Tuesday, 10 June 2014

Ringing Golden Eagle chicks

Golden Eagle habitat in ancient pinewood of the eastern Highlands

As it is now the second week of June, the Golden Eagles chicks in Scotland are well grown, between three and five weeks old. So it is time to ring them while they can be handled easily and safely, for the birds' sake, more than ours.

I was out helping Ewan Weston ring the chicks in some of the nests which he monitors and in three that we checked, all had twins. This is a sign of plenty food and fair weather, and now that they have reached this age, they should all fledge. His study area is in the eastern Highlands and all three nests were in Scots Pines, magnificent old trees

An eyrie set on the upper branches of one of the pines

The adult birds gave a silent fly-past as we approached the nest tree, then they slinked off to watch us from a distant perch. Meanwhile the chicks remained silent too, lying flat and inconspicuous in the eyrie until Ewan came within reach and showed his head over the edge of the nest. He then gently placed them into a bag and lowered them down to be ringed and measured on the ground.

One eaglet sits up on the nest while the other lies low on the far side

In each of the three nests, there was one male and one female chick - the females recognisable by their larger size, especially that of their feet, legs and head. The flight feathers on Golden Eaglets begin to show dark against the white down when the chicks are about four weeks old, and the birds generally lie quietly when laid in the heather below the eyrie while they are ringed. When older, some will strike out with their talons, and hiss, but they seldom snap with their bills.

The chicks were lowered down the tree in a bag for safe processing on the ground

Simon Cherriman from Perth, Australia, who is visiting Scotland with me at the moment came along to learn how we ringed eagles and Jenny Lennon, Ewan's partner, helped guide him through the process. Although the chicks were docile, the rings need to be extra-strong, so that the birds cannot open them and take them off once fully grown. And so, the rings are especially tough to fit and close securely.

Ringing one of the chicks

Each bird was fitted with a standard ring issued by the British Trust for Ornithology, and a colour-ring on the other leg which can be more easily read if the birds venture into the line of view of many of the remote cameras which are being set up throughout the Highlands. This will help to inform us on how much interaction there might be between Golden Eagle home-ranges. Anyone visiting eagle eyries or ringing of eagle chicks must have a licence from Scottish Natural heritage to do so and we were all covered for the work we were doing.

Each bird was fitted with an individually numbered colour ring 

It only took a few minutes to ring the chicks then they were measured to ensure that even if it looked like the larger birds were female they did in fact fit the criteria.  

Several measurements were taken to determine which sex the chicks were, here the hind claw

These young birds already had large talons and bills, but wait until they are fully grown. Then they are really impressive.

And their heads were measured

Ewan, Jenny and I have ringed lots of eaglets the years, so all was done most efficiently and the birds were passed back up the tree. Then we were gone. The chicks lay quietly in their nest and the adults would soon return - as quietly as they left.

And the birds were all set to be returned to the eyrie

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