Manitoba Bird Bird Atlas: Species At Risk

Eastern Whip-poor-will

Early Breeding and Last Migration Dates

South: Regions 1 to 8 Central: Regions 9 to 12 North: Regions 13 and 14
Early Breeding Last Migration Late Breeding Early Breeding Last Migration Late Breeding Early Breeding Last Migration Late Breeding
May-25 Jun-06 Jul-16 Jun-01 Jun-11 Jul-16

Breeding Evidence

The Eastern Eastern Whip-poor-will (Caprimulgus vociferans) and the Mexican Eastern Whip-poor-will (C. arizonae) were very recently split into two species. Only the former occurs in Manitoba and all atlas documentation refers to this species simply as Eastern Whip-poor-will, reflecting the taxonomy of 2010 when the atlas began.

The species is readily detected by their beautiful song, that earns them their common name, meriting the code S (singing – possible breeding). In suitable habitat, it is often possible to increase the level of breeding evidence by listening to find seven or more singing Eastern Whip-poor-wills in a single square on a single night, earning the code M (multiple – probable breeding). As aerial insectivores, Eastern Whip-poor-wills return too late in spring to be detected on nocturnal owl surveys and hence surveying for this nocturnal species requires a special effort to go out at dusk, night or dawn in the summer months. In the late summer, a very lucky atlasser might find a nest or young on the ground – look for the distinctive but shortly held plumage of the dependent young with a strong rusty colour on the back that resembles a dead oak leaf (code FY = fledged young, confirmed bereding). This plumage is in fact one of the differences between Eastern and Mexican Eastern Whip-poor-wills.

Habitat

Breeding Evidence Map

Eastern Whip-poor-wills prefer partly open, upland deciduous or mixed-wood forests; however their breeding habitat is not dependent upon species composition, but rather on forest structure. In Manitoba, they are found in a variety of deciduous forests and mixed forests. Eastern Whip-poor-wills are not usually found in either wide-open spaces or dense forests. They prefer to nest in semi-open forests or patchy forests with clearings, such as barrens or forests that are regenerating following major disturbances. Other necessary breeding habitat elements are thought to involve ground-level vegetation and woodland size. They will often feed in nearby shrubby pastures or wetlands with perches. Areas with decreased light levels where forest canopies are closed are generally not occupied, perhaps because of reduced forage success for this aerial-feeding insectivore.

The northern border of Eastern Whip-poor-wills’ breeding range extends in a diagonal stripe along the aspen parkland transition zone from southeastern Manitoba to eastern central Saskatchewan.

-from COSEWIC and The Birds of Manitoba (p. 239)