"My" sparrowhawk spends a lot of time looking after his feathers. He often visits the perch just to preen although he does also hunt from there. He particularly spends time preening after feeding, when he is not feeling hungry. He collects oil onto his bill from the preen gland (uropygial gland) at the base of his tail and spreads it over his feathers.
Here you can see the papilla of the gland exposed.
This video shows what he gets up to. You can see him collecting the oil from the preen gland. The oil maintains feather integrity and probably also has a waterproofing and antiparasitic effect.
The function of the uropygial gland was first described by Frederick II, Holy Roman Emperor, in De Arte Venandi Cum Avibus in the 13th century. He thought the oil also contained venom which was spread on the claws to help kill the bird's prey, although that has since been shown not to be the case.
The sparrowhawk often sits like this with his tail spread if his feathers are wet after rain.
He won't have his first moult until later this year so keeping his feathers in perfect condition helps him in hunting and improves his chances of survival. Only 34% of young sparrowhawks survive their first year. This one seems to be doing OK so far.
Another superb study of your sparrowhawk! He certainly does a thorough job of maintenance, even applying oil to his knives (talons).
ReplyDeleteHe seems very particular about his feet Florence. He also spends a lot of time cleaning the blood and feathers off them after eating. I once saw a sparrowhawk hovering over the pond to wash its feet after eating a chaffinch.
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