Many birds have very specific requirements for their nest site, while other birds will build their nests in a wide variety of locations. These “generalists”, who are not as particular about nest location, are much less affected by habitat degradation and changing conditions.
Brewer’s blackbirds (Euphagus cyanocephalus) prefer to build their nests in a tree 20 to 40 feet above the ground. However, as these pictures, taken on our ranch near Lookout CA (Modoc County) show, Brewer’s blackbirds will place their nests in a tree, on the ground, on a ledge under the bunkhouse roof or amid coiled cables. Over the years we watched them raise broods in bushes and shrubs, in cliff crevices, in a cattle chute and in a horse lean-to. Brewer’s blackbirds are opportunistic in their choice of nest sites.
The female Brewer’s blackbird constructs a rather bulky, open cup made of grass, weeds, twigs and pine needles lined with fine grass, rootlets and animals hair. Mud or dried manure is often added to the base. Since we have horses, all the Brewer’s blackbird nests on our property contain horse tail hair and horse manure. Blue, orange or white bailing twine is also incorporated into their nests. These clever birds will go into the hay sheds to find the twine.
Four to six pale grey to greenish grey eggs, spotted with brown, are laid in each nest. After 12 to 14 days incubation and 13 to 14 days as nestlings, a new brood of Brewer’s blackbirds is ready to fledge.
By utilizing a wide variety of nesting sites, Brewer’s blackbirds increase their chances for survival in a world where habitat is rapidly being destroyed. Many less adaptable or flexible birds are experiencing decreasing populations.