The diet of the evening grosbeak includes a wide variety of seeds and small fruits, as well as buds, flowers, grains and nuts (2) (3) (4). It also feeds on insects and other invertebrates (2), particularly budworms (Choristoneura spp.) and small beetles or their larvae (3) (4). The evening grosbeak has been known to break small twigs off maple trees to drink the flowing sap, and this species is also strongly attracted to salt and other minerals, even eating salt along roadsides or consuming mineral-rich soil (4).
The evening grosbeak commonly forages on the ground, but also searches for food among the branches of trees and shrubs, and occasionally captures flying insects in the air (4). The evening grosbeak’s powerful bill enables it to crack very large seeds, such as the stones of cherries (2), and this is reflected in the name of its genus, Coccothraustes, which means ‘kernel-cracker’ (4).
A sociable bird, the evening grosbeak is typically found in large flocks in winter, sometimes gathering in groups of up to several hundred individuals. These break up into smaller groups and pairs during the breeding season, but the evening grosbeak is not highly territorial and several pairs may nest in close proximity (4).
The evening grosbeak usually breeds around May to July. Although it is a distinctive and conspicuous bird, it can be quite secretive during the breeding season, with courtship apparently not involving elaborate songs or displays (4). The nest, constructed almost entirely by the female (4), is built in a tree or large shrub and consists of a loose, flattened, saucer-like structure of twigs and roots, lined with grass, pine needles, fine roots and lichens (2) (4).
The female evening grosbeak lays a clutch of between two and five eggs. The eggs are light blue to bluish-green, with brown or purplish blotches (2) (4), and are incubated by the female for 12 to 14 days (4). The male feeds the female during incubation, and both adults feed the hatchlings, which leave the nest at 13 to 14 days old. The maximum recorded lifespan for an evening grosbeak is about 15 years (4).