Gulls with Art Martell
by Heather Harbord, 18 March 2016.
Ten members accompanied Art Martell to Willingdon Beach and Sliammon on Friday.
On the way down to the creek mouth at Willingdon, we stopped to look at a lone Mew Gull with magnificent mirrors on its tail feathers. At the creek, we found three mature California Gulls which loomed clear in Art’s scope showing off their heavy bills with red and black spots. Unfortunately and eagle put all the gulls up and the Californias did not return, leaving only a small huddle of Mews.
Out at Sliammon, we saw Thayers Gulls, Glaucous-winged and Glaucous-winged x Western crosses. Also, Art identified a group of Glaucous-winged x Herring Gull crosses which we likely would not have noticed without him.
He reminded us that among the previous night’s slides were some showing that dark or light eye colour by itself is not a sufficient identification mark. It must be combined with size, beak configuration, shade of grey on the back and tail feather mirrors which all have to match.
Gulls likely to hybridize are those whose breeding colonies overlap such as Glaucous-winged and Western in the Pacific North West or Glaucous-winged and Herring (Larus smithsonianus) in the Gulf of Alaska. The progeny of the former migrate up the centre of Georgia Strait and the latter come down from Alaska in the winter.
75% of Puget Sound gulls are Glaucous-winged x Western crosses and in the Seattle area are often referred to as Olympic Gulls. Unlike popular beliefs about hybrids, these gull hybrids are not sterile and can reproduce with each other quite happily and continuously causing further confusion among birders. A new species could be in the process of evolving.