Evening Grosbeak Life History

Habitat

Habitat ForestsEvening Grosbeaks breed in mature and second-growth coniferous forests of northern North America and the Rocky Mountains, including spruce-fir, pine-oak, pinyon-juniper, and aspen forests. Less commonly, they nest in deciduous woodlands, parks, and orchards. They breed as far south as Mexico at 5,000–10,000 feet of elevation in pine and pine-oak woodlands. In winter Evening Grosbeaks live in coniferous forest and deciduous forest as well as in urban and suburban areas. When wintering in urban environments they are most abundant in small woodlots near bird feeders.Back to top

Food

Food SeedsIn summer, Evening Grosbeaks eat mostly invertebrates such as spruce budworm larvae, caterpillars, and aphids. They also eat a wide variety of seeds—including those of maple, box elder, ash, cherry, apple, tulip poplar, elm, pine, dock, bindweed, and goosefoot—and small fruits, such as ash fruits, cherries, crabapples, snowberries, hawthorn fruits, Russian olive fruits, and juniper berries. They may manipulate fleshy fruits such as cherries in their bills to remove the skin and flesh before cracking and swallowing the seed. Evening Grosbeaks typically feed at the tops of trees and shrubs, but you may see them come to the ground for fallen fruits and seeds or capture aerial insects in flight. They also eat the buds of maple, elm, willow, oak, aspen, and cherry, and drink maple sap by breaking off small maple twigs.Back to top

Nesting

Nest Placement

Nest TreeEvening Grosbeaks nest high in trees or large shrubs, such as red spruce, black spruce, Norway spruce, white spruce, Engelmann spruce, white pine, Jeffrey pine, ponderosa pine, jack pine, balsam fir, Douglas-fir, white cedar, paper birch, beech, sugar maple, and willow. It’s unknown whether male or female Evening Grosbeaks choose the nest sites (although in the closely related Hawfinch of Eurasia, the male selects the site).

Nest Description

The female does most of the nest building, collecting materials from the ground and breaking twigs from trees. She builds a flimsy, saucer-shaped nest of small twigs and roots lined with grasses, fine rootlets, lichens, or pine needles. The nest measures about 5 inches across and 5 inches high, with the inner cup measuring about 3 inches across and 1 inch deep.

Nesting Facts
Clutch Size:2-5 eggs
Number of Broods:1-2 broods
Egg Length:0.8-1.0 in (2-2.6 cm)
Egg Width:0.6-0.7 in (1.4-1.8 cm)
Incubation Period:12-14 days
Nestling Period:13-14 days
Egg Description:Light blue to blue-green with brown or purplish blotches.
Condition at Hatching:Helpless, with eyes closed and dark skin partly covered with white down.
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Behavior

Behavior Ground ForagerEvening Grosbeaks are social birds that forage in flocks in winter and break off into small groups or pairs during the breeding season. Evening Grosbeaks show little aggression toward one another throughout the year. At winter feeders males may drive females and younger males away, but they do not defend feeding territories during the breeding season—probably because their food sources are often extremely abundant in local patches. During the nesting season they form monogamous pairs, after courting quietly without any elaborate song or display. Breeding birds tolerate other birds nearby but occasionally chase away species such as phoebes, Hairy Woodpeckers, American Robins, and Brown-headed Cowbirds. At feeders, Evening Grosbeaks are often accompanied by redpolls and Pine Siskins that glean the food scraps they leave behind.Back to top

Conservation

Conservation DecliningEvening Grosbeaks are numerous and widespread, but populations dropped steeply between 1966 and 2015, according to the North American Breeding Bird Survey—particularly in the East where numbers declined by 97% during that time. Partners in Flight estimates a global breeding population of 4.1 million, with 71% spending some part of the year in the U.S., 57% in Canada, and 5% living in Mexico. Evening Grosbeak rates a 13 out of 20 on the Continental Concern Score and is on the 2016 State of North America's Birds' Watch List, which includes bird species that are most at risk of extinction without significant conservation actions to reverse declines and reduce threats. Because of their irruptive nature, it can be difficult for large-scale surveys to make precise estimates, but a 2008 study of Project FeederWatch data found that the grosbeak’s winter range had contracted and numbers had declined. Evening Grosbeaks were reported at only half the number of sites, and flock sizes were down by 27%, in the early 2000s compared with the late 1980s. Evening Grosbeaks were rare in eastern North America until the mid-nineteenth century, when they began expanding eastward, possibly aided by the spread of box elders (which were increasingly being planted in cities), or possibly to outbreaks of forest insects such as spruce budworm. By the 1920s they were regular winter visitors in New England, and their range expansion peaked in the 1970s and 1980s. Recent declines may be due to logging and other development in the boreal forests of northern North America; to disease outbreaks such as salmonella, West Nile virus, and House Finch eye disease; or to reduced numbers of spruce budworm and other forest insects, in part due to aerial spraying by the U.S. and Canada. As climate change alters the landscape over the next century, balsam fir is expected to recede from New England, and Evening Grosbeaks may disappear from this region.Back to top

Backyard Tips

Although they may not visit your backyard every year, Evening Grosbeaks show up irregularly at feeders during the winter. They eat sunflower seeds and are also attracted to the seeds, berries, and buds of trees and shrubs—especially maples. They are fairly large birds and they often travel in sizeable flocks, so they often use platform feeders as opposed to tube feeders. Find out more about what this bird likes to eat and what feeder is best by using the Project FeederWatch Common Feeder Birds bird list.

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Credits

Gillihan, Scott W. and Bruce E. Byers. 2001. Evening Grosbeak (Coccothraustes vespertinus), version 2.0. In The Birds of North America (P. G. Rodewald, editor). Cornell Lab of Ornithology, Ithaca, New York, USA.

Lutmerding, J. A. and A. S. Love. Longevity records of North American birds. Version 2015.2. Patuxent Wildlife Research Center, Bird Banding Laboratory 2015.

Partners in Flight. 2017. Avian Conservation Assessment Database. 2017.

Sauer, J. R., D. K. Niven, J. E. Hines, Jr. Ziolkowski, D. J., K. L. Pardieck, J. E. Fallon and W. A. Link. The North American breeding bird survey, results and analysis 1966-2015 (Version 2.07.2017). USGS Patuxent Wildlife Research Center 2017.

Sibley, David Allen. 2014. The Sibley guide to birds, second edition. Alfred A Knopf, New York.

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