Peregrine falcon (pealei and anatum/tundrius) COSEWIC assessment and status report: chapter 4
Distribution
Global range
The Peregrine Falcon is nearly cosmopolitan in distribution, breeding in Eurasia, Africa, Australia, North America (Figure 1) and South America. It is absent only from Antarctica, New Zealand, Iceland and islands of the eastern Pacific Ocean (White et al. 2002).
The Anatum Peregrine Falcon breeds from the interior of Alaska, across northern Canada to southern Greenland, then south through continental North America to northern Mexico, except for the coastal Pacific Northwest from Washington north (White et al. 2002; but see Canadian Range). It may also nest in coastal Washington and Oregon (Hayes and Buchanan 2002). The Anatum Peregrine winters from southern Canada south through the USA (White et al. 2002) to northern South America.
The Tundrius Peregrine Falcon breeds from Alaska, across northern Canada to Greenland. There is overlap with the Anatum Peregrine Falcon south of the treeline in some areas. It winters from northern Mexico, as far south as Chile and Argentina.
Figure 1. Breeding distribution of the Peregrine Falcon in North America. (Map: © Modified from Birds of North America Inc.). Birds typically winter south of the dashed line.
The Pealei Peregrine Falcon is restricted to Pacific coastal areas and breeds from the Aleutian Islands and other coastal Alaska islands south to Oregon (Hayes and Buchanan 2002). Some Peale’s remain as residents in most years. However, other birds disperse to the south, wintering in coastal Washington, Oregon and California, and rarely northern Mexico (Campbell et al. 1990; Hayes and Buchanan 2002).
Canadian range
Anatum Peregrine Falcons breed in all Canadian provinces and territories except Prince Edward Island, Nunavut (Rowell 2002) and insular Newfoundland (J. Brazil personal communication (pers. comm.) 2007). They are now known to breed on the southwest coast of British Columbia (southeastern Vancouver Island, the Gulf Islands, and in the lower Fraser River valley (Cooper and Beauchesne 2004; Brown et al. 2007; Figure 2).
Tundrius Peregrine Falcons breed from the north slope of the Yukon east across the low Arctic islands and Nunavut north to Baffin Island, Hudson Bay, Ungava and northernmost Labrador (Figure 1; White and Boyce 1988). The Tundrius subspecies migrates through southern Canada during migration.
Pealei Peregrine Falcons breed on the Queen Charlotte Islands (AOU 1957), Triangle Island off the northern tip of Vancouver Island (Kirk and Nelson 1999), the central coast and northern and western Vancouver Island (Campbell et al. 1990; Figures 1, 2), and on the east coast of Vancouver Island as far south as at least Gabriola Island (Cooper 2006).
Figure 2. Distribution of the Pealei Peregrine Falcon in Canada(British Columbia). Map source: Cooper 2006 (adapted from CWS website).
Geographic boundaries between the three currently recognized subspecies are not precisely defined. For example, the Pealei Peregrine Falcon breeds on the outer west coast of British Columbia, including the west and north coasts of Vancouver Island (Cooper and Beauchesne 2004; Cooper 2006). However, Peregrine Falcons that have established (probably in the 1970s) breeding territories on southeastern Vancouver Island and the Gulf Islands were thought to be Anatums (D. Doyle pers. comm. 2004) but genetic evidence found traits of both subspecies (Brown et al. 2007). Birds fitting morphological descriptions of both Anatum and Tundrius have also been observed throughout Labrador (J. Brazil pers. comm. 2006).
The extent of occurrence (EO) for Anatum is 7 million km², Tundrius is 2 million km², for a combined EO of 9 million km² for Anatum/Tundrius Peregrines. The EO for the Pealei Peregrine Falcon is 47,000 km². EO estimates for Anatum and Tundrius were made by estimating the percentage of Canada’s 9.97 million km² land mass occupied by Anatum and Tundrius Peregrines (including areas with gaps in known distribution). The EO estimate for the Pealei Peregrine Falcon was made by taking British Columbia’s area (9.5% of Canada’s land mass) and multiplying by the estimated area of BC (5%) where Peale’s occur. Anatum/Tundrius Peregrine Falcons occupy most (>90%) of Canada, whereas Pealei occupy about 0.5%.
The area of occupancy (AO) for Anatum is estimated at 252,500 km², for Tundrius at 24,000 km², for a combined Anatum/Tundrius AO of 276,500 km². The AO for Peale’s is estimated at 8,500 km². The AO for Anatum was calculated by multiplying the estimated average home range (500 km², White et al. (2002)) by the number of occupied sites (505) in 2005. The AO for Tundrius was calculated by multiplying the estimated average home range of 500 km² by the number of occupied territories (48) in 2005. The AO is much larger than this estimate, however, particularly for Tundrius, as many nest sites remain undiscovered. The AO for Peale’s was calculated by multiplying a home range of 78 km² (calculated from an estimated 5 km foraging radius reported in Nelson 1990) by the number of occupied sites (109) in 2005.
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