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Evening Grosbeak
The Evening Grosbeak (Hesperiphona vespertina) is a striking and robust finch known for its large, conical bill and vibrant yellow and black plumage in males. These birds are often found in coniferous and mixed forests across North America. Their irruptive migratory behavior, where large flocks move south in search of food during some winters, makes them a welcome sight at bird feeders. Ecologically, they play a significant role in seed dispersal and insect control, particularly during outbreaks of spruce budworm. They are not typically considered culturally significant, although their bright colors and bold presence make them a favorite among birdwatchers.
16-22 cm
Length
30-36 cm
Wingspan
Vulnerable
Conservation Status
Distribution
Breeds across Canada and the western United States, extending south into the mountains of Mexico. During winter, they may irrupt southward into much of the central and eastern United States, sometimes reaching as far south as the Gulf Coast.
Lifespan
Up to 17 years in the wild, though the average lifespan is likely shorter (around 2-5 years). Captive birds can live longer.
Evening Grosbeak's Habitat
Habitat Types
Coniferous forests, Mixed deciduous-coniferous forests, Montane forests, Suburban areas with ample trees and feeders
Climate Zones
Boreal, Temperate, Montane
Adaptations
Their large, powerful bill is an adaptation for cracking open large seeds, and their strong legs and feet are suited for perching on branches and manipulating food items.
Variations
Several subspecies have been described, differing slightly in size, bill dimensions, and plumage coloration. For example, *H. v. brooksi* is found in western North America, while *H. v. vespertina* occupies the eastern part of the range.
Appearance
Breeding Plumage
Breeding males are brightly colored with a yellow forehead and body, black wings with large white patches, and a dark head. Females and non-breeding males are duller, with an overall olive-gray body and yellowish tinges. The white wing patches are present in all plumages.
Seasonal Feather Changes
Plumage is generally brightest during the breeding season (spring and summer). After breeding, birds molt into a duller, non-breeding plumage.
Sex Based Plumage Differences
Significant sexual dimorphism exists, with males having much brighter yellow and black plumage compared to the more subdued olive-gray of females.
Notable Features
Massive, conical bill, Bright yellow eyebrow (in males), Large white wing patches, Stout body
Diet and Feeding
Primary Foods
Seeds, Insects, Buds, Berries
Foraging Behavior
Forages in trees and shrubs, often in flocks. They glean insects from foliage, crack seeds with their powerful bills, and may visit bird feeders, especially for sunflower seeds.
Specializations
The large, strong bill is a specialization for cracking hard seeds, particularly those of conifers and other trees like maples and box elders.
Seasonal Diet Variations
Diet shifts seasonally. During the breeding season, insects, especially spruce budworm larvae, are a major food source. In winter, seeds and buds become more important.
Behavior
Social Structure
Highly social, especially outside the breeding season. Forms flocks that can range from a few individuals to hundreds or even thousands during irruptions.
Communication
Loud, clear 'cleer' or 'peer' calls, Chattering and trilling vocalizations within flocks, Wing-fluttering displays during courtship
Migration
Irruptive migrant. Some populations are resident, while others undertake irregular movements southward in winter, driven by food availability. These irruptions can be dramatic and unpredictable.
Territorial or Group Behaviors
Territorial during the breeding season, defending the area around the nest. Outside of breeding, they are highly gregarious and form large, foraging flocks.
Conservation
Threats
Habitat loss due to logging and deforestation, Climate change, affecting forest composition and insect outbreaks, Collisions with windows, Pesticide use, impacting insect prey
Protection Programs
Sustainable forestry initiatives, Monitoring programs like the Christmas Bird Count and Project FeederWatch
Local National Laws
Protected under the Migratory Bird Treaty Act in the United States and similar legislation in Canada and Mexico.
Population Trend
Decreasing
Population Estimates
The global population is estimated to be around 6.8 million mature individuals (Partners in Flight). Significant declines have been observed in recent decades.
Interesting Facts
Their name 'Evening Grosbeak' is a misnomer.
It was originally thought they were only active in the evening, but they are active throughout the day.
They are known for their irruptive migrations.
These unpredictable movements are driven by fluctuations in seed crops, leading to large flocks appearing in areas where they are not typically seen.
They can consume large quantities of salt.
They are often attracted to roadsides in winter where salt is used for de-icing, presumably to supplement their diet.
They are important predators of spruce budworm.
During outbreaks of this forest pest, Evening Grosbeaks can consume large numbers of larvae, helping to control populations.
Faqs about Evening Grosbeak
Why are Evening Grosbeaks declining?
Several factors contribute to their decline, including habitat loss, climate change impacts on forests, and reduced insect prey due to pesticide use. The loss of mature forests and changes in forest composition are likely major drivers.
What can I do to help Evening Grosbeaks?
Support sustainable forestry practices, reduce pesticide use, plant native trees and shrubs that provide food and shelter, and provide bird feeders with sunflower seeds, especially during winter. Preventing window collisions is also important.
Where can I see Evening Grosbeaks?
Look for them in coniferous and mixed forests across their breeding range. During winter, check bird feeders and areas with abundant seed-bearing trees, especially during irruption years.
Are Evening Grosbeaks aggressive?
They can be assertive at feeders, often dominating smaller birds. This is due to their size and strong beak. However, they are not typically aggressive towards humans.
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