![]() Data from the Breeding Bird Survey (BBS) show Blue Grosbeak to be most common in Texas in an area extending from the northeast corner of the state along the Louisiana border south nearly to the Gulf Coast, and in the Trans-Pecos and Edwards Plateau regions (at densities between 3-10 grosbeaks detected per 40 km BBS route). Two broods per season are frequent (Oberholser 1974, Harrison 1979, Ingold 1993). Nestlings take their first flight after 9-10 days. The female incubates the eggs for 11-12 days. Blue Grosbeak eggs are unlike those of other grosbeaks. They are similar to the eggs of Indigo (Passerina cyanea), Lazuli (P. The female lays 4, (range 3-6), usually unmarked bluish eggs. The inside diameter is 6 cm (2.4 in) and the depth is 5 cm (2 in). Nests are lined with smaller rootlets, grasses and occasionally hair. The deep, cup-shaped nest, placed on a branch of a tree or bush 1-2.5 m (3-8 ft) above ground, is made of leaves, plant stems, rrootlets, grasses, strips of bark, and sometimes bits of snake skin. ![]() They range from open country with scattered trees and bushes, brushy woodland edges, vine or brier tangles, overgrown fields and hedgerows to willows, cottonwoods or other stream-side vegetation (Oberholser 1974). ![]() Blue Grosbeak breeds from sea level to 1800 m (6000 ft) in Texas in a variety of shrubby habitats across this varied state. Departures occur between July 22 and November 24 most Blue Grosbeaks leave from the end of August to mid-October (Oberholser 1974, Lockwood and Freeman 2004).īREEDING HABITAT. TBBA observers found pairs nest-building on May 15 and May 26, a nest with eggs on April 30, a bird on or near a nest on June 30, pairs feeding young from June 4 to July 15 and recently fledged young from May 25 to July 24. Most spring migrants arrive between early April (early May in the Trans-Pecos region) and mid-May. Arrival dates extend from March 2 to June 2. Blue Grosbeak is a summer resident, in Texas. Populations breeding in the United States and northern Mexico move south to winter throughout central Mexico and Central America (Ingold 1993). In other parts of North and Central America, Blue Grosbeaks breed from California east through southern Nevada and Utah, the Great Plains south from southern North Dakota, the Missouri and Ohio rivers, Pennsylvania and New Jersey, then south to the Gulf Coast states, the highlands of Mexico and Central America to Costa Rica and northern Baja California. Other high concentrations of breeding reports are in south Texas below the 27th parallel and western Texas below the 31st parallel and west of the 99th meridian. During the 1987-1992 TBBA project field work, volunteers found Blue Grosbeaks breeding statewide, with records clustered most densely in northeastern Texas east of the 96th meridian and north of the 30th parallel. aeneus) cowbirds, but more data are needed, not surprising for this poorly studied species (Ingold 1993).ĭISTRIBUTION. This species appears to be a common host for Brown-headed (Molothrus ater) and Bronze (M. The species is sexually dimorphic with delayed plumage maturation, so males in their first post-hatching year are essentially brown (like females of all ages), in contrast to the mostly blue plumage of fully adult males (Ingold 1993, Pyle 1995). Blue Grosbeak is a large bunting, now placed in the genus Passerina by the American Ornithologists’ Union, further removing it from other grosbeaks.
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