The Ivory Gull being seen at Canal Park in Duluth has been fed fresh salmon filets, which it eats readily. Nice pink salmon. Coincidentally or because of good research, brightly colored salmon turns out to be an excellent choice. Ivory Gulls like the color red.
“Very responsive to red splashes, unhesitatingly investigates and pecks at red objects left on ice or snow.” That observation comes from the Birds of North America monograph 175, Ivory
Gull, written by Dr. J. Christopher Haney and Stewart D. MacDonald.
The authors tell us that the bird is “rarely, if ever, found far from drifting pack ice at any time of year.” It breeds in northern Canada, Greenland, and archipelagos in the Arctic Ocean off the coasts of Norway and Russia. It does leave the ice to breed, nesting on cliffs and stony ridges, often as far as 15 or 20 miles from the coast.
In 1995, when this monograph was written, the estimated world population of this species was in the order of 30,000. The Defenders of Wildlife, a conservation organization, wrote in 2007 that Ivory Gull numbers were in “steep decline.” It said gull numbers were falling faster than those for Polar Bears, and that there might be more bears than there are Ivory Gulls. The population in 2012 was estimated at between 19,000 and 27,000 birds. The Cornell Lab of Ornithology lists its population status as near threatened.
I spent about five hours with the gull earlier this week. It’s a cool bird, no pun intended. I heard it vocalize once, a very brief call. It did not sound gull-like to me. The Cornell Lab has a recording of the bird’s voice. I think it sounds like a cross between an angry cat and a screech-owl. Have a listen at https://www.allaboutbirds.org/guide/Ivory_Gull/id
On nesting ground and when feeding young the gulls eat small rodents. On the ice, the birds eat fish and other sea life, and mammal blubber. It is reported to be highly opportunistic, to the point of following and attacking wounded, bleeding Polar Bears. It will attack predators.
The authors describe the walk of an Ivory Gull as pigeon-like — it waddles on short legs. That was my thought during my Canal Park visits when the gull walked from the canal wall onto the grassy knoll at the park’s center. Walking away from me it looked just like a pigeon.
The authors describe the appearance of first-year birds as ermine patterned, white with variable blackish-brown marking on its face, wings, tail, chest, and flanks. It molts into adult plumage — white throughout — during the summer of its second year.
Major wintering populations are found offshore from the Canadian Maritime provinces and in the Bering Sea. The paper does not include comment on vagrancy, like showing up in Duluth.