Monday, 17 August 2015

Spring Plumage

Diamond Firetail Stagonopleura guttata in bright adult breeding plumage
Spring is ever nearer in the south-east Australian bush and many of the birds, especially the passerines, are beginning to breed. Which means that they are now in full breeding plumage and looking their best.

Over the past weekend I was part of a team mist-netting birds at The Charcoal Tank Nature Reserve in south-western New South Wales, as part of a long-term study of birds in the area, organised by Mark Clayton. And it was clear by the condition of the birds' plumages that they were fit, healthy and ready to breed.

Diamond Firetail 
There was a flock of Diamond Firetails feeding on grass seeds along the edge of the reserve and they were dazzling as their red rumps flashed through the grasses. The bird shown here is an adult in full breeding plumage, with all the feathers on the head and breast clean and fresh. For these are the feathers which any potential mate or competitor would see when assessing its fitness. However, the flight feathers, the primaries secondaries and their coverts were a bit tatty, with chips and worn edges. For these feathers would have been moulted and re-grown at the end of the previous breeding season, and they will be again at the end of the current season, but for now they are still perfectly functional and there is no need to replace them yet. Birds are almost constantly moulting part of the their plumage at any time of the year, and for the moment it is the bright signalling feathers that need to be in top condition.  

White-plumed Honeyeater Lichenostomus penicillatus
It is not only their feathers which are spruced up for breeding. The white-plumed honeyeaters which we caught, also adopt shiny dark colouring to their bills - they are duller and greyer when not breeding. This adds impact to their dark eye and the slight fringe of dark feathers on their neck, next to their white-plume, which the dark colouring emphasises. By the time the birds are half-way through the breeding season, the best of these colours will have begun to fade.

Chestnut-rumped Thornbill Acanthiza uropygialis
Even the little-brown-jobs, the small dull coloured birds adopt brighter plumage. This chestnut-rumped thornbill had a particularly well marked face pattern, in relative terms, and it's only when we see them up close, in this case in the hand while ringing/banding them, that we can appreciate the detail of these tiny birds' markings. Although to a bird's eye, they see things across a wider spectrum than us, these markings probably also signify the birds health, fitness and hierarchy in the flock, only more demurely.

Chestnut-rumped Thornbill - face
The sexes of all three previous species have similar plumages to one another of their species, they are monochromatic to our vision - but probably not to their own. For birds can see ultra-violet colours and in some species this has been found to be used in their markings to differentiate between the sexes. Do these species sport such colouring?

Golden Whistler Pachycephala pectoralis - male
Some of the brightest birds in the study were the male golden whistlers, and if their plumage is enhanced with ultraviolet colouring they must be amazing to see through a whistler's eyes. This species is dichromatic - there is a colour-difference between the male and female. The female is an almost overall grey colour, which is fit for purpose, as she incubates the eggs and broods the young. That involves a few weeks of her life each year, spent sitting on a nest set amongst grey-barked branches, so the grey colouring acts as camouflage while she is on the nest. The species has evolved for the females to be camouflaged while the males are brightly coloured to show off their fitness and hence value for a female to mate with, or for another less-brightly coloured male to avoid.

Even in her grey plumage, the female can be seen to be healthy and fit to breed as her feathers are clean and fresh. She too is fit to breed.

Golden Whistler - female

Thursday, 6 August 2015

Snuggled up

It's late winter in Canberra with frosty nights and sunny days, and the birds are beginning to show springtime behaviour. The Tawny Frogmouths are drawing closer to their breeding sites, moving in from more distant perches to be close to their nest sites. They will be building their nests soon. Although none have started to do so yet, I have seen birds with well-built nests by this date in previous years, with the earliest eggs laid on the 12th August. Meanwhile, they are making the best use of the sunshine as they roost during the day.

A pair of Tawny Frogmouths Podargus strigoides roost by day in a gum tree
the smaller female sits closer to the trunk as is usually the case - for protection by her mate?
They are medium-sized birds, about the size of a Tawny Owl, and live mostly on invertebrates. However, they have a slow metabolism and as insects and such creatures are not abundant during winter, they move as little as possible, slow down their metabolism even further and sit in sunny situations, all to conserve energy. And to do so while daytime predators are about, they have evolved excellent camouflage for protection.

A pair of frogmouths sit high on a sunny branch
Yet, they don't stay completely motionless all day. This pair mostly roost farther along the branch towards the trunk, but as the sun has crossed the sky, they have shuffled along the branch to stay in the sunshine. Today was cold.

The spot where these birds usually sit is farther to the right, as can be seen by the worn red bark on the branch and a fluff of cast down below where they normally sit.
The frogmouths sit fluffed up and huddled into a rounded shape to keep warm, and by snuggling up close to one another the pair gain extra warmth.

Saturday, 1 August 2015

Scottish Top Ten 2015

I have now returned from my field-trip to Scotland and have a few thousand photographs to catalogue. So it is time to reflect on what I achieved work-wise and image-wise. I thought the first thing I should do is pick out a top ten selection of photographs. These are not necessarily the best photographs, in quality or technique, but they are the ones that I consider as capturing the essence of my days in the field, the places I visited and the wildlife I saw.

And now that I have posted them I have already thought of others which could just as easily have fitted the bill.

Stac Pollaidh from Beinn nan Eoin

Kyle of Durness from the summit of Beinn Spionnaidh.

Golden Plover Pluvialis apricaria -  with snow on the Cairngorms in the background.

A Dunlin Calidris alpina - on breeding grounds on a hilltop in the eastern hills

A Mountain leveret Lepus timidus - lies motionless, as they do all day, for concealment from predators.

Mountain Avens Dryas octopetala - on a Sutherland coastal cliff.

Wild Pansies Viola tricolor  - a dense bloom in sand dunes.

Kittiwake Rissa tridactyla - juveniles soon after fledging.

Rock Ptarmigan Lagopus muta - a hen steps over boulders in the Cairngorms.

Golden Plover chicks - puffs of gold, the most beautiful of wader chicks.

Tuesday, 28 July 2015

Ptarmigan on the rocks

I was up in the Cairngorms surveying ptarmigan last week, Rock Ptarmigan Lagopus muta, and they are well named for they are seldom seen far from rocks in the Scottish hills.

Their breeding season was about two-three weeks later than usual this year due to prolonged and extensive snow-lie. Many of the birds did not have any chicks, perhaps after failing to lay eggs or losing eggs or young? Others had very small broods of only single chicks compared with the usual average of  five or six chicks of about two weeks age - the age of the chicks that I did see.

Several hens which had no young had joined cock post-breeding moulting flocks and were roaming through the boulder fields skulking quietly amongst the rocks. When moulting, these birds typically prefer to walk away from any intruder as they probably feel more secure doing so while they have some flight feathers missing or only partly-grown.

They seemed so at home in the boulders, hopping and skipping over them with no effort at all. At times they were running over what to me was very awkward ground to walk over. They run over any open ground or large open slabs as they feel exposed to predators, then slow down once secure amongst the jumbled rocks again.

I left them to it and watched a snow bunting for a while, singing from the top of a large boulder. And in the meantime the ptarmigan settled down to rest amongst the rocks, disappearing to my eye as their colours blended with those of the lichen-covered boulders.

Here are a few shots of a hen showing her deft footwork on the boulders

Thursday, 23 July 2015

Wild Assynt

The jagged ridge of Stac Pollaidh
While surveying birds in the Highlands, one the extra joys is the magnificent hillwalking that, well just has to be done in such stunning scenery.

Pillars abound in these sandstone hills
I was in the Assynt hills last week and grabbed the best day of the summer for a great walk over one of these relatively small hills. They might be small, but each hill in the area has its own particular character and they pack an amazing variety of landforms into this quiet corner of the north west Highlands.

Sgurr an Fhidhleir points high into the sky
There is so much to explore, around every corner or over every bluff that I don't need to describe where I went. It's all great fun. One of the best experiences in walking these hills is to discover their secrets for oneself. There are landscape-scale features such as the impressive peaks, but take time to look at the finer lines, the hills are covered with little details which mirror the grander features.

A golden eagle added its shadow to the landscape
Then to add cream to the scene; I was walking along a ridge, carefully watching my feet, when a shadow drew over my path. I knew straight away that there was an eagle above, what else could have cast such a shape. And sure enough, I looked up and there was an adult male eagle displaying in deep dives as it cruised along the updraught from the ridge.

The day was already one of my best in the hills this year, now it was probably the best.

Suilven in the evening light
I stayed in the hills til evening, watching the rocks change colour in the sinking west coast light, until I had to finally turn my back on them til next time.

As ever, the trick to any good day is to be there, be out there, do something, do anything, then every once in a while a special day comes.

A wild west sunset