Manitoba Bird Bird Atlas: Species At Risk

Common Nighthawk

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
Jun-01 Jun-11 Aug-01 Jun-06 Jun-11 Aug-01

Breeding Evidence

Common Nighthawks do not build nests; instead, they lay their eggs (usually two) on bare ground or gravelly surfaces. They will lay eggs on gravelled roofs. They breed throughout almost all of Manitoba except north of the treeline.

Habitat

Breeding Evidence Map

The Common Nighthawk is a tricky species to atlas properly because they are a very late arriving migrant and any May or early June records are best considered as migrants. Northern birds also return early in the fall and in early - mid August it is possible to observe flocks containing both local breeding birds and returning migrants. Sometimes these congregations consist of small, loose flocks that form at dusk to hunt insects over marshes, rivers, sewage lagoons and lakeshores. On occasion, very large flocks totalling thousands of birds are observed though this spectacle is sadly becoming an increasingly rare sight. For the above reasons, from late July onward, great care is required in assigning atlas codes for this species.

From June until mid July the most common form of breeding evidence is the booming display (a loud noise presumed to be given only by males created by wind passing over the wing feathers at the bottom of a display dive), that can be coded as S (singing – possible breeding). This behaviour should not be coded as D (display – probable breeding) unless two or more birds are observed together (several males displaying in close proximity and/or interacting with females). Wing clapping is also occasionally reported in this species. The nasal peent call also often heard should not be coded as S if heard in isolation, but rather H (habitat– possible breeding).

Common Nighthawks nest in a wide range of open habitats (images e to i); for example, dunes, beaches, recently harvested forests, burnt-over areas, logged areas, rocky outcrops, rocky barrens, grasslands, pastures, peat bogs, marshes, lakeshores, and river banks. They also inhabit mixed and coniferous forests. Nonetheless, although still quite common in parts of northern Manitoba, they appear to have declined substantially in southern Manitoba.

-from COSEWIC and The Birds of Manitoba (p. 238)


These dates help you determine whether a bird can be considered as a possible or probable breeder for the atlas. The early breeding date is the earliest that breeding may occur in a region. Late spring migrants may still be seen before the last migration date. Therefore, observations made between early breeding and last migration dates should only be reported if there is reasonable chance that the bird will breed there. Late breeders can still actively be maintaining a breeding territory up to the late breeding date.

Observed

X Species observed during its breeding season, but not in suitable nesting habitat (no breeding evidence found).

Possible

H Species observed in suitable nesting habitat during its breeding season.

S Individual singing or producing other sounds associated with breeding (e.g., calls or drumming) in suitable nesting habitat during the species’ breeding season.

Probable

M At least 7 individuals singing or producing other sounds associated with breeding (e.g., calls or drumming), heard during the same visit to a single square and in suitable nesting habitat during the species’ breeding season.

P Pair observed in suitable nesting habitat during the species’ breeding season.

T Presumed territory based on the presence of an adult bird, whether producing sounds associated with breeding (e.g., song, other calls or drumming) or not, at the same place, in suitable nesting habitat, on at least two visits, one week or more apart, during the species’ breeding season.

D Breeding behaviour involving a male and female (e.g., display, courtship feeding and copulation) or antagonistic behaviour between two or more individuals (e.g., territorial disputes or chases), in suitable nesting habitat during the species’ breeding season.

V Bird visiting a probable nest site in suitable nesting habitat during the species’ breeding season.

A Agitated behaviour or alarm call of an adult in suitable nesting habitat during the species’ breeding season.

B Brood patch or cloacal protuberance on an adult individual caught in suitable nesting habitat during the species’ breeding season.

N Nest-building by wrens or nest hole excavation by woodpeckers.

Confirmed

NB Nest building, including the carrying of nesting material, by all species except wrens and woodpeckers.

DD Individual attempting to draw attention away from a nest or young by feigning injury or by using any other distraction display.

NU Empty nest used during the atlas survey period, or the shells of eggs laid during the same period.

FY Recently fledged (nidicolous species) or downy (nidifugous species) young incapable of sustained flight.

AE Adult occupying, leaving or entering a probable nest site (visible or not) and whose behaviour suggests the presence of an occupied nest.

FS Adult carrying a fecal sac.

CF Adult carrying food for young.

NE Nest containing one or more eggs.

NY Nest with one or more young (seen or heard).

Data contained in these maps are provisional data that have not necessarily been reviewed or edited, and may be subject to significant change. These data have been released for public interest only. If you wish to use the data in a publication, research or for any purpose, or would like information concerning the accuracy and appropriate uses of these data, read the data use policy or contact us at: 1-877-592-8527, e-mail: mbatlas@birdscanada.org.

The habitat information has been taken from the COSEWIC web site and from The Birds of Manitoba, which is available at http://www.naturemanitoba.ca