Once again it seems like we have 10 territorial pairs of chough, 9 of which have been confirmed as nest building, the other may just hold territory and not breed - the jury is still out on them. Having spent the last 2 weeks of March prepping their nests deep inside caves and rock crevices, the first two pairs got down to the serious business and began incubating today.
The female usually lays around 5-6 eggs and she alone will carry out the incubation stints. Depending on where in the cave or crevice the nest is, she can sit in near darkness on the ramshackle nest comprised of heather twigs lined with a mixture of dried grass and sheep's wool (and, it has been known, Border Collie hair after I've brushed him in the garden!)
A key sign that incubation has begun is when you start seeing single birds (the male) loitering with intent outside the nest site. They usually return around 1-2 times an hour to feed the female. They either go in and feed her on the nest or they call outside the site until the female relinquishes her instinct to brood and leaves the eggs while she feeds. Today the females were off the nest for some time and headed away to feed, indicating that this was the very early stages of incubation and possibly only a partial clutch has been laid so far. When all eggs are laid the female is usually less inclined to go far, grabbing a takeaway from the male and returning quickly.
Incubation will last around 3 weeks and then around early May we should hopefully see the signs that chicks have hatched when both adults will be busy foraging for the newly hatched young.
Chough nest watching can involve a lot of sitting around interspersed with bouts of frantic activity. I was lucky enough to have a merlin for company at one site today and watched it, unsuccessfully, hunting rock pipits.
More chough updates to follow.....
Not all chough on the island are busy nesting - they don't start breeding until around 3 years of age. These noisy groups of non breeders spend their formative years pairing up and finding a nest site. Recently there has been a flock of over 20 such birds on the island
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