Friday 16 August 2013

Kookaburra bill


Birds often develop deformed bills and I wonder why they occur, accident or disease. I met this Kookaburra in the bush yesterday, and I recognised it by its distinctive bill shape from last year. It was in the same area and probably the same family group's home range as it was displaying with another bird. So although it appears that it might have difficulty feeding with such a long upper mandible compared with the lower one, it must be successful. Kookaburras catch most of their prey by pouncing down on them from a perch and snatching them with their bills. Typically, they catch anything from insects to small reptiles, so they need to be quick and efficient.


Thursday 15 August 2013

Camouflage

Which bird attracts the eye first, least, the sunlit or shadowed one?
Tawny Frogmouths are well known for their ability to blend into their background, yet they repeatedly impress me with their exhibits of just how well they do so. Here are some shots of birds roosting in the daytime close to their nest trees as they enter their breeding season for 2013.

The male sits on the outside, as in about 90% of cases of pairs roosting together

A short stubby branch of the main trunk is a favourite perch
Another bird in the neighbouring territory sat alone, basking in the late winter sunshine. The freckles on her breast merging so well with the dappled shadows.

Easy to see once we know where to look

Thursday 8 August 2013

Tawny  Frogmouth nest-building

A possum investigates the camera
The birds'  breeding season has begun in south-east Australia and the Tawny Frogmouths have started to build their nests. I set the camera trap up at a nest last night and a short version of the results can be seen here on the this video link: Nest building .

The male bird was perched next to the nest when I set up the camera just after dusk, and he sat and watched me quietly with no sense of alarm. Then all was quiet until near midnight, when a Brush-tailed Possum came and sniffed at the camera. No birds came to the nest until six-o'-clock the nest morning, when the male brought in some fresh twigs or fronds and added them to the basic nest. And that was it for the night. Dawn was not far away.

Then at nine in the morning, An Australian Magpie came and investigated the nest, then jumped over to check out the camera.  A quiet but unexpected sequence of events. But Spring is here.

Sunday 28 July 2013

Northern wader habitat

A road meanders north through the extensive birch woodlands and mires
There are few human settlements or other intrusions to the landscape of the region in northern Norway where we go to study waders and the potential breeding grounds for these birds is vast. The forests and mires form a massive extensive mosaic of birch woodland and sedge-filled mires, with many open stretches of water in the form of tiny to wide lakes and formidable fast-flowing rivers.

A typical mire with open water in the centre surrounded by a floating carpet of mosses and sedges, and the whole encircled by willow/birch scrub and birch forest
Waders such as Wood Tringa glareola and Broad-billed Sandpipers Limicola falcinellus, Jack Snipe Lymnocryptes minimus, Red-necked Phalarope Phalaropus lobatus and Reeve Philomachus pugnax nest in the mires, while species such as Whimbrel Numenius phaeopus, Spotted Redshank Tringa erythropus and Greenshank Tringa nebularia nest in the scrub and woodland.

Numerous other northern breeding birds live in the these habitats, mostly summer migrants which go there to breed, then return south to over-winter. One resident species is the Willow Ptarmigan Lagopus lagopus which nests in the forest understorey. These birds can live there throughout the winter because they feed on the leaf and flower buds of the birch and willow which protrude above the blanket of snow that covers all the ground all winter.

A hen Willow Ptarmigan sits on her nest in juniper scrub

The ptarmigan's eggs are cryptically coloured to conceal them while she leaves the nest, perhaps once a day, to feed.

Arctic waders

Adult Wood Sandpiper
Here are a few photographs of waders and their chicks which I was studying recently in northern Norway. Part of the work, which is organised by my brother Rab, involves finding and catching both adults and chicks to ring them in order to help discover such information as where they live in the non-breeding period, whether they return to nesting or natal sites, and how long they live.

A pair of wood sandpipers, ringed and ready for release
The most abundant wader species in the tundra mires is the Wood Sandpiper Tringa glareola and the Broad-billed Sandpiper Limicola falcinellus is one the less common and seldom seen species. Most of the waders live in extensive mires, hidden by lush growth of sedges and other marsh plants.

An adult Broad-billed Sandpiper is measured -  the sexes are similar in plumage, but can be differentiated by size
Wader nests and chicks are notoriously difficult to find due their cryptic plumage and seclusive behaviour, arctic-breeding species are especially so. Wood and Broad-billed Sandpipers nest in the mires and it takes very specialized skills and a very very keen eye to find them.

A Broad-billed Sandpiper nest and chicks lie hidden in a mire

Broad-billed Sandpiper chicks in the nest





Four Wood Sandpiper chicks, a typical brood size
A single Wood sandpiper chick is extremely difficult to see when creeping through the sedge