Northern saw-whet owl (Aegolius acadicus brooksi) COSEWIC update and status report: chapter 4
Distribution
Global range
The distribution of the nominate subspecies of Northern Saw-whet Owl is widespread throughout North America (Figure 2), including the islands on the Alaska panhandle just north of the Queen Charlotte Islands (Sealy 1997). Individuals of the nominate subspecies that breed at more northern latitudes tend to move south in winter, sometimes to areas south of the breeding range. The range of the brooksi subspecies, however, is limited to Haida Gwaii/Queen Charlotte Islands of British Columbia.
Figure 2. Map showing the breeding range of two subspecies of Northern Saw-whet Owl. A. a. acadicus is found on continental North America and A. a. brooksi (black) is found only on Haida Gwaii/Queen Charlotte Islands, off north-western British Columbia (adapted from Cannings 1993).
Canadian range
The brooksi subspecies of the Northern Saw-whet Owl is endemic to Haida Gwaii and is non-migratory (Figure 3).
A. a. brooksi have never been observed off Haida Gwaii, in the range of A. a. acadicus, despite numerous owl banding projects throughout British Columbia (e.g. Rocky Point and Mackenzie Bird Observatories). Although individuals of the nominate subspecies, A. a. acadicus, have been recorded on Haida Gwaii during post-breeding season movements, they are not thought to breed in the area (Sealy 1997). A. a. brooksi has been recorded on both of the large islands of Haida Gwaii (Graham and Moresby; Gill and Cannings 1997, Sealy 1998) as well as on the smaller islands throughout the archipelago, at least in the breeding season (Holschuh, in prep.; Sealy 1998 and references therein). Hence the total Extent of Occurrence is about 10,000 km². The extent of suitable forest habitats on the islands is about 5,488 km², the best estimate for the Area of Occupancy (see Habitat).
Figure 3. Distribution of Aegolius acadicus brooksi (Queen Charlotte Islandsin black).
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