Great Black-backed Gull in St. Louis County
2013-10-30

'Rare Regular' in Minnesota

These two first-cycle Great Black-backed Gulls (Larus marinus) were seen together at Canal Park, Duluth, 30 October 2013. Mike Hendrickson and I were watching and photographing one of them, but we kept hearing another one giving its distinctive long call. Eventually, both birds came in and posed side by side in the water. Karl Bardon has pioneered the identification and tracking of individual gulls by careful examination of tail pattern in immature Great Black-backed and Lesser Black-backed gulls, and wing tip pattern (third-cycle and adult) and tertial pattern (first-cycle and second-cycle) in Iceland and Thayer's gulls. These patterns are best recognized and distinguished by the time-consuming scrutiny of digital images, but may sometimes be apparent after watching individual gulls day after day (and sometimes one year to the next!) at Canal Park or at the Superior Entry. The individual showing its tongue in the top image is the same individual depicted lower right. Though difficult to discern in these in flight images, the tail pattern on the lower left bird shows subtle differences including a V-shaped notch in the exact middle of the tail band. The bird on the lower left also looks paler overall, with relatively more white showing in the median and greater upper wing-coverts, tertials, rump, and upper tail-coverts. When the birds were settled on the water, the differences in overall paleness and the tertial pattern were also evident, but immature Great Black-backeds often look similar to one another at rest and usually do not cooperate for satisfactory views and photography. Another first-cycle Great Black-backed Gull has been seen at the Superior Entry, but not at Canal Park to my knowledge. It is the smallest and most whitish individual that I have ever seen, and it has been cooperative for photographers. When settled on the water amongst a flock of immature Herring Gulls, it can only be picked out by its bill size and pale plumage, since it's clearly smaller than the largest Herring Gulls (suggesting that it's a female). We (Karl, Mike, and Peder) are interested in learning about other observer's experience in distinguishing individual gulls based on plumage, and would appreciate seeing anyone's sharp in flight images of these Rare Regular gull species taken in Minnesota.

Peder H. Svingen