Coccyzus americanus occidentalis

Western Yellow-Billed Cuckoo-Candidate

Description: The Yellow-billed Cuckoo is a small to medium sized bird with uniform brown plumage covering the wings and body with white under-parts. The loose webbed plumage actually accounts for half the cuckoos body weight. Under its long tail are two columns of four to six large white circles. The lower portion of the bill is a yellow color that gives this bird its common name. The bill is short to medium in length and somewhat curved. They have zygodactylous feet, meaning that of the four toes, the middle two point forwards and the outer two point backwards. Sexual differentiation does not exist, except in size.

Habitat: The Yellow-billed cuckoo is a riparian obligate species which requires dense cottonwood-willow forested tracts of at least 16.8 hectares including a minimum of 3.0 hectares of closed-canopy broadleaf forest. It is indicated that the riparian habitat needs to be at least 100 meters wide. Optimal habitat is greater than 80 hectares and wider than 580 meters. Foraging occurs mostly in the cottonwood canopy, but nests are situated almost entirely in willows.

Range: Lately the only consistent set of recent sightings in Nevada is on a stretch of the Carson River. The most recent documentation of Yellow-billed cuckoos breeding in Nevada was a pair at Beaver Dam Wash (Lincoln County). They are neo-tropical migrants that winter in South America.

Breeding: Breeding normally coincides with that of the cicada and tent caterpillar. Studies have shown that in times of prey abundance, production of eggs will increase. This positive reproductive response to the increased abundance of prey indicates exceptional adaptive value. Nests are in small trees or shrubs, 0.6-3.6 m (2-12 ft) above the ground. They lay 1-5 pale bluish green eggs that fade to a light greenish yellow, elliptical to cylindrical in shape, 3 x 0.4 cm (1.2 x 0.9 in).

Diet: Mainly insectivorous, the cuckoo predominantly preys on hairy caterpillars and cicadas. Their diet also includes bird eggs, snails, small vertebrates such as frogs and lizards, berries and some fruit.

Conservation Status: There has been a drastic reduction in breeding range due to riparian habitat alteration or destruction. References: Ehrlich, Paul R., David S. Dobkins and Darryl Wheve. 1988. The Birder's Handbook. Simon and Schuster, Inc., New York. p.286. Fleischer, Robert C., Michael T. Murphy and Lawrence E. Hunt. 1985. Clutch Size Increase and Intraspecific brood parasitism. The Wilson Bulletin. Vol. 97, No.1:125-7. March. Gaines, D.1974. Review of the status of the Yellow-billed Cuckoo in California- Sacramento Valley populations. Condor 76:204 –209. Kingery, H.P. 1979. The Mountain West. American Birds 33(4). Lasley, Greg W. and Chuck Sexton. 1985. South Texas Region. American Birds. Vol 39: 933-36. Laymon, S. A. and M.D. Halterman. 1987. Can the western subspecies of the Yellow-billed Cuckoos in California. USDA Forest Service Gen. Tech. Rpt. PSW – 110. pp. 272 – 277. Parker, Sybil P., ed. 1982. Synopsis and Classification of Living Organisms. Vol. 2: 988-989. McGraw-Hill Inc., New York. pp.988-989. Wolfe, Donald H. 1994 Yellow-billed Cuckoo Hatched in Mourning Dove Nest. Bulletin of the Oklahoma Ornithological Society. Vol XXVII, No. 4: 29- 30. December.