Photo: Arne Ader
Video recorded by Fleur, LK forum
Black-headed gull Naerukajakas Larus ridibundus
They are the same gulls that we saw in fields busy behind the tractors, but with heads coffee brown down to the neck in spring, and we see them also during the autumn field work, but already from the end of July it looks as if we have to do with an altogether different species with a light head, although the size seems to be the same – the black-headed gulls are in their winter plumage.
The birds that nested in Estonia started their migration towards south a few weeks ago but the groups of passing migrants coming from the north will become fewer only in October and we can meet courageous winterers at open waters. A good identification characteristic is the dark patch just behind the eye. The wings of black-headed gulls are white both above and on the underside but the tips of the outer primaries are black, and with folded wings these are visible at the tail. There are more brown colours in the plumage of juveniles. The length of the birds is less than 40 centimetres but the wing span of the birds, weighing on average 300 grams, is up to a metre. Among adults, the males are a little bigger and heavier.
A group such as in the video usually stays in a place for a couple of days, then move on slowly to the next feeding ground (on the seaweed bank we can see waders and farther away mergansers, also on migration). In shore waters there isn’t particularly many fish, so what does such a number of gulls feed on? We are used to the idea that sea gulls feed on fish. Black-headed gulls are instead largely animal- and insect- eaters: in quiet forest lakes or sea bays they are not fishing but hunt dragonflies and other flying insects. When the soil in fields is being turned there are earthworms, insects, their larvae and snails, also mice and frogs. In seashore waters next to the beach they feed on all kinds of invertebrates and if they come across some stickleback this titbit is not refused either.
The menu of city gulls is completely different, consisting of what is left by humans. In autumn we can come across cases of gulls searching for acorns under trees