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Saturday, August 30, 2014

Sign of Spring

A male Shingleback follows a female - slowly

Yesterday I came across this pair of Shinglebacks Tiliqua rugosa in the local bush. They are considered to pair, as they remain in the same partnership for years. They can live for over ten years and they probably share overlapping home ranges, which in turn probably leads them to more likely mate together in spring, rather than with individuals from farther afield. I have only ever seen them this close together in spring when they are about to mate. So, are they a pair or simply in a loose partnership.

The female was longer, and had a fatter tail - probably important for her to be in good breeding condition

The male was creeping along behind the female, following her scent, which contains pheromones, signalling that she will soon be ready to mate. The male would want to be close by all that time to ensure that he is there when she is ready and to ward off any intruding males in the meantime.

The male was following in her tracks, tracing her scent trail

Most skinks are quick to run off as soon as approached and we seldom have time for a decent look at them. Shinglebacks however remain still and rely on that to conceal them - they just look like sticks lying in the shadows, and they are usually under grasses or shrubs.

The scales or scutes of a reptile's skin are perfectly arranged with exquisite detail around the mouth, nose and eyes

I took these photographs from less than two metres, more than close enough to capture the detail of their scale patterns without making them feel insecure and want to run (shuffle) off as a last minute defense.

Shinglebacks are quiet and unobtrusive, they allow  close approach, but I never pick them up - that would be obtrusive

Monday, August 25, 2014

Footprints in the snow

A snow-covered track through the forest
It is now Spring down on the plains and winter seems long ago. Yet it was only a week or so since I was up monitoring Superb Lyrebirds on the high slopes of the Brindabella range west of Canberra, and it was snowing. Fresh snow always adds another dimension to a day out and also a quick and easy method of determining what animals are about as any that walk must leave prints behind.

Lyrebird footprints on the left, fox on the right
Unfortunately the first species I found tracks of was Red Fox, an introduced pest species. I am familiar with these from years spent in Scotland where I have seen countless such tracks while exploring the Highlands in winter. Fox prints are easily recognised by the straight line followed, often along a track as with most predators which patrol large areas in search of prey. They like us, probably use these routes for quick direct access to and from their dens. Local foxes would be familiar with all such features in their territories. The prints are small prints, with four pointed toes tightly set and the hind paws fall neatly into the mark of the front paws, leaving only a single set of paw marks per stride.

Fox prints fall on top of one another when trotting like this one was
There were a few prints from unidentifiable small birds, but none from any other mammals or marsupials. The next obvious trail I found was of a lyrebird. Again, set in a straight line as it had walked along the road, but not for far. The fox had walked for over a kilometre along the path, the lyrebird only for several metres as it had stepped out of the thick scrub on one side of the track, along the line, then down into the scrub on the other side.

Lyrebirds take long strides when walking quickly
The lyrebird's stride was short initially as it left the cover, it lengthened as it entered open ground, then its steps shortened as it pecked for food on the edge before disappearing into thick cover again. As a bird of dense forest it would likely feel exposed and vulnerable to predators while in the open, so was likely in a hurry to regain shelter from the thick scrub.

Prints tell more than just who made them.

The distinctive outline of a lyrebird footprint - three long toes forward, one backward

Wednesday, July 30, 2014

Broad-billed Sandpiper

The broad bill
Following on from the previous post on birds in Norway, here is a brief update of the work done this year as part of a long-term study of Broad-billed Sandpipers Limicola falcinellus. These birds are difficult to find in their breeding habitat of extensive mires with floating mats of vegetation, which can be treacherous (to us), and over the years a tremendous team of expert fieldworkers have taken part in the project. This was my fourth season and I am grateful to my brother Rab Rae and Karl-Birger Strann for organising the study. Simon Foster and Shona Quinn were the other team members this year.

The species has two recognised races divided by their breeding ranges; the western nominate race breeds in Scandinavia and nearby Russia, and the eastern sibirica race breeds in a largely unknown range somewhere in Siberia. The main difference between the races, if they are different, is size, the latter being larger. The highest numbers of wintering birds are found in Asia and as far south as Australia, while the winter range of the western race is described as coastal and estuarine mudflats from Africa to India. All rather vague, and is there an overlap between the races' wintering ranges? There are many unknown details of this elusive wader.

Broad-billed Sandpiper breeding habitat in northern Norway
The birds are only in their breeding grounds from May to July, taking advantage of the abundant invertebrate life in the arctic mires to raise their young. Apart from their display flight when they first arrive they are largely unseen or heard. They spend their time weaving through the dense growth of sedge, they are small, about the same weight as a bunting, and perfectly camouflaged for the habitat, so they are very difficult to find, let alone study.

Broad-billed Sandpipers are inconspicuous as they creep through the sedge-covered mires
The breeding behaviour of Broad-billed Sandpipers in this study has been described and published by  Rae et al 1998, but conservation of a migratory species requires knowledge of their movements, behaviour and habitat requirements at both ends of their distribution. So, we have begun a study of their migration using geolocators. These are tiny, 0.6g devices, Intigeo-W65 from Migrate Technology, which have up to two years recording time. As these birds return to their same breeding areas each year it is planned to catch the birds again next year, remove the geolocators and download the data which will show where the birds have been during the non-breeding period.

The birds were ringed with individual-colour combinations of rings
and fitted with a tiny geolocator (above the knee)
Another aspect of the bird's life which is not clearly understood is the difference in plumage between adult and first-year breeding birds. It is important to know the age of birds when studying them as younger and older birds can behave differently. Most descriptions of the Broad-billed Sandpiper plumage has been of birds caught on wintering or passage grounds, when they are not fully moulted into their summer colouring. From our work so far, we seem to be able to confirm that birds in their first year have three dark outer primary feathers (four including the reduced 11th). This is because they are freshly moulted feathers, in about March, not long before the birds flew north, and they contrast with the paler older primaries which were moulted at the end of the previous year. However, not all first year birds have this feature, and if they have all-old primaries, they resemble older birds which moult all their primaries over one period at the end of the previous year.

One-year old birds have dark outer primaries
So, we are looking for other possible patterns in the bird's plumage which might help distinguish between young and old birds. One feature, might be the colouring of the feathers on the back, rump, scapulars and coverts, which are black with rich rufous edges in the full breeding plumage. Perhaps there are differences between the ages there, but further study is required to test this.

The primaries on birds more than one year old are all a similar pale (faded) brown colour
It only took minutes to catch the birds in a mist net (once they had been found, which can take days), measure and tag them. Then they were off, back into the mire where they disappeared again. We saw them a week later with chicks, which are even smaller and more cryptic to see.

By now, both the adults and their fledglings will be ready to fly south. So if anyone sees a colour-ringed Broad-billed Sandpiper do please report where and when. Help add a little bit of information to this secretive bird.

The birds were processed quickly and soon ready for release

They all flew off back into the mire 

But where are they now?

Sunday, July 27, 2014

Scottish summer summary

Walking over the tops - ptarmigan and dotterel habitat

It's now late July and I am back at the desk after my annual working tour of Scotland. Time to catch up with write ups and organise photographs. This was a quiet season for me as I had pinched a nerve in my spine in January and the sciatica is still hurting, curtailing any climbing, running and jumping. Fortunately a friend, Simon Cherriman, from Western Australia was also over in Scotland while I was there so we teamed up and I showed him around a few places and some of the special wildlife that abounds in such a small country.

While up on the high ground looking for ptarmigan we came across this Mountain Leveret

First of all we went and surveyed my long-term study site up in the hills for Ptarmigan. Their numbers vary between years following a cyclic pattern, and this year their numbers were low with only three pairs in the core area. But there were numerous Mountain Hares which was a welcome surprise. For these animals are being relentlessly killed on some estates managed for red grouse shooting in the belief that they carry parasite and act as a vector for disease in grouse, leading to fewer grouse to shoot. Such a selfish attitude at the cost of these animals which the majority of people visiting the Highlands in search of wildlife would so much like to see.

These three leverets were hiding in one form,
unusual behaviour as the mother usually leaves them in separate forms for safety 

A visit to the bird cliffs is always a tremendous experience
 - Simon rather enjoyed himself

Our next day passed quickly when we went to the sea-cliffs. The smell of guano mixed with the scent of Thrift had to be smelt to be appreciated, so so, different from anything else. 2014 was a splendid year for blossom of all sorts, but for now I'll concentrate on the animals. That day was definitely for the birds, thousands all around us and we must have fired off thousands of shots between us trying to capture the perfect shot of the birds in flight.

A Fulmar cruising past, most shots were out of focus, out of frame or wrongly exposed - hundreds of them

Simon adds colour-rings to a Redshank chick with Raymond Duncan

We spent most of our time based in the north-east and much of the field time ringing wader chicks with members of the Grampian Ringing Group, mainly with my brother Skitts, Ewan Weston and Raymond Duncan. Simon is a trainee ringer/bander in Australia, but has no experience of ringing wader chicks, or any other chicks for that matter. So he gained full-on intensive training from some of the most experienced bird ringers, not only in Scotland but the world.

A colour-ringed Lapwing chick

One of the jobs I had to do was find and fit Greenshank with geolocators as part of a study of their migration being organised by the Highland Ringing group. So we spent a couple of weeks in the far north doing that with Nick Christian and Brian Etheridge. That wasn't all we did there though, as there were so many other birds around us in that stunning landscape, but that has been covered in previous posts. And it would take too long to tell here.

Simon photographing newly hatched Greenshank chicks

The same Greenshank chicks

We ringed various birds during our travels, and as it was springtime most were chicks. They ranged from tiny Willow Warbler nestlings, Redstarts, Skylarks, Meadow Pipits, Pied wagtails, Common and Black-headed Gulls, Kestrels and Common Buzzards, etc. One rather different brood we ringed were Barn Owls which were in a nest in the roof space of an old ruined cottage. 

Simon checking the old cottage for the Barn Owl nest, and Jackdaws

There were five owlets squeezed between the ceiling and the roof

But it was when we had trees to climb that Simon earned his living. As I had hurt my back I was reluctant to climb some of the trees to reach various nests, but Simon is a superb tree-climber, probably the best I have seen. He had timed his trip to Scotland perfectly. I helped him and he helped me - all happy.

Predator in his natural habitat
 - a similarity noted by Mick Marquiss as Simon skipped up a tree
 so like the film character with his dreadlocks and camouflaged gear

Simon, like all of us who climb these trees, really enjoyed the thrill
 and atmosphere of climbing ancient Scots Pines

We helped Skitts and Ewan ring Golden Eagle chicks at various nest sites which they monitor annually. Ewan and Simon would climb the trees, lower the chicks in a bag down to the ground, where they were ringed and measured safely, then they we would pass them back up. Some of these nests are over a hundred years old, in trees that are several hundred if not thousands of years old. And some of these eyries are big, really big. Who wouldn't be impressed by such an experience.

Simon nears a Golden Eagle eyrie in the crown of a Scots Pine
- even he, at two metres tall was dwarfed by the eyrie

Simon studies Wedge-tailed Eagles in Western Australia, so he was perfectly at home and adept at handling the Golden Eaglets. Although they can be big strong birds and they can be in a potentially precarious setting, mixing tender careful handling with confidence ensured slick procedure.

Talking to eaglets always helps - it might not calm the the birds,
but it does calm the handler and helps the work go efficiently 

And that was what I did in Scotland 2014, well a little bit of it, there were also Arctic Terns, Golden Plover, Dunlin, Woodcock, Sparrowhawks and....  Thanks for all the help Simon.

Friday, July 25, 2014

Red-necked phalaropes

An adult male Red-necked Phalarope in breeding plumage - and out of water
For the past few years I have been taking part in a study of arctic-breeding waders in northern Norway. This has been organised by my brother Robert Rae and the local ornithologist Karl-Birger Strann. And there have been numerous other helpers as it is a long-term study.

One of the wader species which breed in the area is the Red-Necked Phalarope Phalaropus lobatus, and when I photographed a bird walking over dry land I could not remember the last time I had seen this behaviour. For Red-necked Phalaropes spend most of their lives on water, whether on oceans during the non-breeding period, or while spinning around catching mosquitoes in tundra bog pools where they breed.

Sedge-lined pools in the arctic tundra - Red-necked Phalarope breeding habitat
We have caught numerous phalaropes over the years, to ring as part of the long-term study on the population and their movements. They are a reverse sexual dimorphic species, where the female is the larger brighter bird which does most of the sexual displaying, and the males are less boldly marked as they do all the incubation and care of the chicks. Although there are some well-marked males and some dull females, so telling their sex in the field can be trickier than suggested in some literature.

An adult male Red-necked Phalarope - a well marked bird
When holding phalaropes in the hand after catching them, one is given a rare chance to see their lobed toes. Their scientific name Phalaropus means coot foot-like and the lobatus emphasizes the reference to their lobed toes. A feature seldom visible when seen in the field.

The lobed toes of a Red-necked Phalarope
The bird I photographed on land was walking a few metres back to its nest after feeding on a nearby pool. Most Red-necked Phalarope nests are set in wet sites, amongst sedges which fringe the pools where they forage, often in extensive beds of sedge on larger pool systems. The birds build a tiny platform of dry sedge stems, just enough to keep the eggs dry above the waterline.

A typical 'wet' nest site - a platform built above water amongst sedges
Some birds select a dry nest site on the edge of a bank next to a pool, or as in this case on top of a dry hummock amongst scattered pools. The nest was right on top of the hummock, tucked beneath a clump of cotton grass and below a dwarf birch.

A dry phalarope nest site on top of a hummock

A closer view of the same dry nest site
As with most waders, Red-necked Phalaropes usually lay four eggs in a clutch, and again like most wader eggs, they are very well coloured and marked for camouflage, to conceal them while the incubating bird is off feeding.

The eggs are well camouflaged to avoid detection by visually-clued predators such as ravens
When the adult bird is on the nest, the whole is even more hidden as the male's dull plumage colouring blends softly with the surrounding vegetation.

The adult bird is also well concealed when sitting on the nest
Phalaropes might be unusual waders in their habit of being mostly swimmers that rarely walk, but the opposite also occurs. I have seen several species of wader swim, usually just to cross a narrow creek or section of deep water, such as Dunlin or Purple Sandpiper in their winter coastal habitats or Spotted Redshank, another species of wader which breeds in the Norwegian tundra next to the phalaropes.

A non-lobed-toe wader swimming - Spotted redshank crossing a deep section of a feeding pool