Your magazine is excellent and I read it from cover to cover. You had an excellent article on seagulls back in June.
Are you able to provide any insight into seagull nesting success in the Victoria area this year? We live in Sidney and there is a pair of nesting seagulls on a rooftop across the street from us that have returned for four years. They have been sitting on two eggs for well over a month now and I think they are slowly giving up. Their time away from the nest is becoming longer and when one bird returns she (?) spends a little time on the nest, looking at the eggs, and sitting a while. She is looking bedraggled. Her feathers are frayed and she looks a lot thinner. It is almost as if she is grieving.
We wonder if the “heat dome” at the end of June killed the eggs and if other nesting birds have also lost their broods?
Gary is referring to our story “The Gull Next Door”. We reached out to Louise Blight, a seabird ecologist at the University of Victoria in British Columbia, who also joined us for a webinar on the topic of gulls and other coastal birds in urban environments. Here’s her answer.
In terms of the gulls, I don’t have a set of study nests this year, but I do have some thoughts about their nesting success based on a few more casual observations from around town and an understanding of avian egg physiology. Bird eggs can withstand quite a few degrees of cooling, down to low ambient temperatures, but they don’t tolerate higher temperatures so well, especially when the embryos are older. Some roof-nesting gulls this year had their nests in places where they were able to keep their eggs cool enough through the heat dome—I know of some urban nests that hatched chicks after the heat event—but others were too exposed and the eggs perished. Probably the chicks that had already hatched before the heat event arrived did better in general as they would be able to seek shade (and the parents will shade young chicks and eggs with their bodies). For the nest being observed by your reader, although it’s not too unusual, the beginning of August is getting pretty late for unhatched eggs, and if those birds have been sitting on their nest for over a month, the clutch has failed. The incubation period for the species is about a month, though as they are seeing, parents will incubate for longer. The bedraggled look is likely because they are beginning their post-breeding molt, which starts in August. Are they grieving? I don’t know—but they are waiting in hope for their chicks to emerge.
If they see the two birds together, the female will be the smaller of the pair, though there isn’t always a size difference that’s observable from afar.