Yellow-billed Cuckoo (Coccyzus americanus)
A familiar denizen of open broadleaved forests in the se. U.S., the “rain crow” has a place in American folklore as a harbinger of wet weather, purportedly delivering its distinctive “ka-ka-ka-ka-kow-kow-kowlp-kowlp-kowlp” call on cloudy summer days prior to the onset of rain. Although the association between its singing activity and precipitation likely is apocryphal, the Yellow-billed Cuckoo would be a welcome addition to riparian landscapes in the American West regardless of whether rain was soon to follow, because it has undergone serious declines in this region. Short-term changes in numbers can be related to outbreaks of tent caterpillars and cicadas, but loss of riparian habitat is the cause of long-term declines in the West. Yellow-billed Cuckoos breed in much of the U.S. east of 104°W south to c. Mexico, the n. Yucatan Peninsula, and the Greater Antilles; they winter in South America, mostly east of the Andes. Their distribution west of the 104th meridian is patchy, and they appear to have been extirpated as breeders in se. British Columbia, Washington, Oregon, and Nevada (Hughes 1999).
Subspecies: Eastern (C. a. americanus) and western (C. a. occidentalis) subspecies delineated on the basis of slight differences in wing, bill, and tail measurements (western birds larger). Validity of these subspecies is controversial (see Banks 1988, Franzreb and Laymon 1993, Pruett et al. 2001); if valid, both subspecies occur in Montana given that specimens from west of of the Continental Divide are slightly larger than those from east of the divide (P. Hendricks, pers. obs.).
Status and Occurrence: Presumed occasional breeding resident, with at least 22 records statewide, although no nests have been found. Determining the exact number of records is complicated by the fact that documentation is poor for most sightings, few of which were evaluated by the MBRC. Earliest confirmed record a male taken along the Tongue R. just south of Miles City, 10 Jul 1921 (FMNH 159258; Hedges 1924). The seven other specimens are from 2 km east of Logan Pass, Glacier NP, 23 Jul 1958 (UMZM 5020; road kill that may have come from elsewhere; see Hoffmann and Hand 1962); Hamilton, 12 Jun 1961 (UMZM 6521); near Tongue R. Res., 7 Jun 1978 (MSUZM 6420); Missoula, 3 Jul 1980 (UMZM 16724); Bozeman, 26 Jun 1982 (MSUZM 6670); near Stevensville, 7 Jun 1988 (UMZM 17500; not “May 1984” as written on label; see AB 42: 1319); and Billings, summer 1996 (exact date unknown; UMZM 18143). Dated records span 7 Jun to 23 Jul; two-thirds of the records are from east of the Continental Divide.
Because of its secretive nature and apparent rarity, the Yellow-billed Cuckoo could easily be overlooked during the breeding season. Studies are needed to determine if this species breeds in the state and to help understand abundance and habitat preferences; variation in numbers owing to changes in food availability makes it difficult to determine population trends.
Habitat: Open woodlands, abandoned farmlands, dense thickets, and riparian woodlands, the latter especially important in the West (Hughes 1999). Most Montana sightings are from riparian cottonwoods and willows. Nest is a rather flimsy platform of twigs built on a horizontal limb or vertical fork in a tree or shrub in dense vegetation, typically 1-6 m above ground (Hughes 1999).
Conservation: Level II Priority and Species of Concern in Montana. West of the Continental Divide (corresponding to C. a. occidentalis), the species is considered a Candidate for listing under the Endangered Species Act. BBS data indicate a decline in numbers of 2.1% per year in the U.S. and Canada from 1980-2007. In California, estimates of 15,000 pairs a century ago have been reduced to about 30 pairs (Hughes 1999). Loss of riparian habitat from agriculture and urbanization is a major factor in population declines of the w. subspecies (Laymon and Halterman 1987). The global population estimate is 9,200,000 birds, 92% of which occur north of Mexico (Rich et al. 2004).
Historical Notes: In examining reports by various 19th-century naturalists, one might conclude that Yellow-billed Cuckoos have been rare in Montana for at least two hundred years. The species was not mentioned by Lewis and Clark, Maximilian, Suckley, Hayden, Coues, Grinnell, or Bendire. Joel Allen (1874: 63) saw a cuckoo along the Yellowstone R. in the summer of 1873 but was unsure of the species. Indeed, the first report of this species in the state is from James Cooper, who was in Fort Benton from 2 Jul to 7 Aug 1860: “I saw this Cuckoo near Fort Benton, but not in the Rocky Mountains, although it may have left for the south when I reached there (Aug. 15), as it departs early” (Cooper 1869a: 597). Cooper obtained no specimen and provided no other details for the sighting. On 3 Jul 1900, Perley Silloway (1901: 30) found an egg on the ground near Bigfork, stating that “In size and appearance, the specimen closely corresponds to the egg of the black-billed cuckoo, or the western representative of the yellow-billed cuckoo.” Saunders (1921: 174) later posited that the egg was from a Yellow-billed Cuckoo because he believed that Black-billed Cuckoos did not occur in w. Montana. Many of Silloway’s nests and eggs are in the University of Montana zoology collection, but the mystery “cuckoo” egg is not among them.
Sponsored by Lou Ann Harris, Bozeman
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