Henslow's sparrow (Centronyx henslowii ) is a passerine bird in the family Passerellidae. It was named by John James Audubon in honor of John Stevens Henslow. It was originally classified in the genus Emberiza and called Henslow's bunting.
Henslow's sparrows are small songbirds found in North America. Adults have streaked brown upperparts with a light brown breast with streaks, a white belly, and a white throat. They have a pale stripe on the crown with a dark stripe on each side, an olive face and neck, rust-colored wings, and a short dark forked tail.
Henslow's sparrows are found in southern Canada, the northeastern United States, and the midwestern United States. They breed in grasslands, wet meadows, shrubby fields, and migrate to marshes and open pine woods in the southeastern United States.
Henslow’s sparrows are extremely secretive birds that are usually found in small groups or alone. They are active during the day spending most of the time foraging near or on the ground. When flushed they fly a short distance and then dive back into the grass and run away from danger by foot. Henslow's sparrows are generally silent and sing only when they attract mates or defend their territory; their song is a quick 'se-lick'.
Henslow's sparrows are carnivores (insectivores) and herbivores (granivores). They mainly eat insects such as grasshoppers, beetles, and caterpillars but also spiders and snails. In winter they feed on seeds and some berries.
Henslow's sparrows are monogamous and form pairs. They breed in early spring and late summer and may raise two broods per year. Females construct a cup-shaped nest that is made of coarse grass and dead leaves; it is usually lined with finer grasses or hair. Nests are located near or on the ground and are always well hidden. Females lay 3 to 5 eggs and incubate them for 10-11 days. The chicks hatch helpless and are able to leave the nest 9 to 10 days later.
The numbers of the Henslow's sparrow are decreasing, probably due to habitat loss of the grasslands that it depends on. In addition, this species is also vulnerable to pesticide exposure, pollution, and collisions with communications towers.
According to the IUCN Red List, the total population size of the Henslow’s sparrow is 390,000 mature individuals. According to Partners in Flight resource, the total breeding population size of this species is 410,000 breeding birds. Overall, currently, Henslow’s sparrows are classified as Least Concern (LC) on the IUCN Red List and their numbers today are increasing.
