Incredibly busy times these are, still occasionally locating nests and measuring eggs but now the time has come to catch and ring Long-tailed Skuas. Actually, we already caught 12 so far in the last days. The skuas area caught on the nest using either a walk-in trap or a spring trap which sets as soon as the bird sits on the eggs. The birds are then equipped with a steel ring on the left tibia, a green colour ring on the left tarsus and a ring with a geologger on the right tarsus, this way the birds have maximum spread of weight on the legs. We take measurements of the bill, head, wing, tail and tarsus. We weigh it, photograph it and then comes a tricky part; getting a blood sample. I’ll spare you the details but will assure you that the birds don’t have any lasting effect of our iny tiny operation. The bird is then released next to the nest after which it most of the time flies off to a small lake to preen or, in some more aggressive individuals, they immediately turn back and start attacking you again. Aggressiveness in the skuas varies a lot, some will attack you when you’re still 200-300m from the nest, they then swoop over you time after time hitting you with either legs or/and wings. Usually birds fly off at 70-100m distance and keep swooping with the occasional hit, often one of the birds will try and lure you away by making chick sounds and faking a nest at some distance from the real nest. Rarely we encounter birds that hardly do anything at all, today we had a pair of which the breeding individual flew up at 40-50m and they perched together on a rock, watching us take measurements of the eggs. The only birds that get a geologger are birds that have surely returned to that area for a/some year(s), remember; the data is only obtainable when you recatch an individual and birds that have returned over the years are more likely to return next year again. Easy aye?!
2 of the nicest pictures I made so far. The Pygmy Weasel was really anxious to get out of her 'den', later we found a litter of 5 cubs which she was probably trying to locate in her new nest.
Geen opmerkingen:
Een reactie posten