as extimus Willow Fly- catchers that were collected in southwestern New Mexico, along the Rio Grande north to Bernardo, Socorro County, and near Farmington on the San Juan River in northwestern New Mexico. One extimus collected in eastern New Mexico at Boone’s Draw, Roosevelt County, on 22 May 1975 was pro- bably a migrant. I have arbitrarily used the New Mexico/Colorado line as the northern limit of extimus at the eastern extreme of its range, on the specula- tion that the transition there from extimus to adastus may be at approximate- ly the same latitude as in Utah. Hubbard (1970, 1978, pers. comm.) reported several breeding or probable breeding localities in New Mexico, extending east at least to the Rio Grande, south to Anthony on the Texas line. Because the current range of Willow Flycatcher in New Mexico is nearly the same as its originally known range, I have described the species’ distribution there under Current Status below. Texas The eastern edge of the range of extimus probably lies between the Rio Grande and Pecos River in western Texas. The subspecies has been collected at Fort Hancock on the Rio Grande (Phillips 1948), in the Guadalupe Moun- tains (A. R. Phillips, pers. comm.), 9 miles southeast of Glenn Springs, and 15 miles northwest of Alpine, Brewster Co., and has been reported breeding in the Davis Mountains (Oberholser 1974). Wauer (1973) called the Willow Flycatcher a rare summer resident in Big Bend National Park, but cited no specific records of breeding or occurrence outside migration periods. Sonora Two specimens of extimus from northern Sonora (17 June 1955, 2 km south-southwest of La Casita, 37 km south of Nogales; 1 June 1952, Agua Caliente, 48 km south of Nogales; A. R. Phillips, pers. comm.) are the only evidence that Willow Flycatchers may breed in mainland Mexico. CURRENT STATUS I derived information on the current status and distribution of extimus from published literature, contract reports to government agencies, personal com- munication with field ornithologists active in the southwestern states, and my own field work. Localities where breeding or summering Willow Flycatchers 152 EMPIDONAX TRAILLII EXTIMUS have been reported since 1970 are plotted as solid circles in Figure 2. The information is most complete for southern California, where intensive surveys of riparian woodlands for Bell’s Vireos have resulted in discovery of a few Willow Flycatcher colonies. Still, the picture for even this area is undoubtedly incomplete. Researchers studying Bell’s Vireos observed Willow Flycatchers only incidentally; several of them stressed to me that their results could not be considered exhaustive. Probably these observers’ abilities to detect and identify this species varied. Nevertheless, the primary reason that so few Willow Flycatchers have been found is that there are so few left to find. The number of localities where the species is known to occur at present is only a fraction of the number of historic localities. E. t. extimus is now absent from the ma- jor areas where it formerly occurred, such as the Los Angeles basin, the San- ta Ana River near Riverside and San Bernardino, and the Colorado River. California The largest remaining colony of extimus in California is on the South Fork of the Kern River near Weldon just east of Lake Isabella, Kern County. Serena (1982) reported 26 singing birds on and near the Nature Conservancy Kern River preserve in the summer of 1982. In addition, a single singing bird was reported farther upstream along the South Fork of the Kern River 18 km east of Onyx Ranch. R. Hewitt (in McCaskie 1984) reported 23 in the Weldon area in 1984. The population increased substantially, to 39 singing birds, by 1986 (Harris et al. 1987) . Harris et al. suggested that this increase may be due to the recovery of the vegetation since the Nature Conservancy acquired the area and reduced cattle grazing. At Big Morongo Wildlife Preserve in southwestern San Bernardino Coun- ty Cardiff et al. (1982) found one nesting pair in 1981. In the seven years from 1977 to 1983 that Cardiff et al. censused breeding birds at this locality, however, they found Willow Flycatchers in only that one year. L. R. Hays (in McCaskie 1986) reported four pairs in the Prado Basin, Riverside County, in 1986. This constitutes the only report from the Santa Ana River, a former center for the species, in over 30 years. All other localities where Willow Flycatchers summer in southern Califor- nia are in San Diego County . The largest population is on the Santa Margarita River in Camp Pendleton, where L, Salata (pers. comm.) has kept careful notes on the Willow Flycatchers he has observed incidentally during his work on Bell’s Vireos from 1981 through 1986. He recorded 5 territorial birds in 1981, 10 in 1982, 10 in 1983, 16 in 1984, 15 in 1985, and 17 in 1986. This apparent increase in the population size at this site coincides with the years in which Brown-headed Cowbirds (Molothrus ater ) were trapped there. The other major Willow Flycatcher colony in southern California, which R. Higson and I discovered in 1984, is along 10 km of the upper San Luis Rey River between Lake Henshaw and the La Jolla Indian Reservation. Higson (pers. comm.) searched this entire section of river on 31 May 1984 and located 12 territorial birds. Goldwasser (pers. comm.), during a survey for Bell’s Vireos on 15 May 1986, detected six singing Willow Flycatchers in this area. All other Willow Flycatcher colonies in southern California are small and apparently occupied only intermittently. Along the Santa Margarita River 3 km northeast of Fallbrook, a short distance upstream from Camp Pendleton, 153 EMPIDONAX TRAILUI EXTIMUS S. Goldwasser (pers. comm.) found two singing birds 2 June- 12 July 1980; I did not find any there on 8 and 9 May 1984 and there have been no subse- quent reports from this locality. Goldwasser also found one singing bird along the lower San Luis Rey River 3 km northeast of Bonsall 4-25 June 1978. Again, I did not find any Willow Flycatchers at that locality on 7 May 1984 and there are no other reports. On 5 June 1984 1 found three singing Willow Flycatchers, plus a silent bird collecting nest material, at the south end of Lake Cuyamaca. I did not find any there, however, on 4 May and 28 June 1986. Eight egg sets of this species had been collected at this locality in 1920 and 1921. E. Copper (pers. comm.) found two territorial Willow Flycatchers at the upper end of Sweetwater Reservoir in 1984. But the only observation there in 1986 was of a single singing bird on 9 July (J. Griffith, pers. comm.). Two egg sets were collected at Sweetwater Reservoir in 1920 and 1921. I found one singing Willow Flycatcher on Jamul Creek at the east end of Lower Otay Lake on 13 July 1975, but this habitat was later flooded by the rising level of the reservoir. Although suitable habitat has regenerated, no Willow Flycatchers have been reported subsequently from that locality. The Willow Flycatcher population in the Tijuana River Valley increased from one territorial bird in 1981 to two in 1982 to five on 9 June 1984 (G. McCaskie, pers. comm.). McCaskie found no Willow Flycatchers during a visit to part of the habitat there on 22 June 1986, however. Riparian woodland suitable for breeding Willow Flycatchers has developed along the Tijuana River only since the late 1970s, so occurrence of the species there indicates that it still has the potential to colonize new localities. Baja California Outside of southern California, available information on the current distribu- tion of extimus is very sketchy. During a two-day trip to several tracts of riparian woodland in northern Baja California, M. Evans, P. Fromer, and I found on- ly a single singing individual, along the Rio Santo Tomas 5 km northwest of the town of Santo Tomas on 21 June 1986. Particularly in comparison to our finding of 21 territorial Bell’s Vireos during this same survey, it is clear that Willow Flycatchers are extremely rare in Baja California. Nevada/Utah I have no recent information from southern Nevada. W. H. Behle (pers. comm.) states that no recent information is available on the species’ status in southern Utah. He notes that the Willow Flycatcher was always rare in that region and believes that a recent change in status is likely only along the Virgin River in the vicinity of St. George, where riparian habitat has been lost to urban development. Some habitat along the Colorado River in southeastern Utah was lost by the creation of Lake Powell, but Behle believes that suitable habitat still persists along tributaries. Arizona Probably the steepest decline in the population levels of extimus has oc- curred in Arizona, though the subspecies was always localized and uncom- 154 EMPIDONAX TRAILLII EXTIMUS mon there. The largest known colony occurs along the Colorado River in the upper Grand Canyon, where B. T. Brown (Brown and Johnson 1985, 1987; Brown et al. 1985) found two pairs in 1982, four in 1983, four in 1984, eight in 1985, and 11 in 1986. The Grand Canyon birds occur in two areas: between River Miles 47 and 54, about 24 km above the confluence of the Colorado and the Little Colorado rivers (9 pairs in 1986) and at River Mile 71 (2 pairs in 1986). Along the San Pedro River in 1985, W. C. Hunter (pers. comm.) located at four singing birds at Dudleyville and three at San Manuel, plus one nesting pair and two apparently unmated singing birds on the Gila River at Fort Thomas. One pair summered at Cook’s Lake, 5 miles south of Dudleyville, in 1978 and 1979, but the species was absent there in 1986 (W. C, Hunter, pers. comm.). According to Hunter (pers. comm.), a small population probably persists in the White Mountains, since the birds have been seen recently in summer along the south fork of the Little Colorado River near Springerville, along the Black and Blue rivers, and at Greer. A. M. Rea collected one extimus V 2 mile east of Fort Apache on 29 May 1972 (AMR 3915), but no more recent information is available from the White River. Fur- ther exploration is needed, but it is clear that extimus has been extirpated from much of the area from which it was originally described, the riparian woodlands of southern Arizona. New Mexico Most of the remaining population of extimus breeds apparently in New Mex- ico. The largest known population lives along the upper Gila River in southwestern New Mexico, where Montgomery et al. (1985) in 1983 found 19 pairs or singing birds along 3-km section of river near Redrock and 53 along an 8-km section near Cliff. Egbert (1981) found 28 and 50, respective- ly, in these same areas in 1981, though some of these may have been migrants. J. F. Hubbard and G. Monson (pers. comm.) found a nesting pair at Glen- wood, San Francisco River valley, on 10 July 1972, and Hubbard (1970 and pers. comm.) cites Pleasanton and Reserve as additional breeding localities on this river. “Small numbers” were reported at Zuni, McKinley County, from 21 June to 27 July 1982 and two or three were there in the summer of 1984 (J. Trochet in Hubbard 1982, 1984); the species has now been confirmed as breeding there. Schmitt (1976) found the species at Kirtland, San Juan River (five on 15 July 1971), and collected on 28 July 1972 a female that had recently finished breeding. Near the Colorado line, Willow Flycatchers occur along the Rio Chama in the Chama and Los Ojos/Park View areas (Hubbard and Hundertmark, pers. comm.) and near Canjilon in the San Juan Mountains (one on 20 June 1982, Hubbard 1982). Willow Flycatchers summer in small numbers at many places along the Rio Grande from Alameda (and at least formerly, Dixon; Hubbard pers. comm.) south. Hink and Ohmart (1984) reported eight probably breeding pairs along the middle Rio Grande in 1981 and 1982. According to W. H Howe (pers. comm.), this report is based on observations of one singing bird at Albuquer- que in 1981, two or three at Isleta in both 1981 and 1982, one at Los Lunas in 1981, and four at La Joya in 1982. C. A. Hundertmark (pers. comm.) found two singing Willow Flycatchers at Oxbow Marsh, Albuquerque, on 6 July 1985 and one on 7 June 1986. Howe (pers. comm.) found two singing 155 EMPIDONAX TRAILLII EXTIMUS 3 miles north of Bernardo on 20 June 1983 but noted that the birds were absent from La Joya in 1986 and that the habitat there had been dredged by the local water conservancy authority. Farther south along the Rio Grande, summering Willow Flycatchers have occurred recently at Bosque del Apache National Wildlife Refuge (one 6-26 June 1982, D. and S. Huntington in Hub- bard 1982) and Caballo Lake (J. P. Hubbard, pers. comm.). At Elephant Butte Marsh, Hundertmark (1978) found 10 nests or family groups in 1974, six in 1975. The tract where these Willow Flycatchers occurred has since been flooded by rising water levels, and although additional suitable habitat has grown farther upstream, Willow Flycatchers were not relocated there during surveys conducted from 1979 to 1981 (C. A. Hundertmark, pers. comm.). The Willow Flycatcher may now be absent from the Rio Grande in Dona Ana County, where it nested at Radium Springs and Anthony (Hubbard 1970) and was collected at Las Cruces (A. R. Phillips pers. comm.) but has not been reported recently. Hubbard (1970, 1978) lists several other New Mexico localities as possible breeding sites or as sites of records needing further substan- tiation (not plotted in Figure 2) . Hubbard (pers. comm .) believes the species’ status in New Mexico has not changed in recent years and that the population there may number several hundred pairs. He notes that many tracts of suitable habitat remain uninvestigated, however. Summary On the basis of the maximum population counted in any year at each of the 10 sites, the known Willow Flycatcher population in the California range of extimus consists of 87 pairs. Because so much of the riparian woodland of this area has been surveyed in recent years, I believe this number represents a substantial majority of the actual population. The population in Arizona can- not be more than a few dozen pairs and may be less. Even if a few hundred pairs persist in New Mexico, the total population of the subspecies is well under 1000 pairs; I suspect 500 is more likely. Although the data reveal no trend during the past few years, the population is clearly much smaller now than 50 years ago, and no change in the factors responsible for the decline seems likely. GENERAL BIOLOGY Migration Schedule Proper field studies of Willow Flycatchers require an understanding of the species’ migration. The northwestern race £. t. brewsteri is far more numerous than extimus and is common in migration in the western part of the latter’s range. E, t. brewsteri is one of the latest spring migrants in western North America, not arriving until about 15 May. The earliest specimens I have iden- tified were collected on 7 May (1908, near Cabazon, MVZ 1686) and 11 May (1906, Ventura, MVZ 6898). Peak numbers pass through southern California around 1 June, and Garrett and Dunn (1981) state that Willow Flycatchers are still migrating north until about 20 June. The latest spring date on which I have identified brewsteri in the California range of extimus is 13 June (1953, 6 miles southwest of Niland, SBCM 31042), but Phillips et al. 156 EMPIDONAX TRAILLU EXTIMUS (1964) reported a brewsteri collected in Arizona on 23 June (1932, Bates Well, Organ Pipe Cactus National Monument) . Fall migrant brewsteri arrive in southern California by 18 July (1908, near Colton, MVZ 3184). This date may seem inordinately early for fall migration of a land bird, but is in fact no earlier than the beginning of fall migration of such familiar species as Western Tanager (Piranga ludoviciana ) and Black-headed Grosbeak ( Pheucticus melanocephalus) . Thus brewsteri is present in the range of extimus during most of the latter’s breeding season, so single observations are often useless for indicating the local status of Willow Flycatchers. Any survey must encom- pass the period 20 June- 15 July and must include repeated visits to each site to verify that any Willow Flycatchers seen are resident and territorial. Surveys for E. t. extimus must be more intensive than surveys for a seden- tary species or a migratory species, such as Bell’s Vireo, that is uncomplicated by large numbers of nonlocal breeders. The spring migration of extimus is earlier than that of brewsteri. The nor- mal arrival of extimus in both southern California and southern Arizona (Phillips et al. 1964) is the first week of May. Hubbard (pers. comm.) found apparently territorial Willow Flycatchers along the Gila River in New Mexico on 6 May in 1960 and 1961. In four out of five years L. Salata recorded a first arrival date on the Santa Margarita River in the first week of May; his average date was 6 May. In 1981 E. Copper found the Willow Flycatcher in the Tijuana River Valley on 2 May. On the basis of sight records, April arrival has been reported twice: at Potholes, Colorado River, on 28 April 1910 (Grinnell 1914) and at Weldon on 30 April 1977 (McCaskie 1977). The Grand Canyon population, near the northern edge of the subspecies’ range, is an exception to this pattern; B. T. Brown (pers. comm.) has found that breeding Willow Flycatchers do not arrive there until 15 May. Vocalizations Territorial Willow Flycatchers are most easily located by their songs, the notorious “witch'-pew” (usually rendered “fitz-bew”) and a less frequent but equally characteristic “brrrit!” My very limited observations suggest that only early to mid morning is a suitable time for counting extimus. Near Weldon on 15 May 1984 I counted from one bird 52 songs between 0805 and 0815 and 56 between 0935 and 0945, but only four between 1105 and 1115 and none between 1515 and 1525. A secondary peak of singing occurs near dusk (S. A. Laymon pers. comm.). Willow Flycatchers begin singing in spring as soon as they arrive on their breeding territories, but stop singing in July, well before their fall departure. I found the birds still present but not singing on the San Luis Rey River on 26 July 1986. L. Salata (pers. comm.) finds that the frequency of singing on the Santa Margarita River drops after about 15 July, and B. T. Brown (pers. comm.) does not believe that Willow Flycatchers can be located reliably by song after 1 July. Any accurate survey of Willow Flycatcher populations must accommodate the birds’ singing frequency with respect to both time of day and time of year. Uncertainty in song frequency as much as uncertainty in occurrence of migrants demands that accurate censuses include repeated visits to each colony site. 157 EMPIDONAX TRAILLIl EXTIMUS Migrating Willow Flycatchers rarely sing in southern California, contra Scott (1983). For example, between 1 and 10 June 1977, when I visited Point Loma, San Diego County, and saw migrant Willow Flycatchers almost daily, I did not hear a single song . This is one of the few factors that simplifies inter- pretation of Willow Flycatcher observations. A bird heard singing repeatedly is probably on its breeding territory. Still, migrants do sing occasionally. This possibility must be considered especially in May because male Willow Fly- catchers tend to migrate before females. In northern California, migrants ap- parently sing more frequently (T. Manolis pers. comm.), possibly reflecting increasing hormone levels as the birds approach their breeding grounds. Reproductive Biology The following data on nesting season, clutch size, and nest placement are based largely on the egg collections in WFV2, SBCM, and UA. Most sets from the range of extimus were from the coastal slope of southern California; 35 were from the Colorado River, and one was from Fairbank, upper San Pedro River, Arizona. On the basis of 187 dated sets, extimus usually begins nesting about 1 June. The sets range in date from 24 May to 30 July; the mean date is 16 June. In coastal California, the complete clutch consists of either three or four eggs; 60% of the sets had three eggs, 40% had four. On the Colorado River, average clutch size is smaller: of 28 unparasitized sets with clutch size recorded, 18% had two eggs, 82% had three eggs, and none had four. The usual natural nest site for extimus is the fork of a willow. Of 172 nests whose site was specified, 148 (86%) were in willows ( Salix spp.), 7 (4%) were in nettles ( Urtica dioica), 4 (2%) were in grapevines ( Vitis girdiana), 3 (2%) were in blackberry vines ( Ruhus ursinus ), 3 (2%) were in uniden- tified vines, 3 (2%) were in alders ( Alnus rhombifolia) , 2 (1%) were in ar- rowweed ( Pluchea odorata), 1 (0,5%) was in a sycamore ( Platanus racemosa ), and 1 was in a rosebush ( Rosa calif ornica) . In New Mexico, Hubbard (pers. comm.) has found the species nesting predominantly in Salix gooddingii. At least in the eastern part of its range, however, the subspecies may now be adapting to the tamarisks ( Tamarix spp.) that are replacing the natural vegeta- tion in desert riparian areas. B. T. Brown (pers. comm.) has data suggesting that Willow Flycatchers in the Grand Canyon select tamarisks for nest sites in preference to native vegetation, and Hundertmark (1978) found that the species nested predominantly in tamarisks at Elephant Butte Marsh, New Mexico. The elevation of the nest above the ground is quite variable, ranging from 0.6 m (2 feet) to 5.5 m (18 feet). The mean nest height is 2.3 m with a stan- dard deviation of 0.92 m. Although the flycatchers nest exclusively in trees or in vegetation under trees, marsh plants such as cattails ( Typha spp.) are often part of their territories and foraging habitat. Cowbird Brood-Parasitism Brown-headed Cowbirds, which invaded coastal southern California be- tween 1910 and 1920, were parasitizing extimus heavily by the 1930s. W. C. Hanna (in Willett 1933) reported that it was “now difficult to find a nest 158 EMPIDONAX TRAILL1I EXTIMUS of this flycatcher, near Colton [San Bernardino Co.], that does not contain at least one egg of the Dwarf Cowbird.” On the card accompanying an egg set he collected at the Santa Clara River mouth, Ventura Co., on 11 July 1937, M. C. Badger noted that cowbird eggs were “nearly always found in nests of this species.” Cowbirds have been present throughout recorded history in most of the range of extimus from the Colorado River eastward. Yet only two of 34 nests collected in 1902 near Yuma had been parasitized, and in New Mexico, only four of 21 nests found by Hubbard (pers. comm.) had been parasitized. Brood- parasitism by cowbirds undoubtedly has played some part in the decline of E. t. extimus, but its relative contribution and the ways, if any, that the fly- catchers have adapted to parasitism remain unknown. OUTLOOK The available evidence indicates that the population of extimus has declined precipitously and that the subspecies is now rarer than many other birds for- mally designated as endangered. The subspecies is now absent from many areas were it was once common, and most of the remaining population is restricted to a few colonies. Even in New Mexico, where the largest numbers persist, the Willow Flycatcher’s continuing survival is threatened by progressive loss of riparian habitat, especially the marshy situations the birds use most extensively (J. P. Hubbard, pers. comm.). Riparian habitat destruction is probably most responsible for the decline of extimus. For example, the water conservancy authority along the middle Rio Grande regularly dredges out the willow thickets in drainage channels where the flycatchers occur, at a minimum forcing the birds to shift frequently from site to site and leaving no opportunity for population recovery (W. H. Howe, pers. comm.). Several of the colony sites are threatened by proposed reser- voirs. Recent bird surveys that have located Willow Flycatcher colonies, such as those of Montgomery et al. (1985) and Hink and Ohmart (1984), were prompted by proposals for dams whose construction would inundate exten- sive riparian zones. Protection and restoration of riparian woodland is clearly the flycatchers’ primary need, but their basic biology, particularly habitat re- quirements and response to cowbird parasitism, must be known better before specific management practices can be adopted. ACKNOWLEDGMENTS For loans of specimens and museum data I thank John Bates and Thomas R. Huels (UA), Eugene A. Cardiff (SBCM), Kimball Garrett (LACM), Ned K. Johnson (MVZ), Lloyd Kiff (WFVZ), James R. Northern (UCLA), David W. Steadman (NYSM), and Roger Clapp (US). For information on current colonies of extimus 1 thank John P. Hubbard, Charles A. Hundertmark, and William H. Howe (New Mexico), Bryan T. Brown, W. Charles Hunter, and Gale Monson (Arizona), William H Behle (Utah), John Harris, Larry Salata, Roger Higson, Sharon Goldwasser, John Griffith, Elizabeth Cop- per, and Guy McCaskie (California). Rick Hewitt generously offered information and hospitality during my visits to Weldon. Amadeo M. Rea made the resources of both the San Diego Natural History Museum and his own collection freely available to me. For review and comment on the manuscript I thank Bryan T. Brown, Alice Fries, John 159 EMPIDONAX TRAILLII EXTIMUS P. Hubbard, Ned K. Johnson, Stephen A. Laymon, Tim Manolis, Allan R. Phillips, Gregory K. Pregill, and Amadeo M. Rea. 1 thank especially Roger Higson, for his help with collecting the specimen from the San Luis Rey River, and Allan R. Phillips, for his help in identifying specimens, information on specimens from the eastern part of the range of extimus, and his constant encouragement of this study. LITERATURE CITED Aldrich, J. W. 1951. A review of the races of the Traill’s Flycatcher. Wilson Bull. 63:192-197. American Ornithologists’ Union. 1957. Check-list of North American Birds, 5th edi- tion. American Ornithologists’ Union, Baltimore. American Ornithologists’ Union. 1973. Thirty-second supplement to the American Or- nithologists’ Union check-list of North American birds. Auk 90:411-419. Audubon, J. J. 1828. Birds of America (folio). Vol. 1. Edinburgh. Bailey, A. M., and Niedrach, R. J. 1965. The Birds of Colorado. Denver Museum of Natural History, Denver. Behle, W. H. 1960. The birds of southeastern Utah. Univ. Utah Biol. Ser. 12:1-56. Behle, W. H. 1985. Utah birds: Geographic distribution and systematics. Utah Mus. Nat. Hist. Occas. Publ. 5. Behle, W. H., Bushman, J. B., and Greenhalgh, C. M. 1958. Birds of the Kanab area and adjacent high plateaus of southern Utah. Univ. Utah Biol. Ser. 11:1-92. Brown, B. T., Carothers, S. W., Haight, L. T., Johnson, R. R., and Riffey, M. 1985. Birds of the Grand Canyon region: An annotated checklist, 2nd edition. Grand Canyon Nat. Hist. Assoc, Monogr, 1. Brown, B. T., and Johnson, R. R. 1985. Glen Canyon Dam, fluctuating water levels, and riparian breeding birds: The need for a management compromise on the Co- lorado River in Grand Canyon. Proc. 1st N. Am. Riparian Conf., U. S. Dept. Agric., Forest Serv. Gen. Tech. Rep. RM- 120:76-78. Brown, B. T,, and Johnson, R. R. 1987. Fluctuating flows from Glen Canyon Dam and their effect on breeding birds of the Colorado River. U. S. Bureau of Reclama- tion, Salt Lake City. Burleigh, T. D. 1972. The Birds of Idaho. Caxton, Caldwell, Ida. Cardiff, E. A., Kniffen, J., and Kniffen, R. 1982. Breeding bird survey 197. Desert riparian-freshwater marsh and ponds. Am. Birds 36:102-103. Egbert, J. 1981. Field inventories in New Mexico of selected Gila Valley birds. Un- published report to New Mexico Department of Game and Fish, supplied by J. P. Hubbard, New Mexico Department of Game and Fish, Santa Fe. Garrett, K., and Dunn, J. 1981. Birds of Southern California. Los Angeles Audubon Soc., Los Angeles. Grinnell, J. 1914. An account of the mammals and birds of the lower Colorado valley. Univ. Calif. Publ. Zool. 12:51-294. Harris, J. H., Sanders, S. D., and Flett, M. A. 1987. Willow Flycatcher surveys in the Sierra Nevada. W. Birds 18: Hink, V. M., and Ohmart, R. D. 1984. Middle Rio Grande biological survey. U. S. Army Corps of Engineers, Albuquerque. 160 EMPIDONAX TRAILLII EXTIMUS Hubbard, J. P. 1970. Check-list of the birds of New Mexico. N. M. Ornithol. Soc. Publ. 3. Hubbard, J. P. 1978. Revised check-list of the birds of New Mexico. N. M. Ornithol. Soc. Publ. 6. Hubbard, J. P. 1982. The breeding season. New Mexico. Am. Birds 36:1006-1007. Hubbard, J. P. 1984. The breeding season. New Mexico. Am. Birds 38:1050-1052. Hundertmark, C. A. 1978. Breeding birds of Elephant Butte Marsh. N. M, Ornithol. Soc. Publ. 5. Linsdale, J. M. 1936. The birds of Nevada. Pac. Coast Avifauna 23. Mayr, E. 1969. Principles of Systematic Zoology. McGraw-Hill, New York. Mayr, E., and Short, L. L. 1970. Species taxa of North American birds. Publ. Nuttall Ornithol. Club 9. McCaskie, G. 1977. The spring migration. Southern Pacific coast region. Am, Birds 31:1046-1049. McCaskie, G. 1984. The breeding season. Southern Pacific coast region. Am. Birds 38:1060-1063. McCaskie, G. 1986. The breeding season. Southern Pacific coast region. Am. Birds 40:1254-1257. Monson, G., and Phillips, A. R. 1981. Annotated Checklist of the Birds of Arizona. Univ. Ariz. Press, Tucson. Montgomery, J. M., Mills, G. S., Sutherland, S., and Spicer, R. B. 1985. Wildlife and fishery studies, upper Gila water supply project. Part 1: Terrestrial wildlife. U. S. Bureau of Reclamation, Boulder City, Nev. Oberholser, H. C. 1918. New light on the status of Empidonax traillii (Audubon). Ohio J. Sci. 18:85-98. Oberholser, H. C. 1932. Descriptions of new birds from Oregon, chiefly from the Warner Valley region. Sci. Publ. Cleveland Mus. Nat. Hist. 4:1-12. Oberholser, H. C. 1947. A new flycatcher from the western United States. Proc. Biol. Soc. Washington 60:77-78. Oberholser, H. C. 1974. The Bird Life of Texas. Univ. Tex. Press, Austin. Phillips, A. R. 1944. The wing formula in Empidonax traillii. Auk 61:293. Phillips, A. R. 1948. Geographic variation in Empidonax traillii. Auk 65:507-514. Phillips, A., Marshall, J., and Monson, G. 1964. The Birds of Arizona. Univ. Ariz. Press, Tucson. Schmitt, C. G. 1976. Summer birds of the San Juan Valley, New Mexico. N. M. Or- nithol. Soc. Publ. 4. Scott, S. L. (ed.) 1983. Field Guide to the Birds of North America. Natl. Geogr. Soc., Washington, D. C. Serena, M. 1982. The status and distribution of the Willow Flycatcher (Empidonax traillii) in selected portions of the Sierra Nevada, 1982. Wildlife Mgt. Admin. Rep. 82-5, Calif. Dept. Fish and Game. Short, L. L. Jr., and Crossin, R. S. 1967. Notes on the avifauna of northwestern Baja California. Trans. San Diego Soc. Nat. Hist. 14:283-289. Smithe, F. B. 1975. Naturalist’s Color Guide. Am. Mus. Nat. Hist., New York. Snyder, L. L. 1953. On eastern empidonaces with particular reference to variation in E. traillii. Contr, R, Ont. Mus. Zool. Paleontol. 35:1-26. 161 EMPIDONAX TRA1LLII EXTIMUS Stein, R. C. 1958. The behavioral, ecological, and morphological characteristics of two populations of the Alder Flycatcher, Empidonax traiilii (Audubon). N. Y. State Mus. Sci. Serv. Bull. 371:1-63. Stein, R. C. 1963. Isolating mechanisms between populations of Traill’s Flycatchers. Proc. Am. Philos. Soc. 107:21-50. Traylor, M. A., Jr. 1979. Check-list of Birds of the World, Vol. VIII. Mus. Comp. Zool., Cambridge, Mass. Wauer, R. H. 1973. Birds of Big Bend National Park and Vicinity. Univ. Tex. Press, Austin. Willett, G. 1912. Birds of the Pacific slope of southern California. Pac. Coast Avifauna 7. Willett, G. 1933. A revised list of the birds of southwestern California. Pac. Coast Avi- fauna 21. Zink, R. M. 1986. Patterns and evolutionary significance of geographic variation in the schistacea group of the Fox Sparrow (Passerella iliaca) . Ornithol. Monogr. 40. Accepted 20 August 1987 162 BREEDING BIRDS OF AN ALPINE HABITAT IN THE SOUTHERN SNAKE RANGE, NEVADA DEAN E. MEDIN, Intermountain Research Station, Forest Service, U.S. Department of Agriculture, Forestry Sciences Laboratory, 316 East Myrtle Street, Boise, Idaho 83702 Alpine ecosystems occur as isolated islands on the highest of the Great Basin mountain ranges. These include the Wassuk, White, Humboldt, Toiyabe, Toquima, East Humboldt, Ruby, Grant, Schell Creek, Snake, Deep Creek, and Stansbury mountains {Cronquist et al, 1972). Like other altitudinally zoned ecosystems of Great Basin mountain ranges, alpine ecosystems have been neglected in the past because of difficult access and false impressions of biotic sterility (Johnson 1978) . Recently, more attention has been directed to the scientific study of these unique environments and to their wise use and management (Ives and Barry 1974, Thilenius 1975, Bill- ings 1978, Johnson 1979, Braun 1980). There are few quantitative assessments of alpine breeding bird popula- tions. Such data are basic to understanding the ecology of alpine birds and to the preservation of their habitats (Freedman and Svoboda 1982). This paper describes features of the passerine breeding bird population of an alpine habitat in the southern Snake Range of east-central Nevada. STUDY AREA I conducted the study above timberline (about 3350 m) on Bald Mountain in Great Basin National Park, 62 km southeast of Ely, Nevada. Bald Moun- tain (3524 m) is shaped like a shallow inverted bowl and joined to the higher and larger mass of nearby Wheeler Peak by a long, narrow saddle. Wheeler Peak (3981 m), the highest peak in the eastern Great Basin, is the dominant feature of the local landscape. Mean annual precipitation is about 76 cm, most of it falling as snow in late winter (Beasley and Klemmedson 1980) . Large and persistent snowfields are on the north-facing slope of the alpine zone on Bald Mountain. Soils, derived mostly from quartzite, are shallow and rocky. Boulderfields and talus slopes are scattered throughout the area. Over 40% of the study site is covered by rock. There has been little or no grazing by domestic livestock in the alpine en- vironments of Bald Mountain and Wheeler Peak (R. P. DeMeule, pers. comm.) . The only access is by foot or horseback. There is substantial recrea- tional use, especially along developed trails. At their lower elevational limits the treeless slopes of Bald Mountain grade into the mixed conifer forest of Engelmann Spruce ( Picea engelmonnii ) and Limber Pine (Pinus flexilis) typical of the Snake Range. The alpine vegetation is open and scanty, consisting mostly of low perennial herbs. Common grasses and forbs include Alpine Fescue ( Festuca ouina), Skyline Bluegrass (Poo epilis ), Alpine Avens ( Geum rossii). Powder Phlox ( Phlox pulvinata), and Moss Silene ( Silene acaulis). Blackroot Sedge ( Carex elynoides ) is locally abundant. Alpine Prickly Currant ( Ribes montigenum) occurs in scat- tered clumps (M. E. Lewis, unpubl.). Western Birds 18:163-168, 1987 163 NEVADA ALPINE HABITAT METHODS Using the Williams spot-mapping method (International Bird Census Com- mittee 1970), I censused a 20-ha plot for breeding birds. Oelke (1981) sum- marized the methodological difficulties and limitations of this mapping method. I chose the plot location that best represented the alpine environ- ment on Bald Mountain. In general, the square plot straddled the summit of the mountain with the sides of the plot sloping downward in all directions. The lower boundaries of parts of the plot approached timberline. The plot was surveyed and gridded in a Cartesian coordinate system with points numbered with stakes at 75-m intervals. I made 10 census visits annually to the plot between 20 June and 21 July from 1981 to 1983 and did most of the census work from sunrise to late morn- ing. With the exception of the large snowfields on the north-facing slope, I cen- sused the plot by walking within 50 m of all points on the grid, varying the cen- sus routes through the plot. At the end of each annual sampling period, I marked concentrated groups of observations and coded activity patterns to in- dicate areas of activity or approximate territories. Fractional parts of boundary territories were included in the results. Species richness was expressed as the total number of bird species nesting on the plot. Plant names are from Welsh et al. (1981). Bird nomenclature follows the 1983 AOU check-list (American Ornithologists’ Union 1983). RESULTS AND DISCUSSION The density of breeding birds occupying the alpine census plot ranged from 3.7 to 5.2 pairs over the 3-year period of study (Table 1). There were 37 to 52 individual breeding birds/km 2 . Total standing crop biomass ranged from 7.8 to 10.2 g/ha. Only two species, both passerines, were breeding birds on the study plot. The most common of these was the Water Pipit ( An - thus spinoletta), which I found generally throughout the plot. The Rock Wren ( Salpinctes obsoletus) was less common and found only in more restricted habitats. Rosy Finches ( Leucosticte arctoa), although frequent visitors to the plot, apparently nested off the area in nearby cliff habitats. The Rosy Finches were L.a. atrata, which breeds in alpine habitats from central Idaho, Montana, and Wyoming south to southeastern Oregon, east-centTal Nevada, and central Utah (American Ornithologists’ Union 1983). Other species, observed as occasional visitors to the alpine zone (less than 10 observations annually), included the Broad-tailed Hummingbird (Selosphorus platycercus) , Clark’s Nutcracker ( Nucifraga columbiana), American Robin ( Turdus migrator! us) , Townsend’s Solitaire (Myadestes townsendi) , Mountain Bluebird ( Sialia currucoides) , and Dark-eyed Junco (Junco hyemalis). Less frequently observed birds (less than five observations annually) were the Northern Harrier ( Circus cyaneus), Red-tailed Hawk (Buteo jamaicensis ) , Golden Eagle ( Aquila chrysaetos), American Kestrel (Falco sparuerius), Violet- green Swallow (Tachycineta thalassina), Common Raven (Coruus corax), Mountain Chickadee (Parus gambeli) , and Cassin’s Finch { Carpodacus cassinii ) . Most of the visitors observed in or flying above the alpine habitat were inhabitants 164 NEVADA ALPINE HABITAT of subalpine plant communities and visited the alpine only sporadically. Raptors occurred more commonly from mid-summer to late summer. Water Pipit The Water Pipit was the dominant breeding bird of the alpine zone in both numbers and standing crop biomass (Table 1). It was widely distributed on the study tract. Pipits established territories on a variety of topographies, but highest densitites were on the steep and relatively wind-sheltered, north- facing slope where territorial boundaries were contiguous and sometimes overlapping (Figure 1). Most of the breeding territories on the north-facing slope included parts of extensive snowfields that persisted summer-long on that aspect. The amount and distribution of snow in the spring are important in determining when and where birds breed in alpine habitats (Weeden 1960). Also, as noted by Pattie and Verbeek (1966), snowfields provide im- portant habitats for the Water Pipit. Pipits on Bald Mountain often foraged for cold-numbed insects on the surface of the snow. Water from melting snowbanks contributed to a more mesic environment on the north-facing slope where grass and forb ground coverage was notably higher than on other aspects. I recorded Water Pipits least frequently on the windward side of the plot, where strong westerly winds were the rule and where vegetation was less abundant and boulderfields and talus more common. I found two Water Pipit nests, one on 27 June that contained five eggs and the second on 6 July that contained four eggs. Incubating females were flushed from the nests when discovered. Nestlings were last observed on 20 July. Both Pipit nests were sunk in sloping ground and sheltered from above, one by an overhanging rock and the other by a thick mat of Alpine Avens. Nest locations fit Verbeek’s (1970) descriptions as “rock nests” and “sod nests.” Table 1 Density, Standing Crop Biomass, and Other Attributes of Passerine Breeding Birds, Bald Mountain, Southern Snake Range, Nevada, 1981-1983 Population density (pairs/20 ha) Foraging Nesting Species category substrate 1981 1982 1983 Water Pipit Ground insectivore Ground 3.5 3.7 3.7 Rock Wren Ground insectivore Rocks 1.7 + 6 1.0 Rosy Finch Ground omnivore Cliffs + + + Number of breeding species 2 1 2 Total pairs/20 ha 5.2 3.7 4.7 Total individua!s/km z 52 37 47 Standing crop biomass (g/ha)“ 10.2 7.8 9.4 "Species weights from Dunning (1984). * + indicates that a species was only infrequently observed or that breeding territories could not be delineated. 165 NEVADA ALPINE HABITAT Rock Wrens Rock Wrens were irregular and relatively uncommon breeding birds on the alpine study plot (Table 1). I located all or parts of only five separate breeding territories within the boundaries of the 20-ha census plot during the 3-year WATER PIPIT ROCK WREN 2J UNOCCUPIED AREA t Figure 1. Annual dispersion patterns of Water Pipit and Rock Wren territories on the 20-ha alpine study plot. 166 NEVADA ALPINE HABITAT study (Figure 1). These were centered on shattered outcroppings of exposed bedrock or, in one case, on a steep talus slope. Weather may have been a factor in the failure of the Rock Wren to establish breeding territories on the study plot in 1982. Spring was unusually late that year and alpine snowfields were larger and persisted longer. Snow still covered almost half the study plot in late June 1982. I found no nests of the Rock Wren but observed territory establishment, singing, courtship, pairing, and other breeding activities. Later, I saw adult Rock Wrens carrying food items as they flew nearby. Rosy Finches I often saw Rosy Finches on the alpine zone of Bald Mountain both as single birds and in small groups of up to 10 or more. Paired birds or groups of three to five birds that included both males and females were most common. Finches were seldom seen below an elevation of about 3350 m. Spot-mapping methods are inappropriate for censusing the Rosy Finch. The mapping method applies primarily to territorial and noncolonial passerines and other species of birds that have similar dispersion mechanisms and distribution patterns (International Bird Census Committee 1970). The “territory” of the Rosy Finch is centered around the female and varies in loca- tion and size with the movements of the female. It is the female rather than an area that is defended (French 1959) , Thus, estimates of breeding densitities for the Rosy Finch are not listed in Table 1. Rosy Finches did not nest on the Bald Mountain study plot. They ap- parently nested in the cirque headwalls, cliff faces, and talus slopes above treeline on nearby Wheeler Peak. Their flights to and from Bald Mountain were almost invariably in the direction of Wheeler Peak. French (1959) noted that nest sites of the Rosy Finch may be widely separated from feeding areas. Rosy Finch activities on Bald Mountain were devoted largely to foraging. Most foraging took place on the surface of the snow, along the margins of receding snowbanks, or on snow-free areas adjacent to snowfields. Cold- numbed insects were apparently gleaned from the surface of the snow. Much of the food of Rosy Finches consists of seeds (French 1959), but insects can be a major food item, especially early in the breeding season (Twining 1940) . I saw Rosy Finches most often on or near the snowfields that persisted on the north-facing aspect of Bald Mountain. ACKNOWLEDGMENTS I gratefully acknowledge the valuable field assistance of J. Russell Groves and Michael D. Carter. John Shochat of the Humboldt National Forest at Baker, Nevada, and Warren P. Clary of the Forestry Sciences Laboratory at Boise, Idaho, provided support and contributed in many other ways. LITERATURE CITED American Ornithologists’ Union. 1983. Check-list of North American Birds. 6th Ed. Am. Ornithol. Union. Washington, D.C. 167 NEVADA ALPINE HABITAT Beasley, R. S., and Klemmedson, J, O. 1980. Ecological relationships of bristlecone pine. Am. Midland Nat. 104:242-252. Billings, W. D. 1978. Alpine phytogeography across the Great Basin, in Intermoun- tain Biogeography: A Symposium (K. T. Harper and J. L. Reveal, eds.), pp. 105-117. Great Basin Nat. Memoirs 2, Brigham Young Univ., Provo, Utah. Braun, C. E. 1980. Alpine bird communities of western North America: Implications for management and research, in Workshop Proceedings: Management of Western Forests and Grasslands for Nongame Birds (R. M. DeGraff, tech, coord.), pp. 280-291. USDA Forest Serv. Gen. Tech. Rep. INT-86. Cronquist, A., Holmgren, A. H., Holmgren, N. H., and Reveal, J. L. 1972. Inter- mountain Flora: Vascular Plants of the Intermountain West. Vol. 1. Hafner, New York. Dunning, J. B,, Jr. 1984, Body weights of 686 species of North American birds. W. Bird Banding Assoc. Monogr. 1. Freedman, B., and Svoboda, J. 1982. Populations of breeding birds at Alexandra Fjord, Ellesmere Island, Northwest Territories, compared with other arctic localities. Can. Field-Nat. 96:56-60. French, N. F. 1959. Life history of the Black Rosy Finch. Auk 76:159-180. International Bird Census Committee. 1970. An international standard for a mapping method in bird census work. Audubon Field Notes 24:722-726. Ives, J. D., and Barry, R. G., eds. 1974. Arctic and Alpine Environments. Methuen, London. Johnson, D. A., ed. 1979. Special management needs of alpine ecosystems. Soc. Range Mgt. Range Sci. Ser. 5. Johnson, N. K. 1978. Patterns of avian geography and speciation in the Intermoun- tain Region, in Intermountain Biogeography: A Symposium (K. T. Harper and J. L. Reveal, eds.), pp. 137-159. Great Basin Nat. Memoirs 2. Brigham Young Univ., Provo, Utah. Oelke, H. 1981. Limitations of the mapping method, in Estimating Numbers of Ter- restrial Birds (C. J. Ralph and J. M. Scott, eds.) . Studies Avian Biol. 6: 114- 118. Pattie, D.L., and Verbeek, N. A. M. 1966. Alpine birds of the Beartooth Mountains. Condor 68:167-176. Thilenius, J. F. 1975. Alpine range management in the western United States— prin- ciples, practices, and problems: The status of our knowledge. USDA Forest Serv. Res. Pap. RM-157. Twining, H. 1940. Foraging behavior and survival in the Sierra Nevada Rosy Finch. Condor 42:64-72. Verbeek, N. A. M. 1970. Breeding ecology of the Water Pipit. Auk 87:425-451. Weeden, R. B. 1960. The birds of Chilkat Pass, British Columbia. Can. Field-Nat. 74:119-129. Welsh, S. L., Atwood, N. D., Goodrich, S., Neese, E., Thorne, K. H., and Albee, B. 1981. Preliminary index of Utah vascular plant names. Great Basin Nat. 41:1-108. Accepted 3 October 1987 168 169 Water Pipit hatchling and egg. Frobisher Bay. Baffin Island, N.W.T. , Canada. Photo by Jeanne A. Conry Common Ground-Dove Sketch by Cameron Barrows 170 NOTES RANGE EXTENSION OF THE COMMON GROUND- DOVE INTO SANTA BARBARA AND VENTURA COUNTIES, CALIFORNIA KEVIN T. SPENCER, 437 San Nicolas Avenue, Santa Paula, California 93060 Recent sightings of Common Ground -Doves (Columbina passerina) in Santa Bar- bara County and, especially, Ventura County, California, indicate that this dove is less rare in those counties than previously thought. This apparent change in status may not be due to inadequate coverage in the past, but rather may reflect a population increase due to relatively recent changes in agricultural practices and dramatic increases in avocado acreage in Ventura and southern Santa Barbara counties. Webster et al. (1980) listed only three records of the Common Ground-Dove for this area: up to two seen near Santa Paula 20-21 August 1947, a single bird at McGrath State Beach on 13 September 1974, and another at Goleta on 2 October 1977. An additional record from Carpinteria, 25 August 1923 (Lehman 1982), was omitted by Webster et al. According to Garrett and Dunn (1981), the resident popula- tion closest to this area occurs in northeastern Orange County, including Garden Grove, Yorba Linda, and near Whittier. Recent records for Los Angeles County in- clude at least five individuals near the Orange County line in Hawaiian Gardens, a residential area of northeastern Long Beach, since 1984 (McCaskie 1984c). Other reports come from the San Gabriel Valley; however, there is very little habitat suitable for ground doves in heavily urbanized lowland Los Angeles County. In Santa Barbara County and, especially, Ventura County, ground doves have been recorded frequently since these publications. In the extreme southeastern corner of Santa Barbara County, the species has been recorded in small numbers on a number of occasions in the Carpinteria area, including three to four seen from 4 Oc- tober 1984 to 23 November 1984 (McCaskie 1985a) and up to four seen from 30 November 1984 to 9 January 1985 (McCaskie 1985b) . Goleta has had records of one or two individuals each fall from 1982 to 1985 (McCaskie 1983a, 1984a, 1985a, 1986) . The foothills and canyons near Goleta represent the northernmost extension of significant commercial avocado and lemon orchards. Common Ground-Doves recorded in Ventura County include up to nine individuals seen throughout the winter of 1981- 1982 near Camarillo, where they had been present at least the previous two years (McCaskie 1982), up to five near Oxnard during September and October 1982 (McCaskie 1983a), three in Santa Paula on 23 February 1983 (McCaskie 1983b), and one individual seen from 26 February to 11 March 1984 near Castaic Junction, where the Santa Clara Valley extends into Los Angeles County (McCaskie 1984b) . With access into private citrus and avocado groves in Ventura County in 1984 and 1985, I have found that the Common Ground-Dove is uncommon to fairly common in the Las Posas Valley (west of Moorpark) and in the El Rio area of the Oxnard floodplain. I have seen this species also on many occasions, but less commonly, throughout the Santa Clara Valley. Around the perimeter of roughly 40-acre parcels of avocado or lemon orchards in the Las Posas Valley and in the El Rio area I saw, on the average, three to five individuals, while in the Santa Clara Valley 1 found an Western Birds 18:171-174, 1987 171 172 Figure 1. Recent sighting and nesting locations of the Common Ground-Dove in Santa Barbara and Ventura counties, California. • Sight location; ▲, nesting location. NOTES average of one to two individuals around parcels of the same size, if Common Ground-Doves were present. On 3 October 1984 1 counted an unusually high number, 29 individuals, on a 100-acre ranch in the Las Posas Valley. My ground dove sightings during 1984 and 1985 were continuous through the year. 1 eventually observed Common Ground-Doves on all the properties 1 visited in the Las Posas Valley and in the El Rio area, whereas 1 observed them on about 10% of the proper- ties I visited in the Santa Clara Valley. On 11 September 1985 I located a Common Ground-Dove nest, the first nesting record for Ventura County, in an orchard on Sycamore Road, four mites west of Fillmore. Grinnell and Miller (1944) mentioned that the Common Ground-Dove seemed to increase and spread with the irrigation of low-lying desert lands. Over the past 15 years or so, as avocados have become more profitable, there has been a large increase in avocado acreage in both counties. There also has been a widespread conversion from furrow to drip and sprinkler irrigation systems, reducing the amount of ground disturbance through cultivation, and this change may also have been a factor in the Common Ground-Dove's expansion into this area. This conversion has been carried out most widely in lemon orchards. Most of my observations during 1984 and 1985 were in lemon and avocado orchards; a few were in orange groves. The doves were attracted especially to orchards that had eucalyptus windrows, where 1 have observed them on the roads below the trees, tipping the eucalyptus capsules for their seeds. They favored the younger avocado orchards where the trees had not closed their crowns, thus leaving more edge area. Unlike avocado trees, lemon trees are pruned regularly, keeping the tree’s crown low and the orchard relatively open, so ground doves occurred in lemon orchards of all ages. All of my observations of ground doves outside orchards in this area have been in arroyos not far from an orchard and in association with eucalyptus, willow, and/or California (Peruvian) Pepper (Schinus molle ) . Ventura County and, to a lesser extent, Santa Barbara County have large tracts of agricultural habitat suitable for ground doves, and, though urban development pressure is increasing, it will be several years before the existing orchards are seriously threatened. I thank Kimball Garrett and Paul Lehman very much for their information, com- ments, and help on the manuscript. LITERATURE CITED Garrett, K., and Dunn, J. 1981. Birds of Southern California: Status and Distribution. Los Angeles Aud. Soc., Los Angeles. Grinnell, J., and Miller, A.H. 1944. The distribution of the birds of California. Pac. Coast Avifauna 27. Lehman, P. 1982. The status and distribution of the birds of Santa Barbara County, California. Unpublished master’s thesis, University of California, Santa Barbara. McCaskie, G. 1982. The winter season. Southern Pacific Coast region. Am. Birds 36:330-333. McCaskie, G. 1983a. The autumn migration. Southern Pacific Coast region. Am. Birds 37:223-226. McCaskie, G. 1983b. The winter season. Southern Pacific Coast region. Am. Birds 37:337-340. McCaskie. G. 1984a. The autumn migration. Southern Pacific Coast region. Am. Birds 38:245-248. McCaskie, G. 1984b, The winter season. Southern Pacific Coast region. Am. Birds 38:356-359. 173 NOTES McCaskie, G. 1984c. The nesting season. Southern Pacific Coast region. Am. Birds 38:1060-1063. McCaskie, G. 1985a. The autumn migration. Southern Pacific Coast region. Am. Birds 39:101-105. McCaskie, G. 1985b. The winter season. Southern Pacific Coast region. Am. Birds 39:209-212. McCaskie, G. 1986. The autumn migration. Southern Pacific Coast region. Am. Birds 40:157-161. Webster, R., Lehman, P., and Bevier, L. 1980. The birds of Santa Barbara and Ven- tura Counties, California. Santa Barbara Mus. Nat. Hist. Occ. Pap. 10. Accepted 22 June 1987 174 NOTES A RING-BILLED GULL ON THE GALAPAGOS ISLANDS MIKLOS D.F. UDVARDY, California State University, Sacramento, California 95819 TORBJORN SALL, Swedish Agricultural University, Svalov, Sweden On 30 June 1983, on South Plaza Island, Galapagos Archipelago, we observed a gull obviously different from the resident Swallow-tailed (Creagrus furcatus ) and Lava ( Larus fuliginosus) gulls of the islands. We found the gull initially in one of the abun- dant tide pools along the island’s rocky shore. From there it flew a short distance to a sea lion carcass, where it supplanted a Lava Gull and fed on the maggots covering the rotting carcass. The gull then flew a few hundred meters to a pool where several of our party took close-up photographs (e.g.. Figure 1) that show the bird to have been a Ring-billed Gull (Larus delawarensis) in adult plumage. The bird was aberrant in that it lacked white tips or mirrors on the outermost primaries. However, at least one published photograph of an adult-plumaged Ring- billed Gull shows a bird with all-black wing-tips (Weseloh and Blokpoel 1979) . The bird we observed might have retained the outer primaries from the second-winter plumage, or else, less likely, wore off the white mirrors. Our photographs document the first record of the Ring-billed Gull on the Galapagos Islands and in the Republic of Ecuador. According to the A.O.U. Check-List (1983), the wintering range of the species extends south normally to southern Mexico, casual- ly to El Salvador and Costa Rica. Harrison (1983) mentions stragglers from Trinidad and Panama, and Grant (1982) likewise marks Panama as the approximate southern Figure 1. Ring-billed Gull, South Plaza Island, Galapagos Archipelago, 30 June 1983. Photo by Monica L. Udvardy Western Birds 18:175-176. 1987 175 NOTES limit of the species’ winter/ nonbreeding range. Westward, stragglers have been noted on several of the Hawaiian Islands (Berger 1972 and M.D.F. Udvardy, unpublished records) . Eastward, the Ring-billed Gull has been sighted as far as the coast of Sweden at the North Sea (Wallander and Mogren 1983). Thus it is not unexpected that a vagrant Ring-billed Gull should reach the Galapagos. Gulls are excellent travelers, many species covering much larger distances on regular seasonal migrations than be- tween the Galapagos Archipelago and the nearest breeding colonies of this species in the Great Lakes area of North America. Actually, this distance is less than that be- tween the Atlantic coastal North American breeding colonies and the British Isles, where the Ring-billed Gull is reported annually (Grant 1982), or between the Hawaiian Islands and the nearest colonies in the Pacific Northwest of North America. Indeed, in view of the recent increase and expansion of the species’ breeding col- onies (Conover 1983) , it is likely that vagrant Ring-billed Gulls will be reported even more widely. C.V. Peterson, T. Sail, and M L. Udvardy all furnished color slides, which helped greatly to verify the sighting on 30 June 1983. We also thank Dr. M. Harris (pers. comm., 1983), for corroborating the fact that, to his knowledge, no previous sighting of the Ring-billed Gull in Galapagos has been reported. LITERATURE CITED American Ornithologists’ Union. 1983. Check-list of North American Birds. 6th ed. Am. Ornithol. Union, [Washington, D.C.]. Berger, A.J. 1972. Hawaiian Birdlife. University Press of Hawaii, Honolulu. Conover, M.R. 1983. Recent changes in Ring-billed and California gull populations in the western United States. Wilson Bull. 95:362-383. Grant, P.J. 1982. Gulls. A Guide to Identification. Poyser, Calton. Harrison, P. 1983. Seabirds. An Identification Guide. Croom Helm, London. Wallander, J., and Mogren, J. 1983. (First record of Ring-billed Gull, Larus delauiarensis, in Sweden.) Var Fagelvarld 42:431-433. Weseloh, D.U., and Blokpoel, H. 1979. Hinterlands Who is Who. Ring-billed Gull. Pamphlet. 4 pp. Can. Wildlife Serv., Ottawa. Accepted 17 Ju/y 1987 176 Volume 18, Number 3, 1987 Empidonax traiilii extimus: An Endangered Subspecies Philip Unitt 137 Breeding Birds of an Alpine Habitat in the Southern Snake Range, Nevada Dean E. Medin 163 NOTES Range Extension of the Common Ground-Dove into Santa Barbara and Ventura Counties, California Kevin T. Spencer 171 A Ring-billed Gull on the Galapagos Islands Miklos D. F. Udvardy and Torbjorn Sail 175 Cover photo by Jules Evens, Point Reyes Station, California: Adult Long-tailed Jaeger ( Stercorarius longicaudus), Meade River, Alaska, 20 June 1979. Western Birds solicits papers that are both useful to and understandable by amateur field ornithologists and also contribute significantly to scientific litera- ture. The journal welcomes contributions from both professionals and amateurs. Appropriate topics include distribution, migration, status, identifica- tion, geographic variation, conservation, behavior, ecology, population dynamics, habitat requirements, the effects of pollution, and techniques for censusing, sound recording, and photographing birds in the field. Papers of general interest will be considered regardless of their geographic origin, but particularly desired are reports of studies done in or bearing on the Rocky Mountain and Pacific states and provinces, including Alaska and Hawaii, western Texas, northwestern Mexico, and the northeastern Pacific Ocean. Send manuscripts to Philip Unitt, 3411 Felton Street, San Diego, CA 92104. For matter of style consult the Suggestions to Contributors to Western Birds (8 pages available at no cost from the editor) and the Council of Biology Editors Style Manual (available for $24 from the Council of Biology Editors, Inc., 9650 Rockville Pike, Bethesda, MD 20814. Reprints can be ordered at author’s expense from the Editor when proof is returned or earlier. Good photographs of rare and unusual birds, unaccompanied by an article but with caption including species, date, locality and other pertinent information, are wanted for publication in Western Birds. Submit photos and captions to Photo Editor. Vol. 18, No. 4, 1987 WESTERN BIRDS Quarterly Journal of Western Field Ornithologists President: Tim Manolis, 808 El Endno Way, Sacramento, CA 95864 Vice-President: Narca A. Moore-Craig, F.O. Box 254, Lakeview, CA 92353 T teas urer /Membersh ip Secretary: Howard L. Cogswell, 1548 East Avenue, Hayward, CA 94541 Recording Secretary: Jean-Marie Spoeiman, 4629 Diaz Drive, Fremont, CA 94536 Circulation Manager : Jerry R. Oldenettd, 4368 37lh Street, San Diego, CA 92105 Directors: Peter Gent, Virginia P. Johnson, John S. Luther, Guy McCaskie, Timothy Manolis, Robert McKeman, Narca Moore-Craig, Joseph Medan, Janet Wlasman Editor: Philip Unrtt, 3411 Felton Street, San Diego, CA 92104 Associate Editors: Cameron Barrows, Tim Manolis, Narca A. Moore-Craig, Thomas W. Keeney Layout Artist: Virginia P. Johnson Photo Editor: Bruce Webb, 5657 Cazadero, Sacramento, CA 95822 Review Editor: Richard E, Webster, P.O. Box 6318, San Diego, CA 92106 Secretory, California Bird Records Committee: Don Roberson, 282 Grove Acre Ave., Pacific Grove, CA 93950 Editorial Board: Robert Andrews, Alan Baldridge, Andrew J. Berger, Laurence C. Barrford, David F. DeSante, Jon L. Dunn, Richard Erickson, Kimball L. Garrett, Joseph R. Jehl, Jr., Ned K. Johnson, Virginia P. Johnson, Brina Kassel, Stephen A. Laymon, Paul Lehman, John S. Luther, Guy McCaskie, Joseph Moiian, Harry B. Nehfe, Den- nis R. Paulson, Stephen M. Russell, Oliver K. Scott, Ela Sorensen, Richard W. Stallcup, Charles Trost, Terence R. Wahl, Roland H. 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Published April 29, 1988 ISSN 0045-3897 WESTERN BIRDS ADVERTISING RATES AND SPECIFICATIONS Full page 4 x (PA inches $60 per issue $200 per year Half Page 4x3% inches $40 per issue $130 per year Quarter Page 4 x V %, inches $30 per issue $110 per year Offset printing, one column per page, 4 inches wide. Glossy, black and white photos are ac- ceptable; half-tone screen size: 133 Bne. Photo-ready copy is requested, ff this is not posstrfe, extra charges for typesetting will be made as follows: $15 full page, $10 half page, $5 quarter page. Send copy with remittance to the Treasurer. Make checks payable to Western Field Ornithologists. A 15% commission is allowed for agencies. WESTERN BIRDS Volume 18. Number 4. 1987 THE BIRDS OF SAN ELIJO LAGOON, SAN DIEGO COUNTY, CALIFORNIA DAVID B. KING JR., A-022, Scripps Institution of Oceanography, La Jolla, Califor- nia 92093 MONA BAUMGARTEL and JOHN DE BEER, 1034 Bermuda Drive, Edwardsville, Illinois 62025 TERRY MEYER, Department of Biochemistry, University of Arizona, Tucson, Arizona 85721 A group of volunteers conducted monthly bird surveys at San Elijo Lagoon, San Diego County, California, over the ten-year period from November 1973 to October 1983. This paper summarizes the data gathered on these surveys and includes noncount records from before, during, and after the survey period to give a comprehensive picture of the lagoon’s avi- fauna through April 1987. The large number of surveys (120) on a regular basis makes possible a quantitative assessment of each species’ status. DESCRIPTION AND HISTORY OF THE SURVEY AREA San Elijo Lagoon, one of eight coastal lagoons in northern San Diego County, is located at 33°00' N, 117°20' W, between the communities of Solana Beach to the south and Cardiff-by-the-Sea to the north, about 35 km north of the city of San Diego. The lagoon is shaped roughly like an hourglass, being between 0.3 and 1 km wide north-south and about 2 km long from the coast inland (east- west). State Road 21 and a railroad cross the lagoon near the beach, and the Interstate 5 freeway crosses in the center; all three run north -south. The west basin (west of Interstate 5) has large areas of tidal mudflats, deep meandering channels, and emergent salt-marsh vegetation. The east basin is less saline and is filled largely with cattails ( Typha sp.), one of the largest cattail stands in San Diego County. Bordering the lagoon on the north and south are alluvial slopes of unconsolidated material, covered mostly with scrub. In low areas where sand and silt have been deposited recently, a few dense stands of willows ( Salix spp.) have grown up. A large stand of acacia, eucalyp- tus, and other nonnative trees occurs on the upper slope on the south side of the lagoon, just west of the freeway; a few scattered eucalyptus trees grow Western Birds 18: 177-208, 1987 177 BIRDS OF SAN ELIJO LAGOON elsewhere on the upper slopes. Eroded sandstone cliffs rise above most of the alluvial slopes. Rather flat mesas extend back from the tops of the cliffs at elevations of 20 to 60 m. The survey area (Figure 1) includes the lagoon and the surrounding upland slopes but not the adjacent beach and ocean (nothing west of State Road 21) nor the mesa tops to the north and south. The lagoon receives water intermittently from both the east and west. Two freshwater creeks feed the eastern end of the lagoon. At the beach, the tide flows into the lagoon only about half the time, when the mouth is not blocked by a sand berm. While the mouth is open, it tends to be closed gradually by waves, which wash sand into the inlet. The mouth remains closed until the lagoon water level rises (from freshwater runoff) high enough to overtop and wash out the berm. Then the lagoon drains rapidly and becomes tidal again. Typically, this cycle occurs a few times during the year, more frequently during the winter rainy season. Several important man-made changes have altered San Elijo Lagoon. A railroad was first built across the lagoon in 1887, reducing water circulation. The coast road was built in 1932, the freeway in the 1960s. Between 1934 and 1973, sewage from several sources was discharged into the lagoon. Be- tween 1937 and 1971, organized duck hunting took place, and several dikes and berms were constructed, many of which still remain. Before and during the study period, the adjacent mesas were slowly con- verted from chaparral to housing tracts. Also, a section of the northeast alluvial slope was converted from chaparral to an agricultural field. In 1987, con- struction began on a community college on another portion of the northeast slope. These developments have led to an increase in human activity (jog- ging, bird watching, motorcycling, walking of dogs, etc.) at the lagoon. Ur- banization considerably increased the sedimentation rate into the lagoon (Barry et al. 1976), most noticeably in the northwest and southeast areas, where formerly wet areas are now sandy and being invaded by willows. Because of this, during the winter of 1981-1982 the San Diego County Department of Public Works carried out a scheme designed by the California Department of Fish and Game, clearing and dredging some of the east basin and creating a permanent water pool with two sandy islands to provide nesting habitat for Least Terns. METHODS Because of several development proposals, Allen and Karin Altman or- ganized in November 1973 a group of volunteers to survey the lagoon’s birdlife monthly. Subsequent count leaders were Bill Lenarz, then Mona Baumgartel and John DeBeer. Counts were conducted usually on the first Sunday of each month by 8 to 15 people. Table 1 lists the count dates. The lagoon was divided into five areas, and count paths were established in each area (Figure 2) . Participants assembled between 0730 and 0800 and divided into four groups. One group covered both the NE and NW areas (NE first) ; the other three groups each took one of the other three areas (W, SW, and SE). Each group consisted of two or more participants, at least one of whom was familiar with the local birds and the count path. 178 SAN ELIJO LAGOON BIRDS OF SAN ELIJO LAGOON ui -•-O 179 Figure 1. Vegetation of San Elijo Lagoon. The survey area is inside the dotted line. A, acacia and eucalyptus trees; B, brush (sage scrub and chaparral); C, cattail marsh; D, dry open sandy areas; F, agriculture, mostly vegetable farms; G, dry grass and pasture; M, wet grass meadow; O, open shallow water or mudflat; R, residential area; S, Salicornia, flooded during high water; T, oak grove; W, willow thicket. Unlabeled white areas are permanent water. Table 1 Dates of Monthly San Elijo Lagoon Surveys BIRDS OF SAN ELIJO LAGOON u CD Q > o 2 o O a v cO CO 3 < 3 "3 c 3 "3 (0 2 a < — icolo^o vo coavr^coov^tcvioor'^vn oo cOvOi-^vOlO^Oi— ir^vo vo vOlO«— iCTNOOr^v^i— -o 181 Figure 2. The five survey areas at San Elijo Lagoon. Heavy dots, survey area boundaries; light dots, trails. BIRDS OF SAN ELIJO LAGOON Table 2 Area Surveyed, Time Spent, and Distance Traveled in Dif- ferent Habitats during Each Monthly Survey 8 Habitat Area (ha) Time (h) Distance (km) Woodland (acacia, eucalyptus, and willow) 20 2.5 1 Brush (sage scrub and chaparral) 90 7.0 7 Cattail marsh 180 3.0 2 Open water, mudflat, sand, wet grass, and Salicornia 60 10.5 8 Dry grass and pasture 20 1.0 1 Total 370 24.0 19 "Total times and distances are about 1.5 times the amount actually spent and traveled since frequently more than one type of habitat was being surveyed at a time. Groups recorded all identified birds plus date, area, weather, water level, and observers on a field card. Table 2 shows the amount of time and the distances traveled in each type of habitat. Leaders had some flexibility in the amount of time spent at different locations, and groups frequently made a special effort to find birds known to be in their areas in low numbers. Never- theless, each group covered its entire path and returned by noon for a compilation. To produce this paper, we entered the count totals plus the data for each area into a computer and cross-checked them to eliminate errors. We then compared our data for each species with the information in Garrett and Dunn (1981) and Unitt (1984) and with our own knowledge of local bird distribu- tion. We deleted or put into unidentified groups (e, g., Empidonax sp.), as appropriate, isolated unseasonal sightings and sightings of rare birds that were not verified independently. Two sightings of a Sandwich Tern ( Sterna sand- uicensis), 16 May 1982 (TM) and 24 Apr 1987 (SW), were deleted by the editor because they have not been evaluated by the California Bird Records Committtee. The number of changes was small; we changed fewer than 100 data points out of a total of over 51,000. Systematic variations from pub- lished information were rare and usually minor (e. g., Heermann’s Gull). The data we present are based primarily on the 120 monthly surveys; all statistics were computed from the survey data only. For rare species, however, we attempted to compile all available records. We also cite noncount records for more common species if they are unseasonal or represent exceptionally high numbers for the lagoon. Noncount data from before 1960 are limited mostly to a few specimen records. 182 BIRDS OF SAN ELIJO LAGOON Breeding activity was not systematically sought or recorded on most surveys, so the breeding status of many species is not well known. To remedy this partially, we made a special effort during the spring and summer of 1982 and 1983 to note evidence of breeding on both count and noncount days. The original data sheets, edited survey data on 5.25-inch floppy disks (ASCII files readable on a personal computer with an MS DOS operating system) , computer printouts, and relevant reports have been archived in the library of the San Diego Natural History Museum under the title “San Elijo Lagoon Monthly Bird Survey.” DATA INTERPRETATION For a few conspicuous species (e. g., Great Blue Heron), the number re- corded on each count was probably close to the number actually present in the survey area. Most species, however, undoubtedly were systematically undercounted, a major unresolved problem with bird censuses (see Ralph and Scott 1981). The amount of undercounting varied not only between species but also with season, weather, and observer skill (see Dawson 1981a). A number of species were more vocal or conspicuous during the breeding season (e. g., Rufous-sided Towhee). Others (e. g., Blue-winged Teal) were in more easily identifiable plumage at certain times of the year. The weather during the counts was generally benign; however, occasional bad weather probably reduced numbers found (see Robbins 1981). Variability in the skills of individual observers had an unquantifiable, but surely major, effect on the number of birds recorded (see Faanes and Bystrak 1981). In the species ac- counts, the numbers given are the numbers recorded except for the few dele- tions described above. We made no other attempt to calibrate the data to account for these or other effects. However, most of the variability from year to year in the number of birds recorded appeared to be due to true variability in the number of birds rather than to various forms of observer error just discussed. For instance, there was considerably less variation in territorial species than in gregarious species. Typical values of the coefficient of variation (the standard deviation divided by the average) ranged from around 0.5 for territorial birds (e. g., Northern Mockingbird) to 1.0 or higher for some gregarious birds (e. g., ducks). This variation, due to many factors, was large but is expected in biological data (see Cushing 1962). For virtually every species, the distribution of numbers counted in any par- ticular month was positively skewed. That is, there were a few values much higher than the average without corresponding values much lower than the average. (The data followed a Rayleigh rather than a Gaussian distribution.) This tendency, more evident in flocking than in territorial species, is an ex- ample of temporal patchiness, a common biological phenomenon (see Dawson 1981b). Because of this skewing, a few years’ of data would not have given a reliable picture of the distribution of most species. Over 10 years, however, the fluctuations averaged out so that the plots of average numbers by month curved smoothly (for example, see Table 3). In the species accounts, we give two measures of the central tendency, the average and the median. Someone interested in the long-term use of the 183 Table 3 Example of the Data: Numbers of Pied-billed Grebes Seen on Each of the Monthly Counts BIRDS OF SAN ELIJO LAGOON u Q o ^ CO ^ o X r — t-- x x on vo > o Z c-' X LO 00 'mQ ^ lo lo r- vo CM r-H T—i vO u o X OJ X ON >— ' X X X X X f“H i— i H CM a CD co CM ^ ' X CM t-* O X CXI t— 1 r- 1 ^ CM O) 3 < X X o CM ON o CO X X 3 "3 CM CO CO CM ON c 3 ^oxxxcMXor"C> X lO <0 2 r-~ cm <— ' 0 -— icocolo lo co a < ^XOOXX'vtCM^CM flj 2 X JD QJ LU X X X CM O' c "3 X on x X X X X X X X X ON o i — ^ CM X t-' C-» r- r-~ X X X X ON ON ON ON ON O' ON Ov ON ON O' H t-H H r-H H f-H H t-H 184 Average BIRDS OF SAN ELIJO LAGOON lagoon by a particular species might find the average value most useful, while someone visiting the lagoon for a day would probably be more interested in a median value. These two numbers also allow qualitative inferences about the variance and skewness. Because the data are skewed positively, the average values are greater than median values. If the average and median are relatively close, the variance and skewness are smaller than if the average is much greater than the median. DISTRIBUTION OF SPECIES Of the 281 species recorded at the lagoon, 46 are rare visitors not record- ed on any monthly surveys. Another 70 species were recorded on <5% of the counts. Together, these 116 rare species constitute 41% of the species list for the lagoon. At the other extreme, 35 species were seen on 95% or more of the counts, including 17 species that were found on all counts. The average numbers of water bird species, land bird species, and total species recorded per month (about 90) are shown in Figure 3. The highest number of species occurred during spring migration, largely a result of late- departing wintering birds overlapping with early-arriving summering birds, with water birds peaking in April and land birds peaking in May. The maximum number of species recorded on a count was 114 on 7 April 1974, and the minimum number was 68 on 12 July 1981, Figure 4 shows the average number of birds of all species recorded per month. The average number of land birds (asterisks) remained fairly constant Figure 3. Average number of species Figure 4. Average number of individual recorded at San Elijo Lagoon by month birds recorded at San Elijo Lagoon by (solid line). month. Solid line, number of total species; asterisks, number of land bird species (Falconiformes, Galliformes, Columbiformes, and all subsequent groups in the A. O. U. (1983) check- list) . Thus the distance between the asterisks and solid line represents the number of water bird species. 185 BIRDS OF SAN ELIJO LAGOON throughout the year, while the average number of water birds decreased greatly from winter to summer. While the numbers of species and of individual birds reported from San Elijo Lagoon are impressive, the area is not a “vagrant trap ” San Elijo Lagoon is important to birds not so much because of the high number of species but because so many species use the area regularly. This is demonstrated by the large number of species, 131 (47% of total), that has been recorded on at least half the counts during at least one season of the year, CHANGES IN THE LAGOON AVIFAUNA One purpose of the 10-year survey was to determine whether and how the avifauna of the lagoon was changing. Figures 5 and 6 show the average number of species and birds, respectively, recorded at the lagoon on each monthly count by year. Clearly, the gross distribution of birds at the lagoon did not change significantly during the survey. We then analyzed each species to determine which had increased or decreased during the count period. For each species, we plotted the total number seen per year versus year and used a two-tailed Student’s t test to determine if a least mean square line through the plot had a significant nonzero slope. We combined the results of this (objective but simplistic) test with our understanding of each species’ status (a subjective but more complex test) to determine which species were increasing or decreasing. Numbers of only 25 species changed significantly during the survey. Twelve species increased: Brown Pelican, Double-crested Cormorant, Least Bittern, Great Egret, Mallard, Gadwall, American Wigeon, Red-shouldered Hawk, Figure 5. Average number of species recorded at San Elijo Lagoon in each month by year. — i — i — i — i — i — i — i — i — i — r 74 75 76 77 78 79 60 61 62 83 Figure 6. Average number of individual birds recorded at San Elijo Lagoon in each month by year. Solid line, total species; asterisks, land bird species (see Figures 3 and 4). The year “74” corresponds to the twelve counts from November 1973 to October 1974, etc. 186 BIRDS OF SAN ELIJO LAGOON Anna’s Hummingbird, Cassin’s Kingbird, Black-tailed Gnatcatcher, and Hut- ton’s Vireo. Thirteen decreased: Snow Goose, Canvasback, California Quail, Common Snipe, Greater Roadrunner, Horned Lark, Violet-green Swallow, Rough-winged Swallow, Cactus Wren, California Thrasher, Wilson’s Warbler, Song Sparrow, and House Sparrow. More species than this probably changed their status at the lagoon, but these changes were masked by the variability in the data. Although the reasons for many of these changes are unclear, a few associa- tions suggest themselves. Five of the increasing species are herons and ducks whose primary habitats include shallow water or shorelines, whereas the one decreasing duck uses deep water, correlating with the lagoon’s siltation. Very preliminary results of study by Michael Soule of the fauna of 37 canyons in San Diego isolated by housing subdivisions, reported in an interview (Stewart 1987) , indicate that small, long-isolated canyons have lost the greatest number of chaparral-dependent birds. The California Quail, Greater Roadrunner, and California Thrasher were found to be the first species to disappear from these isolated canyons. Our results agree with these findings and show that the birds of San Elijo Lagoon are being affected by the adjacent suburban development. We examined in detail changes in numbers of water birds in the east basin during the last two years of the survey because of the dredging and island construction done in 1981. Numbers of no species noticeably decreased in the east basin from 1981 to 1983. Pied-billed Grebes, Double-crested Cor- morants, and Ruddy Ducks increased throughout the year, evidently as a result of the increase in the extent of deep water. Spotted Sandpipers increased during the summer, but this reflects their southward range expansion, not an effect of island creation. Least Terns increased in 1982, the first year they nested on the island, but decreased subsequently (see further information below under Status of Endangered Species). STATUS OF ENDANGERED SPECIES Of special interest are the population levels of endangered species. Eight species on California and/or Federal Threatened, Rare, or Endangered Species lists have been recorded at the lagoon; another 28 species are on the California “Species of Special Concern” list (Remsen 1979). Six of these 36 breed regularly at the lagoon: Least Bittern, Light-footed Clapper Rail, Snowy Plover, California Least Tern, California Black-tailed Gnatcatcher, and Belding’s Savannah Sparrow. The Least Bittern was observed regularly in summer in small numbers dur- ing the last six years of the count. It is unclear whether the paucity of records in the first four years (one sighting) was because the birds were absent or merely overlooked. Count participants made a greater attempt to locate this species in the latter years of the count when it came to be expected. Most sightings were in dense cattails east of the freeway. In 1981, the Clapper Rail was discovered breeding at San Elijo Lagoon in an uncharacteristic habitat, the cattail marsh east of the freeway (R. L. Zem- bal in Unitt 1984). Clapper Rails were found that year in similar habitats at a number of other locations in southern California. It is unclear whether the rail was overlooked at these locations in the past, whether it had expanded 187 BIRDS OF SAN ELIJO LAGOON (temporarily?) into a new habitat, or whether it was being driven into marginal habitat by deterioration of its preferred marshes. During 1984 and 1985 the populations of Clapper Rails crashed throughout southern California (McCaskie 1986) . The fate of the San Elijo birds is not known for certain because no recent extensive searches have been made for them; however, no observers have reported them since 1983. Snowy Plovers have nested at San Elijo Lagoon at several locations east of the freeway with varying success. Some of these nesting attempts were reported by Page and Stenzel (1981). Nesting success has been low primari- ly because of fluctuations in water level. In 1982, one pair bred successfully on the newly created islands in the east basin, and 10 to 15 pairs bred there in 1983. Their subsequent numbers and success there are unknown. During the count period, the Least Tern has nested regularly at San Elijo Lagoon. Between 1974 and 1981, 2 to 20 pairs nested at various sandy spots around the lagoon without establishing a permanent colony site . Nests were usually in insecure locations and were subject to destruction by high water, predators, and motorcyclists. During the summer of 1982, approximately 35 pairs nested on the newly created islands east of the freeway. In subsequent years, however, the colony decreased, to about 25 pairs in 1983, 17-22 in 1984, 13 in 1985, 9 in 1986, and 13 in 1987. Their success has remained low (at most 10 fledglings in 1984, none in 1985, two in 1986, and four in 1987) , as a result of continued predation (E. Copper pers. comm.). The California Black-tailed Gnatcatcher is easily overlooked and confused with the Blue-gray Gnatcatcher by observers unfamiliar with its call. Therefore, its status at the lagoon is not entirely clear. This gnatcatcher was seldom record- ed at the lagoon during the summer until 1980, after which a few were noted regularly. One nest with four young was found in the southeast area in June 1980. Therefore, it appears that in 1980 the Black-tailed Gnatcatcher col- onized the lagoon or at least increased. This is a hopeful sign but does not negate the serious regional decline of this species shown by Atwood (1980). The Belding’s Savannah Sparrow is easy to recognize in the field and was recorded separately from migrant Savannah Sparrows. It is a common resi- dent, recorded on all counts, but the data show a decline in the number of birds (6% per year) over the years of the count. This rate translates into about half as many birds at the end of the survey as at the beginning. While this decline is not pronounced enough to be unequivocal (because of scatter in the data), there is considerable cause for concern. SUMMARY AND RECOMMENDATIONS This study found that San Elijo Lagoon is an important location for birds for three reasons. First, it is a breeding locality for six rare or endangered species. Second, it is used by a large number of birds, most notably wintering water birds. Third, it is an area that is regularly used by a large number of species. The state and county have recognized the importance of San Elijo Lagoon by declaring it an ecological preserve. However, urbanization con- tinues to degrade the habitat. Ideally, a buffer zone of open space should separate the lagoon from the surrounding development, and corridors of undeveloped, natural habitat should link the lagoon to other undeveloped 188 BIRDS OF SAN ELIJO LAGOON areas. Residential and industrial developments should be planned to minimize erosion and the subsequent siltation of the lagoon basins. This study has shown serious cause for concern at San Elijo Lagoon for three endangered species: the Clapper Rail, the Least Tern, and the Belding’s Savannah Sparrow. As these birds are also doing poorly throughout their southern California range, clearly much more effort must be directed toward their preservation. The nesting islands in the east basin do not appear to have been of lasting benefit to the Least Tern, possibly because predators have learned that the colony is an easy food source. Furthermore, creating sandy islands by removing cat- tails and Salicornia marsh entails a loss of habitat for Least Bittern, Clapper Rail, and Belding’s Savannah Sparrow. ACKNOWLEDGMENTS The data presented in this paper were collected entirely by volunteers, and this study would not have been possible without the effort of these many people who participated in the counts with no reward other than the enjoyment of birding. These people, plus the others who contributed noncount information and records, include Don Adams, Doug Alden (DA), Paula Aleiss, Allen and Karin Altman, Barbara Anderson, David Au, Kim Banks, Tom Barnes, Mona Baumgartel (MB), Paul Boch, Clement Bordier, Janice Brehm, Paul Brown, John Butler (JB), John Callender, Bill Chriswell, Cathy Cibit Cook, Elizabeth and Robert Copper (RC), Al and Betty Davis, John DeBeer (JDeB), Alice DeBolt, Susan DeVincent, Dale and Linda Delaney, Craig Denson (CD), David Dingman, Marilyn Dudley, Pat Duffy, Jon Dunn (JD), Claude Edwards (CE), Jim English, Richard A. Erickson (RAE), Mike Evans, William T. Everett (WTE), Larry and Donna Fisher, Rosie Fletcher, Bob Florand (BF), Larry and Meredith Ford, Alice Fries (AF), Ken Goldman, Jim Greaves, David Gregory, Charlotte Grumbay, Bob and Martha Hall, Marj Halterman, Paul Harris, Don and Marjorie Hastings (D & MH), Bob Hawkins, Jean and Dick Hawkins, Merideth Helland, Diana Herron, Betty Higgins, Glenda Hightower, Roger Higson, Ken Hill, Liz Hutson, Harlow Hyde, Bonnie Jackson, Warren Jacoby (WJ), Art Jebens, Bernice Johnson, Carrie Johnson, Pat Jones, Paul Jorgenson (PJ), Mary Kelley, Nancy and David Kelly, Doug Kicak, David (DK) and Joyce King (JK), Rosemary and Chuck Kimball, Marge Knothe, Steve Kornfeld (SK), Jerry Langham (JL), John Larson, Bill, Alice, and Jim Lenarz, Jayne Lesley, Susan Levenson, Theresa Lisak, Ilene Littlefield, Eric Lodge, Cliff Lyons, Allec MacCall, Dave MacKensie, Paul Mandel, Radames Martinez, Pat Masters, Peggy McBride (PMcB), Guy McCaskie (GMcC), Jetty McCubbin, Jane McMillan, Jane McNeil, Susan Mer- rifield, Liz Meyer, Terry Meyer (TM), Bob and Sonia Meyerhof, Barbara Moore (BM), Hugh Moore, Joanne Moore, Mary Jane Moore, Betty Morin, Norman Muller, Marge Naughton, March Nelson, Jeff Nystuen, Pat O’Mera, Jerry Oldenettel (JO), Mike Or- field, Chris Parrish, Robert Patton (RP), Terry Polanski, Mary Pomeroy, Mark Prager, Barbara Pratt, Ray Quigley (RQ), Denyse Racine, Sylvia Raney (SR), Alex Richter, Maggie Riegelhuth, Martha Jo Rogers, Elwood and Pearl Root, Steve Rossi, Arthur Saddington (AS), Andy Salmi, Jim and Donna Sams (J & DS), Luis Santaella (LS), Joan Schmitt, Tom Scott (TS), Peter and Carolyn Schroeder, David Seay, Ann Sen- sibaugh, Barbara Seymour, Juanita Smith, Jim Snowden, Tom and Rene Steller, Irene Streeter, Steve Summers (SS), MiaTegner, Wayne Thompson, Margaret Thornburgh, Elizabeth Uguride, Philip Unitt (PU), Howie Usher, Stan Valentin, Stan Walens (SW), Ron Warchek, Ron Warner (RWa), Richard Webster (RW), Margorie Weldon, Mary Jane Wheeler, Abby White (AW), Carrie Willingham, Carrie Willison, Cora Wilson, Larry Wing, Susan Wise, Jane Witman, and Linda Zarins. Partial funding for data reduc- tion was provided by Marine Ecological Consultants of Solana Beach and the San Diego County Fish and Wildlife Advisory Committee. Some or all of the data and manuscript 189 BIRDS OF SAN ELIJO LAGOON were reviewed by Alice Fries, Guy McCaskie, and Philip Unitt. To all the above people and organizations we are deeply appreciative. LITERATURE CITED American Ornithologists’ Union. 1983. Check-list of North American Birds. 6th Ed. Am. Ornithol. Union., Lawrence, KS. Atwood, J. L. 1980. The United States distribution of the California Black-tailed Gnat- catcher. W. Birds 11:65-78. Barry, 100 per count, very common = average of 30-100 per count, common = average of 10-30 per count, fairly common = average of 3- 10 per count, uncommon — average of 1-3 per count, occasional = average of < 1 per count, rare = found on 5 or fewer counts, exceptional - very few records for coastal southern California. If a species was recorded on five or fewer counts, all known occurrences (both count and non- count) are usually listed. Numbers in parentheses following dates refer to the number of birds seen on that date. If only one bird was seen, the number and parentheses are omitted. If a species was seen on more than five counts, the average and median in a given season are listed, separated by a slash. For example, “Ave 11/7 Sep- Feb” should be read as an average of 11 and a median of 7 birds seen on the monthly surveys from September to February. If the median is zero, it and the slash are omitted. No noncount data were used to compute averages or medians, which are rounded to two significant figures. Frequently, not all months are mentioned; statistics for unmen- tioned months are intermediate between those for mentioned months. Bear in mind that the surveys took place near the beginning of the month (average date the 6th; see Table 1) . Also included are any early, late, or unseasonal records, the maximum number of individuals reported for the lagoon, and the species’ breeding status. These may be count or noncount data. “Common breeder” indicates that several pairs bred each year; “yearly breeder” indicates that one or a few pairs bred each year. In addition to the 280 main species on this list, several supplementary entries, enclosed in brackets, are included for any of the following reasons: (1) More than 5% of the individual birds of a group were not identified to species (e. g. , dowitcher sp .) . In these cases the data for the group as a whole are discussed before the individual species. (2) The species has been reported at the lagoon, we believe reliably, but without a specific date. (3) The species has occurred very near the lagoon and can reasonably be expected at the 191 BIRDS OF SAN ELIJO LAGOON lagoon. Not included in this group are coastal or pelagic species which may be seen from shore . (4) All records are presumed or known to pertain to escaped captives or hybrids. We rarely kept records of exotic species. Dated records cite the first published source unless a later source discusses the record more fully. AB refers to American Birds, AFN to Audubon Field Notes. Specimen and egg records are indicated by museum and number: SD refers to the San Diego Natural History Museum, SB to the San Bernardino County Museum, and WF to the Western Foundation for Vertebrate Zoology. Unpublished noncount records are indicated by the observer’s initials (see acknowledgments) ; records without sources are from the monthly surveys. Some uncited records from the monthly surveys have been published previously by Unitt (1984). Red-throated Loon Gavia stellata. 0, 0. Rare; 3 Dec 1972 (SS). Pacific Loon Gavia pacifica. 1, 1. Rare; one in breeding plumage 27 Apr-4 May 1980 (TM). Pied-billed Grebe Podilymbus podiceps. 1041, 115. Common in fall and winter, fairly common in spring and summer. Ave 11/7 Sep-Feb, falling to 5.7/4 Mar-Jul. Max 67 on 4 Nov 1973, Yearly breeder. Horned Grebe Podiceps auritus. 10, 5. Rare winter visitor; 10 Oct 1976, 13 Oct 1974, 5-11 Jan 1975 (6) (SS), 8 Jan 1978, 9 Mar 1975. Eared Grebe Podiceps nigricollis. 1669, 96. Common in winter, uncommon in sum- mer. Ave 22/9 Oct- Apr, falling to 1.3 Jun-Sep. Max 250 on 6 Feb 1983. Bred in 1968 (AFN 22:647, 1968). Western Grebe Aechmophorus occidentalis. 205, 47. Fairly common in winter, rare in summer. Ave 3.2/2 Nov- Apr, Jun-Sep records 7 Mar-1 Aug 1976 and 13 Jul 1980. Max 22 on 5 Dec 1976. Clark’s Grebe Aechmophorus clarkii. 1, 1. Not distinguished from Western Grebe dur- ing most of the count period. Identified on 8 Nov 1986 (RP) and 9 Jan 1983. American White Pelican Pelecanus erythrorhynchos. 4, 2. Rare from fall through spring; 2 Nov 1985 (BF), 7 Nov 1971 (AF), 2-5 Dec 1973 (SS), 16 Jan 1982 (BM), 17 Mar 1970 (PMcB) , 11 Apr 1976 (3), 29 May 1970 (AF). Brown Pelican Pelecanus occidentalis. 335, 18. Increasing; 1980-1983, very com- mon in fall and uncommon in winter. Ave. 1980-1983 61/40 Oct, 1.8 Nov-Feb, none Apr-Jun. Only one record, 11 Jul 1976 (2), 1973-1979. Max 160 on 4 Oct 1981. Double-crested Cormorant Phalacrocorax auritus. 2956, 99. Very common in winter, fairly common in summer; increasing. Ave 34/32 Oct-Apr, falling to 4.6/1 Jun-Jul. Max 150 on 1 Feb 1981. Magnificent Frigatebird Fregata magnificens. 0, 0. Rare summer visitor; 26 Jun 1976 (WTE), 6 Jul 1985 (JO). American Bittern Botaurus lentiginosus. 73, 45. Occasional, mainly in winter. Ave 0.9/1 Nov-May, 0.2 Jun-Oct. Max 4 on 4 Nov 1973, 4 Mar 1979, and 1 Apr 1979. Least Bittern Ixobrychus exilis. 27, 17. Uncommon in summer, rare in winter. Only one record, 7 Apr 1974, in first four years. Ave 1979-1983 1.0/1 Jun-Oct. One winter (Nov-Mar) record, 7-17 Jan 1979 (AB 33:312, 1979). Max 3 on 1 Jun 1980 and 7 Jun 1981. Bred in 1980 (TM) and 1982 (RW) (see also under Status of Endangered Species) . Great Blue Heron Ardea herodias. 1086, 120. Fairly common nonbreeding resident. Ave 9.8/8 Jun-Mar, 5.4/5 Apr-May. Max 31 on 7 Mar 1982. Great Egret Casmerodius albus. 1147, 90. Common in winter, uncommon in sum- mer; increasing. Ave 15/9 Oct-Apr, falling to 2.3/1 May-Sep. Max 98 on 4 Oct 1981. 192 BIRDS OF SAN ELIJO LAGOON Snowy Egret Egretta thula, 2393, 107. Very common in fall, common in winter, fairly common in summer. Ave 50/26 Sep-Oct, 18/14 Nov-Apr, 5.7/4 May-Jul. Max 280 on 4 Oct 1981. Little Blue Heron Egretta caerulea. 0, 0. Rare; single adults on 20 May 1978 (TM) and 19 Jun 1977 (AB 31:1188, 1977). Tricolored Heron Egretta tricolor. 2, 2. Rare; nine records 5 Oct-4 Mar; one 5 Jun 1977 (JDeB). Only three winter records since 1972: 16 Nov 1980 (TM), 3 Jan 1979 (MB), and 23 Feb-4 Mar 1979 (AB 33:312, 1979). Max 6 from 1 Nov to 23 Dec 1963 (McCaskie 1964). Reddish Egret Egretta rufescens. 0, 0. Rare; 29 Sep 1968 (AFN 23:107, 1969), 13 Dec 1969 (PMcB). The bird seen 11-18 Sep 1962, ascribed by Unitt (1984) to San Elijo Lagoon, was actually at Batiquitos Lagoon. 8 km north of San Elijo (AFN 17:67, 1963) . Cattle Egret Bubulcus ibis. 6, 4. Rare in fall and winter; 15 Oct 1986 (J & DS) , 3 Dec 1978 (2), 6 Dec 1981, 7 Dec 1980, 8 Jan 1978 (2). Green-backed Heron Butorides striatus. 207, 83. Uncommon resident. Ave 2.3/2 Jul- Nov, falling to 1.3/1 Jan -Jun. Max 9 on 3 Apr 1977. Bred once in “mid 1970s” (JB). Black-crowned Night-Heron Nycticorax nycticorax. 1267, 112. Common nonbreeding resident. Ave 11/8 throughout year. Max 200 on 11 Sep 1963 (GMcC). Yellow-crowned Night-Heron Nycticorax violaceus. 5, 5. Exceptional. One probable immature 1-11 Nov 1963 (McCaskie 1964); one aduli recorded intermittently 25 Oct 1981-21 Jun 1986 (Binford 1985, Morlan 1985. AB 40:1255, 1986), presumably the same bird found intermittently in a night-heron ror.ke'y at the Scripps Institution of Oceanography, La Jolla. White-faced Ibis Plegadis chihi. 474, 37. Fairly common in winter, uncommon in sum- mer; sporadic. Ave 5.9 Oct- Apr, 1.2 May-Sep. Max 60 on 2 Mar 1980, summer max 20 on 4 Aug 1974 and 3 Aug 1985 (DK). Wood Stork Mycteria americana. 1,1. Rare in summer; 25-26 May 1986 (AB 40:523, 1986), 30 Jul-3 Aug 1975 (AB 29:1030, 1975), 31 Jul-2 Aug 1964 (AFN 18:535, 1964) , 6-10 Aug 1963 (AFN 18:73, 1964), 29 Aug 1961 (18) (AFN 15:492, 1961). [Greater Flamingo Phoenicopterus ruber. 0, 0. Escapees have occurred on several oc- casions. Max 3 on 13 Dec 1969 (PMcB).] [Fulvous Whistling-Duck Dendrocygna bicolor. 0, 0. Probable escapee recorded on 10 Sep 1972 (AB 27:120, 1973).] Tundra Swan Cygnus columbianus. 0, 0. Rare; 19 Nov- 11 Dec 1971 (AB 26:120, 1972), 6 Dec 1963 (2) (AFN 18:386, 1964). [Bean Goose Anser fabalis. 1, 1. Escapee; 3 Oct 1982.) Greater White-fronted Goose Anser albifrons. 3, 2. Rare; 4 Oct-1 Nov 1981 (2), 25-26 Oct 1986 (LS), 2 Nov 1969 (GMcC), 13 Dec 1969 (PMcB), 4 Dec 1970 (AF), 27 Dec 1986 (SK), 17 Mar 1970 (PMcB), 15 Apr 1987 (J & DS). Snow Goose Chen caerulescens. 24, 11. Uncommon winter visitor; decreasing. Only one seen 1977-1983, 23 Nov-7 Dec 1980. Ave 1974-1976 2.0/2 Dec-Feb, none Apr-Oct. Max 6 on 13 Dec 1969 (PMcB). Ross’ Goose Chen rossii. 0, 0. Rare; 18 Dec 1982-30 Jan 1983 (3) (LS, DK), 20 Dec 1986 (LS). Brant Branta bernicla. 65, 5. Rare in spring; 22 Feb 1984 (LS), 6 Mar 1983 (2), 13 Mar 1977 (60), 29 Mar-9 May 1981, 4 Apr 1982, and 27 Apr 1973 (SS). Canada Goose Branta canadensis. 77, 4. Rare in winter; about 10 records between 16 Nov and 13 Mar. Max 400 on 21 Jan 1987 (BM). 193 BIRDS OF SAN ELIJO LAGOON (Common Shelduck Tadorna tadorna. 1, 1. Escapees; 1 Jun-6 Jul 1975 (2) (TM).] Green-winged Teal Anas crecca. 11366, 89. Abundant in winter, occasional in sum- mer. Ave 220/200 Dec -Mar, falling to four records Jun-Jul and none in Aug. Max 640 on 6 Feb 1977, summer max 5 on 3 Jul 1983. One male A. c crecca 18-24 Mar 1973 (AB 27:662, 1973). Mallard Anas pfatyrhynchos. 7557, 119. Abundant in summer, very common in winter; increasing. Ave 110/90 Jun-Sep, falling to 32/25 Oct-Apr. Max 510 on 4 Sep 1983. Common breeder. Small numbers of feral ducks were resident at the lagoon but not counted on the surveys. Northern Pintail Anas acuta. 28768, 94. Abundant in winter, fairly common in sum- mer. Ave 470/230 Sep-Feb, highest 1100/670 Dec, falling to 4.1 May-Aug. Max 5300 on 8 Dec 1974. Blue-winged Teal Anas discors. 50, 25. Uncommon spring migrant, occasional other- wise. Ave 1.0 Mar- Jun, falling to 0.1 Aug -Jan. Max 8 4 - on 19 Oct 1985 (D & MH) . Cinnamon Teal Anas cyanoptera. 9576, 116. Abundant spring migrant, very com- mon otherwise. Ave 180/130 Feb -Apr, falling to 42/21 Jun -Jan. Max 920 on 16 Feb 1975. Bred in 1967 (chick SD 36283). Northern Shoveler Anas clypeata. 36389, 94 Abundant in winter, occasional in sum- mer. Ave 300/240 Oct-Nov, 600/480 Dec-Apr, 7.6/2 May, 0.6 Jun-Aug. Max 2000 on 2 Apr 1978, summer max 6 on 6 Jul 1979, Gadwall Anas strepera. 3401, 105. Very common in winter, fairly common in sum- mer; increasing. Ave 42/20 Nov-Apr, falling to 8.8/2 Jul-Oct. Max 180 on 9 Jan 1983. Bred in 1975, 1978 (AF), and 1980. Eurasian Wigeon Anas penelope. 6. 6. Occasional in winter since 1981. Ave 1981-1983 0.5 Nov-Mar. All records (7 Feb- 19 Apr 1981 (AB 35:863, 1981), 12 Oct- 13 Dec 1981 (AB 36:217, 1982), 24 Oct 1982-6 Feb 1983 (AB 37:223, 1983), 2 Oct 1983 (AB 38:246, 1984), and 29 Sep 1985 (AB 40:158, 1986)) may refer to the same male bird. American Wigeon Anas americana. 6274, 70. Abundant late fall to early winter, very common late winter to early spring, rare in summer; increasing. Ave 150/95 Nov- Jan, 39/24 Feb- Apr, Late spring to early fall records include 3 May -7 Jun 1981 (15), 4 May 1980, 4 Aug 1974, 27 Aug 1985 (RW), and four early Sep records (max 12). Max 460 on 6 Dec 1981. Canvasback Aythya valisineria. 147, 16. Decreasing; since 1979, a rare winter visitor. 85% of birds found the winter of 1973-1974; only two birds seen 1979-1983. Ave 1973-1975 49/19 Nov-Dee, 5/4 Jan-Apr. One summer (May-Sep) record, 3 Jul 1965 (AF). Max 59 on 4 Nov 1973. Redhead Aythya americana. 1310, 58. Common in winter and spring, occasional in late summer. Ave 15/4 Nov-Jun, falling to 0.6 Aug-Sep. Max 420 on 5 Dec 1976. Bred in 1965 (AF) . Ring-necked Duck Aythya co/laris, 0, 0. Rare; 26 Dec 1974-11 Jan 1975 (2) (SS). [Tufted Duck x Greater Scaup Aythya fuligula x marila. 0, 0. Exceptional; 20 Feb-22 Mar 1987 (SR).] Greater Scaup Aythya marila. 0, 0. Rare; 21 Dec 1986 (2) (LS), 26 Dec 1974 (SS). Lesser Scaup Aythya affinis. 1193, 51. Common winter visitor. Ave 23/9 Dec-Apr, falling to none May-Sep. Max 200 on 6 Jan 1980. Oldsquaw Clangula hyemalis. 0, 0. Rare; 4 Dec 1984 (BM). Surf Scoter Melanitta perspicillata , 5, 4. Rare in winter and spring; 17 Dec 1986 (RP), 1 Feb 1981, 13 Apr-4 May 1980, 6 May 1979 (2). Common to abundant in winter 194 BIRDS OF SAN ELIJO LAGOON in the surf seaward of the lagoon. Common Goldeneye Bucephala clangula. 0, 0. Rare. One female from “Cardiff,” 13 Jan 1958 (SD 30069), presumably was from San Elijo Lagoon. Bufflehead Bucephala albeola. 939, 60. Common winter visitor. Ave 18/15 Dec- Apr, falling to none Jul-Sep. Four May records; one June record, 1 Jun 1980, One October record, 10 Oct 1976. Max 58 on 6 Mar 1983. Hooded Merganser Lophodytes cucullatus. 0, 0. Rare; 21 Dec 1986 (LS). Common Merganser Mergus merganser. 0, 0. Rare; one specimen from “Solana Beach” 18 Dec 1932 (SD 16152). Red-breasted Merganser Mergus serrator. 181, 31. Fairly common in late winter, oc- casional at other times. Ave 3.6/2 Jan-Apr, 0.3 May-Nov. Max 20 on 1 Feb 1981. Ruddy Duck Oxyura jamaicensis. 11136, 113. Abundant in winter, common in sum- mer. Ave 160/80 Dec- Apr, falling to 23/12 Jun-Sep. Max 970 on 6 Apr 1975. Bred in 1964 (egg set WF 52570) and 1982. Turkey Vulture Cathartes aura. 8, 6. Occasional from fall through spring. Ave 0. 1 Oct- May, none in other months. Max 2 on 13 Mar 1977 and 2 Oct 1983. Osprey Pandion haliaetus. 9, 8. Occasional from fall through spring. Ave 0.1 Sep- Apr, none in other months. Max 2 on 2 Nov 1980. Black-shouldered Kite Elanus caeruleus. 199, 75. Uncommon in fall and winter, occa- sional in spring and summer. Ave 2.7/3 Sep-Jan, falling to 0.5 Mar-Jun. Max 7 on 4 Oct and 1 Nov 1981. Bred in 1982 (three young fledged) (TM). Bald Eagle Haliaeetus leucocephalus. 1,1. Rare; 8 Dec 1974. Northern Harrier Circus cyaneus. 65, 42. Uncommon in winter, rare in summer. Ave 1.4/1 Nov-Jan. Summer (May-Aug) records 5 Jun 1977 and 13 Jul 1980. Max 3 on six dates. Bred in 1920 (egg set WF 52470). [Accipiter spp. 134, 65. Includes 36% Sharp-shinned and 57% Cooper’s Hawks plus 7% not identified to species. All unidentified were found Sep-Mar.) Sharp-shinned Hawk Accipiter striatus. 48, 34. Occasional winter visitor, Ave 0.7 Nov- Apr, falling to none May-Aug. Max 4 on 7 Mar 1976. Cooper’s Hawk Accipiter cooperii. 77, 52. Uncommon in winter, occasional in sum- mer. Ave 1.5/1 Nov-Jan, falling to 0.2 Apr-Sep. Max 3 on five Dec and Jan dates. Red-shouldered Hawk Buteo lineatus. 84, 51. Uncommon in fall and winter, occa- sional in spring and summer; increasing. Ave 1.1/1 Oct-Jan, falling to 0.4 Mar-Jul. Max 5 on 10 Jan 1982. Red-tailed Hawk Buteo jamaicensis. 689, 120. Fairly common in winter, uncommon in summer. Ave 10/9 Dec-Feb, falling to 2.9/3 May-Sep. Max 19 on 5 Jan 1975. Yearly breeder near, but not at, lagoon. Ferruginous Hawjc Buteo regalis. 0, 0. Rare; fall 1986-7 Jan 1987 (RP, LS, SW). Rough-legged Hawk Buteo iagopus. 1, 1. Rare; 4 Dec 1977. Golden Eagle Aquila chrysaetos. 1, 1. Rare; 4 Oct 1981, 7 Apr 1979 (2) (DA). Dixon (1937) included San Elijo Lagoon within the territory of a pair that nested at Olivenhain, 1.5 miles northeast of the lagoon, until the 1950s (RQ, fide TS). Urbanization has eliminated this territory (Unitt 1984) . American Kestrel Falco sparuerius. 640, 118. Fairly common resident. Ave 6.9/6 Sep- Jan, 3.9/4 Mar-Jul. Max 16 on 2 Dec 1979. Probably breeds occasionally; bred in 1919 in “San Elijo Canyon” (egg set WF 55068), which may or may not be San Elijo Lagoon , 195 BIRDS OF SAN EL1JO LAGOON Merlin Faico columbarius. 1, 1. Rare in fall and winter; 11 Oct 1963 (GMcC), 12 Oct 1985 (CE), 18 Oct 1980 (TM), 22 Oct 1978 (TM), 18 Dec 1985 (BM), 9 Jan 1983, 20 Mar 1980 (CD). Peregrine Falcon Faico peregrinus. 2, 2. Rare; 3 Oct 1982, 5 May 1974. Prairie Falcon Faico mexicanus. 2, 2. Rare winter visitor; 7 Nov 1976, 5-11 Jan 1975 (SS). Ring-necked Pheasant Phasianus colchicus. 2, 2. Rare; 27 Sep-25 Oct 1981 (2) (TM), 10 Oct 1976, Mar 1985 (BM). [Common Peafowl Pavo cristatus. 0, 0. Feral birds have been seen on several occa- sions east of the freeway.] California Quail Callipepia californica. 12197, 120. Abundant resident, decreasing. Ave 100/88 throughout the year. Max 340 on 5 Jan 1975. Common breeder Black Rail Laterallus jamaicensis. 0, 0. Rare in winter; 28 Oct 1973 (AF), 11 Nov 1963 (AFN 18:73, 1964), 15 Nov 1969 (AF), 17 Jan 1964 (Unitt 1984), 21 Feb 1983 (AB 37:338, 1983). A specimen from “Encinitas" 8 Dec 1886 (SD 148) Unitt (1984) sug- gested was from either San Eli jo or Batiquitos lagoons. Clapper Rail Rallus longirostris. 27, 11. Uncommon resident from 1981 through at least 1983. The only records between 1947 (Wilbur 1974) and 1981 were in 1972 (3) (Wilbur etal. 1979) and on 21 Sep 1977 (RC). In Jun 1981, at least 10 birds were found east of the freeway (Unitt 1984). One to three birds were occasionally recorded through 1983, but none has been reported since then. Presumably bred 1981-1983 (PJ). (See also under Status of Endangered Species.) Virginia Rail Ralius limicola. 220, 71. Fairly common in winter, occasional in summer. Ave 3.3/2 Oct- Jan, falling to 0.4 Jun-Jul. Max 17 on 4 Nov 1973. Yearly breeder. Sora Porzana Carolina, 708, 90. Fairly common in fall and winter, common in spring, rare in summer. Ave 5.8/6 Sep-Jan, 13/11 Mar-Apr. The only Jun-Jul records are 6 Jun 1982, 8 Jul 1979, and 11 Jul 1976. Max 38 on 9 Mar 1975. Common Moorhen Gallinula chloropus. 45, 25. Occasional. Ave 0.5 Oct-May, fall- ing to 0.2 Jun -Sep. Max 6 on 5 Dec 1976. Bred (adults with chicks as late as 7 Aug) in 1983. American Coot Fulica americana. 59348, 120. Abundant in winter, very common in summer. Ave 1000/860 Nov-Jan, 66/17 Jun-Sep, Max 2000 on 4 Dec 1977. Com- mon breeder. Black-bellied Plover Pluuialis squatarola. 2665, 106. Very common in fall, common in winter and early spring, fairly common in late spring and summer. Ave 47/38 Aug- Sep, 25/20 Oct-Mar, 6.2/5 Apr-Jul. Max 120 on 5 Sep 1982. Lesser Golden Plover Pluuialis dominica. 0, 0. Rare fall migrant; 1-9 Aug 1964 (AFN 18:535, 1964), 16 Aug 1981 (MB), 22 Aug 1968 (AFN 23: 108, 1969), 19 Sep 1967 (AFN 22:89, 1968), 12 Oct 1981 (SS). Snowy Plover Charadrius alexandrinus. 888, 63, Common in fall, fairly common other- wise. Ave 16/7 Jul-Sep, falling to 4.6 Oct- Jun. Max 74 on 5 Dec 1982. Yearly breeder (see also under Status of Endangered Species). Semipalmated Plover Charadrius semipalmatus. 277 4, 93. Very common in fall, com- mon in winter and spring, fairly common in summer. Ave 53/28 Aug -Oct. 15/6 Nov- May, 5.9/1 Jun-Jul. Max 330 on 1 Oct 1978. Killdeer Charadrius uociferus. 5692, 120. Very common resident. Ave 62/60 Jul- Aug, 45/40 Sep-Jun, min 32/29 Apr-May, Max 160 on 7 Nov 1976. Common breeder. Black-necked Stilt Himantopus mexicanus. 8756, 119. Abundant in summer, very corn- 196 BIRDS OF SAN EL1JO LAGOON mon otherwise. Ave 110/97 Jun-Sep, falling to 46/41 Nov-Mar. Max 280 on 11 Jul 1976. Common breeder. American Avocet Recurvirostra americana. 11657, 114. Abundant in spring, very com- mon otherwise. Ave 220/200 Mar-Apr, 56/25 Aug-Jan. Max 780 on 7 Dec 1980. Common breeder. Greater Yellowlegs Tringa meiano/euca. 706, 90. Common in fall, fairly common in winter and spring, rare in summer. Ave 15/14 Aug-Sep, 4.3/3 Nov-Apr. The only May and June records are 1 May 1983 (late spring migrant), 1 Jun 1975 (2), 5 Jun 1977 (4) (summering?), and 27 Jun 1976 (Unitt 1984) (early fall migrant). Max 33 on 1 Aug 1976. Lesser Yellowlegs Tringa flavipes. 480, 70. Fairly common spring and fall migrant, uncommon in winter. Ave 1.4/1 Jul, 10/8 Aug-Sep, 1.8/1 Nov-Feb, 7.5/4 Mar- Apr, none in Jun. Late spring records 2 May 1982 (2) and 4 May 1975. Fall max 44 on 12 Sep 1976, winter max 10 on 6 Dec 1982, spring max 37 on 1 Apr 1979. Solitary Sandpiper Tringa solitaria. 1, 1 (12 Sep 1976). Rare in fall; nine records 16 Aug (1981, TM) to 21 Sep (1962, AFN 17:68, 1963). One spring record, 12 Apr 1975 (AB 29:908, 1975). Max 2 on 3 Sep 1968 (GMcC). Wiliet Catoptrophorus semipalmatus. 2654, 111. Very common in fall migration, com- mon in winter and spring migration, fairly common in late spring and summer. Ave 55/45 Aug-Sep, 14/13 Nov-Apr, 5.9/4 May- Jun. Max 400+ on 2 Sep 1969 (AF). Wandering Tattler Heterosceius incanus. 3, 3. Rare in spring; 5 Apr 1981, 2 May-6 Jun 1982. Spotted Sandpiper Actitis macularia. 493, 105. Fairly common from fall to spring; recent- ly a few birds have summered. Ave 7 .4/7 Sep, 4.3/4 Oct-Apr, 5.5/5 May, 0.8 Jun- Jul. Max 17 on 10 Sep 1978. Bred in 1982 (AB 36: 1016, 1982) , 1983 (AB 37: 1027, 1983), and 1984 (DK). Whimbrel Numenius phaeopus. 848, 55. Very common in fall, occasional in winter, uncommon otherwise. Ave 36/18 Jul-Aug, 0.3 Nov- Jan, 1.4 Feb- Jun. Max 230 on 6 Aug 1978. Long-billed Curlew Numenius americanus. 19, 10. Occasional in fall and winter. Ave 0.1 Jul-Oct, 0.4 Nov-Feb. One spring record, 7 May 1978. Max 5 on 1 Feb 1981. Marbled Godwit Limosa fedoa. 1072, 90. Common in summer, fairly common in winter. Ave 14/13 Jun-Sep, 3.4/1 Nov-Jan, 16/13 Mar, 4.9/3 Apr-May. Max 180 on 3 Aug 1985 (DK). These data differ from Garrett and Dunn (1981) and Unitt (1984), who indicate that in southern California generally this species is more common in winter. Ruddy Turnstone Arenaria interpres. 78, 35. Uncommon in spring and fall, occasional in summer and winter. Ave 1.5/1 Apr, 0.4 May- Aug, 1.3 Sep-Oct, 0.2 Dec-Jan. Max 8 on 12 Oct 1980. Black Turnstone Arenaria melanocephala. 47, 23. Uncommon in spring, rare in sum- mer, occasional in fall and winter. Ave 0.2 Sep-Jan, 1.2 Mar-Apr. Summer (May-Aug) records 5 May-2 Jun 1974, 3 Jul 1977 (Unitt 1984), and 4 Aug 1974. Max 7 on 2 Mar 1980. Surfbird Aphriza virgata. 0, 0. Rare; 3 Jan 1964 (Unitt 1984). Red Knot Calidris canutus. 97, 15. Fairly common in fall. Ave 7.4/1 Sep, none Nov- Apr. One spring record, 7 May 1978 (2); one summer record (early fall migrants?), 13 Jul 1980 (3). Max 41 on 10 Sep 1978. Sanderling Calidris alba. 5814, 77. Abundant in fall, very common in winter and spring, occasional in summer. Ave 100/55 Sep, 57/21 Oct-May, falling to none in Jun, 0.4 in Jul. Max 590 on 7 Sep 1980. 197 BIRDS OF SAN ELIJO LAGOON [Peeps Calidris spp. 40328, 110. Includes, Semipalmated, 53% Western, 13% Least, and Baird’s Sandpipers plus 34% not identified to species. Max 4000 on 14 Oct 1979.] Semipalmated Sandpiper Calidris pusilla. 1, 1. Rare fall migrant; 20 Aug 1980 (DK), 7 Sep 1980. Western Sandpiper Calidris mauri. 21453, 98. Abundant in fall and spring, very com- mon in winter, rare in summer. Ave 400/150 Sep -Nov, 95/25 Jan -Mar, 220/110 Apr. Only June records 1 Jun 1975, 12 Jun 1983 (DK). Max 2500 on 14 Oct 1979. Least Sandpiper Calidris minutilla. 5288, 96. Very common in fall and winter, fairly common in spring, occasional in summer. Ave 65/41 Aug-Feb, falling to 8.8/1 Apr- May. One June record, 1 Jun 1980. Max 680 on 12 Oct 1980. Baird’s Sandpiper Calidris bairdii. 5, 3. Rare fall migrant. Thirteen records in 1960s of about 25 birds between 14 Aug and 21 Sep. Max 5 on 15 Aug 1965 (Unitt 1984). More recent records 6 Aug 1978 (2), 27 Aug 1985 (2) (RW), 30 Aug 1981 (TM), 7 Sep 1975, 8 Sep 1985 (3) (JD), 10 Sep 1972 (SS), 17 Sep 1986 (3) (J & DS), 23 Sep 1984 (2) (RW), 5 Oct 1975 (2). Pectoral Sandpiper Calidris melanotos. 8, 5. Rare fall migrant. About 20 records dur- ing 1960s of about 90 birds between 8 Aug and 18 Oct. Max 20 on 10 Oct 1965 and 11 Oct 1963 (Unitt 1984). More recent records 29 Jun 1977 (exceptionally early) (AB 31:1190, 1977), 6-7 Sep 1981 (TM), 8 Sep 1985 (JD), 17-18 Sep 1972 (SS), 1-8 Oct 1978 (2) (TM), 2 Oct 1983 (3), 5 Oct 1975 (2), 10 Oct 1976. Dunlin Calidris alpirta. 970, 55. Common winter visitor. Ave 13/4 Oct-Apr, falling to none Jun- Aug. Four early fall (Sep) records, earliest 4 Sep 1977 (2). Max 340 on 10 Nov 1974. Curlew Sandpiper Calidris ferruginea, 0, 0. Exceptional. One adult 4 Jul 1981 (Bin- ford 1985), the only record for San Diego County. Stilt Sandpiper Calidris himantopus. 0, 0. Rare in fall, exceptional in winter; 2 Sep 1985 (4) (AB 40:158, 1986), 13-25 Sep 1964 (AFN 19:79, 1965), 16 Sep 1967 (GMcC) , 21 Sep 1962 (AFN 17:68, 1963), 29 Sep-8 Oct 1984 (3) (AB 39:103, 1985), 21 Oct 1962 (AFN 17:68, 1963), and 21-22 Feb 1982 (AB 36:331, 1982), the only winter record for San Diego County. Ruff Philomach us pugnax. 0, 0. Rare; 21-23 Sep 1962 (McCaskie 1963). (Dowitchers Limnodromus spp. 19675, 114. Includes 4% Short-billed and 28% Long- billed Dowitchers plus 68% not identified to species. Abundant in winter, common in summer. Ave 200/150 Sep-May, falling to 42/21 Jun- Jul. Max 705 on 9 Sep 1979.] Short-billed Dowitcher Limnodromus griseus. 747, 51. Common in fall, fairly com- mon in winter, uncommon in spring. Ave 18/12 Sep-Oct, 3.7 Nov-Apr, 1.1 May- Jun. Max 100 on 3 Jul 1977 (Unitt 1984). Long-billed Dowitcher Limnodromus scolopaceus. 5506, 85. Very common from fall through spring, uncommon in summer. Ave 55/18 Aug-May, 1.2 Jun-Jul. Max 390 on 9 Sep 1979. Common Snipe Gallinago gallinago. 44, 21. Uncommon winter visitor; decreasing. Only four records 1978-1983. Ave 1974-1977 1.6/2 Nov-Apr, none Jun-Aug. Late spring record 4 May 1975. Max 5 on 9 Nov 1975. Wilson’s Phalarope Phalaropus tricolor. 1419, 30. Very common in fall, exceptional in winter, fairly common in spring, rare in summer. Ave 13/1 Jul, 99/27 Aug, 22/9 Sep, none Nov-Mar except 5 Jan 1964 (AFN 18:387, 1964), 4.4 May, and Jun records 2 Jun 1974 and 7 Jun 1981. Max 360 on 5 Aug 1979. Red-necked Phalarope Phalaropus lobatus. 5654, 35. Abundant in fall, occasional in spring. Ave 250/140 Sep-Oct, none Dec-Apr, 0.4 May, none Jun-Jul. Max 1400 on 4 Sep 1977. 198 BIRDS OF SAN ELIJO LAGOON Red Phalarope Phalaropus fulicaria. 220, 4. Rare in winter and spring; 1-9 Nov 1963 (100) (SD 30725), 7 Nov-5 Dec 1982 (30), 28 Nov 1969 (AS), 5 Dec 1976-9 Jan 1977 (170), 18 May 1978 (PU), 24-25 May 1980 (10) (TM), Pomarine Jaeger Stercorarius pomarinus. 0, 0. Rare; 6 Mar 1964 (GMcC). Parasitic Jaeger Stercorarius parasiticus. 0, 0, Rare; 15 Jul 1984 (GMcC), east of the freeway. Franklin’s Gull Larus pipixcan. 0, 0. Rare in fall; 11 Oct-7 Nov 1964 (5) (McCaskie and Cardiff 1965), 25-29 Oct 1969 (2) (AFN 24:100a, 1970), 20 Nov 1971 (AB 26:121, 1972). Bonaparte’s Gull Larus Philadelphia. 2884, 74. Very common in winter, fairly com- mon in summer. Ave 52/21 Nov-Mar, falling to 3.1 May-Oct. Max 350 on 9 Jan 1977, summer max 41 on 10 Jul 1977. Heermann’s Gull Larus heermanni. 394, 30. Common in fall, occasional otherwise. Ave 12/5 Jul-Sep, falling to 0.2 Nov-Jun. Max 69 on 10 Jul 1977. Although this species is common along the coast of southern California Jul- Feb (Garrett and Dunn 1981), apparently it uses brackish lagoons commonly during its northbound (fall) migra- tion only. [Large gulls Larus spp. 25977, 120. Includes 38% Ring-billed, 10% California, 10% Western, and 1% Mew, Herring, Thayer’s, and Glaucous-winged Gulls, plus 41% not identified to species. Abundant in fall and winter, very common in summer. Ave 470/270 Dec-Mar, 59/26 May-Jul, 120/87 Sep-Nov. Max 1980 on 16 Feb 1975.] Mew Gull Larus canus. 1, 1. Rare; 10 Oct 1976. Ring-billed Gull Larus delawarensis. 9991, 117. Abundant in winter, common in sum- mer. Ave 190/120 Feb-Mar, 21/9 May-Jul, 110/87 Nov-Jan. Max 830 on 7 Mar 1976, summer max 230 on 5 Jun 1977. California Gull Larus californicus . 2647, 62. Uncommon in fall, very common in winter, rare in summer. Ave 2.4 Aug-Oct, 68/23 Jan-Mar, The only Jun-Jul records are 4-5 Jun 1977 (3), 27 Jun 1976 (Unitt 1984), and 29 Jun 1977 (Unitt 1984) Max 340 on 6 Feb 1977. Herring Gull Larus argentatus. 69, 22. Uncommon winter visitor. Ave 1.3 Dec-Apr, falling to none Jun-Oct. Late spring records 1 May 1977 and 2 May 1976. Max 10 on 9 Mar 1975 and 7 Mar 1976. “ Thayer’s Gull Larus thayeri. 4, 4. Rare winter visitor; 7 Dec 1975, 8 Jan 1978, 11 Jan 1976, 7 Mar 1976. Western Gull Larus occidentalis. 2603, 114. Very common in summer, common in fall and winter, fairly common in spring. Ave 40/13 Jun-Aug, 18/11 Sep-Mar, 8.1/5 Apr-May. Max 350 on 2 Jul 1978. Glaucous-winged Gull Larus glaucescens. 1, 1. Rare; 27 Nov 1981 (TM), 31 Dec 1972 (SS), 4 Apr 1982, 22 Apr 1968 (AF). [Glaucous Gull Larus hyperboreus. 0, 0. One on the beach 100 meters north of the lagoon on 7 Mar 1982 (TM).] Black-legged Kittiwake Rissa tridactyla. 2, 2. Rare in spring; 7 Mar 1976, 3 Apr 1977 (both dead birds), 22 Apr 1968 (AF). Caspian Tern Sterna caspia. 1359, 79. Very common in spring, common in summer and fall, occasional in winter. Ave 38/30 Apr, 15/11 May- Jun, 26/11 Jul-Aug, 0.5 Oct-Jan. Max 140 on 7 Aug 1983. Royal Tern Sterna maxima. 623, 79. Fairly common in spring and fall, uncommon in summer and winter. Ave 8.3/4 Apr-May, 2.8 Jun-Jul, 8.1/4 Sep-Oct, 1.9/1 Dec- Jan. Max 45 on 6 May 1979. 199 BIRDS OF SAN ELIJO LAGOON Elegant Tern Sterna elegans. 8398, 69. Very common in spring, abundant in late sum- mer. Ave 45/17 Apr, 12/4 May-Jun, 250/67 Jul-Sep, falling to none Jan-Feb. Early spring record 13 Mar 1977, late fall records 2 Dec 1973 and 7 Dec 1980 (5). Max 2000 on 4 Aug 1974. [Common/Forster’s Tern Sterna spp. 10605, 115. Includes 8% Common and 81% Forster’s Terns plus 11% not identified to species. Max 550 on 12 Jul 1980.] Common Tern Sterna hirundo. 809, 31. Very common in fall, rare in spring and sum- mer. Ave 34/2 Aug-Sep, falling to none Nov-Mar. Spring and summer (Apr-Jun) records include 12 Apr 1969 (Unitt 1984), 4 May 1980, 4 Jun 1978, 5 Jun 1977 (11), and 7 Jun 1981. Max 240 on 7 Sep 1980. Forster’s Tern Sterna forsteri. 8600, 115. Abundant in late summer, very common otherwise. Ave 120/76 Jul-Sep, 46/32 Oct-Jan, 86/56 Feb-Mar, 50/38 Apr-Jun. Max 370 on 10 Jul 1977. Least Tern Sterna antillarum. 1088, 45. Common in summer. Ave 10/7 May, 20/21 Jun, 38/34 Jul-Aug, falling to none Oct-Mar. Extreme dates 6 Apr 1970 (AF) and 13 Apr 1980 in spring, 23 Sep 1969 (AF) in fall. Max 66 on 2 Aug 1981. For data on breeding, see under Status of Endangered Species. Black Tern Chlidonias niger. 13, 8. Occasional in fall, rare in winter and spring. Ave 0.4 Aug-Oct. Nov-Jun records 8-11 Nov 1963 (AFN 18:74, 1964), 11 Feb-9 Mar 1968 (AFN 22:478, 1968), 2 May 1982, 11 May 1980 (TM). Max 3 on 4 Aug 1974. Black Skimmer Rynchops niger. 0, 0. Rare; records during the study period are 6 Aug 1983 (WJ), 28 Sep 1982 (3) (SW), 12 Oct 1981 (SS). There are several subsequent records for this species, which is expanding its range. Max 10 from 27 Oct to 19 Nov 1984 (BM). Common Murre Uria aalge. 0, 0. Rare. A sick bird found east of the freeway on dried mud on 15 Jun 1982 had died by the next day (DK) , A specimen from “Cardiff” on 4 Feb 1942 (SD 18950) was probably found on the beach near the lagoon. Rock Dove Columba livia. 6774, 115. Abundant in winter, very common otherwise. Ave 110/85 Dec-Feb, 31/24 Mar-Aug, 56/44 Sep-Nov. Max 380 on 6 Jan 1980. Common breeder. Band-tailed Pigeon Columba fasciata. 0, 0. Rare in spring; 5 Apr 1974 (SS), 26 Apr 1981 (2) (TM). Spotted Dove Streptopelia chinensis. 23, 18. Occasional. Ave 0.2 throughout the year. Max 2 on five dates. White-winged Dove Zenaida asiatica. 1, 1. Rare migrant; 4 Sep 1978 (RAE), 20 Sep 1964 (GMcC), 22 Sep 1962 (AFN 17:69, 1963), 3 May 1981. Mourning Dove Zenaida macroura. 8744, 120. Very common resident. Ave 100/97 Jun-Sep, falling to 55/42 Nov-Apr. Max 220 on 6 Feb 1983. Common breeder. Greater Roadrunner Geococcyx californianus. 57, 42. Occasional; decreasing. Ave 0.5 throughout the year. Max 4 on 5 Apr 1981. Probable yearly breeder. Common Barn-Owl Tyto alba. 17, 11. Occasional. 1-3 seen each month Apr-Sep 1974, 6 scattered records later. All but 1 found along cliffs on N side of lagoon E of freeway. Whitewashed rocks in this habitat suggest this species is regular. Five egg sets (WF) were collected near Cardiff and Solana Beach from 1922 to 1939. Great Horned Owl Bubo uirginianus. 3, 3. Rare; 4 Sep 1977, 12 Sep 1976, 23 Nov 1980 (TM), 28 Feb 1982 (TM), 6 May 1976. Egg set from “east of Solana Beach” on 10 Mar 1936 (WF 4514). Burrowing Owl Athene cunicularia. 4, 4. Rare winter visitor; 2 Nov 1980, 7 Dec 1975- 1 Feb 1976. 200 BIRDS OF SAN ELIJO LAGOON [Long-eared Owl Asio otus. 0, 0. Listed as a rare winter visitor by Summers (1975), but we know of no specific occurrences.] Short-eared Owl Asio flammeus . 0, 0. Rare winter visitor; 19 Oct 1980 (TM), 27 Nov 1981 (TM), 30 Dec 1984 (LS), winter 1969-1970 (TM), 7 Mar 1965 (GMcC). Lesser Nighthawk Chordeiles acutipennis. 0, 0. Rare; 23 May 1976 (TM). [Common Poorwill Phalaenoptilus nuttallii. 0, 0. Specimen from “Cardiff’ 21 Nov 1915 (SD 31452).] [Swifts. 767, 65. Include Black, Chimney, 26% Vaux’s, and 65% White-throated Swifts plus 9% not identified to species.] Black Swift Cypseloides niger, 0, 0. Rare; 19 May 1981 (AB 35:864, 1981). Chimney Swift Chaetura pelagica. 0, 0. Rare; 29 Jun-22 Aug 1968 (5) (AFN 22:649, 1968; SD 36690). Vaux’s Swift Chaetura uauxi. 202, 11. Common in spring, uncommon in fall. Ave 19/2 May, none Jun-Aug, 1.3 Oct. Early fall record 7 Sep 1975 (2). Winter (Nov- Mar) records 6 and 22 Mar 1964 (AFN 18:388, 1964). Max 160 on 5 May 1974. White-throated Swift Aeronautes saxatalis. 498, 62. Fairly common in spring, uncom- mon otherwise. Ave 9.7/8 Feb- Apr, falling to 1.1 Aug-Dec. Max 200 on 6 Mar 1964 (Unitt 1984). Probable common breeder in cliffs in northeast area. Black-chinned Hummingbird Archilochus alexandri. 20, 10. Occasional migrant. Ave 0.3 Apr, 0.6 Jul-Sep, none in other months. Max 6 on 7 Aug 1977. Anna’s Hummingbird Calypte anna. 2851, 120. Common resident; increasing. Ave 27 / 26 Aug- Apr, 12/12 Jun-Jul. Max 56 on 12 Oct 1980. Common breeder. Costa’s Hummingbird Calypte costae. 19, 15. Occasional. Ave 0.5 Apr-May, 0.1 Jun- Aug, 0.2 Sep-Oct, 0.1 Nov-Mar. Max 3 on 6 Apr 1975. [Rufous/ Allen’s Hummingbird Selasphorus spp. 404, 42. Includes 32% Rufous and 8% Allen’s Hummingbirds plus 59% not identified to species. Fairly common in spring, common in fall, rare in winter. Ave 3.9/2 Apr, none Jun, 12/6 Jul-Sep. Oct-Jan records of unidentified birds on 2 Oct 1977, 4 Nov 1979 (3), and 3 Dec 1978. Max 110 on 11 Jul 1976.] Rufous Hummingbird Selasphorus rufus. 130, 20. Fairly common in fall, uncommon in spring. Ave 5.2 Jul- Aug, none Sep- Jan, 0.2 Feb-Mar, 2.1/1 Apr, and none Jun. Early and late spring dates 4 Feb 1979 and 4 May 1980. Max 74 on 11 Jul 1976. Allen’s Hummingbird Selasphorus sasin. 32, 7. Uncommon in fall, rare in spring. Ave 1.6 Jul-Aug. One record Sep-Jun, 3 Apr 1977. Max 10 on 12 Jul 1981. Belted Kingfisher Ceryle alcyon. 214, 86. Uncommon from fall through spring, Ave 2.6/2 Sep-Mar, falling to none Jun. Late spring record 1 May 1977. Max 6 on 4 Aug 1974 and 1 Nov 1981. One summer record after the study period of one 7 Jun 1984 carrying food, presumably to nestlings. Red-naped Sapsucker Sphyrapicus nuchalis. 3, 2. Rare fall migrant; 18 Oct 1981 (TM), 9 Nov 1975, 10 Nov 1974 (2). Red-breasted Sapsucker Sphyrapicus ruber. 4, 4. Rare fall migrant and winter visitor; 1 Oct 1978, 6 Nov 1977, 2 Dec 1973, 6 Feb 1977. Nuttall’s Woodpecker Picoides nuttallii. 304, 109. Uncommon resident. Ave 2.5/2 throughout the year. Max 7 on 2 Aug 1981, Yearly breeder. Downy Woodpecker Picoides pubescens. 3, 3. Rare in late summer; 8 Jul 1979, 3 Aug 1980, 6 Sep 1981. Hairy Woodpecker Picoides uillosus. 3, 3. Rare in fall through spring; 20 Sep- 12 Oct 1975 (AB 30:127, 1976), 3 Oct 1982, 7 Dec 1975, 2 May 1976. 201 BIRDS OF SAN ELIJO LAGOON Common Flicker Colaptes auratus. 538, 109. Fairly common in winter, uncommon in summer. Ave 8.2/8 Nov- Jan, falling to 1.9/2 Apr-Sep. Max 20 on 9 Nov 1975. Probable yearly breeder. Apparent Yellow-shafted Flickers ( C. a. luteus) were record- ed 1 Nov 1986 (LS), 9 Nov-7 Dec 1975, 8 Dec 1974, and 3 Feb 1974. Olive-sided Flycatcher Contopus borealis. 23, 13. Uncommon in spring, exceptional in summer, rare in fall. Ave 1.7/1 May, 0.4 Jun, none Jul-Aug except for single record of breeding, 8 Sep 1974, none Oct-Mar. Max 6 on 1 May 1977. Exceptional breeding record 2 May-5 Jul 1982 (TM, DK) of a pair raising one young in a nonnative cypress (not a eucalyptus as reported AB 36:1017, 1982). Western Wood-Pewee Contopus sordidulus. 69, 19. Fairly common spring migrant, occasional fall migrant. Ave 3.0/1 May-Jun, none Jul, 0.7 Sep, none Nov-Apr. Max 20 on 1 Jun 1975. [Empidonax spp 129, 36. Includes 3% Willow, 3% Hammond’s, and 60% Western Flycatchers plus 33% not identified to species. Fairly common in spring, uncommon in fall. Ave 7.6/4 May, none Jul, 1.3/1 Sep-Oct, none Nov-Mar. Max 35 on 4 May 1975.] Willow Flycatcher Empidonax trai/lii. 4, 3. Rare migrant; 21 May 1985 (RW), 1 Jun 1975, 5 Jun 1977, 12 Sep 1976 (2). Hammond’s Flycatcher Empidonax hammondii. 5, 3. Rare in spring; 11 Apr 1976, 17 Apr 1973 (SS), 2 May 1982, 5 May 1974 (3). Western Flycatcher Empidonax difficilis. 78, 30. Fairly common in spring, uncommon in fall. Ave 3.8/2 May, none Jul, 1.1/1 Sep-Oct, none Nov-Mar. Max 20 on 4 May 1975. Black Phoebe Sayornis nigricans. 785, 118. Fairly common. Ave 8.4/8 Jul-Jan, fall- ing to 3.5/3 Mar-Jun. Max 33 on 7 Aug 1983. Probable occasional breeder. Eastern Phoebe Sayornis phoebe. 2, 2. Rare winter visitor; 5 Dec 1976-6 Feb 1977 (AB 31:374 1977). Say’s Phoebe Sayornis saya. 315, 62. Fairly common in winter, rare in summer. Ave 6.6/6 Oct- Jan. The only records May-Aug are of a bird that summered in 1980. Ear- ly fall dates 5 Sep 1982 (2) and 6 Sep 1981; late spring dates 4 Apr 1982 and 7 Apr 1974. Max 14 on 6 Jan 1980. Vermilion Flycatcher Pyrocephalus rubinus. 0, 0. Rare; 20 Sep 1964 (AFN 19:80, 1965). Ash-throated Flycatcher Myiarchus cinerascens. 114, 35. Uncommon in summer. Ave 2.3/1 May-Sep, none Oct-Mar. Max 14 on 3 Aug 1975. Probable yearly breeder. Tropical Kingbird Tyrannus melancholicus. 0, 0. Rare in fall; 20 Sep 1963 (McCaskie et al. 1967a; SD 30768) , 22 Sep 1964 (AFN 19:80, 1965) , 28 Sep 1967 (AFN 22:90, 1968), 5 Dec 1965 (AFN 460, 1966). Cassin’s Kingbird Tyrannus vociferans. 468, 89. Fairly common in fall, uncommon otherwise; increasing. Ave 8.3/4 Sep-Oct, falling to 2.3/2 Dec-Jun. Max 50 on 6 Sep 1981. Yearly breeder. Western Kingbird Tyrannus verticalis. 124, 35. Fairly common in spring, uncommon in summer. Ave 3.9/2 Apr- May, 1.1 Jun-Sep, none Nov-Mar, Max 25 on 5 Apr 1981. Eastern Kingbird Tyrannus tyrannus. 1, 1. Rare fall migrant; 6 Aug 1978, 27 Aug 1964 (McCaskie et al. 1967a), 25 Sep-2 Oct 1964 (McCaskie et al. 1967a), 28 Sep 1963 (McCaskie et al. 1967a; SD 30767), 28 Sep-1 Oct 1986 (AB 41:145, 1987). Scissor-tailed Flycatcher Tyrannus forficatus. 1, 1. Rare in fall; 8-10 Nov 1974 (AB 29:122, 1975), 22 Nov 1963 (McCaskie et al. 1967a; SD 30769). 202 BIRDS OF SAN ELIJO LAGOON Horned Lark Eremophila alpestris. 134, 22. Fairly common in spring, occasional in winter; decreasing. Only 8 birds seen 1978-1979 and none 1980-1983. Ave 1974-1977 5.8/3 Mar-Jul, none Aug-Sep, 0.5 Oct-Feb. Max 20 on 3 Apr 1977, 5 May 1974, and 1 Jun 1975. Probably bred formerly; egg set from “near Olivenhain” (1.5 miles northeast of the lagoon) on 23 May 1922 (WF 5123). Purple Martin Progrte subis. 1, 1. Rare; 22 Mar 1964 (2) (Unitt 1984), 6 Apr 1975, 10 Sep 1972 (SS). Tree Swallow Tachycineta bicolor. 2674, 37. Very common in winter and abundant in spring but sporadic; rare otherwise. Ave 7.0 Nov-Dec, 41/1 Jan-Feb, 160/18 Mar. Late spring to early fall (May-Sep) records 2 May 1982 (10), 7 May 1978 (10), 6 Jun 1976 (3), 3 Jul 1983 (8), 4 Aug 1974 (2), 7 Sep 1980. Max 760 on 9 Mar 1975 and 750 on 16 Feb 1987 (JK). Violet-green Swallow Tachycineta thalassina. 156, 13. Common but irregular in spring; decreasing. Ave 11/1 Mar, 2.0 Apr-May, none Jul- Feb. Late spring records 1 Jun 1980 (2) and 5 Jun 1983. Max 65 on 3 Mar 1974. Northern Rough-winged Swallow Stelgidopteryx serripennis. 2265, 70. Very common in spring and summer, fairly common in fall, rare in winter; decreasing. Ave 22/21 Mar, 60/43 Apr-May, 33/21 Jun-Jul, 5.8/2 Aug-Oct. Nov-Feb records 5 Dec 1976 (3), 5 Jan 1975, 16 Feb 1975 (2). Max 220 on 11 Jul 1976. Yearly breeder. Bank Swallow Riparia riparia. 0, 0. Rare; 11 Apr 1975 (Unitt 1984), 4 Jun 1984 (JO), 19 Aug 1973 (SS), 13 Sep 1981 (TM), 21 Sep 1980 (2) (TM). Cliff Swallow Hirundo pyrrhonota. 10400, 64. Abundant in summer. Ave 230/190 Apr- Jul, falling to none Nov- Jan. Early record 16 Feb 1975, late record 4 Oct 1981 (8). Max 620 on 3 Jun 1979. Common breeder; main nesting area is under freeway bridge. Barn Swallow Hirundo rustica, 316, 42. Fairly common spring and fall migrant, occa- sional in summer. Ave 1.4 Mar-Apr, 6.4/5 May, 0.3 Jun-Aug, 7.2/3 Sep-Nov. Dec- Feb records 9 Jan 1977 and 16 Feb 1987 (3) (DK) . Max 46 on 4 Oct 1981. Probable occasional breeder; egg set from “Solana Beach” 16 May 1933 (WF 6578). Scrub Jay Aphelocoma coerulescens . 1069, 119. Common in fall, fairly common other- wise. Ave 19/18 Sep, 6.9/7 Nov-May, 10/10 Jul-Aug. Max 32 on 6 Sep 1981. Yearly breeder. American Crow Coruus brachyrhynchos. 63, 29. Occasional in winter. Ave 0.8 Oct- Apr, 0.1 May-Sep. Max 10 on 4 Oct 1981. Common Raven Corvus corax. 267 , 87. Fairly common in spring, occasional in sum- mer, uncommon in fall and winter. Ave 3.8/2 Mar-Jun, 0.5 Aug-Sep, 1.9/2 Oct- Feb. Max 16 on 6 Jun 1976. Occasional breeder; egg set from “Solana Beach” on 30 Apr 1966 (SB 19352). Verdin Auriparus flauiceps. 1, 1. Exceptional; 9 Jan-17 Feb 1975 (AB 29:743, 1975). Bushtit Psaltriparus minimus. 14636, 120. Abundant in fall and winter, very common in spring and summer, Ave 160/150 Sep-Feb, falling to 88/78 Mar- Aug. Max 430 on 6 Nov 1977. Common breeder. [Red-breasted Nuthatch Sitta canadensis. 0, 0. Listed as a rare fall migrant by Sum- mers (1975), but we know of no specific occurrences.] Cactus Wren Campylorhynchus brunneicapillus. 74, 47. Previously an uncommon resi- dent, now extirpated. No records after 6 Sep 1981 when the habitat was converted to farmland. Ave 1973-1981 0.9 throughout the year. All records were from Opuntia patch on slopes of northeast area. Max 6 on 9 Mar 1975. Formerly, probable yearly breeder. 203 BIRDS OF SAN ELIJO LAGOON Rock Wren Salpinctes obsoletus. 2, 2. Rare; 13 Oct 1974, 10 Apr 1983. Bewick’s Wren Thryomanes beivickii. 733, 114. Fairly common resident. Ave 6.1/5 throughout the year. Max 28 on 8 Jan 1978. Common breeder. House Wren Troglodytes aedon. 320, 93. Fairly common in fall, uncommon other- wise. Ave 4 9/4 Sep-Dec, falling to 1.4/1 Mar-Aug. Max 15 on 7 Sep 1980. Marsh Wren Cistothorus palustris. 2432, 119. Common in winter, fairly common in summer. Ave 29/25 Jan-Jun, 7.3/6 Jul-Sep, 15/16 Oct-Dec. Max 96 on 1 Jun 1975. Common breeder. Golden-crowned Kinglet Regulus satrapa, 1,1. Rare; 10 Nov 1976. Ruby-crowned Kinglet Regulus calendula. 428, 60. Fairly common winter visitor. Ave 8.0/8 Nov-Mar, none Jun-Sep. Late spring (May) records 2 May 1976, 3 May 1981 (2), and 6 May 1979. Max 26 on 1 Nov 1981. [Gnatcatchers Polioptila spp. 299, 73. Includes 48% Blue-gray and 37% Black-tailed Gnatcatchers plus 14% not identified to species. Max 14 on 11 Jan 1981.] Blue-gray Gnatcatcher Polioptila caerulea. 145, 46. Uncommon winter visitor. Ave 2.1/1 Sep -Mar, none Apr -Aug. Max 9 on 2 Nov 1980. Black-tailed Gnatcatcher Polioptila me/anura. 112, 38. Uncommon resident; increas- ing. Only records 1974- 1978 were 7 Dec 1975-7 Mar 1976 (max 3) . Ave 1979- 1983 1.4/1 throughout the year. Max 9 on 5 Dec 1982. Bred in 1980. (See also under Status of Endangered Species.) Western Bluebird Sialia mexicana. 56, 8. Uncommon winter visitor. Ave 1.4 Nov- Feb, none in other months. Max 20 on 6 Feb 1983. Townsend’s Solitaire Myadestes townsendi. 1, 1 Rare; 1 Feb 1976. Swainson’s Thrush Catharus ustulatus. 5, 4. Rare; five records 4 May-2 June, 20 Jun 1982 (heard singing in willows, TM), 9 Sep 1979. Max 3 from 4 to 13 May 1975 (TM). Hermit Thrush Catharus guttatus. 189, 38, Fairly common winter visitor. Ave 3.5/2 Nov-Mar, falling to none May-Sep. Max 20 on 9 Nov 1975. American Robin Turdus migratorius. 5, 3, Rare winter visitor; 25 Oct 1981 (TM), 17 Dec 1974 (SS), 8 Jan 1978, 19 Mar -2 Apr 1978 (2). Varied Thrush Ixoreus naeuius. 0, 0. Rare; 8 Jan 1982 (RWa). Another 16 Jan 1973 (AF) at nearby Glen Park in Cardiff. Wrentit Chamaea fasciata. 2229, 120. Common resident. Ave 19/19 throughout the year. Max 34 on 11 Jul 1976. Probable common breeder. Northern Mockingbird Mimus polyglottos. 1946, 120. Common resident. Ave 22/22 Jun-Oct, falling to 11/10 Nov- Apr. Max 53 on 3 Aug 1975. Common breeder. Sage Thrasher Oreoscoptes montanus. 1, 1. Rare; 6 Feb 1977. Bendire’s Thrasher Toxostoma bendirei. 0, 0. Rare; 27 Aug 1964 (McCaskie et al. 1967b). California Thrasher Toxostoma redioiuum. 852, 116. Fairly common resident; decreas- ing. Ave 7.1/6 throughout the year. Max 21 on 8 Sep 1974. Common breeder. Water Pipit Anf/ius spinoletta. 879, 44. Common winter visitor. Ave 15/2 Nov-Apr, falling to none May-Sep. Max 100 on 7 Feb 1982. Cedar Waxwing Bombycilla cedrorum. 218, 9. Fairly common but very sporadic winter visitor. Ave 8.5 Jan-Feb. Single records in Nov, Mar, May, and on 6 Jul 1975 (25). Max 70 on 10 Feb 1980. Phainopepla Phainopepla nitens. 14, 7. Occasional in summer. Ave 0.4 Jun-Aug, none Oct-May. Max 4 on 5 Jun 1983 and 7 Aug 1977. 204 BIRDS OF SAN ELIJO LAGOON Loggerhead Shrike Lanius ludouicianus, 942, 119. Fairly common resident, Ave 7.8/8 throughout the year. Max 19 on 10 Sep 1978. Yearly breeder. European Starling Sturnus uulgaris. 6626, 120. Very common resident. Ave 66/54 Jul-Feb, falling to 31/22 Mar-May. Max 230 on 7 Nov 1976. Common breeder; first known to breed in 1964 (egg set WF 75235). Bell’s Vireo Vireo bellii. 0, 0. Rare; 20 May 1986 (AW), 21 May 1985 (CE). Solitary Vireo Vireo solitarius. 5, 3. Rare migrant; 6 Apr 1975 (2), 19 Apr 1987 (SW), 4 May 1975 (2), 5 May 1974, 14 Sep 1980 (TM). Hutton’s Vireo Vireo huttoni. 13, 9. Occasional after 1980; possibly overlooked previous- ly. Ave 1981-1983 0.4 throughout the year. Max 3 on 2 May 1982. Bred in 1981 and 1982 in thicket of nonnative acacia. Warbling Vireo Vireo giluus. 136, 27. Common spring migrant, uncommon fall migrant. Ave 11/7 May, none Jul, 1.0/1 Sep, and none Nov-Mar. Early fall migrant 1 Aug 1976. Max 30 on 4 May 1980. Tennessee Warbler Vermivora peregrina. 1,1. Rare fall migrant; 19 Sep 1962 (AFN 17:70, 1963), 28 Sep 1962 (AFN 17:70, 1963), 13 Oct 1974, 30 Oct 1964 (AFN 19:81, 1965). Orange-crowned Warbler Vermiuora celata. 251, 66. Fairly common in spring, un- common in fall, occasional otherwise. Ave 5.3/2 Mar-May, 0.5 Jun-Aug, 2.6/2 Sep- Oct, 0.6 Nov-Feb. Max 43 on 6 Apr 1975. Nashville Warbler Vermiuora ruficapiila. 42, 15. Uncommon in spring, occasional in fall. Ave 1.5 Apr-May, none Jun-Aug, 0.5 Sep-Oct, none Dec-Mar. Max 21 on 4 May 1975. Virginia’s Warbler Vermiuora virginiae. 0, 0. Rare; 8 Sep 1966 (GMcC), 11-13 Sep 1964 (AFN 19:81, 1965), 12 Oct 1962 (GMcC). Northern Parula Parula americana. 1, 1. Exceptional in winter; female 8 Mar 1981 (AB 35:864, 1981). Yellow Warbler Dendroica petchia. 45, 21. Uncommon migrant. Ave 1.7/1 May, none Jul-Aug, 1.1 Sep-Oct. One Dec-Mar record, 5 Jan 1975. Fall records 12 Aug 1967 (Unitt 1984) to 11 Nov 1964 (AFN 19:80, 1965). Max 5 on two May, one Sep dates. Yellow-rumped Warbler Dendroica coronata. 7862, 75. Abundant winter visitor. Ave 130/120 Nov-Apr, falling to none Jun-Sep. Max 280 on 8 Jan 1978. Myrtle Warblers identified 6 Apr 1975, 16 Apr 1978 (TM). Black-throated Gray Warbler Dendroica nigrescens. 58, 16. Uncommon in spring, occa- sional in fall. Ave 2.8/1 Apr-May. none Jun-Aug, 0.1 Sep, none Oct-Mar. Max 21 on 4 May 1975 Townsend’s Warbler Dendroica townsendi. 75, 13. Fairly common in spring, occa- sional in fall. Ave 6.9/5 May, none Jul-Aug, 0.2 Sep-Oct, none Nov-Mar. Early spring record 10 Apr 1983 (2). Max 21 on 4 May 1975. Hermit Warbler Dendroica occidentals. 26, 8. Uncommon spring migrant. Ave 2.6/1 May, none in other months. Max 10 on 5 May 1976. Prairie Warbler Dendroica discolor. 0, 0. Rare; 17 Oct 1964 (2) (AFN 19:81, 1965), 19-28 Oct 1962 (McCaskie and Banks 1964). Palm Warbler Dendroica palmarum. 0,0. Rare; 12 Oct 1962 (McCaskie and Banks 1964) . Blackpoll Warbler Dendroica striata. 0, 0. Rare; 30 Sep 1967 (AFN 22:91, 1968). Black-and-white Warbler Mniotilta uaria. 2, 2. Rare in spring; 2 May 1982, 5 May 1976. 205 BIRDS OF SAN ELIJO LAGOON American Redstart Setophaga ruticilla. 3, 3. Rare; 13 Sep 1981 (TM), 3 Oct 1982, 2-7 Dec 1973 (SS), 7 Jun 1981. Northern Waterthrush Seiurus noueboracensis. 2, 2. Rare; 2 Sep 1965 (AFN 20:92, 1966), 8 Sep 1985 (JL), 5 Oct 1975, 18 Dec 1974 (AB 29:744, 1975), 5-7 Apr 1974 (AB 28:854, 1974). MacGillivray’s Warbler Oporornis tolmiei. 10, 7. Occasional migrant. Ave 0.3 Sep- Oct, 0.2 Apr-May, none in other months. Max 2 on three dates. Common Yellowthroat Geothlypis trichas. 2056, 120. Common resident. Ave 27/22 May-Jun, 13/12 Aug-Dec, 18/17 Jan-Apr. Max 70 on 2 May 1982. Common breeder. Wilson’s Warbler Wilsonia pusilla. 341, 37. Common in spring, occasional in fall; decreas- ing. Ave 4.6/3 Apr, 27/21 May, none Jul, 0.8/1 Sep-Oct, none Dec-Mar. Max 74 on 4 May 1975. Yellow-breasted Chat Icteria u/rens. 1, 1. Rare; 20 May 1978 (TM), 8 Sep 1974. Summer Tanager Piranga rubra. 1, 1. Rare; 5 Sep 1982. Western Tanager Piranga ludoviciana. 52, 14. Fairly common spring migrant, occa- sional fall migrant. Ave 4.0/2 May, none Jul, 0.5 Aug-Sep, none Oct-Apr. Max 21 on 4 May 1975. Black-headed Grosbeak Pheucticus melanocephalus. 167, 37. Fairly common in sum- mer. Ave 4.0/3 Apr-Aug, falling to none Nov-Mar. Max 20 on 3 Aug 1980. Yearly breeder in willows. Blue Grosbeak Guiraca caerulea. 0, 0. Exceptional in winter, rare in spring; 22 Feb- 13 Mar 1964 (McCaskie et al. 1967c), 23 Apr 1973 (SS), 28 Apr 1984 (BM). Lazuli Bunting Passerina amoena. 5, 2. Rare spring and fall migrant; 18 Apr 1982 (TM), 26 Apr 1981 (2) (TM), 3 May 1981, 4 May 1975 (4), 10 Sep 1972 (SS). Green-tailed Towhee Pipilo chlorurus. 0, 0. Rare; 6 Dec 1973 (SS). Rufous-sided Towhee Pipilo erythrophthalmus, 413, 94. Fairly common in spring, un- common otherwise. Ave 8.3/8 May-Jun, falling to 2.0/2 Aug-Mar. Max 17 on 4 May 1975. Common breeder. Brown Tohwee Pipilo fuscus. 4358, 120. Very common resident. Ave 36/35 throughout the year. Max 74 on 5 Jan 1975. Common breeder. Rufous-crowned Sparrow Aimophila ruficeps. 14, 8. Occasional. Ave 0.1 throughout the year. Max 5 on 12 Jui 1980. Chipping Sparrow Spizella passerina. 5, 4. Rare migrant; 5 Apr 1981, 2 May 1976 (2), 4 May 1975, 10 Sep 1972 (SS), 5 Oct 1975. Vesper Spanow Pooecetes gramineus. 9, 5. Rare in fall and winter; 4 Oct 1981, 5 Oct 1975, 1 Nov 1981 (3), 6 Jan-2 Mar 1980 (2). Lark Sparrow Chondestes grammacus. 1, 1. Rare; 8 Dec 1974. (Savannah Sparrow Passerculus sandwichensis. 4736, 120. The resident race was re- corded separately from migrants.] Belding’s Savannah Sparrow P. s. beldingi. 4233, 120. Very common resident; decreas- ing. Ave 35/32 throughout the year. Max 120 on 1 May 1977. Common breeder; see also under Status of Endangered Species. Migrant Savannah Sparrows. 503, 44. Fairly common in winter. Ave 7.1/1 Oct-Apr, none Jun-Aug. Late spring records 1 May 1977 (2), 2 May 1976. Max 60 on 2 Dec 1979. Large-billed Sparrow (P. s. rostratus) identified fall 1981 (TM). Grasshopper Sparrow Ammodramus savannarum. 0, 0. Rare; 11 Apr 1982 (TM). 206 BIRDS OF SAN ELIJO LAGOON Fox Sparrow Passerella iliaca. 9, 8. Occasional winter visitor. Ave 0.2 Oct-Feb. None in other months. Song Sparrow Melospiza melodia. 7819, 120. Very common resident; decreasing. Ave 89/82 Jan-Jun, falling to 39/31 Jul-Nov. Max 200 on 5 Jan 1975. Common breeder. Lincoln’s Sparrow Melospiza lincolnii. 73, 36. Uncommon winter visitor. Ave 1.0 Oct- Apr, falling to none Jun-Aug. Early record 7 Sep 1975, late record 6 May 1979. Max 7 on 6 Apr 1975. Swamp Sparrow Melospiza georgiana. 4, 4. Rare winter visitor; 2-9 Nov 1980 (TM), 10 Dec 1976 (AB 31:375, 1977), 21 Dec 1986 (LS), 9 Jan-6 Mar 1983. White-throated Sparrow Zonotrichia albicollis. 4, 2. Rare winter visitor; 8 Jan 1978 (2), 9 Jan 1983 (2). Golden-crowned Sparrow Zonotrichia atricapilla. 134, 40. Uncommon in winter, fair- ly common in spring. Ave 1.8/1 Nov-Mar, 5/3 Apr, none Jun-Oct. Max 18 on 3 Apr 1977. White-crowned Sparrow Zonotrichia leucophrys. 7262, 75. Abundant winter visitor. Ave 130/99 Nov-Mar, falling to none Jun-Aug. Early record 10 Sep 1978. Max 500 on 11 Jan 1976. Dark-eyed Junco Junco hyemalis. 6, 3. Rare winter visitor; 13 Oct 1974, 4 Nov-2 Dec 1973 (4), 13 Jan 1973 (SS). Bobolink Dolichonyx oryziuorus. 0, 0. Rare fall migrant; 30 Sep 1967 (SS). Red-winged Blackbird Agelaius phoeniceus, 8828, 118. Very common resident. Ave 100/83 Mar-Jun, falling to 60/35 Jul-Feb. Max 440 on 1 May 1977. Common breeder. Tricolored Blackbird Agelaius tricolor. 27, 3. Rare and sporadic from fall through spring; 25 Jul-10 Sep 1972 (35) (SS), 24 Oct 1981 (BM), 6 Nov 1977 (25), 6 Feb 1977, 1 May 1977, 11 May 1982 (BM), 27 May 1981 (BM). Western Meadowlark Sturnella neglecta. 2657, 120. Very common in winter, com- mon in summer. Ave 32/25 Nov- Apr, falling to 13/10 May-Oct. Max 88 on 1 Feb 1981. Common breeder. Yellow-headed Blackbird Xanthocephalus xanthocephalus. 2, 2. Rare from fall to spring; 18 Oct 1981 (4) (TM), 7 Nov 1982, 4 Feb 1970 (2) (AF), 1-17 May 1983 (4) (BM), 20 May 1979 (TM). Brewer’s Blackbird Euphagus cyanocephalus. 2530, 113. Very common in winter, com- mon otherwise. Ave 44/35 Jan-Feb, 12/9 Apr-Aug, 21/17 Sep-Dec. Max 150 on 1 Feb 1981. Yearly breeder. Great-tailed Grackle Quiscalus mexicanus. 0, 0. Rare; 10-11 Feb 1987 (RP). Brown-headed Cowbird Molothrus ater. 152, 36. Fairly common summer visitor. Ave 3.3/2 Apr-Jul, falling to none Dec-Feb. Max 17 on 7 Apr 1974. Yearly breeder; in 1982, seen parasitizing Common Yellowthroat (TM). Orchard Oriole Icterus spurius. 0, 0. Rare; 26-28 Oct 1962 (AFN 17:71, 1963), 27 Oct-3 Nov 1973 (AB 28:110, 1974). Hooded Oriole Icterus cucullatus , 159, 40. Fairly common in summer. Ave 3.1/3 Apr- Aug, falling to none Nov-Mar. Max 11 on 4 May 1975. Yearly breeder. Northern Oriole Icterus galbula, 334, 50. Fairly common in summer. Ave 7.8/7 Apr-Jul, falling to none Oct-Feb. Early record 3 Mar 1974. Max 23 on 2 Jun 1974. Yearly breeder. Baltimore Orioles I. g. galbula recorded 2 Jan 1973 (AB 27:665, 1973), 25-29 Sep 1973 (AB 28:110, 1974). Scott’s Oriole Icterus parisorum. 0, 0. Rare; 11 May 1980 (TM). Purple Finch Carpodacus purpureus. 3, 1. Rare; 11 Apr 1976 (3). 207 BIRDS OF SAN ELIJO LAGOON House Finch Carpodacus mexicanus. 25177 , 120. Abundant resident. Ave 280/250 Aug-Dec, falling to 110/95 Mar-May. Max 540 on 12 Oct 1980. Common breeder. Pine Siskin Carduelis pinus. 3, 1. Rare; 7 Dec 1975 (3). Lesser Goldfinch Carduelis psaitria. 2556, 114. Common resident. Ave 21/17 throughout the year. Max 100 on 7 Dec 1980. Common breeder. Lawrence’s Goldfinch Carduelis lawrencei. 212, 20. Sporadic; fairly common in spring, uncommon in fall. Ave 4.3 Mar-Jun, none Jul, 1.2 Aug-Oct, none Nov- Jan. Half of the individuals were found in 1975. Max 50 on 9 Mar 1975. American Goldfinch Carduelis tristis. 303, 51. Uncommon resident. Ave 2.5 throughout the year. Max 38 on 11 Jan 1976. Probable occasional breeder. House Sparrow Passer domesticus. 340, 61. Uncommon resident; decreasing. Ave 2.8/1 throughout the year. Max 37 on 5 Jan 1975. Accepted 26 August 1987 Green-backed Heron 208 Sketch by Eric Lichtwardt CHARACTERISTICS OF LEWIS’ WOODPECKER HABITAT ON THE MODOC PLATEAU, CALIFORNIA WILLIAM M. BLOCK, Department of Wildlife, Humboldt State University, Areata, California 95521 (present address: Department of Forestry and Resource Management, 145 Mulford Hall, University of California, Berkeley, California 94720) LEONARD A. BRENNAN, Department of Wildlife, Humboldt State University, Areata, California 95521 The Lewis’ Woodpecker ( Melonerpes lewis ) breeds throughout western North America in open Ponderosa Pine ( Pinus ponderosa) forests, logged or burned coniferous forests, open riparian woodlands, and oak (Quercus spp.) woodlands (Bent 1939, Snow 1940, Bock 1970, Jackman 1974), Features of each habitat include an open tree canopy, snags, and a shrub understory (Bock 1970, Jackman 1974, Sousa 1983). The nomadic habits of the Lewis’ Woodpecker make quantitative study of its habitat difficult, A population of this species may occur at a location during one breeding season, then disappear from the same location during subsequent years. Bock (1970) attributed this irregular pattern of habitat occupancy to fluc- tuations in food supply. In this paper we present quantitative descriptions of Lewis’ Woodpecker habitat in northeastern California. STUDY AREA AND METHODS Our study took place on the Modoc Plateau region of the Modoc National Forest approximately 32 km northwest of Adin, Modoc County, California. The habitat structure of the study area was heterogeneous because a 47,000-ha fire in 1976 had eliminated much of the tree canopy and shrub understory in some areas while leaving other areas undisturbed. Unburned portions of the study area consisted of an open-canopied forest of Jeffrey Pine (Pinus jeffreyi), Douglas-fir (Pseudotsuga menziesii), and Incense Cedar ( Calocedrus decurrens) with an understory of Curl-leaf Mountain-mahogany ( Cercocarpus ledifolius) , Green-leaf Manzanita (Arctostaphylos patula). Big Sagebrush ( Artemisia tridentata), Bitter- brush ( Purshia tridentata ), Choke Cherry ( Prunus virginiana) , Bitter Cherry (P. emarginata) , and Golden Currant (Ribes aureum). The fire altered the habitat by replacing the tree canopy with numerous charred snags and removing most of the understory. By 1982 a shrub layer consisting of Green-leaf Manzanita, Choke Cherry, Golden Currant, and Ceanothus species was present in burned areas. Our study site encompassed approximately 2100 ha and included both burn- ed (900 ha) and unburned (1200 ha) habitat. We used a systematic-random sampling scheme (Cochran 1977) to place six 1000-m-long transects in each habitat. Transects were spaced 200 m apart and sampled the entire habitat. We conducted 25 surveys (11 in burned and 14 in unburned habitats) from June through August in both 1982 and 1983 to note the presence of Lewis’ Woodpeckers. A chi-square test was used to determine whether the species used both habitats equally (Sokal and Rohlf 1969). To describe the habitat used by Lewis’ Woodpeckers, we randomly selected 25 sampling points each in the burned and unburned habitats. Sampling points Western Birds 18: 209-212, 1987 209 LEWIS’ WOODPECKER HABITAT were systematically placed along the existing survey transects. At each sampling point we used the point-center quarter method to estimate density, basal area, and average height of snags and live trees (Cottam and Curtis 1956). Total and relative cover by shrub species were estimated along a 15-m line intercept. Average shrub height was calculated as the mean height of five systematically sampled shrubs along the line intercept. We recorded the number of shrub species within a 7.5-m radius of the sampling point. One-way analysis of variance was used to test for differences between burned and unburned habitats (Sokal and Rohlf 1969) . A Spearman rank-order correla- tion coefficient (r s ) was calculated to compare relative frequencies of shrub species occurrences between habitats (Conover 1971). RESULTS Lewis’ Woodpeckers used burned habitat more frequently than unburned habitat during the period 1 June through 15 July, but showed no significant preference for habitat during the period 16 July through 31 August (Table 1). Burned habitat contained significantly more but smaller snags than did unburned habitat (Table 2) . The density of live trees was significantly greater on unburned than on burned habitat. Although the number of shrub species and the amount of shrub cover in the two habitats differed only slightly, the unburned habitat had taller shrubs than the burned habitat (Table 2) . The relative frequencies of shrub species were independent of whether or not the area had burned (r = 0.46; df = 20; P< 0.05). DISCUSSION Lewis’ Woodpeckers on the Modoc Plateau used burned habitat with greater frequency than unburned habitat (Table 1). Although they occupied burned habitat throughout our sampling period, they were observed in unburned areas no earlier than August of either year. Furthermore, by locating three nests and observing fledged young, we verified that woodpeckers bred in the burned habitat, but we observed no breeding activity in the unburned habitat. Therefore we conclude that Lewis’ Woodpeckers used burned habitat for breeding and after nesting expanded their habitat to include unburned areas. Table 1 Numbers of Surveys on Which Lewis’ Woodpeckers Were Observed in Burned and Unburned habitats on the Modoc Plateau, 1982 and 1983 Dates Burned habitat 1 Unburned habitat x 2q Present Absent Present Absent 1 June- 15 July 4 1 0 7 5.58* 16 July-31 August 5 1 3 4 0.86 1 June-31 August 9 2 3 14 4.68* °Chi-squared test for goodness of fit: df = 1: ‘. significant (P< 0.05) x 2 value. 210 LEWIS’ WOODPECKER HABITAT Table 2 Comparisons of Burned and Unburned Habitats Used by Lewis’ Woodpeckers on the Modoc Plateau 0 Variable Burned habitat Unburned habitat Mean SE b Mean SE Shrub cover (%) 13.4 3.2 26.5 3.7* Average shrub height (m) 0.6 0.1 0.9 0.1“ Number of shrub species 4.5 0.3 5.6 0.4* Snag basal area (m 2 /ha) 11.8 3.0 1.9 0.9** Tree basal area (m 2 /ha) 3.8 1.9 31.7 3.6’“ Snag density (snags/ha) 471.5 115.2 99.1 19.6“ Tree density (trees/ha) 203.2 38.6 912.7 104.4*** Average snag height (m) 8.3 0.7 16.1 1.2* * * Average tree height (m) 12.2 0.9 10.7 1.0 °Sample size is 25 for each group. One-way analysis of variance; df = 1,48. Significance levels: * , P< 0.05. **, P< 0.01, ***, P< 0.001. ^SE. standard error. Results of our habitat analysis are not in total agreement with the conclusions of previous studies. Bock (1970) suggested that Lewis’ Woodpecker habitat is characterized by snags, an extensive shrub layer, and an open tree canopy. Sousa (1983) stated that optimal breeding habitat should have at least 50% shrub cover and 2.5 snags/ha. In our study area, both the burned and unburned habitats had open tree canopies and sufficient numbers of snags, but neither had an extensive shrub layer. Thus, we suggest that additional factors play major roles in attracting nesting Lewis’ Woodpeckers. SUMMARY We studied Lewis’ Woodpecker habitat in burned and unburned areas of the Modoc Plateau, California. Although both habitats appeared suitable, the species was observed more frequently in burned habitats. We verified that the woodpecker nested on burned habitat, but we observed no nesting activities on unburned habitat. We suggest that factors other than habitat structure alone predispose Lewis Woodpeckers to use an area. ACKNOWLEDGMENT Carl E. Bock, Rocky Gutierrez, Michael L. Morrison. Martin G. Raphael, and J. Patrick Ward commented on earlier drafts of this paper and provided helpful suggestions. LITERATURE CITED Bent. A.C. 1939. Life histories of North American woodpeckers. U.S. Natl. Mus. Bull.174. Bock, C.E. 1970. The ecology and behavior of the Lewis’ Woodpecker (Asyndesmus lewis). Univ. Calif, Publ. Zool. 92. 211 LEWIS’ WOODPECKER HABITAT Cochran, W.G. 1977. Sampling Techniques. 3rd ed. Wiley, New York. Conover, W.J. 1971. Practical Non-parametric Statistics. Wiley. New York. Cottam, G., and Curtis, J. 1956. The use of distance measures in phytosociological sampling. Ecology 37:451-460. Jackman, S.M. 1974. Woodpeckers of the Pacific Northwest: Their characterics and role in the forest. Unpubl, M.S. thesis, Oregon State Univ,, Corvallis. Snow. R.B. 1940. A natural history of the Lewis Woodpecker. Asyndesmus lewis (Gray). Unpubl M.A thesis, Univ. Utah, Logan. Sokal, R.R. and Rohlf, F.J. 1969. Biometry. Freeman, San Francisco. Sousa. P.J. 1983. Habitat suitability index model: Lewis’ Woodpecker. U.S. Fish and Wildlife Service, Office of Biological Services Publ. 82/10.32. U.S. Government Printing Office, Washington, D.C. Accepted 3 November 1987 Lewis’ Woodpecker Sketch by Narca Moore -Craig NOTES A SPECIMEN RECORD OF THE ANCIENT MURRELET FROM NEW MEXICO C. GREGORY SCHMITT, New Mexico Department of Game and Fish, State Capitol, Santa Fe, New Mexico 87503 AARON A. MILLER, Route 4, Box 60 A, Santa Fe, New Mexico 87501 The Ancient Murrelet (Synthlihorhamphus antiquus) occurs casually in interior western North America, with records as far inland as the upper Midwest and Great Lakes region (A.O.U. 1983). There are no previous records of this species from New Mexico (Hubbard 1978; New Mexico Omithol. Soc. 1962 - 1985) ; however, the eventual occurrence of S. antiquus in New Mexico might have been expected in view of the proximity of specimen and sight records of this species in Colorado (Bailey and Niedrach 1967), Utah (Behle and Perry 1975), and Nevada (Monson and Phillips 1981). This note presents data on the first specimen of S. antiquus found in New Mexico. On 6 November 1985, 4 km north of Santa Fe on U.S. Highway 84-285 near its junc- tion with Tano Road, elevation 2195 m, Santa Fe Co., Miller found a live Ancient Murrelet sitting on U.S. Highway 285. The Ancient Murrelet made no apparent attempts to escape capture when he approached it. The specimen was taken to a local pet shop, where it was kept in an aquarium until its death the following day. When dissected, the specimen showed no apparent wounds nor did it appear emaciated. It was prepared as a skin and trunk skeleton and is now 600008 in the United States National Museum, Washington, D. C. We recorded the following data while preparing the specimen: testes Flesh Color, left 1x4 mm, right 1x3 mm; weight 172.6 g; no fat; skull less than 10% ossified; immature plumage; no body molt; total length 238 mm; maxilla Pale Neutral Gray with tip, culmen, and basal 5-6 mm Blackish Neutral Gray; mandible Pale Neutral Gray with angle of gonys, tip, and basal 5-7 mm Blackish Neutral Gray; tarsi Pale Neutral Gray with Blackish Neutral Gray line along entire length of posterior; webs, bottoms of feet, and dorsal toe joints Blackish Neutral Gray; toes Pale Neutral Gray; irides Vandyke Brown. Names of colors of soft parts are from Smithe (1975, 1981) . The specimen’s stomach contained small bones of fish, at least part of which the bird obtained while it was in the aquarium. Weather conditions in western North America between 28 October and 6 November 1985 were characterized, to some degree, by west to northwest winds from the north- western United States and adjacent Canada (N.O.A.A. 1985). The direction and high velocity of winds both at the surface and at the 500-millibar height contour may explain, at least in part, this extralimital record in New Mexico of this pelagic species. Although an Ancient Murrelet in New Mexico is an extreme extralimital and new state record, it does conform to a temporal pattern of distribution summarized by Munyer (1965) and Verbeek (1966) that most inland records of this species are in the fall (November) . This species has been recorded in several of the interior western and northern United States (DeSante and Pyle 1986) , but a record of this species in the Southwest is a noteworthy deviation from previously described geographic distributions of inland records of Ancient Murrelets. We thank John P. Hubbard, Robert Andrews, and an anonymous reviewer for com- ments and suggestions on this note. LITERATURE CITED American Ornithologists’ Union. 1983. Check-list of North American Birds, 6th ed. Ameri- can Ornithologists’ Union, [Washington, D.C.] Western Birds 18: 213-214, 1987 213 NOTES Bailey, A.M, , and Niedrach, R. J. 1967. Pictorial Checklist of Colorado Birds. Denver Mus. Nat. Hist., Denver. Behle, W.H., and Perry, M.L. 1975. Utah birds: Checklist, Seasonal and Ecological Occurrence Charts and Guides to Bird Finding. Utah Mus. Nat. Hist., Salt Lake City. DeSante, D., and Pyle, P. 1986. Distributional Check-list of North American Birds. Vol. 1: United States and Canada. Artemisia Press, Lee Vining, CA. Hubbard, J.P. 1978. Revised check-list of the birds of New Mexico. N,M. Ornithol. Soc. Publ. 6. Monson, G., and Phillips, A.R. 1981. Annotated Checklist of the Birds of Arizona. Univ. Ariz. Press, Tucson. Munyer, E.A. 1965. Inland wanderings of the Ancient Murrelet. Wilson Bull. 77:235-242. New Mexico Ornithological Society. 1962-1985. Field Notes, Vol. 1, 1962, to Vol. 24, No. 3., 1985. N.M. Ornithol. Soc. N.O.A.A. 1985. Environmental Data and Information Service, Oct. 28-Nov. 3; Nov. 4-10, Daily Weather Maps. U.S. Department of Commerce, U.S. Government Print- ing Office, Washington, D.C. Srnithe, F.B. 1975. Naturalist’s Color Guide. Parti, Color Guide. Am. Mus. Nat. Hist., New York. Srnithe, F.B. 1981. Naturalist’s Color Guide. Part II, Color Guide. Am. Mus. Nat. Hist., New York. Verbeek, N.A.M. 1966. Wanderings of the Ancient Murrelet: some additional comments. Condor 68:510-511. Accepted 13 January 1988 Ancient Murrelets Sketch by Tim Manolis 214 NOTES AN AMERICAN OYSTERCATCHER IN IDAHO DANIEL A. STEPHENS, Department of Biological Sciences, Idaho State University, Pocatello, Idaho 83209 JAMES E. STEPHENS, 634 Railroad Ave., Ontario, Oregon 97914 The American Oystercatcher ( Haematopus palliatus ) breeds along the American Atlantic coast from Massachusetts south to Argentina and along the Pacific coast from central Baja California south to Chile (A.O.U. 1983). Although generally a sedentary coastal species, it wanders occasionally (Hayman et al. 1986). Vagrants have been recorded as far north as Labrador on the Atlantic coast and San Luis Obispo Co., California, on the Pacific coast (two records from northern California are unsubstantiated, Roberson 1986) . In the west, in- land records exist for California, three individuals together, Salton Sea, 14-30 August 1977 (Luther 1980); New Mexico, one individual, Hidalgo Co., 10 August 1976 (Huntington and Huntington 1983, John P. Hubbard pers. comm.); and Idaho, one individual, Payette Co. , 19 April 1981 (Rogers 1981) . This note presents detailed documentation of the Idaho record and discusses this unusual occurrence. We observed a black and white oystercatcher with a brown back 3.3 miles south of Fruitland (along Whitley Drive), Payette Co., Idaho, between the hours of 1910 and 1945 on 19 April 1981. Rogers (1981) stated “north of Fruitland” and “18 April,” both of which are mistakes. The American Oystercatcher is the only black and white oystercatcher record- ed in North America (A.O.U. 1983) , and all other black and white oystercatchers are black rather than brown above (Hayman et al. 1986) . The oystercatcher was in the south section of a several-hundred-acre pond/ marsh area about 1 mile east of the Snake River. It was wading along the edge of a small island in a shallow 8- to- 10-acre alkali pond. The banks of the pond were covered with grasses, predominantly salt grass ( Distichlis stricta). We studied the oystercatcher through a 32 x spotting scope at a distance of about 35 meters and drew a sketch and took careful notes while observing it. The sky was overcast. The following detailed description of the bird’s plumage and soft parts may shed light on its age and subspecies (words in quotes are directly from field notes; all others are from the field sketch): (1) legs “pinkish-gray”; (2) proximal half of bill “pale orange” and distal half “dark”; (3) “iris pale brown”; (4) scapulars and lesser/median wing coverts “brown” with some pale fringes; (5) upper tail coverts barred with black; (6) border between black breast and white belly not clearly defined, but black spots not noted near the border or on the bel- ly. We did not hear any vocalizations or see the bird fly, but it momentarily extended its wings, allowing a view of its upper tail coverts. Retention of some pale-fringed scapulars and lesser/median wing coverts from its juvenile plumage, dark-tipped bill, and pale brown iris establish the bird as one year old (Prater et al. 1977, Hayman et al. 1986). Only two subspecies of American Oystercatcher have flecking or barring on their upper tail coverts: frazari and galapagensis (Hayman et al. 1986) . The subspecies frazari breeds along the west coast of Mexico and is therefore the subspecies occurring closest to Idaho; galapagensis is endemic to the Galapagos Islands. The oystercatcher we observed was closely associated with four Black-necked Stilts (Himantopus mexicanus). It appeared nervous and followed the stilts as they fed but showed little interest in feeding, although it probed into the shallow water four or five times. After nearly 30 minutes it followed two stilts onto the small island and lay down. We re- turned the next day to attempt to photograph the oystercatcher but it was not there, although the Black-necked Stilts were still in the same area. Neither species was present at this location during the mid-afternoon on 18 April. It does not seem likely that this was a weather-induced vagrancy since storm systems in west-central Idaho usually come from the west and American Oystercatchers occur along the Gulf of California, far south of Idaho. Mid-April weather charts obtained from the Na- tional Climatic Data Center show a low-pressure area over the central part of the Gulf of Western Birds 18: 215-216, 1987 215 NOTES California on 17 April 1981. The charts show no fronts moving between the Gulf of Califor- nia and Idaho in mid- April. No clear pattern of seasonal occurrence exists for the American Oystercatcher in the western U S. In addition to the inland records for the west mentioned above {one spring, two summer) , five records exist for the California coast, including up to three individuals present year-round for at least 18 years in Santa Barbara Co. (Roberson 1986). West Mex- ican populations are apparently nonmigratory, and immature Eurasian Oystercatchers ( Haematopus ostralegus ) remain on their wintering grounds all year (Hayman et al. 1986), making this extralimital record difficult to explain. We thank Dennis Paulson for his valuable comments on several drafts of this note. We also thank Jon Dunn, Robert Humphrey, Tim Reynolds, John Pitcher, and Chris Chappell for their comments. LITERATURE CITED American Ornithologists’ Union. 1983. Checklist of North American Birds, 6th edition. Am. Ornithol. Union, [Washington D.C.] Hayman, P., Marchant, J., and Prater, T. 1986. Shorebirds: An Identification Guide to the Waders of the World. Houghton Mifflin, Boston. Huntington, D,, and Huntington, S, 1983. Rare and unusual birds of New Mexico. N.M. Ornithol. Soc. Publ. 7. Luther, J. 1980. Fourth report of the California bird records committee. W. Birds 11: 161-173. Prater, A.J., Marchant, J.H., and Vuorinen, J., 1977. Guide to the Identification and Ageing of Holarctic Waders. BTO Guide 17, British Trust for Ornithology, Tring, England. Roberson, D. 1986. Ninth report of the California bird records committee. W. Birds 17: 49-77. Rogers. T.H. 1981. The spring migration. Northern Rocky Mountain-Intermountain Region. Am. Birds 35: 843-846. Accepted 26 December 1987 216 NOTES BARRED OWL SPECIMEN RECORDS FOR MONTANA DAVID H. ELLIS, Montana Department of Fish, Wildlife and Parks, 1420 E. Sixth, Helena, Montana 59620 (present address: U.S. Fish and Wildlife Service, Patuxent Wildlife Research Center, Laurel, Maryland 20708) DWIGHT G. SMITH, Biology Department, Southern Connecticut State University, New Haven, Connecticut 06515 PHILIP L. WRIGHT, Department of Zoology, University of Montana, Missoula, Montana 59812 Taylor and Forsman (1976) reported recent range extensions of the Barred Owl (Strix uaria ) in western North America. Boxall and Stepney (1982) described the species’ distribu- tion and status in Alberta. Shea (1974) summarized sightings, a photographic record, and several vocalization records of Barred Owls in western Montana but collected no specimens. Although published nesting records are not available, D. Flath (pers. comm.) stated that breeding is occasionally reported for the Blackfoot, Bitterroot, and Fisher river valleys (see also Skaar et al. 1985). Marks et al. (1984) reported prey identified from 37 Barred Owl pellets from western Montana. Saunders (1921) reported that Thomas col- lected three Barred Owls near Billings, but the specimens have never been located and Skaar (1975 and pers. comm.) questioned their authenticity. Here we report the first extant Barred Owl specimens for Montana and a range extension east across the continental divide . During 1974 three Barred Owls were found dead in Montana. The first specimen (Univ. Montana No. 15710), a road kill, was found by Ellis and Gus Wolfe on 13 April on Highway 200 1.6 km west of the junction of highways 200 and 287 in Lewis and Clark County, east of the continental divide. The location is on the open prairie about 30 km east of the forested foothills of the Rocky Mountains. On 26 April Peter Widener IV and Ellis located the remains of a second Barred Owl in Powell County about 0.5 km south of the north fork of the Blackfoot River and approximately 73 km southwest of the first specimen. The scattered remains of this owl (Univ. Montana No. 15709) su gg ested that it had been plucked by an avian predator perched ca.5 m up on a horizontal limb in a mature stand of Ponderosa Pine ( Pinus ponderosa). The third bird, an adult female (Univ. Montana No. 15807), was picked up (finder unknown) dead near Patomac, Missoula County, in September 1974. Two other records are well substantiated and deserve mention. An injured bird, recovered 21 December 1976, was rehabilitated by the John Craighead family and re- leased 6 February 1977 on the Lee Metcalf National Wildlife Refuge, Ravalli County. Final- ly, a road-killed female was found 4 October 1981, 1.6 km west of Patomac Bar, Highway 200, Missoula County, by Lynne Meggs and delivered to the University (Univ. Montana No. 17145). In the years following collection of the 1974 specimens, occasional sightings and vocalization records were reported in issues of American Birds. These, the unpublished references to nesting, the food habits report (Marks et al. 1984), and the two additional specimen records all suggest that the Barred Owl has become increasingly common in Montana since the early 1970s. P.D. Skaar provided information on early literature and kindly read a previous version of this manuscript. Ellis’ travels were financed by the Montana Department of Fish, Wildlife and Parks. LITERATURE CITED Boxall, P C., and Stepney, P.H.R. 1982. The distribution and status of the Barred Owl in Alberta. Can. Field-Nat. 96: 46-49. Western Birds 18: 217-218, 1987 217 NOTES Marks, J.S., Elendricks, D.P., and Marks, V.S. 1984 Winter food habits of Barred Owls in western Montana. Murrelet 65: 27-28. Saunders, A. A. 1921. A distributional list of the birds of Montana. Pac. Coast Avifauna 14. Shea, D.S. 1974. Barred Owl records in western Montana. Condor 76: 222. Skaar, D., Flath, D., and Thompson, L.S. 1985. P.D. Skaar’s Montana bird distribution. Mont. Acad. Sci. Monogr. 3. Skaar, P.D. 1975. Montana bird distribution. Preliminary mapping by latilong. P.D. Skaar. Bozeman, MT. Taylor, A.L. Jr., and Forsman, E.D. 1976. Recent range extensions of the Barred Owl in western North America, including the first records for Oregon. Condor 78: 560-561. Accepted 30 November 1987 218 Barred Owl Sketch by Cameron Barrows NOTES OCCURRENCE OF BIRD NESTS ON JUMPING CHOLLA CACTI NAVJOT S. SODHI, Department of Biology, University of Saskatchewan, Saskatoon, Saskatchewan S7N OWO, Canada To study the use of Jumping Cholla cacti (Opuntia fulgida) by birds for nesting, I searched a 200-sq-m area at Organ Pipe Cactus National Monument, Arizona, in April 1987. It was also my aim to find out if nesting birds select particular heights of cacti. Sixty-three bird species breed in Organ Pipe Cactus National Monument (Huey 1942, Groschupf et a!. 1987). 1 classified cacti into three height categories: <1 m, 1-2 m, and >2 m tall; broken cacti and half-built nests were excluded. 1 found nests of only two bird species, the Cactus Wren ( Campylorhpnchus brunneicapillus ) and Curve-billed Thrasher (Toxostoma curuirostre ) . It is possible that one or two older thrasher nests may have been of the Bendire’s Thrasher (T. bendirei ), which also occurs in the study area. Out of 128 cacti, 23 (18.0%) had nests, of which three were active at that time (two of the Cactus Wren and one of the Curve-billed Thrasher) . No nests were in cacti <1 m tall, while 31.3 and 68.7% of cacti that were, respectively, 1 - 2 m and >2 m tall had nests. Previous observations on the Cactus Wren and Curve-billed Thrasher showed that they seldom nest lower than 1 m from the ground (Bent 1948). Out of all nests, 13 (56.6%) were of the Cactus Wren and 10 (43.4%) were of the Curve-billed Thrasher. The mean height of the Cactus Wrens’ nests was 1.51 ± 0.38 m, of the Curve-billed Thrashers’, 1.14 ± 0.28 m. This nest height difference be- tween these two species is statistically significant (p < 0.05, Mann-Whitney U test). Of Cactus Wren nests, 30.7, 30.7, 30.7, and 7.9% had nest entrance east, north, south, and west, respectively. The Cactus Wrens may select nest entrances to avoid winds during cooler early parts of the breeding season and face them during hot parts of the season (Ricklefs and Hainsworth 1969), or nest orientation may be selected at random (Anderson and Anderson 1973). 1 thank Dr. Lynn W. Oliphant for his help and comments on the manuscript. LITERATURE CITED Anderson, A. H., and Anderson, A. 1973. The Cactus Wren. Univ. Ariz. Press, Tucson. Bent, A. C. 1948. Life histories of North American nuthatches, wrens, thrashers, and their allies. U.S. Natl. Mus. Bull. 195. Groschupf, K., Brown, B. T. , and Johnson, R. R. 1987. A Checklist of the Birds of Organ Pipe Cactus National Monument. Southwest Parks and Monument Assoc., Tucson. Huey, L. M. 1942. A vertebrate faunal survey of the Organ Pipe Cactus National Monument, Arizona. Trans. San Diego Soc. Nat. Hist. 9:353-376. Ricklefs, R. E., and Hainsworth, F. R. 1969. Temperature regulation in nestling Cactus Wrens: The nest environment. Condor 71:32-37. Accepted 22 October 1987 Western Birds 18: 219, 1987 219 PRESIDENT’S MESSAGE Have you noticed you’ve been getting issues of Western Birds more frequently than usual in recent months? Editor Philip Unitt has done an excellent job of speeding up the rate of publication in order to get the journal back on schedule. There is perhaps one disconcerting aspect of this, however. Renewal notices come enclosed with issue number four of each volume, because WFO memberships are due by the volume, not by the year. Under ideal circumstances, of course, each volume matches a given year, and the reason we are speeding publication is to catch up to a point where this match occurs. Our goal is to be back on schedule by the end of 1989. Until then, we ask your indulgence if we seem constantly to be asking for renewals. You will be getting a full set of four issues — and good value for your money — each time you renew, regardless of how frequently that may seem to be! One exciting development of which you have already been apprised is our arrange- ment with British Birds, arguably the best journal of its kind in the world and the model for Western Birds, whereby WFO members may claim a 25% discount on a subscrip- tion to the British journal (the discount applies annually as long as you maintain your subscription to Western Birds ) . Our thanks to the publishers of British Birds for allow- ing us to offer this service to you. Presentation of the first Alan M. Craig Award to Alan M. Craig (second from left) at the 1987 WFO meeting in Bellingham, Washington. Shown with Alan are, from left, WFO President Tim Manolis, Vice-President Narca Moore-Craig, and Board Member and Past President Guy McCaskie. 220 Photo by Bruce Webb NEW TREASURER/MEMBERSHIP SECRETARY FOR WFO. After a brief, but much appreciated, stint as WFO treasurer and membership secretary, Art Cupples in- formed the WFO Board of Directors he would be unable to continue in the position. Our thanks to Art for his contributions to WFO in a difficult job. We have been for- tunate in having quickly found a replacement. Howard L. Cogswell, an eminent western field ornithologist in the definitive sense, has volunteered to serve in this capacity. Howard’s years of experience in various official capacities for many ornithological societies will certainly be of great benefit to WFO, and we are happy to welcome him aboard. WFO’S 12TH ANNUAL MEETING. The 12th Annual Meeting of Western Field Or- nithologists was held at Western Washington University, Bellingham, Washington, from 21 to 23 August 1987. Attending the meeting were 130 members, family, and friends, including 48 new members. All were treated to warm, sunny weather, good birding, and stimulating speakers. A special highlight was presentation of the first Alan M. Craig Award to Alan himself (see below) . Special credit goes to Terry Wahl and his local committee for organiz- ing a very successful convention where, as Terry put it, “a whole new population of bird people was exposed to the organization.” THE ALAN M. CRAIG AWARD. Special tribute was paid at the Bellingham meeting to Alan M. Craig’s long years of service as editor of Western Birds. At the annual ban- quet, Alan was the surprised recipient of a special WFO award named in his honor. The first Alan M. Craig Award— a painted bronze statuette of the WFO logo, a flying Sabine’s Gull— was presented by WFO’s first president, Guy McCaskie. Befitting the magnitude of Alan’s contribution to WFO, future Alan M. Craig Awards will be made only on an irregular basis for exceptional service to the organization. Tim Manolis, WFO President 221 WESTERN BIRDS, INDEX, VOLUME 18, 1987 Compiled by Mildred Comar Accipiter cooperii, 12, 13, 15, 91, 92, 195 striatus, 195 Actitis macularia, 92, 197 Aechmophorus clarkii, 92, 98, 192 occidentals, 92, 98, 110, 112, 192 Aegolius funereus, 105, 107 Aeronautes saxatalis, 93, 201 Agelaius phoeniceus, 93, 207 tricolor , 207 Aimophila botterii, 92 carpalis, 92 cassinii, 93 ruficeps, 93, 206 Amazilia uioliceps, 92 Ammodramus henslowii , 98, 104 savannarum, 93, 206 Amphispiza bilineata, 93 quinquestriata , 93 Anas acuta, 92, 112, 194 americana, 112, 186, 194 clypeata, 194 crecca, 112, 194 cyanoptera, 92, 194 discors, 92, 183, 194 penelope, 194 platyrhynchos, 92, 110, 112, 194 strepera, 92, 112, 186, 194 Anderson, Berlin W., see Hunter, W. Ani, Groove-billed, 98, 104 Anser albifrons, 193 Anthus spinoietta, 164, 165, 166, 169, 204 Aphelocoma coerulescens, 203 Aphriza virgata , 197 Aquila chrysaetos, 92, 164, 195 Archilochus alexandri, 91, 92, 201 Ardea herodias, 92, 112, 183, 192 Arenaria interpres, 197 melanocephala , 197 Asia flammeus, 201 otus, 92, 201 Athene cunicularia, 93, 200 Auriparus flauiceps, 92, 203 Avocet, American, 92, 197 Aythya affinis, 112, 194 americana, 92, 194 collaris, 194 fuligula, 194 mari/a, 110, 112, 194 ualisineria , 187, 194 Baker, William S., see Hayes, F. Barn-Owl, Common, 92, 200 Baumgartel, Mona, see King, D. Beardless Tyrannulet, Northern, 13, 15, 92 Becard, Rose-throated, 13, 15, 93 Beezley, John A., and John P. Rieger, Least Bell’s Vireo management by cowbird trapping, 55-61 Bittern, American, 92, 192 Least, 92, 186, 187, 189, 192 Blackbird, Brewer’s, 207 Red-winged, 93, 207 Tricolored, 207 Yellow-headed, 93, 207 Black Hawk, Common, 12, 13, 15, 91, 92, 94, 98, 100 Block, William M., and Leonard A. Brennan, Characteristics of Lewis’ Woodpecker habitat on the Modoc Plateau, California, 209-212 Bluebird, Mountain, 164 Western, 204 Bobolink, 207 Bobwhite, Northern, 92 Bomby cilia cedrorum, 204 Botaurus lentiginosus, 92, 192 Brachyramphus marmoratus, 98, 104 Brambling, 98, 104, 106 Brant, 193 Branta bernicla, 193 canadensis, 193 Brennan, Leonard, A., see Block, W. Bubo uirginianus, 92, 125, 200 Bubulcus ibis, 193 Bucepha/a albeola, 113, 194 clangula, 113, 114, 194 islandica, 104, 113 Bufflehead, 113, 195 Bunting, Indigo, 93 Lazuli, 93, 206 Painted, 93 Varied, 92 Bushtit, 203 Buteo albonotatus, 12, 15, 92 jamaicensis, 92, 164, 195 lagopus, 195 lineatus, 195 nitidus, 15, 91, 92 platypterus, 79, 80, 105 regalis, 92, 195 sujainsoni, 92 Buteogatlus anthracinus, 12, 13, 15, 91, 92, 94, 98, 100 Butorides striatus, 92, 193 Western Birds 18: 223-232, 1987 223 Ca/carius pictus, 99 Calidris alba, 197 alpina, 113, 198 bairdii, 198 ferruginea, 198 himantopus, 198 mauri, 126, 198 melanotos, 126, 128, 198 minutiila, 126, 128, 198 pusilla, 198 subminuta, 126 Callipepla californica, 187, 196 gambelii, 92 squamata, 92 Calothorax lucifer, 93 Calypte anna , 92, 98, 104, 201 costae, 92, 201 Camptostoma imherbe, 13, 15, 92 Campylorhynchus brunneicapillus, 93, 203, 219 Canvasback, 187, 194 Caprimulgus ridgwayi, 92 Caracara, Crested, 92 Cardinal, Northern, 14, 15, 93, 105 Cardinalis cardinalis, 14, 15, 93, 105 sinuatus, 93 Carduelis lawrencei, 93, 208 psaltria, 93, 208 tristis, 208 Carpodacus cassinii, 164 mexicanus, 93, 207 purpureas, 207 Casmerodius albus, 92, 186, 192 Cathartes aura, 92, 195 Catharus fuscescens, 79, 80 guttatus, 204 ustulatus, 204 Catherpes mexicanus, 92 Catoptrophorus semipalmatus, 197 Centrocercus urophasianus, 117-121 Cepphus columba, 113 Certhia americana, 19, 80 Ceryle alcyon, 92, 201 Chaetura pelagica, 201 uauxi, 201 Chamaea fasciata, 204 Charadrius alexandrinus, 92, 187, 188, 196 semipalmatus, 196 uociferus, 92, 113, 196 Chat, Yellow-breasted, 12, 13, 15, 93, 206 Chen caerulescens, 193 rossii, 193 Chickadee, Black-capped, 80 Mountain, 164 Chlidonias niger, 200 Chondestes grammacus , 93, 206 Chordeiles acutipennis, 93, 201 Circus cyaneus, 164, 195 Cistothorus palustris, 93, 204 Clangula hyemalis, 113, 194 Coccyzus americanus, 12, 13, 14, 15, 17, 19-25, 26, 86, 91, 92, 94 Colaptes auratus, 12, 13, 15, 92, 202 Colinus uirginianus, 92 Collins, Charles T., Breeding record of a Dark-eyed Junco on Santa Catalina Island, California, 129-130 Columba fasciata, 200 liuia, 93, 200 Columbina inca, 93 passerina, 92, 170-174 Contopus borealis, 202 sordidulus, 92, 202 uirens, 80, 82 Coot, American, 92, 113, 133, 196 Coragyps atratus, 93 Cormorant, Double-crested, 92, 112, 186, 187, 192 Olivaceous, 97, 99 Pelagic, 112 Coruus brachyrhynchos, 203 corax, 92, 164, 203 cryptoleucus, 93 Cowbird, Bronzed, 93 Brown-headed, 32, 34, 38, 39, 41, 42, 46, 55-61, 62, 63-70, 81, 93, 94, 153, 158, 159, 207 Crane, Sandhill, 131-132 Creeper, Brown, 79, 80 Crotophaga sulcirostris, 98, 104 Crow, American, 203 Cuckoo, Yellow-billed, 12, 13, 14, 15, 17, 19-25, 26, 86, 91, 92, 94 Curlew, Long-billed, 197 Cygnus buccinator, 98, 100 columbianus, 193 Cynanthus latirostris, 92 Cypseloides niger, 201 DeBeer, John, see King, D. Dendragapus canadensis, 133 Dendrocygna autumnalis, 92, 98, 99 Dendroica castanea, 105 coronata, 205 discolor, 205 kirtlandii, 63, 67 224 nigrescens, 205 occidentals, 98, 104, 205 palmarum, 205 petechia, 12, 15, 91, 93, 94, 205 striata, 205 townsendi, 205 Dolichonyx oryzivorus, 207 Dove, Common Ground-, 92, 170-174 Inca, 93 Mourning, 92, 133, 200 Rock, 93, 200 Spotted, 200 White-winged, 92, 200 Dowitcher, Long-billed, 198 Short-billed, 198 Dryocopus pileatus, 79, 80, 81 Duck, Black-bellied Whistling, 92, 98, 99 Harlequin, 112 Ring-necked, 194 Ruddy, 92, 187, 195 Tufted, 194 Dunlin, 113, 198 Eagle, Bald, 14, 15, 91, 92, 94, 115, 195 Golden, 92, 164, 195 Eider, Common, 99 Egret, Cattle, 193 Great, 92, 186, 192 Reddish, 193 Snowy, 92, 193 Egretta caerulea, 193 rufescens, 193 thula, 92, 193 tricolor, 193 Elanus caeruleus, 195 Ellis, David H , Dwight G. Smith, and Philip L. Wright, Barred Owl specimen records for Montana, 217-218 Ellis, Kevin L., Joseph R, Murphy, and Gary H. Richins, Distribution of breeding male Sage Grouse in northeastern Utah, 117-121 Empidonax alnorum, 104, 137, 138, 143, 144 difficilis, 202 hammondii , 202 trail lii, 6, 12, 13, 15, 17, 27-36, 37-42, 67, 92, 137-162, 202 Eremophila alpestris , 93, 203 Eudocimus albus, 97, 99 Euphagus cyanocephalus, 207 Falco co/umbarius, 196 femoralis, 92 mexicanus, 92, 192 peregrinus, 92, 196 sparuerius, 92, 164, 195 Falcon, Aplomado, 92 Peregrine, 92, 196 Prairie, 92, 196 Finch, Cassin’s, 164 House, 93, 208 Purple, 207 Rosy, 98, 164, 165, 167 Flett, Mary Anne, and Susan D. Sanders, Ecology of a Sierra Nevada population of Willow Flycatchers, 37-42; see also Harris, J. Flicker, Northern, 12, 13, 15, 92, 202 Flycatcher, Alder, 104, 137, 138, 143, 144 Ash-throated, 92, 202 Brown -crested, 12, 15, 92 Hammond’s, 202 Olive-sided, 202 Scissor-tailed, 202 Vermilion, 12, 15, 92, 105, 202 Western, 202 Willow, 6, 12, 13, 15, 17, 27-36, 37-42, 67, 92, 137-162, 202 Fowler, Norman E., and Robert W. Howe, Birds of remnant riparian forests in northeastern Wisconsin, 77-83 Franzreb, Kathleen E., Perspectives on managing riparian ecosystems for endangered bird species, 3-9; Endangered status and strategies for conservation of the Least Bell’s Vireo ( Vireo bellii pusillus) in California, 43-49 Fregata magnificens, 97, 99, 192 Frigatebird, Magnificent, 97, 99, 192 Fringilia montifringilla, 98, 104, 106 Fulica americana, 92, 113, 133, 196 Gadwall, 92, 112, 186, 194 Gallinago g allinago, 128, 187, 198 Gallinula chloropus, 92, 196 Gallinule, Purple, 98, 100 Garrison, Barrett A., Joan M. Humphrey, and Stephen A. Laymon, Bank Swallow distribution and nesting ecology on the Sacramento River, California, 71-76 Gauia adamsii, 97, 99 225 arctica, 98 immer, 110, 112 pacifica, 98, 192 stellata, 110, 112, 192 Gent, Peter R., Colorado Field Ornithologists’ Records Committee report for 1978-1985, 97-108 Geococcyx caiifornianus, 92, 187, 200 Geothlypis trichas, 93, 206 Gilligan, Jeff, Owen Schmidt, Harry Nehls, and David Irons, First record of Long-toed Stint in Oregon, 126-128 Glaucidium brasilianum, 12, 13, 15, 17, 91 Gnatcatcher, Black-tailed, 92, 187, 188, 204 Blue-gray, 93, 188, 204 Godwit, Marbled, 105, 197 Goldeneye, Barrow’s, 104, 113 Common, 113, 114, 195 Goldfinch, American, 208 Lawrence’s, 93, 208 Lesser, 93, 208 Goose, Canada, 193 Greater White-fronted, 193 Ross’, 193 Snow, 187, 193 Grackle, Great-tailed, 93, 105, 207 Greaves, James M., Nest-site tenacity of Least Bell’s Vireos, 50-54 Grebe, Clark’s, 92, 98, 192 Eared, 192 Horned, 112, 114, 192 Pied-billed, 92, 184, 187, 192 Red-necked, 112 Western, 92, 98, 110, 112, 114, 192 Grosbeak, Black-headed, 157, 206 Blue, 14, 15, 91, 93, 206 Ground-Dove, Common, 92, 170-174 Grouse, Sage, 117-121 Sharp-tailed, 133 Spruce, 133 Grus canadensis, 131-132 Guillemot, Pigeon, 113 Guiraca caerulea, 14, 15, 91, 93, 206 Gull, Bonaparte’s, 199 California, 199 Franklin’s, 199 Glaucous, 199 Glaucous- winged, 98, 100, 113, 199 Great Black-backed, 98, 100, 102 Heermann’s, 199 Herring, 199 Little, 98, 100 Mew, 98, 100, 101, 199 Ring-billed, 175-176, 199 Ross’, 98, 100, 103 Thayer’s, 199 Western, 199 Haematopus ostralegus, 216 palliatus, 215-216 Haight, Lois T,, see Johnson, R. Haliaeetus leucocephalus, 14, 15, 91, 92, 94, 114, 195 Halterman, Mary D., see Laymon, S. Harrier, Northern, 164, 195 Harris, John H., Susan D. Sanders, and Mary Anne Flett, Willow Flycatcher surveys in the Sierra Nevada, 27-36 Hawk, Broad-winged, 79, 80, 105 Common Black, 12, 13, 15, 91, 92, 94, 98, 100 Cooper’s, 12, 13, 15, 91, 92, 192 Ferruginous, 92, 195 Gray, 15, 91, 92 Harris’, 12, 13, 15, 91, 93 Red-shouldered, 186, 195 Red-tailed, 92, 164, 195 Rough-legged, 195 Sharp-shinned, 195 Swainson’s, 92 Zone-tailed, 12, 15, 92 Hayes, Floyd E., and William S. Baker, Loggerhead Shrike feeds on a dead American Coot, 133-134 Heron, Great Blue, 92, 112, 183, 192 Green-backed, 92, 193 Little Blue, 193 Tricolored, 193 Heteroscelus incanus, 197 Himantopus mexicanus, 92, 196, 215 Hirundo fulva, 125 pyrrhonota, 93, 203 rustica, 93, 203 Histrionicus histrionicus, 112 Holloway, Gaylin D., see Littlefield, C. Howe, Robert W., see Fowler, N. Hummingbird, Allen’s, 201 Anna’s, 92, 98, 104, 201 Black-chirmed, 91, 92, 201 Broad-billed, 92 Broad-tailed, 164 Costa’s, 92, 201 Lucifer, 93 Rufous, 201 Violet-crowned, 92 226 Humphrey, Joan M., see Garrison, B. Hunter, William C,, Robert D. Ohmart, and Bertin W. Anderson, Status of breeding riparian -obligate birds in southwestern riverine systems, 10-18 Hylocichla mustelina, 79, 80, 81, 82, 84 Ibis, Glossy, 99 White, 97, 99 White-faced, 193 Icteria virens, 12, 13, 15, 93, 206 Icterus cucullatus, 12, 15, 93, 207 galbulo, 15, 93, 207 parisorum, 93, 105, 207 spurius, 207 Ictinia mississippiensis, 11, 15, 92 Irons, David, see Gilligan. J. Ixobrychus exilis, 92, 186, 187, 189, 192 Ixoreus naevius, 204 Jacana, Northern, 123-124 Jacana spinosa, 123-124 Jaeger, Parasitic, 199 Pomarine, 199 Jay, Scrub, 203 Johnson, L. Scott, Song in a female Plain Titmouse, 135 Johnson, R, Roy, Lois T, Haight, and James ML Simpson, Endangered habitats versus endangered species: A management challenge, 89-96 Junco, Dark-eyed, 98, 129-130, 164, 207 Junco hyemalis, 98, 129-130, 164, 207 Kestrel, American, 92, 164, 195 Killdeer, 92, 113, 196 King, David B., Jr., Mona Baumgartel, John DeBeer, and Terry Meyer, The birds of San Elijo Lagoon, San Diego County, California, 177-208 Kingbird, Cassin’s, 91, 92, 202 Eastern, 202 Thick-billed, 13, 15, 93 Tropical, 15, 92, 202 Western, 91, 93, 202 Kingfisher, Belted, 92, 201 Kinglet, Golden-crowned, 204 Ruby-crowned, 204 Kite, Black-shouldered, 195 Mississippi, 11, 15, 92 Kittiwake, Black-legged, 199 Knot, Red, 197 Lanius excubitor, 133 ludouicianus, 92, 133-134, 205 Lark, Horned, 93, 203 Larus argentatus, 199 calif ornicus, 199 canus, 98, 100, 101, 199 delawarensis, 175-176, 199 glaucescens, 98, 100, 113, 199 heermanni, 199 hyperboreus, 199 marinus, 98, 100, 102 minutus, 98, 100 occidentalis, 199 Philadelphia, 199 pipixean, 199 thayeri, 199 Laterallus jamaicensis, 92, 98, 100, 196 Laymon, Stephen A., Management and preservation of endangered birds in riparian ecosystems: A symposium presented in conjunction with the Cooper Ornithological Society Annual Meeting, 10 September, 1986, 1-2; and Mary D. Halterman, Can the western subspecies of the Yellow-billed Cuckoo be saved from extinction?, 19-25; Brown-headed Cowbirds in California: Historical perspectives and management opportunities in riparian habitats, 63-70; see also Garrison, B. Leucosticte arctoa, 98, 164, 165, 167 Limnodromus griseus, 198 scolopaceus , 198 Limosa fedoa, 105, 197 Littlefield, Carroll D., and Gaylin D. Holloway, The first record of a four- egg clutch for Sandhill Cranes, 131-132 Longspur, Smith’s, 99 Loon, Arctic, 98 Common, 110, 112, 114 Pacific, 98, 192 Red-throated, 110, 112, 192 Yellow-billed, 97, 99 Lophodytes cucullatus, 113, 195 Mallard, 92, 110, 112, 186, 194 Martin, Purple, 93, 203 Meadowlark, Eastern, 93 Western, 93, 207 Medin, Dean E., Breeding birds of an alpine habitat in the southern Snake Range, Nevada, 163-168 227 Melanerpes aurifrons, 92 lewis, 209 uropygialis, 12, 13, 15, 91, 92 Melanitta fusca, 110, 113 nigra, 110, 113, 114 perspicillata, 110, 113, 194 Melospiza georgiana, 207 lincolnii, 207 melodia, 52, 93, 187, 207 Merganser, Common, 92, 113, 195 Hooded, 113, 195 Red-breasted, 113, 195 Mergus merganser, 92, 113, 195 senator, 113, 195 Merlin, 196 Meyer, Terry, see King, D. Micrathene whitneyi, 12, 13, 15, 92 Miller, Aaron A., see Schmitt, C. G. Mimus polyglottos, 92, 183, 204 Mniotilta uaria, 79, 80, 205 Mockingbird, Northern, 92, 183, 204 Molothrus aeneus, 93 ater, 32, 34, 38, 39, 41, 42, 46, 55-61, 62, 63-70, 93, 94, 153, 158, 159, 207 Moorhen, Common, 92, 196 Murphy, Joseph R., see Ellis, K. Murre, Common, 110, 113, 200 Murrelet, Ancient, 213-214 Marbled, 98, 104 Myadestes townsendi, 164, 204 Mycteria americana, 193 Myiarchus cinerascens, 92, 202 tyrannulus, 12, 15, 92 Nehls, Harry, see Gilligan, J. Nighthawk, Lesser, 93, 201 Night-Heron, Black-crowned, 92, 193 Yellow-crowned, 104, 193 Nightjar, Buff-collared, 92 Nucifraga Columbiana, 164 Numenius americanus, 197 phaeopus, 197 Nutcracker, Clark’s, 164 Nuthatch, Red-breasted, 79, 80, 82 White-breasted, 15, 80, 82, 91, 93 Nycticorax nycticorax, 92, 193 uiolaceus, 104, 193 Ohmart, Robert D., see Hunter, W. Oldsquaw, 113, 194 Oporomis Philadelphia, 104 tolmiei, 206 Oreoscoptes montanus, 204 Oriole, Hooded, 12, 15, 93, 207 Northern, 15, 93, 207 Orchard, 207 Scptt’s, 93, 105, 207 Osprey, 92, 195 Otus kennicottii, 91, 92, 98 Ovenbird, 79, 80, 81, 82, 84 Owl, Barred, 217-218 Boreal, 105, 107 Burrowing, 93, 200 Elf, 12, 13, 15, 92 Ferruginous Pygmy, 12, 13, 15, 17, 91 Great Horned, 92, 125, 200 Long-eared, 92, 201 Short-eared, 201 Western Screech, 91, 92, 98 Oxyura jamiacensis, 92, 195 Oystercatcher, American, 215-216 Eurasian, 216 Pachyramphus aglaiae, 13, 15, 93 Pandion ha/iaetus, 92, 195 Parabuteo unicinctus, 12, 13, 15, 92, 93 Parula, Northern, 205 Parula americana, 205 Parus atricapillus, 80 bicolor, 135 gambeli, 164 inornatus, 135 woilweberi, 15, 93, 135 Passer domesticus, 93, 187, 208 Passerculus sandwichensis, 187, 188, 189, 206 Passerella iliaca, 207 Passerina amoena, 93, 206 ciris, 93 cyanea, 93 versicolor, 92 Pelecanus erythrorhynchos, 192 occidentalis, 186, 192 Pelican, American White, 192 Brown, 186, 192 Phainopepla, 93, 204 Phainopepla nitens, 93, 204 Phalacrocorax auritus, 92, 112, 186, 187, 192 oliuaceus, 97, 99 pelagicus, 112 Phalaenoptilus nuttallii, 93, 201 Phalarope, Red, 199 Red-necked, 198 Wilson’s, 198 Phalaropus fulicaria, 199 228 lobatus, 198 tricolor , 198 Phasianus colchicus, 196 Pheasant, Ring-necked, 196 Pheucticus melanocephalus, 157, 206 Philomachus pugnax, 198 Phoebe, Black, 92, 202 Eastern, 202 Say’s, 93, 202 Picoides nuttallii, 201 pubescens, 201 scalaris, 91, 92 uillosus, 79, 80, 201 Pigeon, Band-tailed, 200 Pintail, Northern, 92, 112, 194 Pipilo aberti, 15, 91, 93 chlorurus, 206 erythrophthalmus, 183, 206 fuse us, 91, 93, 206 Pipit, Water, 164, 165, 166, 169, 204 Piranga flaua, 105 ludouiciana, 157, 206 oliuacea, 80 rubra, 12, 13, 15, 91, 93, 206 Plegadis chihi, 193 falcinellus, 99 Plover, Black-bellied, 113, 196 Lesser Golden, 196 Semipalmated, 196 Snowy, 92, 187, 188, 196 Pluuialis dominica, 196 squatarola, 113, 196 Podiceps auritus, 112, 114, 192 grisegena, 112 nigricoilis, 192 Podilymbus podiceps, 92, 184, 187, 192 Polioptila caerulea, 93, 188, 204 melanura, 92, 187, 188, 204 Polyborus plane us, 92 Pooecetes gramineus, 206 Poor- will, Common, 93, 201 Porphyrula martinica, 98, 100 Porzana Carolina, 92, 196 Progne subis, 93, 203 Psaltriparus minimus, 203 Pygmy-Owl, Ferruginous, 12, 13, 15, 17, 91 Pyrocephalus, rubinus, 12, 15, 92, 105, 202 Pyrrhuloxia, 93 Quail, California, 187, 196 Gambel’s, 92 Scaled, 92 Quiscalus mexicanus, 93, 105, 207 Rail, Black, 92, 98, 100, 196 Clapper, 92, 187, 188, 189, 196 King, 98, 100 Virginia, 92, 196 Rallus elegans, 98, 100 limicola , 92, 196 longirostris, 92, 187, 188, 189, 196 Raven, Chihuahuan, 93 Common, 92, 164, 203 Recurvirostra americana, 92, 197 Redhead, 92, 194 Redstart, American, 206 Regulus calendula, 204 satrapa, 204 Rhodostethia rosea, 98, 100, 103 Richins, Gary H., see Ellis, K. Rieger, John P,, see Beezley, J. Riparia riparia, 93, 71-76, 203 Rissa tridactyla, 199 Roadrunner, Greater, 92, 187, 200 Robin, American, 93, 164, 204 Ruff, 198 Rynchops niger, 200 Sail, Torbjorn, see Udvardy, D. Salpinctes obsoletus, 93, 164, 165, 166, 167, 204 Sanderling, 197 Sanders, Susan D., see Harris, J.; see Flett, M, Sandpiper, Baird’s, 198 Curlew, 198 Least, 126, 128, 198 Pectoral, 126, 128, 198 Semipalmated, 198 Solitary, 197 Spotted, 92, 197 Stilt, 198 Western, 126, 198 Sapsucker, Red-breasted, 201 Red-naped, 98, 210 Sayornis nigricans, 92, 202 phoebe, 202 say a, 93, 202 Scaup, Greater, 110, 112, 194 Lesser, 112, 194 Schmidt, Owen, see Gilligan, J. Schmitt, C. Gregory, and Aaron A. Miller, A Specimen record of the Ancient Murrelet from New Mexico, 213-214 Scoter, Black, 110, 113, 114 Surf, 110, 113, 194 White-winged, 110, 113 229 Screech-Owl, Western, 91, 92, 98 Seiurus aurocapillus, 79, 80, 81, 82, 84 noueboracenis, 206 Selasphorus platycercus, 164 rufus, 201 sasin, 201 Setophaga ruticilla, 206 Shaw, Carrie Anne, The California natural diversity data base and riparian ecosystem conservation, 85-88 Shoveler, Northern, 194 Shrike, Loggerhead, 92, 133-134, 205 Northern, 133 Sialia currucoides, 164 mexicana, 204 Simpson, James M., see Johnson, R. Siskin, Pine, 208 Sitta canadensis, 15, 79, 80, 82 carolinensis, 80, 82, 91, 93 Skimmer, Black, 200 Smith, Dwight G., see Ellis, D. Snipe, Common, 128, 187, 198 Sodhi, Navjot S., Occurrence of bird nests on Jumping Choila cacti, 219 Solitaire, Townsend’s, 164, 204 Somateria mollissima, 99 Sora, 92, 196 Sparrow, Belding’s Savannah, 187, 188, 189, 206 Black-throated, 93 Botteri’s, 92 Cassin’s, 93 Chipping, 206 Five-striped, 93 Fox, 207 Golden-crowned, 207 Grasshopper, 93, 206 Henslow’s, 98, 104 House, 93, 187, 208 Large-billed Savannah, 206 Lark, 93, 206 Lincoln's, 207 Rufous-crowned, 93, 206 Rufous- winged, 92 Savannah, 187, 188, 189, 206 Song, 52, 93, 187, 207 Swamp, 207 Vesper, 206 White-crowned, 207 White-throated, 207 Speich, Steven M., and Steven P. Thompson, Impacts on waterbirds from the 1984 Columbia River and Whidbey Island, Washington, oil spills, 109-116 Spencer, Kevin T., Range extension of the Common Ground-Dove into Santa Barbara and Ventura Counties, California, 171-174 Sphyrapicu s nuchalis, 98, 201 ruber, 201 Spizella passerina, 206 Starling, European, 93, 205 Stelgidopteryx serripennis, 92, 203 Stephens, Daniel A., and James E. Stephens, An American Oyster- catcher in Idaho, 215-216 Stephens, James E., see Stephens, D. Stercorarius parasiticus, 199 pomarinus, 199 Sterna antillarum, 105, 200 caspia, 100, 199 elegans, 200 forsteri, 200 hirundo, 200 maxima, 199 paradisaea, 98, 100 Stilt, Black-necked, 92, 196, 215 Stint, Long-toed, 126 Stork, Wood, 193 Strix uaria, 217-218 Sturnella magria, 93 neglecta, 93, 207 St urn us vulgaris, 93, 205 Surfbird, 197 Swallow, Bank, 71-76, 93 Barn, 93, 203 Cave, 125 Cliff, 93, 203 Northern Rough- winged, 92, 203 Tree, 203 Violet-green, 164, 203 Swan, Trumpeter, 98, 100 Tundra, 193 Swift, Black, 201 Chimney, 201 Vaux’s, 201 White-throated, 93, 201 Synthliborhamphus antiquus, 213-214 Tachycineta bicolor, 203 thalassina, 164, 203 Tanager, Hepatic, 105 Scarlet, 80 Summer, 12, 13, 15, 91, 93, 206 Western, 157, 206 Tattler, Wandering, 197 230 Teal, Blue-winged, 92, 183, 194 Cinnamon, 92, 194 Green-winged, 112, 194 Tern, Arctic, 98, 100 Black, 200 Caspian, 100, 199 Common, 200 Elegant, 200 Forster’s, 200 Least, 105, 200 Royal, 199 Thompson, Steven P., see Speich, S. Thrasher, Bendire's, 93, 204, 219 California, 187, 204 Crissal, 15, 92 Curve-billed, 92, 219 Le Conte’s, 93 Sage, 204 Thrush, Hermit, 204 Swainson’s, 204 Varied, 204 Wood, 79, 80, 81, 82, 84 Thryomanes bewickii, 93, 204 Titmouse, Bridled, 15, 93, 135 Plain, 135 Tufted, 135 Towhee, Abert’s, 15, 91, 93 Brown, 91, 93, 206 Green-tailed, 206 Rufous-sided, 183, 206 Toxostoma bendirei, 93, 204, 219 curvirostre, 92, 219 dorsale, 15, 92 lecontei, 93 rediuiuum, 187, 204 Tringa flavipes, 197 melanoleuca , 197 solitaria, 197 Troglodytes aedon, 204 troglodytes, 79, 80, 81 Turdus migratorius, 93, 164, 204 Turnstone, Black, 197 Ruddy, 197 Tympanuchus phasianellus, 133 Tyrannulet, Northern Beardless, 13, 15, 92 Tyrannus crassirostris, 13, 15, 93 forficatus, 202 melancholicus, 15, 92, 202 tyrannus, 202 uerticalis, 91, 93, 202 uociferans, 92, 202 Tyto alba, 92, 200 Udvardy, Miklos D. F., and Torbjorn Sail, Ring-billed Gull on the Galapagos Islands, 175-176 Unitt, Philip, Empidonax traillii extimus: An endangered subspecies, 137-162 Uria aalge, 110, 113, 200 Veery, 79, 80 Verdin, 92, 203 Vermivora celata, 205 luciae, 15, 91, 93, 94 peregrina, 205 ruficapilla, 205 uirginiae, 205 Vireo, Bell’s, 6, 7, 12, 13, 14, 15, 17, 43-49, 50-54, 55-61, 63, 66, 93, 94, 153, 154, 157, 205 Hutton’s, 187, 205 Red-eyed, 80, 82 Solitary, 205 Warbling, 205 Vireo beilii, 6, 7, 12, 13, 14, 15, 17, 43-49, 50-54, 55-61, 63, 66, 93, 94, 153, 154, 157, 205 giluus, 205 huttoni, 187, 205 olivaceus, 80, 82 solitarius , 205 Vulture, Black, 93 Turkey, 92, 195 Warbler, Bay-breasted, 105 Black-and-white, 79, 80, 205 Blackpoll, 205 Black-throated Gray, 205 Hermit, 98, 104, 205 Kirtland’s, 63, 67 Lucy’s, 15, 91, 93, 94 MacGillivray’s, 206 Mourning, 104 Nashville, 205 Orange-crowned, 205 Palm, 205 Prairie, 205 Tennessee, 205 Townsend’s, 205 Virginia’s, 205 Wilson’s, 187, 206 Yellow, 12, 15, 91, 93, 94, 205 Yellow-rumped, 205 Waterthrush, Northern, 206 Waxwing, Cedar, 204 231 West, Steve, Great Horned Owl predation on Cave Swallows, 125 Whimbrel, 197 Whistling-Duck, Black-bellied, 92, 98, 99 Wigeon, American, 112, 186, 194 Eurasian, 194 Willet, 197 Williams, Sartor O., Ill, A Northern Jacana in Trans-Pecos Texas, 123-124 Wilsonia pusilla, 187, 206 Wood-Pewee, Eastern, 80, 82 Western, 92 Woodpecker, Downy, 201 Gila, 12, 13, 15, 91, 92 Golden-fronted, 92 Hairy, 79, 80, 201 Ladder-backed, 91, 92 Lewis’, 209, 212 Nuttall’s, 201 Pileated, 79, 80, 81 Wren, Bewick’s, 93, 204 Cactus, 93, 203, 219 Canyon, 92 House, 204 Marsh, 93, 204 Rock, 93, 164, 165, 166, 167, 204 Winter, 79, 80, 81 Wrentit, 204 Wright, Philip L., see Ellis, D. Xanthocephalus xanthocephalus, 93, 207 Yellowlegs, Lesser, 197 Greater, 197 Yellowthroat, Common, 93, 206 Zenaida asiatica, 92, 200 macroura, 92, 133, 200 Zonotrichia albicollis, 207 atricapilla, 207 leucophrys, 207 232 Volume 18, Number 4, 1987 The Birds of San Elijo Lagoon, San Diego County, California Dauid B. King, Jr. , Mona Baumgartel, John DeBeer, and Terry Meyer 177 Characteristics of Lewis’ Woodpecker Habitat on the Modoc Plateau, California William M. Block and Leonard A. Brennan 209 NOTES A Specimen Record of the Ancient Murrelet from New Mexico C. Gregory Schmitt and Aaron A. Miller 213 An American Oystercatcher in Idaho Daniel A. Stephens and James E. Stephens 215 Barred Owl Specimen Records for Montana Dauid H. Ellis, Dwight G . Smith, and Philip L. Wright 217 Occurrence of Bird Nests on Jumping Cholla Cacti Navjot S. Sodhi 219 President’s Message Tim Manolis 220 Bulletin Board 222 Index Mildred Comar 223 Cover photo by Darrell Gulin (Nature’s Images, Seattle, Washington): Cinnamon Teal (Anas cyanoptera) , Malheur National Wildlife Refuge, Harney County, Oregon, June 1985. Western Birds solicits papers that are both useful to and understandable by amateur field ornithologists and also contribute significantly to scientific litera- ture. The journal welcomes contributions from both professionals and amateurs. Appropriate topics include distribution, migration, status, identifica- tion, geographic variation, conservation, behavior, ecology, population dynamics, habitat requirements, the effects of pollution, and techniques for censusing, sound recording, and photographing birds in the field. Papers of general interest will be considered regardless of their geographic origin, but particularly desired are reports of studies done in or bearing on the Rocky Mountain and Pacific states and provinces, including Alaska and Hawaii, western Texas, northwestern Mexico, and the northeastern Pacific Ocean. Send manuscripts to Philip Unitt, 3411 Felton Street, San Diego, CA 92104. For matter of style consult the Suggestions to Contributors to Western Birds (8 pages available at no cost from the editor) and the Council of Biology Editors Style Manual (available for $24 from the Council of Biology Editors, Inc., 9650 Rockville Pike, Bethesda, MD 20814. Reprints can be ordered at author’s expense from the Editor when proof is returned or earlier. Good photographs of rare and unusual birds, unaccompanied by an article but with caption including species, date, locality and other pertinent information, are wanted for publication in Western Birds. Submit photos and captions to Photo Editor.