By: Dr. Annamarie Hatcher
It is all a matter of perspective, I guess.
Many species, including some of my friends who are scientifically identified as Homo sapiens, migrate to more southerly climates at this time of year. When I picture them in February, I imagine the migrators shaking off the chill of winter on a sunny, warm beach, mangrove swamp or golf course in Central and South America.
However, the Bras d’Or Lake Biosphere is the southerly destination for at least one species, a bird. The Iceland Gull nests in remote cliffs in the far Arctic and a group of them fly south to our biosphere to spend the winter. As a participant in the annual Christmas bird count, I am fascinated by this bird that chooses Cape Breton as its winter playground when many other species sensibly choose much warmer winter escapes.
Your interest may be piqued now, driving you to hike along the shore of the Bras d’Or estuary to see one of these winter visitors. Gulls (in Mi’kmaq: kloqntiej) are notoriously difficult to identify because they change their colouration as they age. It may be an exercise in frustration if you try to identify gull species in a flock. The visiting Iceland Gull (scientific name: Larus glaucoides) is very similar to our year-round resident, the Herring Gull (Larus argentatus). To make identification even more difficult, colouration changes with age in both species. So, how do you tell the difference between the resident and the seasonal visitor? If there are several in a group, you may notice that there are some that are a bit smaller. That could be the gender difference, with males of both species being bigger than females. However, there are also species differences. Mature Iceland Gulls are about 14 per cent shorter and 38 per cent lighter than Herring Gulls (allowing for the gender differences). If you have binoculars, look at the bird’s face.
According to the bird bible (The Sibley Guide to Birds published by the National Audubon Society) the Iceland Gull has a “gentle expression” because of its round head and short bill. In the biosphere, Iceland Gulls have little or no black on their wingtips whereas the Herring Gulls do. This is particularly obvious when they are flying. If you see them flying, they have broader wings than the Herring Gulls. When they are standing, the wings extend past the tail.
In the biosphere, Herring Gulls are usually coarsely-patterned brown with blurry steaks on the breast during their first winter. During their second winter, the patterning is less pronounced, some grey appears on the wings and they often have whiter heads. During the third winter, they have more grey on their wings, a whiter breast and a white and brown streaked head.
The Iceland Gull has much less distinct colouration. During the first winter, the breast is a smooth grey-brown. Although the adults may have a grey back, all ages have pale wingtips compared to the Herring Gull.
If you still aren’t sure about your identification, watch the gulls flying. If there is open water and they are feeding, the Iceland Gulls appear to be much more graceful fliers than Herring Gulls, with fairly quick wingbeats. They forage by flying low over the water and swooping down to pick up fish or other food without landing.
If you are a bird lover, you must be a patient person by nature. You may enjoy watching for a gentle expression and graceful fliers. However, if you are in a hurry, look at the gull’s wingtips. If the undersides have no black, you are probably looking at an Iceland Gull. It would have arrived here around mid-November and will be heading back north as the biosphere starts to shake off its winter cloak.
The recent reports from the biosphere indicate that Iceland Gulls are more common from Groves Point to the Sydney Bight than other areas of the lake (Eskasoni, East Bay, Big Pond, Whycocomagh), but these numbers can vary as a function of available food.
By far the most common gulls in the Bras d’Or Lake Biosphere year-round are the Herring Gulls. The other fairly common year-round resident is the Great Black-backed gull, the largest North American gull species. It is distinctive, being 20 per cent longer and 44 per cent heavier than the Herring Gull with dark grey or almost black wings on the adult that are a stark contrast to the light grey wings of the adult Herring and Iceland Gulls. Its large size also makes it easy to identify. Both Herring and Great Black-backed Gulls breed in the biosphere.
Now, let’s talk about the less common gulls. In Mi’kmaq, these gulls, which are smaller and more slender than “kloqntiej,” are known as “nktu’niej.” Did you know that there were so many species with so many interesting stories? For example, as you are gazing upon that flock of gulls in the estuary, you may see one or two smaller species that look a bit different. There are a few Bonaparte’s Gulls (Larus philadelphia) in early winter and a few Black-headed Gulls (Larus ridibundus) all winter in the Biosphere. Ring-billed Gulls (Larus delawarensis) can be found in more urban environments in the summer to early winter, often around fast food establishments. In true gull fashion, these birds all have colouration that varies with age. However they are 30 to 46 per cent shorter and around 56 to 80 per cent lighter than Herring Gulls. I’d suggest that you consult a good birding guide to help with identification of these species.
So, now that you appreciate the diversity of gulls in the biosphere why not join a bird watching group or volunteer for the Christmas bird count. Check out the Cape Breton Naturalists Facebook page or the Nova Scotia Bird Society Web site: (https://www.nsbirdsociety.ca/) for more information.
Dr. Annamarie Hatcher is a consulting ecologist and a board member of the Bras d’Or Lake Biosphere Reserve Association. For more information about the Bras d’Or Lake Biosphere Reserve Association, please visit http://blbra.ca/.