Red-spotted Bluethroat

Adult male Red-spotted Bluethroat

While in Norway studying the waders in the marshes, we were constantly surrounded by the songs of local passerines. The main species were Willow Warbler Phylloscopus trochilus, Mealy Redpoll Carduelis flammea flammea and Red-spotted Bluethroat  Luscinia svecica svecica. As there are few ornithologists working in the field in northern Norway, to help discover the wintering ranges of these birds, we ringed any passerine chicks we came across and caught adults in mist nests. The warblers and redpolls do not vary much in plumage between breeding and wintering periods, but the Bluethroats were spectacular in full breeding plumage, especially the males.

The blue throat

The blue-throat of these birds is truly stunning, being of a metallic hue. It is so bright and obvious when seen in the filed, however, when in the hand and viewed face-on, these birds exhibit a clear and bright yellow gape. The yellow line complements the blue and red tones so well, it must have a purpose in the bird's display.

The abundance of waders and passerines in the Arctic is largely attributable to the supper-abundance of mosquitoes. They can be a pest for field-workers, with their incessant buzzing and biting, but without them the mires would not be such a tremendous breeding ground for birds - so many species are dependent on them for rearing their young.

Mosquitoes are ever-present in the Arctic scrub

Broad-billed Sandpiper

A Broad-billed Sandpiper in breeding plumage

I have recently returned from a trip to Norway where I have been helping my brother Rab on a long-term study of the birds in the norther marshes, including the breeding biology of Broad-billed Sandpipers Limicola falcinellus. Typically of Arctic-breeding waders, these birds fly north to nest as soon as the snow melts and their breeding grounds are clear enough for them to feed and build a simple nest on the floating mires. The main function of their journey is to find a nursery area for rearing their chicks, and the whole breeding period from egg-laying to fledging is over in a matter of weeks, Then the birds fly south to their wintering grounds, which to date are unknown for the Norwegian population. To help answer this question we began tagging birds with geo-locators, and plan to re-catch the birds next year to download data which should indicate where the birds have spent the non-breeding period, the longest part of their lives.

The broad bill

One of the individual characteristics of wader species is the specific bill shape, and the broad bill of these sandpipers is not usually appreciated when seen in the field in profile. However, when the bird is in the hand, it is obvious. As these birds spend most of their time in their winter quarters, it is likely that their bill is adapted for catching certain prey there, giving them advantage over other species for a specific food source. The bill is not only broad, but has delicate flutings along its length, which suggest that the bill is a very tactile and maneuverable organ, not just a simple horny probe.

The not-so-simple bill of a Broad-billed Sandpiper

Cuckoo chick

The birds' breeding season in Scotland is now well drawing to a close with many species feeding fledglings. This is tough enough when feeding their own young, but feeding that of a Cuckoo Cuculus canorus must be especially demanding for the adult birds which have been so duped.

A young cuckoo sits in a meadow pipit nest, well camouflaged under heather

Young Cuckoos can be very noisy when begging for food, but the go silent when approached. Then they rely on their cryptic plumage to hide them in the understorey of the heather moor where their foster parents, Meadow Pipits Anthus pratensis have their nest.

Young Cuckoo giving a defensive threat display

Once they know they have been detected, the young Cuckoos adopt a threatening posture, and flash their orange gape.

The young Cuckoo looks down from a fluffed-up posture

When relaxed they often take on a round, puffed out posture, holding their head back and extending a bulge of throat feathers, so typical of cuckoo species.

Young cuckoos have a bright orange gape

Their bright orange gape acts as an exaggerated stimulus for their foster parents to supply the extra amount of food required by the young Cuckoo above the demands of a normal brood of four smaller chicks.

The empty nest after the bird had fledged

Once the bird has left the nest, it is recognisable as having held a young Cuckoo by the widened and flattened shape of the nest cup.

Golden Eagle prey

Some of the prey items below the eagle eyrie

Whenever we visit a Golden Eagle eyrie, we always search around below the nest for pieces of prey dropped from the nest, and whoever climbs to the nest also has a good rummage through the nest lining for any more pieces.

Yesterday, while at the eyrie described in the previous post, we found remains of a Red Deer calf, a Roe Deer calf, a hen Rock Ptarmigan, a Red Grouse and what seemed to be feathers from a Common Gull in a pellet.

Both the deer were new-born calves, distinguishable by the unbroken cuticles on the soles of their hooves as seen in the photograph below.

The hoof of a Red Deer calf on the left, and a Roe Deer calf on the right. Very similar, but that of the Roe is smaller. A Golden Eagle can easily lift a Roe Deer calf, although a Red Deer calf must be a bit heavy to carry very far. Hence, both calves had been dismembered before they were carried to the chick in the eyrie, which might have been several kilometres from the place they were found.

Ringing a Golden Eagle chick

A four-week old Golden Eagle chick with a wonderful view from its eyrie. What an entrance to the world.

Yesterday I was up helping members of the Highland Raptor Study Group ring a Golden Eagle chick in an eyrie which I found a few days before. The eyrie was in an old Scots Pine, set about twelve metres up on the main stem where the branches split into a multi-fork. This presented a bit of difficulty in climbing up to the nest, but Brian Etheridge rose to the challenge.

Brian negotiates a route up over the eyrie

The eyrie was about two metres deep and two metres wide

Adam with the chick, a strong, well-fed male. 

For safety, the chick was lowered from the tree in a bag and ringed on the ground. Adam Ritchie ringed it as he had only done a a couple before, and putting on the extra-strong rings takes a bit of practice. The chick was a strong, healthy male, readily sexed by his relatively small feet and quiet nature. Females are larger with big strong legs and feet, and they are usually much more aggressive.