Saturday 5 July 2014

North Norway


I have recently returned from a trip to north Norway, well within the arctic circle, but still within the northern treeline. The higher hills are above the altitudinal treeline have long-lying snowbeds and where the snow has melted are covered with heath.The lower ground is largely covered with birch forest, only a few metres tall, with other areas covered with dwarf birch and willow scrub less than a metre tall.  The dominant ground cover in the heath and forest floor is lichen, often referred to collectively as reindeer lichen as that is the traditional food of the vast herds of semi-domestic reindeer that are held the there.  


The landscape as a whole is a complex mosaic of birch woodland, scrub, heath, mires and lakes. The winter snow is late to thaw and a cold north wind held the spring growth back this year.


The sky was often grey, but carried very little rain, most of it falling as showers, the clouds lit pink in the low midnight sun.


And midnight rainbows ran over the horizon.


Then as the wind turned to the south the air warmed and cleared, and the low sun cast soft backlight through the birches.


Although much of the lichen-heath has been heavily grazed by reindeer, there are still some carpets of reasonable size and depth, and they give a hint of the thick intricate growth of numerous species of lichen which should cover most of the dry ground.


The lichens are fragile, and crunch when trodden upon, it seems tragic to destroy so much art.


But the lichens are prolific and do grow back, to spread over twigs, leaves, branches and cast reindeer antlers.


Even a reindeer skull.

So when, or if ever, the reindeer herds are reduced enough, the lichens will return their former glory.


However, attractive as the woodlands and lichens are, I was there to study birds like this male Bar-tailed Godwit and other species of wader which come to these lands for a few months each year to raise their young. More of which I shall describe in further posts.

Sunday 29 June 2014

Auks

A Guillemot stands between three Razorbills
Following on from the previous post on seabirds, I thought I should add a page on the guillemots and razorbills, two species of auk, often overshadowed by their more famous related species, the puffin. Yet, these two species have a special appeal of their own, if one just spends time watching them.

These shots were all taken on a recent visit to the Scottish coast where seabirds nest in the thousands during May/June/July.

Guillemots stand in a crowd on a slab below the breeding cliff
I avoid disturbing these birds on their nest or rather egg ledges (they do not build a nest, but simply lay their single eggs on bare rock ledges), I prefer to capture shots of them on points of rock or slabs where they congregate away from the dense breeding ledges. The guillemots gather on slabs below the cliffs, where when seen from above they look like a busy human street scene, all coming and going, and interacting in individual ways.

The sleek head and bill of a Guillemot, perfect for swimming quickly underwater
By lying quietly on a viewpoint, I could easily catch images of the birds which show their basic black and white plumage is not as featureless as at first perceived. The guillemots have wonderfully sleek feathering on their heads and necks, they are as smooth as skin, probably smoother. It has to be for the birds to dive deep and chase fish underwater.

Beads of water cling to the belly feathers of a Guillemot fresh out of the water
Those feathers are also well oiled (from the oil gland at the base of their tail and spread all over by the bird with its bill) and as they fly up from the water, most the water is rapidly shaken off. When they land, hundreds of tiny water droplets cling to the birds, giving them a luxurious sheen, but they too are quickly shed.

Adult Razorbills have grooved and striped bills, and subtle chocolate colouring on the throat
 - not black like that on the upperparts of their body
Razorbills mostly lay their eggs in niches large enough for only one pair, and they tend to be dotted over the cliffs rather than clumped in large ledges like the guillemots. When seen close up, they too have gorgeous feathering. The white eye-stripe is a stunning feature as are the stripe and grooves on their bill. They have very dark eyes and their dark brown throat feathers can only be seen in their true colour under favourable light.  It pays to take time to take a good long look at these characterful birds.

A pair of Razorbills in full copulation - his tail is tucked under hers, both birds are relaxed with wings and bills closed. Birds are often shown in photographs of them copulating with wings and bills flapping and gaping. Those are incomplete mating attempts, or pre-copulation positions
I especially like to watch seabirds, such as the auks for their behaviour. As there are so many birds in view at any time, there is usually something going on somewhere in the colony; display, calling, mating or aggression in tight spaces. There really is never a dull moment, nor a finer way to spend a few hours of a summer day.

A Razorbill sky-points, a formal display posture often adopted high on a cliff edge

Sunday 22 June 2014

Seabird flight

Two Kittiwakes soaring over the sea
While visiting some seabird colonies on the Scottish coast recently I took a few images of the birds in flight to capture their comparative morphology and technique. For each has its own, which fits the species' life.

Herring Gulls have a heavy appearance 
Herring Gulls, like most gulls are more land birds than seabirds, for they forage onshore, often well inland, as much as at sea. Even when at sea they mostly inhabit coastal waters. So these birds have a generalist type of flight; they can soar and they can flap with deep strokes. They are recognisable by their strong, bulky body and thick set appearance.

Kittiwakes have a straight edged tail and bent wings even when gliding
Kittiwakes are true oceanic gulls. They are light buoyant fliers, only coming ashore to rest or nest. Most of their lives are spent foraging out at sea, where they glide, flutter and dip into the surface waters for food. These are delicate gulls, recognisable by their slender build. It is not so much their colouring or markings that identify them, but their agility and knack of switching from a long oceanic gliding flight to a tern-like fluttering dance, with their legs hanging down as they dip for food.

Fulmars have rounded tails and their wings are held rigid most of the time when flying
Fulmars are true seabirds. They spend most of their life on the wing, gliding on stiffly-held wings as they flip low over the waves. And they seem to fly more easily the stronger the wind. They might be clumsy on land when they come ashore to nest, waddling on their short weak legs as they scrabble onto their nest ledges. But those short legs are suffice for their purpose, when out at sea, they are an advantage, as they are tucked into the body feathers and never hinder the birds' aerodynamics. The whole bird is a slick flying form, using the wind for lift and thrust, and they are a delight to watch as they wheel around and around the airspace off the nesting cliffs.

Fulmars, like all petrels and albatrosses are true masters of oceanic flight
I have not mentioned the auks or shags which also breed on the Scottish coast, for they are more swimmers that fly, than flier that swim like the birds listed above. The auks' and shags' forte is their diving ability - they swim underwater.

Monday 16 June 2014

Precocial and Altricial young

Birds in Scotland are busy hatching and rearing their young at the moment, with June being the month when most species have dependent young at some age. I have been ringing, with other members of the Grampian Ringing Group, various species of chicks from common and tiny Willow Warblers to large and rare Golden Eagles, and all sorts between. While doing so, I have as ever been impressed by how well each species has adapted the best method of post-egg development to suit its lifestyle.
 
Common Gull eggs, with cracklines and holes - the chicks are beginning to hatch

I have been ringing gull and wader chicks and took a sequence of photographs at one Common Gull colony to show the development of their chicks. The typical clutch size is three eggs and the chicks hatch one after another, over about two days. The first chick to hatch stays in the next and are brooded by the adult birds until the last chick hatches and dries. Then they all begin to wander from the nest, usually set on the ground, and hide beneath the surrounding vegetation.

One dry chick, one wet chick and one still on its way out

Gull chicks have cryptically-coloured down which keeps them concealed from predators and warm. They can walk sand run strongly and are known as precocial young.

A fully dry Common Gull chick - two days old and now three metres from the nest

Or rather, gull chicks are better described as Semi-Precocial young, those which are downy and can walk and can leave the nest soon after hatching. e.g. in the case of terns and gulls, although they still rely on their parents for heat and nourishment.

True fully precocial, self-dependent young would be such as Mallee Fowl which find their own food without even guidance from either parent.

This is so different from the familiar nestling birds, which are Altricial - where the young are naked, blind, weak-limbed at hatch and rely totally on their parents for food and heat.

Semi-altricial young such as raptors are downy at hatch, but weak and rely on their parents for heat and food.

Four Skylark chicks in their nest











Two other terms which are used to describe young birds are; Nidifugous - those that leave the nest soon after hatching, generally once the whole brood has hatched and their down dried, and Nidicolous - those which remain in the nest for several days or weeks after hatching.

A three-day old Skylark chick, still partially naked and blind

The nestling stage is a very vulnerable period for young birds and the variety of concealment and protection methods taken by the parent birds is, to me even more fascinating. From secretive single nests to noisy colonies, each works for the protection of different species. But more on that later.

Five kestrel chicks - ranging from about one to two weeks old

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