Sea-eagle and sandpiper

It has been a hectic week, or rather two weeks for me recently, trying to study greenshanks and golden eagles in the far north of the Scottish Highlands. All due to late snow showers and strong northerly winds. It's rather difficult to watch birds when I can't hold binoculars steady or even hold myself steady in buffeting winds. But, today turned out successful and I am back early enough to post an update.

The young white-tailed sea-eagle lifts off its feeding site leaving some morsels to a waiting raven

One evening last week, while out watching greenshank, I noticed a great black-backed gull standing on a hillside above a river. That seemed a bit out of place out on the moors, so I spied it, and immediately I saw why it was there. A white-tailed sea-eagle was a little downhill from the gull, feeding on something, I couldn't make out what. But I would not have noticed the eagle itself as it was an immature bird with no white on it. It's dark grey-brown body merged into the grey-brown hillside in the driving rain. I noticed the gull only because it was white on a dark background. I stopped and watched until the eagle had eaten enough and flew off. And as it did so, I grabbed a few poor long-range photographs through the rain, to check if it was ringed. And it was, but I couldn't make out the colours or numbers on the ring. It looks like it had been ringed as a nestling in 2014 by one of my colleagues in the Scottish Raptor Study Group, so I sent them a copy of the photograph in case they can make something of it.

Blue over yellow on the left, and dark green over metal on the right - the male of a pair a common sandpipers that have bred in the northern Highlands three times and been to Africa twice in that time, at least.

Then, on the next morning, on my way out to look for greenshanks, I saw a pair of common sandpipers feeding along a loch shore, so I stopped to check their legs for colour rings, and sure enough, both were ringed. These had been ringed by Ron Summers and Brian Etheridge of the Highland Ringing Group two years previous and when I told them about my sightings, they said the birds had not been there the day before, so the sandpipers had only just arrived back from their winter quarters in Africa that morning, or the night before. And there they were, looking as fresh as can be, having flown all those miles, not once but for their third time at least, back to their breeding grounds by a Highland loch. Wonderful birds.

Spring snow and cuckoos

Snow covering the eastern Highlands - a view from above the North Sea

I flew into Scotland on Monday, the day after a snow storm and the hills were white with Spring snow. However, the weather continued to be wild and windy so it was few days before I could have a clear day on the hills. When I did reach the high ground I could see that the winter had been windy as there were lots of long-lying snowbeds, filled with drifted winter snow; on top and between there was a thin covering of soft new snow, lower down the ground was pie-bald with fresh patches. The whole landscape sparkled in the Spring light between the continuing showers.

The snowy ridge of Creag Leacach under a heavy sky

It was the 1st of May, and after the previous run of warm weather I expected the plants and animals to be well on in their fresh growth and breeding behaviour, no so. The buds on the heather and other heath plants had only just begun to expand, none had opened yet, and the hen red grouse were still feeding up to make their eggs, none had laid a full clutch and begun incubation. The cock grouse were calling out to mark their territories, with an occasional squabble between neighbours, but mostly they were walking along behind their hens, overseeing their safety from predators and keeping suitors away.

A male rock ptarmigan sits quietly - tricky to see as his pie-bald plumage merges well with the patchy snow lie 

My main purpose for the day was to count the numbers of pairs of red grouse and rock ptarmigan on a hill where I have been studying them for over twenty years. So after watching over the ground for a couple of hours, mapping the birds' locations, I ventured on up and slowly quartered the study area. The grouse numbers were high, but there were only a few pairs of ptarmigan and they were rather difficult to see in the snow.

He watches over his female as she feeds on fresh spring growth farther down the slope

As the day drew on, the temperature up on the hill began to drop, so when I came down I enjoyed the warmth of the glen. The birches were opening their leaves and when I stopped by a loch for a look around, I heard my first cuckoo of the year. A cuckoo and Spring snow, a nice day, and rather a nice start to my summer season in the Highlands.

Tawny Frogmouths in their winter roosts

A Tawny Frogmouth roost-tree in open woodland

It's now late autumn and migrant birds such as the yellow-faced honeyeaters are flying over the house and general area on their annual migration to the northern and coastal forests. While other birds like the tawny frogmouths are settling down in the local woods for the winter. The frogmouths stay in their breeding territories over the winter, probably because they are a valuable resource and worth defending. And in the bird world, occupiers usually win over any intruder. So to keep warm in the cooler months, during the day they settle on a favourite perch where they can catch the winter sun.

A Tawny Frogmouth sits quietly in her roost

I know most of the local birds' perches and  most days they will be in one of perhaps two or three, for they have sussed that those branches offer shelter from predators and exposure to the sun. Exposure to the sun is important to them, for the morning sun warms them up. Also, these birds can go into torpor for part of the day to conserve energy. And that is not their only two strategies for enduring the winter, they also build up body fat. The female I found dead last week was carrying 88 grams of fat, approximately 16% of her weight, and her stomach was full of beetles and large moths. The contents formed 8% of her weight. She had been feeding hard catching the last of the autumn insects before the lean times ahead in the cold nights. (I acknowledge Gil Pfitzner of CSIRO for this information as he was the one who prepared her skin for the national collection and took these measurements).

This bird is several years old - I know her by the pattern of her bib,
and she knows me because she has seen me so often over the years

The more we look at birds, or any other wildlife, the more we can learn about how well adapted each species is for its own niche. As for the tawny frogmouths, they have so many adaptations, they continue to fascinate me. No doubt they will have more that I don't know of - just what is the purpose of those bristles above their eyes and bill?

Here she has closed her eyelids, almost. She is still peeping through a slit and even if she closed her eyes further, she could watch me through tiny gaps between her eyelids. For her eyelids have rippled edges allowing her to see out, but not for a predator to see her eyes. Frogmouths are very well adapted for concealment, right down to their eyelids, and surveillance at the same time. Eyes can be a big betrayer of camouflage. This bird hasn't gone into full defensive pose as she is familiar with me and does not feel under threat. She is just basking in the sun - with a little caution.

A true Tawny Frogmouth

A truly red/rufous coloured Tawny Frogmouth found in Canberra - a victim of road kill

It was wet with heavy rain last night, and all day today, and when I drove into town in the morning I saw a dead bird lying in the cycle lane. It looked like a Boobook, the common local owl in Canberra, but it didn't look right for one. So I took note of where it was in order to check it on my return. Maybe it was something else, what? Then an hour later, as I approached the bird from the other direction, I saw straight away that it was a Tawny Frogmouth, but it was so red, and that is why I hadn't recognised it first time. Although I study these birds and have seen hundreds of individuals, none have been as red as this bird.

All the frogmouths I have seen in the Canberra area have, despite their name, been predominately grey. The males have, if any, only a little red on the sides of their face or a touch on their wings coverts. The females are usually more rufous in the same parts, and a few have a bit more red on their wings, but none I have seen have been so red as this bird. I would so much have liked to have met her when alive in the bush.

The whole of her upper body was red
 apart from her primary and secondary feathers which were dark brown/black

The bird's body was in good condition apart form the obvious head injury that killed her outright. So I gathered her up and took a few measurements for my own records. Her corpse is now in the freezer and on Monday I shall deliver her to the Australian National Wildlife Collection, which is conveniently held by CSIRO here in Canberra, the national capital.

I must look up the type-specimen of Tawny Frogmouth one day to see whether that bird was truly tawny, or grey like most in south-east Australia.

She still had a recently caught moth in her bill when she died

The moth was large, with a body about 8-9 cm long, and grey overall with no particularly obvious features. If anyone has an idea of what it might have been please drop a note. It was obviously too large a prize for the bird to ignore as she risked the traffic to catch it. Let that be lesson to us all: take care on the roads especially while there is heavy rain.

Mixed Foraging Flock

A Buff-rumped Thornbill: they glean food from the lower branches, trunks and ground litter

Now that autumn is well on the way here in Canberra, the woodland passerines are gathering into their mixed foraging flocks. These flocks are similar to those in northern-hemisphere woodlands where several species; such as coal tits, blue tits, great tits, goldcrests and treecreepers all join together and roam through a local patch of woodland. In and around Canberra, a typical mix of species would be like one I saw yesterday which consisted of; several buff-rumped thornbills, several yellow-rumped thornbills, perhaps ten grey fantails, I think three white-throated treecreepers, a family party of superb fairy-wrens, two scarlet robins, a pair of speckled warblers and a grey shrike-thrush.

A Yellow-rumped Thornbill: they flit down to the ground for their food

These mixed flocks are an efficient strategy for the birds to collect food within the safety of their group. Many eyes are better than one for locating food and for detecting any approach of potential predators. And each species has its own preferred type of food or place to gather it from. The buff-rumped thornbills pick away at the bark for insects beneath and they might not catch every insect they disturb. Then the fantails might zip in and snatch a insect trying to escape, or a speckled warbler following along on the ground can pick up any grubs that the thornbills dislodge. The yellow-rumped thornbills keep in their own flock within the mixed flock, dropping to forage on the ground then flying back up to the lower branches after a quick feed. The superb fairy-wrens probably only joined the party as the flock moved through their home patch, taking the advantage of the group foraging behaviour while they could.

A Grey Fantail: they fly-catch tiny insects, often those disturbed by the other birds in the flock

Two male Scarlet Robins dispute in the branches

Within each mixed foraging flock there are usually two scarlet robins, one male and one female. They seem to adopt the flock as their winter/non-breeding season territory and they defend it from all other scarlet robins. Yesterday I watched two such male robins displaying and threatening one another in such a dispute for ownership. The resource of a mixed foraging flock, with its advantages for survival, is clearly a valuable commodity for woodland birds.

That mixed flock seemed to consist of mainly lower branch- or ground-feeding birds. I saw another two like that later and one flock which was formed mostly of striated thornbills and striated pardalotes, working their way through the canopy, picking food from the leaves and twigs, never venturing near the ground. Each bird in each flock will know their local patch of the woodland and together, they will work their way through the habitat every day of autumn and the oncoming winter.

Then in spring, they will disband and settle into pairs on breeding territories.