Xanthocephalus xanthocephalus
Yellow-headed Blackbird males are strikingly plumaged with their bright yellow heads and breasts contrasting sharply with their black wings tail and remaining body plumage. The female’s only similarity is her dull or buffy yellow throat and breast. During the breeding season these birds consume and feed their young aquatic prey (primarily insects), but after the young birds are independent, large flocks of Yellow-headed Blackbirds forage in agricultural areas and open country for waste grain and seeds of wild plants, returning at night to roost in the emergent vegetation of wetlands. These flock usually include other blackbird species (Twedt and Crawford 1995, Pyle 1997).
DISTRIBUTION. During the 1987-1992 field work of the TBBA project, researchers found 3 confirmed, 4 probable and 5 possible breeding records in the High Plains region (see map in Lockwood and Freeman [2004]). All but one of these records are in counties mentioned by these authors as being the only breeding sites for this species in Texas..
Elsewhere the species breeds from British Columbia and the Canadian prairies south to the lower southwestern deserts between the Cascade and Sierra Nevada mountains on the west and Wisconsin, central Nebraska and central Kansas. In winter most of the population moves south to the desert southwest of the United States and mainland Mexico south to the Isthmus of Tehuantepec (Twedt and Crawford 1995).
SEASONAL OCCURRENCE. Northbound Yellow-headed Blackbirds pass through Texas from March 7 to June 24 with most present between early April and late May. Southbound migrants are present between July 4 and November 26; with the peak movement occurring from mid-July to early November (Oberholser 1974, Lockwood and Freeman 2004). In Colorado (where a much larger population breeds in similar habitat) confirmed breeding was found between April 21 and August 5 (Winn 1998). The timing of the Texas breeding season is probably similar.
BREEDING HABITAT. In Colorado where nesting habitats have been quantified and the eastern part of the state resembles the High and Rolling Plains of Texas, almost all Yellow- headed Blackbird nesting occurred in emergent vegetation (cattails, bulrushes, sedges, rushes or arrow weed; Winn 1998). These blackbirds breed in large, thickly populated colonies with as many as 25-30 nests per 21 m2 (225 ft2). Males may have as many as 5 mates. The nest is built by the female in 2-4 days. She may build and abandon several nests before starting to lay eggs. Nests are built in vegetation growing in water 0.6-1.2 m (2-4 ft) deep. Red-winged Blackbirds (Agelaius phoeniceus) usually nest over shallower water. Yellow-headed Blackbird nests are placed 15-91 cm (6-36 in) above water level. The bulky nest is built of water-soaked aquatic vegetation woven to upright-growing plants. It is lined with dry aquatic vegetation. As the nest dries it becomes more tightly attached to its supports. The outside diameter is 13×15 cm (5×6 in), height 10 cm (4 in), inside diameter 8 cm (3 in) and the cup depth is 6 cm (2.5 in; Harrison 1979).
The female commonly lays 4 (range2-5) smooth, glossy grayish white to pale greenish white eggs (see Harrison [1979] for photo of markings). Incubation, by the female, usually lasts 12-13 days and may start after the 2nd egg is laid. Young birds generally leave the nest between 9-12 days after hatching, but occasionally as early as 7 or as late as 14.
Females raise only 1 brood per season. (Harrison 1979, Twedt and Crawford 1995).
STATUS. Lockwood and Freeman (2004) characterize Yellow-headed Blackbird as a common to uncommon migrant in the western half of Texas and very local summer residents in the Panhandle. The Breeding Bird Survey does not sample this species in this state. Data from 679 routes across the western United States and Canada produce a 95% confidence interval (There is a 95% chance that the actual population trend will be between these two numbers.) of -0.3 to +2.1% population change per year for the period 1966-2004 (Sauer et al. 2005). This is encouraging for the future of Yellow-headed Blackbird in Texas. Text by Robert C. Tweit (2006)
Literature cited.
Harrison, H. H. 1979. A field guide to western birds’ nests. Houghton Mifflin, Boston, MA.
Howell, S. N. G. and S. Webb. 1995. A guide to the birds of Mexico and northern Central America. Oxford University Press, New York.
Lockwood, M. W. and B. Freeman. 2004. The TOS handbook of Texas birds. Texas A&M University Press, College Station.
Oberholser, H. C. 1974. The bird life of Texas, Vol. 2. University of Texas Press, Austin.
Pyle, P. 1997. Identification guide to North American birds, part 1. Slate Creek Press, Bolinas, CA.
Sauer, J. R., J. E. Hines, and J. Fallon. 2005. The North American Breeding Bird Survey, results and analysis 1966-2004. Version 2005.1. USGS Patuxent Wildlife Research Center, Laurel MD (Web site, http://www.mbr-pwrc.usgs.gov/bbs).
Twedt, D. J. and R. D. Crawford. 1995. Yellow-headed Blackbird (Xanthocephalus xanthocephalus). In The birds of North America, No. 192 (A. Poole and F. Gill, eds.). The Birds of North America, Inc., Philadelphia, PA.
Winn, R. A. 1998. Yellow-headed Blackbird (Xanthocephalus xanthocephalus). In Colorado breeding bird atlas, pp. 506-507 (H. E. Kingery, ed.), Colorado Bird Atlas Partnership, Denver.