Blue grosbeak a summer visitor to NM
The blue grosbeak is a summer visitor to New Mexico. The male grosbeak is aptly named. It has a dark blue body, rufous wing bars and like other grosbeaks has a noticeably heavy bill. The female is the same size, about 6.75 inches long, but has a light brown body, brown wing-bars with a hint of blue on the upper wings.
This grosbeak prefers fairly open habitat such as agricultural fields, cleared forested areas with heavy undergrowth and forest edges. The blue grosbeak is not commonly seen in urban settings; however, I have often seen this grosbeak when walking along the bosque at the Rio Grande Nature Center State Park in Albuquerque.
Male blue grosbeaks arrive shortly before the females in spring. The males often form small groups that perch on trees and bushes and sing to attract a female and establish a nesting territory. Their song is a rich, husky warbling. Listening for this song is usually the best way to catch a glimpse of this rather elusive grosbeak.
Once mated, the female does most of the nest building, using dried leaves, twigs, roots and hair and cotton to line the nest. Both parents defend the nesting territory from predators. Blue grosbeaks will have one or two broods of young during the summer nesting season. Because the blue grosbeak nests in habitat frequented by cowbirds, their nests are vulnerable to being parasitized by cowbirds. Cowbirds use other birds’ nests to lay their eggs and will sometimes throw out the host bird eggs.
The blue grosbeaks diet consists of seeds and insects. They eat a variety of grains and usually forage on or near the ground. They will visit backyard bird feeders. Their seed of choice is black-oil sunflower seed. They eat a variety of insects, including grasshoppers, crickets, caterpillars and cicadas. When feeding insects to their young, they first remove the head, legs and wings.
In early fall, after nesting season, blue grosbeaks form flocks and feed heavily before migrating south to their wintering grounds in Mexico and Central America. During this migration, the western birds fly over land and the eastern birds fly across the Gulf of Mexico.
The blue grosbeak is widespread across southern North America and has expanded its range northward. One possible reason for this expansion is that 19th and 20th century forest cutting created additional, suitable blue grosbeak habitat.
Now is the time to listen for the blue grosbeaks’ warbling song throughout New Mexico.
Mary Schmauss is the owner of Wild Birds Unlimited in Albuquerque. A lifelong birder and author of “For the Birds: A Month-by-Month Guide to Attracting Birds to Your Backyard.”