Peregrine Falcon (Falco peregrinus tundrius)
Gyrfalcon (Falco rusticolus)

Population Status

Distribution:

Gyrfalcon nesting sites are widespread at relatively even densities across the North Slope, but are most common along the major drainages. The gyrfalcon with its particularly long nesting period is believed to winter on the North Slope during periods of prey (ptarmigan) abundance. Tundra peregrines are strictly summer residents of the Yukon North Slope where their nesting sites are restricted to low elevations (<700 m) along the major drainages.

Population size:

Peregrines have not been abundant on the Yukon North Slope in recent times. In 1975, young were produced in only 5 of 14 known nesting sites. Since then there has been a steady decline with the last known nest producing young in 1979. From 1980 through 1988 there were no records of peregrine breeding pairs on the Yukon North Slope. In 1989 one known eyrie supported a pair of peregrines. In surveys from 1992 to 1994 two to three territorial pairs were observed during surveys, with one to two pairs successfully producing broods of young each year. This marks the beginning of a possible population recovery. Gyrfalcons are relatively prolific on the Yukon North Slope, reaching the highest known breeding density in the Yukon at about 1 pair/167-211 km2 in suitable habitat. As many as 107 gyrfalcon nesting territories have been located on the Yukon North Slope. The highest nesting densities are along the Firth and Anker rivers; this coincides with the highest nesting densities of golden eagles.

Population trend:

Peregrines have suffered heavily since the early 1970s, reaching their lowest levels in 1980. The absence of peregrines on the Yukon North Slope during 1980 to 1989 was in contrast to the partial or full recovery of peregrine populations in the NWT and along the coast of Alaska. Surveys in the early 1990s indicate that tundra peregrines may be returning to the Yukon North Slope. Gyrfalcons are presumably at natural densities. By nature they cycle numerically, driven by the availability of ptarmigan, which experience significant and cyclic changes in abundance. This produces considerable annual variation in breeding numbers, productivity, and presumably survival rates. For example, from peak to trough in the ptarmigan cycle, gyrfalcon productivity on the North Slope has varied by as much as 70%.

Unique or special characteristics:

Habitat Features

Both tundra peregrines and gyrfalcons are habitat specialists, nesting on steep cliffs in tundra environments. Neither species builds its own nests but rather uses ledges or the nests of golden eagles, ravens, and rough-legged hawks. Peregrines typically require wide valleys or sea coast to facilitate hunting opportunities, where they are largely avian predators. Gyrfalcons hunt both avian and mammalian prey, but because of a very long nesting period and therefore advanced laying, they require nest sites that offer adequate protection against winter conditions. Gyrfalcons have specialized food habits during part of their annual life history and are, over most of their range, restricted to areas where ptarmigan are common. Peregrines are most common in wetlands where their preferred prey is typically waterfowl. Of interest, the few peregrine pairs that were located in 1992-1994 were found in different habitats from those traditionally used. The distinction between these traditional and current habitats is unclear.

Local Importance

Harvest:

n/a

Eco-tourism:

Gyrfalcons and peregrines hold significant value as a tourist resource. Gyrfalcons are rarely seen in the south and are therefore a preferred attraction to birders travelling in the north. Peregrines, and in particular tundra peregrines, are likewise a valuable attraction to naturalists. Opportunities for falcon observing are good along the Firth River, to the appeal of river rafters.

Threats

Probably the biggest threat to peregrine falcons is the indiscriminate use of pesticides on their winter range. Gyrfalcons are for the most part dependent on non-migratory prey and are therefore less predisposed to chemical contamination. Both falcons are potentially threatened by nest site disturbance or poaching of nestlings from nest sites for captive breeding or falconry.

Research/Monitoring

Annual population monitoring program:

A national peregrine recovery program has organized an inventory of peregrines every five years. The Yukon Department of Renewable Resources has participated in this inventory. The Yukon North Slope gyrfalcon population has been subject to annual monitoring of nest sites to determine occupancy rates and nestling production. The last monitoring occurred in 1991 of the Yukon North Slope (included Gyrfalcons). Occupancy rates of Gyrfalcon nests have been monitored.

Harvest information data collection:

n/a

Research:

Ecological data such as prey use and nest site characteristics has been collected incidental to periodic census of falcon breeding pairs. A management project involving the cross-fostering of captive-raised tundra peregrine chicks into gyrfalcon nests on the Yukon North Slope was continued for three years during which time 32 young were fostered. There has been no systematic tracking of these individuals, although a band return indicates that at least one peregrine was successfully fledged and attained adult status. Currently a proposal has been advanced to investigate aspects of the apparent tundra peregrine recovery, to determine demographic characteristics and pesticide levels in the new population and its prey, and to describe current peregrine nesting habitat. Funding for this proposal has not been guaranteed. No research has been proposed for gyrfalcons. Aircraft disturbance studies involving Gyrfalcons have been conducted.

Deficiencies:

For reasons unknown, the Yukon North Slope tundra peregrine population has not fully recovered from its decline in the 1970s. Factors retarding the recovery are not well understood. Of interest, recent surveys have found peregrines in habitat not occupied in the 1970s. There is merit to further study of the peregrine population recovery and peregrine habitat use on the North Slope.

Information Sources Used

Dave Mossop, personal communication, Yukon Department of Renewable Resources, Whitehorse.

Jingfors, K. 1989. Wildlife of Northern Yukon National Park, Chapter 9 in: Northern Yukon National Park resource description and analysis. Natural Resource Conservation Section, Canadian Parks Service, Prairie and Northern Region, Winnipeg.

Management

Terms and conditions of harvest:

As there is no harvest, the WMACs have not involved themselves to date in the management of these species. Interests of these species are dealt with mainly by the territorial governments. The harvest of non-game birds is prohibited under the Yukon Wildlife Act. Canada, as a signatory to CITES, has complied with legislation (Wild Animal and Plant Protection and Regulation of International and Interprovincial Trade Act) to prohibit the export and import of wild-raised gyrfalcons in the Yukon. While there is no commercial harvest allowed, an individual may capture a falcon, with a permit, for personal use.