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COSEWIC Assessment and Update Status Report on the Ross’s Gull in Canada

Distribution

Global Range

The Ross’s Gull is primarily an Arctic and subarctic species with a circumpolar distribution (Macey 1981). The species breeds in Russia, and nests locally and perhaps irregularly in Greenland, Svalbard and Canada (Burger and Gochfeld 1996). The main breeding grounds are found in northeastern Siberia, from the Taymyr Peninsula east to the River Kolyma (Macey 1981), with additional breeding locations on Spitsbergen Island in Svalbard, Norway, Peary Land and Disko Bay in Greenland, and in northern Canada (Rand 1947, Blomqvist and Elander 1981, Alvo et al. 1996, Béchet et al. 2000, Mallory et al. 2006). The wintering distribution is still poorly known but likely populations winter along the edge of the pack ice in the Pacific Basin from Anadyr Bay and St. Lawrence Island in the northern Bering Sea south along both coasts of the Kamchatka Peninsula, and from the northern Sea of Okhotsk to Sakhalin Island and the southern Kurile Islands, and in the open waters of the Arctic (NatureServe 2005).

There appears to have been a significant increase in the number of Ross’s Gulls reported south of traditional wintering areas in the last 30 years. In the British Isles, the species occurs almost annually now with a maximum of 8 in 2002 (British Birds Rarities Committee 2006), in Iceland there have been 40 records up to 2002, most in the last 10 years (Icelandic Rarities Committee 2002), and there are about 25 records in the lower 48 states of the U.S.A., all since the famous individual at Newburyport, Massachusetts, in 1975 (BirdWeb 2006). Even granted variables such as greater awareness, increase in birders and so on, it appears that there has been an actual increase in the number of Ross's Gulls in the Northern Atlantic, perhaps indicating a shift in wintering patterns of part of the Siberian population.


Canadian Range

There are four known breeding localities in Canada, three in Nunavut Territory and one in Manitoba at Churchill (Figure 1).

Cheyne Islands

The Cheyne Islands (760 18’N, 970 30’W) (IBA site NU 049) consist of three islands of similar size, oriented north-south with approximately two km of open water between each island. North, Middle, and South Cheyne islands lie five km off the eastern coast of Bathurst Island, near Reindeer Bay. All three islands are of low relief (up to three m above sea level) and are composed of alluvial material. The islands are located on the west side of Penny Strait; several small polynyas develop in May or June on the east side of this strait (MacDonald 1978).

Prince Charles Island

A Ross’s Gull nest was discovered at the northwest corner of Prince Charles Island, Nunavut (68º 13’N, 76º 29’W) on 8 July 1997 (Bechet et al. 2000). This interesting find was only 200 km from where Ross collected the type specimen in June 1823, on the east coast of Melville Peninsula. Single Ross’s Gulls were tentatively identified on the southeastern coast of Prince Charles Island in 1984 (A.J. Gaston, pers. comm., cited in Bechet et al. 2000). Prince Charles Island is a large, low-lying island with an area of 9,521 km² (3,676 sq mi). It is located in Foxe Basin, off the west coast of Baffin Island, in the Qikiqtaaluk Region of Nunavut, Canadahttp://www.answers.com/ topic/ prince-charles-island

Penny Strait

A previously undiscovered colony of four and possibly five breeding pairs was located on an unnamed island in Penny Strait in 2005 (75º 08’N, 96º 30’W) (Mallory et al. 2006). This location is only 80 km from the nesting sites on the Cheyne Islands. The island is about 3 km2.

Manitoba

The first sighting for Manitoba was a photographed adult at Churchill 18 to 23 June 1978 (Manitoba Avian Research Committee 2003). In 1980, three nests were located (58º 47’N, 94º 12’W) (Chartier and Cooke 1980).From 1980 through 1995, Ross’s Gulls nested almost annually in the area around Churchill (Alvo et al. 1996, Manitoba Avian Research Committee 2003, R.F. Koes, pers. comm. 2006, IBA Site MB 003). Since then, breeding has become sporadic, with only single birds reported some years and up to four in other years, including 2005. There have been persistent reports of nestings upstream from the end of the Hydro Roadalong the Churchill River, where apparently there were five nests in 2002, although after the mid-1980s locations of nests have usually been kept secret (R. Koes, pers. comm. 2006).

Figure 1: Known Breeding Occurrences of Ross’s Gulls in Canada

Figure 1: Known breeding occurrences of Ross’s Gulls in Canada.

Locations from the top are: 1. The Cheyne Islands, 2. Unnamed island in Penny Strait, 3. Prince Charles Island, 4. Churchill area.Modified from Environment Canada (Edmonton)'s data base.

Summer records away from the Nunavut sites in the Canadian Arctic include six specimens in breeding plumage taken on Seymour Island, Nunavut (76º 08 N, 101º 03’W) in 1974 and 1975 (CMNAV 60081, 60082, 60083, S2074, S584, S845) (Macey 1981, M. Gosselin, pers. comm. 2006). There were sight records in 1973 at the McConnell River, Nunavut (Macey 1981, Alvo et al. 1996), and further sight records on the Boothia and Melville Peninsulas, Cornwallis Island, Prince Leopold Island, and Broughton Island (Godfrey 1986). A previous record of nesting Ross’s Gulls on the Meighen Islands was subsequently shown to be erroneous (Macey 1981, Alvo et al. 1996).

Other summer records in Nunavut include East Bay, Southampton Island, in 2000 (Stenhouse et al. 2001), and Cambridge Bay on 28 June 1994, a sub-adult (Alvo et al. 1996) andon 28 June 2000, chasing a Long-tailed Jaeger (Stercorarius longicaudus) (J. Richards, pers. comm. 2006). Further records in the Canadian Arctic were of a probable adult female Ross’s Gull taken on 14 June 1985 at Arctic Bay (73º 01’N, 85 07’W) on Baffin Island by Glen Williams (CMNAV 86167, M. Gosselin, pers. comm. 2006),.

Status in Other Parts of Canada

Northwest Territories - Records from the Northwest Territories (NT) are remarkably few, especially in light of the autumnal migration of Ross’s Gulls along the north shore of Alaska. The species is reported from the Mackenzie Delta region and may occur at the Taglu site and the Niglintgak site (A. Thompson, pers. comm. 2006, BSIMPI 2002). However, there are no known specimens or documented records of Ross’s Gulls from the NT (J. Hines, pers. comm. 2006), nor from specific parts of the NT, such as the Inuvialuit Settlement Region (K. Thiesenhausen, pers. comm. 2006).

British Columbia – There is one record, a bird filmed and photographed at Clover Point, Victoria, British Columbia, on 27 October 1966 and 9 November 1966 (D. Fraser, pers. comm. 2006).

Ontario – The first record for subarctic Ontario occurred from 14 to 23 May, 1983, at Moosonee, an adult apparently migrating with Bonaparte’s Gulls (L. philadelphia)(Abraham 1984).There was a report of a Ross’s Gull on the Winisk River in August 2004 (D. Sutherland, pers. comm. 2006). This record is of interest as there appears to be suitable breeding habitat, such as sedge-bordered marshy taiga lakes with Arctic Tern (Sterna paradisaea) colonies, in the general vicinity of Peawanuck and elsewhere in the northern Hudson Bay Lowland, although considerable scouting of the area has produced no results (D. Sutherland, pers. comm. 2006). Elsewhere in Ontario, there have been a few records on the lower Great Lakes, such as at Port Weller, Lake Ontario, and Point Pelee, Lake Erie.

Quebec – In Quebec, the Ross’s Gull is considered an “occasional visitor” (D. Banville, pers. comm. 2006). There are only five records, three in May and June, and two in November and December, from Sainte-Anne-des-Monts in 1976, Metabetchouan in 1991, Chambly in 1994 and 1995, and Bergeronnes in 1995 (David 1996).

Alberta, Saskatchewan, New Brunswick and Prince Edward Island – There are no known records of Ross’s Gulls from these provinces and the species is classed as hypothetical (Semenchuk 1992, Smith 1996).

Nova Scotia – There are four records from Nova Scotia; December 1987 and June 1988 at the Canso Causeway, July 1995 at Ile Madame, and December 1995 at Chebucto Head (I. McLaren, pers. comm. 2006).

Newfoundland and Labrador – An adult in basic plumage was shot off Fogo Island, Newfoundland, on 18 December 1976 (CMNAV 70031) (with location given as ‘Seal Cove’) (Godfrey 1986, M. Gosselin, pers. comm. 2006, P. Linegar, pers. comm. 2006). Otherwise, records are of a first summer bird at Trepassey in May 1985, an adult or possible second winter bird photographed at Stephenville in January 1986 feeding in a sewage carrying stream, an adult 3 km off L’Anse-aux-Meadows in September 1986 and a summer plumaged adult in the harbour there in August 1991, an adult in Cow Head Harbour in December 1991, and an adult in breeding plumage near Ramea Harbour in June 1993 (P. Linegar, pers. comm. 2006).


Extent of Occurrence and Area of Occupancy

The Extent of Occurrence (EO) is 300 000 km2, calculated by including areas of all breeding locations (see Figure 1). The Area of Occupancy (AO) is 31 000 km2, calculated by using a 50 km radius around each of the four known breeding locations.