Lesser Black-backed Gull - November 2018

On November 26, 2018 I visited the sandbar at in mouth of Vernon Creek where it empties into Okanagan Lake at Okanagan Landing. This spot is one of the best sites in interior B.C. for viewing different species of gulls. Herring, California, and Ring-billed Gulls are almost always present except in a complete freeze-over or in the height of summer when human beach goers abound. Beginning in October a few Glaucous-winged Gulls can usually be found as well. On November 26, a stranger stood out among the usual species. It was a Lesser Black-backed Gull, not the North Okanagan's first by any means, but rare enough so that it got my heart pumping.

Figure 1 - The first image I got of the Lesser Black-backed Gull was with my iPhone held up to my Kowa scope. I had my usual camera with me but had accidentally left the photo card at home.

Depending upon the species, gulls take 1-4 years to attain mature plumage. For each year of immaturity, the gull will have a distinctive plumage, quite different from its adult feathers. The Lesser Black-backed Gull is a three year gull. Its first-year plumage is quite obscure, but its second year plumage is pretty distinctive. Look for the pale head and chest contrasting with the grey-brown back and wing coverts.

I returned after lunch with my regular camera, this time with a card in it, and took several images of the bird when it re-appeared around 2 p.m. Unfortunately it stubbornly remained in one spot near the tip of the sandbar and all of my images for that session look like this:

Figure 2. Lesser Black-backed Gull - second year plumage. American Herring Gull in the background.

The Lesser Black-backed Gull has unusually long primaries, which is to say the flight feathers visible as black in Figure 2. They extend well beyond the tip of the tail.

During my initial sighting of the gull, it had taken flight and chased another gull quite aggressively. I had been quite impressed with its black tail and white rump, so two days later, when I re-sighted the gull on the sandbar, I made a special effort to stick around until the gull flew. The flight shots reveal the dramatic contrast between the upper wings and the pale body. 

Figure 3. A slightly over-exposed shot of the Lesser Black-backed Gull in flight.

Figure 5. The white rump had a strong tendency to throw off the meter of my camera, over exposing the shot. I spent the next 20 minutes trying to get better exposed images.

Figure 6. Note the long white axillary ('wing pit") feathers. 

Figure 7

Figure 8. In sunlight the mantle or saddle is quite grey, and the coverts are shades of brown. Note the white tipped tertials. 

Figure 9 

Figure 10. Note that there are a scattering of bars down the centre of the rump.

I left the gull as it returned time after to to a small dead fish that a California Gull had initially dragged onto the edge of the bar. The Lesser Black-back once again displayed an aggression that enabled him to reclaim the fish from other smaller scavenging gulls.

Lesser Black-backed Gulls are interesting in that the species is not known to breed in North America, aside from a small colony in Greenland (Dunne and Carlson 2019). The species normally breeds along the coasts of northwestern Europe and Iceland. Beginning in the 1940s the species began to expand its range north and westward. The first occurrence in North America came in 1934 (Olsen and Larsson 2003) and in Canada in 1968 (Godfrey 1986). The first B.C. record was made by the late Doug Powell of an adult at Revelstoke from October 26 to November 10 1989 (Weber and Cannings 1990).  The second record occurred at Burton, south of Nakusp from 26 September to 18 October 1993.  Beginning about 2002, the species has become almost annual  in the Okanagan Valley, with one bird occurring most winters somewhere between Vernon and Osoyoos. Most records have been of adults. For a more complete status report on this species in British Columbia see Rick Toochin, Don Cecile, and Jamie Fenneman's efauna document.

References

Dunne, P. and K. Karlson. 2019. Gulls Simplified.

Godfrey, W.E. 1986. The Birds of Canada 2nd edition.

Olsen, K.M. and H. Larsson. 2004. Gulls of North America, Europe, and Asia.

Toochin, R., D. Cecile and J. Fenneman. date? Status and Occurrence of Lesser Black-backed Gull (Larus fuscus) in B.C. ibis.geog.ubc.ca/biodiversity/efauna/documents/Lesser_Black-backed_Gull-RT.DC.pdf.

Weber, W. C. and R. J. Cannings. 1990. Fall season: August 1 – November 30, 1989- British Columbia and Yukon Region. American Birds 44: 144-149

Acknowledgement: Thanks to birding veteran Gary Davidson of Nakusp for improving the accuracy of the Lesser Black-back Gull's provincial status.