Pine Grosbeak Life History

Habitat

Habitat Open WoodlandsPine Grosbeaks live in open evergreen forests with spruce, pine, or fir across Canada, in mountainous regions in the West, and in subalpine forests in Eurasia. In the Sierra Nevada in California they occur in open red fir and lodgepole pine forests usually higher than 6,000 feet. In the Rocky Mountains they are most common in valleys near timberline (above 9,000 feet). In the winter they either stay in similar habitat, move to lower elevations, or to areas with abundant mountain ash, maple, and ash fruits and seeds. Back to top

Food

Food SeedsNearly 100% of their diet is made up of buds, seeds, and fruits from spruce, pine, juniper, birch, mountain ash, maple, box elder, crabapple, blackberry, ragweed, and burdock. They forage on the ground or in trees, grabbing seeds and fruits or nipping fresh buds and needles from the tips of branches. Though they are primarily vegetarian they catch insects and spiders in the summer. These protein-rich items are often fed to their growing young along with mixed plant foods. In the winter they also eat grit and salt along roadsides. They frequently visit feeders with black oil sunflower seeds or suet. Grosbeaks drink water or eat snow daily.Back to top

Nesting

Nest Placement

Nest TreePine Grosbeaks nest in evergreen trees often near the trunk where the nest is well concealed by dense vegetation. They tend to nest between six and 16 feet above the ground.

Nest Description

The female builds a loose foundation of evergreen twigs into which she weaves roots and smaller twigs. She then builds the inner cup of the nest with rootlets, twigs, and grass. She lines it with lichen, evergreen needles, soft grasses, and feathers. The nest is around 6–9 inches across and 3–4 inches deep on the outside with an inner cup around 2.5–3 inches across.

Nesting Facts
Clutch Size:3-4 eggs
Egg Length:1.0-1.0 in (2.5-2.6 cm)
Egg Width:0.7-0.7 in (1.7-1.8 cm)
Incubation Period:13-14 days
Nestling Period:13-20 days
Egg Description:Pale blue with darker dots and markings.
Condition at Hatching:Naked with a few downy feathers on the head and back.
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Behavior

Behavior Foliage GleanerIn trees Pine Grosbeaks sluggishly hop between braches nipping off the new growth of trees or snatching seeds and fruits. They also hop or walk along the ground when they are searching for fallen seeds or fruits. When boreal tree species produce larger seed crops Pine Grosbeaks often raise more young and are more likely to survive the winter. But when those trees fail to produce seed crops the next season, the now larger population of grosbeaks wanders or irrupts outside of the normal breeding range to find food. During these irruptions they often turn up at bird feeders farther south than normal. In the winter, they forage in groups from 5–15 individuals. In areas where different call types exist, individuals with the same song type stick together; they do not forage with other groups with different flight calls. During the breeding season, they form monogamous pairs. Males sing from treetops to defend their breeding territory. Mated pairs have identical flight calls, which may indicate that they form strong bonds with each other. Back to top

Conservation

Conservation Low ConcernPine Grosbeaks are fairly uncommon in the United States as they only breed in small pockets of forest in western mountains and they are easy to overlook. Much of their far-northern breeding range lies outside of the area covered by the North American Breeding Bird Survey, making it hard to estimate population trends precisely. Nevertheless, North American Breeding Bird Survey data suggest that populations of Pine Grosbeaks declined by 2.4% per year between 1966 and 2015, resulting in a cumulative decline of 70%. Partners in Flight estimates a global breeding population of 8.9 million with 18% spending some part of the year in the United States and 34% in Canada. Pine Grosbeak is not on the 2016 State of North America's Birds' Watch List, and rates a 10 out of 20 on the Continental Concern Score. Research modeling the projected impacts of climate change on birds in the Sierra Nevada suggests that Pine Grosbeaks are vulnerable to climate change at least in California. Back to top

Backyard Tips

Pine Grosbeaks frequently visit feeders especially in the northern states during the winter. Because of their size a large tube feeder, platform feeder, or large hopper is best. Fill one of these feeders with black oil sunflower seeds or hulled sunflower seeds. Learn more at Project FeederWatch.

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Credits

Adkisson, Curtis S. 1999. Pine Grosbeak (Pinicola enucleator), version 2.0. In The Birds of North America (P. G. Rodewald, editor). Cornell Lab of Ornithology, Ithaca, New York, USA.

Dunne, Pete. 2006. Pete Dunne's essential field guide companion: Houghton Mifflin Harcourt.

Ehrlich, P. R., D. S. Dobkin and D. Wheye. 1988. The birder's handbook. A Field Guide to the natural history of North American birds, including all species that regularly breed north of Mexico. New York: Simon and Schuster, Inc.

Koenig, W. D. and J. M. H. Knops. 2001. Seed-crop size and eruptions of North American boreal seed-eating birds. Journal of Animal Ecology no. 70 (4):609-620.

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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