Sunday 17 May 2015

Frogs spawning in a mountain pool 


Common Frog Rana temporaria in a high hilltop spawning pool


It is now mid-May and frogs are spawning in the hill pools in the Highlands. Sadly, there have been many days of snow showers recently and there are lots of late lying snowbeds for the frogs to contend with.

Ben More Assynt from one of the frog pools on the summit ridge of Glas Bheinn
I was up on Glas Bheinn in Assynt yesterday surveying ptarmigan on the high rocky ground, and while walking past a small pool at about 700m I noticed some frogspawn in the margins. I counted about 75 separate clumps of spawn and some of the tadpoles had begun to hatch. Then I checked a second pool where there was still snow lying around the edge, and there was one massive accumulation of spawn in a corner. Some of it had been frosted and the embryos were dead. The spawn had a grey opaque appearance. Then I noticed that there were numerous dead frogs lying on the bottom of the pond, while others were still amplexed together and swimming in the near-freezing water.

Late-lying snow edged the pool and the grasses had not yet started to grow


Life for those frogs up on the high hills is so different from that of those in the warmer lowland waters. They must be so wonderfully well adapted to survive in such conditions. They are amphibians, cold blooded animals, yet they were getting on with life right on the margin of their physiological capabilities. Meanwhile, I was all wrapped up in windproof clothing and still felt cold in the northerly wind. Well done the frogs that managed to lay their eggs and their tadpoles that hatched. Well done.

A large clump of frogspawn lay in the shallows, and dead frogs lay in the depths


Wednesday 13 May 2015

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.

Sunday 3 May 2015

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.

Sunday 26 April 2015

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.


Friday 17 April 2015

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.