About Hesperiphona vespertina (W.Cooper, 1825)
The evening grosbeak (Hesperiphona vespertina) is similar in appearance to the Eurasian hawfinch: both are bulky, heavily built finches with large bills and short tails. Evening grosbeaks measure 16 to 22 cm (6.3 to 8.7 in) in length, with a wingspan of 30 to 36 cm (12 to 14 in). In a large winter sample of the species from Pennsylvania, males weighed 38.7 to 86.1 g (1.37 to 3.04 oz), averaging 60 g (2.1 oz), while females weighed 43.2 to 73.5 g (1.52 to 2.59 oz), averaging 58.7 g (2.07 oz). Standard measurements for the species are as follows: wing chord ranges from 10.45 to 11.6 cm (4.11 to 4.57 in), tail from 6 to 6.95 cm (2.36 to 2.74 in), bill from 1.6 to 2 cm (0.63 to 0.79 in), and tarsus from 1.95 to 2.2 cm (0.77 to 0.87 in). Adults have a short black tail, black wings, and a large pale bill. Adult males have a bright yellow forehead and body, a brown head, and a large white patch on the wing. Adult females are mainly olive-brown, with greyer underparts and white patches on the wings. Evening grosbeaks have a loud, distinctive 'chew' call, described as similar to an amplified house sparrow call. Their breeding habitat is coniferous and mixed forest across Canada, and the western mountainous areas of the United States and Mexico. It is an extremely rare vagrant to the British Isles, with only two recorded sightings to date. Evening grosbeaks build their nests on a horizontal tree branch or in a tree fork. Their migration patterns are variable; in some winters, individuals may wander as far south as the southern United States. These birds forage in trees and bushes, and sometimes forage on the ground. Their diet consists mainly of seeds, berries, and insects. Outside of the nesting season, they often feed in flocks, and will sometimes swallow fine gravel. The species' range has expanded far to the east in historical times, which may be due to the planting of Manitoba maples, other maples, and shrubs around farms, as well as the availability of winter bird feeders.
