Like all falcons, Peregrines do not build a nest of their own. They nest on a ledge or scrape on a cliff, quarry or building, sometimes using the old nests of other species in those locations; for example, in Gloucestershire we have had them nesting in old Raven nests on cliffs and on pylons.
So we were very excited to receive a call in June from Andy Jayne saying that he thought he had stumbled upon a pair of Peregrines nesting in a hedgerow oak tree! He could see both adult birds, which were being very noisy, and he thought he could hear the calls of young from the tree. He could not immediately see a nest, but he correctly withdrew because the birds were alarmed. A few days later two of us returned to the site with Andy and viewed with telescopes from a safe distance. Both adults were present again and this time we managed to find the nest. It was not easy to see, being partly obscured, but we could see that there was just one chick, which we estimated to be about 2 weeks old. The nest – probably an old Carrion Crow’s nest – looked rather small, although it was balanced across the centre of a horizontal branch, and the chick was very visible in it. Andy returned a week or so later and sadly, although both adults were still there, they were silent and the nest was clearly empty. Gareth checked over the site a few days after that and (under licence) used a drone to check the nest – there were no birds present and no sign of the chick below the tree. Of course we do not know what happened, but it seems quite likely that the chick tumbled out of the nest, and indeed may have had siblings that had suffered the same fate.
As far as we know this is a first for Gloucestershire. There have been very occasional reports of tree-nesting Peregrines elsewhere in Britain, from Scotland, Sussex, Shropshire, and Wiltshire. Peregrines are usually very faithful to their nest-site and in the Shropshire and Wiltshire cases the same tree was used for several years, successfully producing young, so – as is the case with most nests – we are not disclosing the site in case this pair return next year to try again.
Peregrine Falcons occur, in various sub-species, across much of the globe, and tree-nesting does occur elsewhere. The following examples are taken from the excellent book “The Peregrine Falcon” by Richard Sale and GRMG’s Steve Watson (Snowfinch Publishing, 2022). In Victoria, Australia, a study found that of 95 nest-sites identified over 2 years, 62 were in cliffs or quarries, 17 in tree hollows and 16 in stick nests of other species in trees. In both Alaska and Kenya, Peregrines have been recorded nesting in tree nests of eagles (of different species of course!), and on New Caledonia in the South Pacific the Melanesian Peregrine sub-species, which in that location hunts mainly seabirds at the coast, often uses the stick nests of Ospreys.
Nearer to home, tree-nesting was once widespread in central-east Europe but is now concentrated in Germany and Poland, probably because of reintroductions in that area which started in 1990 and which used birds relocated from areas where tree-nesting was common. It seems that Peregrines raised in nests in trees are fairly likely to do so themselves when they mature, although they may also use a cliff, building etc. It is extremely rare however for a bird raised in a nest that was not in a tree to go on to nest in a tree. Not very long ago, it was unusual for a Peregrine to nest on a building in Britain, but now it is entirely commonplace. Will tree-nesting catch on?…
