John Muir Trust Staff blog: Recording wintering waterbirds
Article originally published on John Muir Trust Staff Blog February 2016
Quinag conservation officer Romany Garnett discovers that shags take a little leap at the start of a dive during a BTO survey of wintering waterbirds.
On a cold January morning I set off, with two other local volunteers, across wet heathland to the northern coast of the Trust’s property in Assynt, a small stony bay east of Torr a’Ghamhna.
Our objective was to record wintering waterbirds at low tide for the Non-estuarine Waterbird Survey, run locally by the Assynt Field Club on behalf of the British Trust of Ornithology. The main aim of the survey is get a clearer idea of wintering wader numbers, but birds using a strip of land 100m deep along the coastline, and the sea out from it, are also logged, together with maritime mammals. The survey started in the 1980s and takes place about every 10 years.
There was hardly a breath of wind as we walked down to the sea; it was so calm and still we seemed to be the only signs of life about that day. The survey units are approximately 2 km in length, and as we approached our section I became worried that we wouldn’t see any birds at all. The sea looked quiet, tranquil and empty; however once our eyes were attuned and binoculars focussed, tiny black shapes emerged into view.
The work begins!
The more we looked at the sea, the more birds became apparent. Putting names to them was another matter. It was not difficult to narrow down the most numerous to members of the auk family, but were they guillemots or razorbills?
Close up and in summer plumage, identification is easy; the thick beak of the razorbill, with its white bar, is really distinctive. Bobbing about on the sea in the middle distance, all in winter plumage, not so easy. However, with the help of a telescope carried by one of the party, we finally agreed the majority of the auks were razorbills.
Similar problems arise with cormorants and shags. In the summer the two are readily identifiable, with the shag’s distinctive tuft and dark plumage. In the winter, however, the tuft has gone and both have pale undersides. There is quite a marked difference in size, but this is only obvious in distant silhouettes when both species are present. Shags also take a little leap at the start of any dive. In the end we agreed that those we were looking at were shags.
After these conundrums, it was a relief to spot and confidently name two red-breasted mergansers paddling about in a nearby bay, dipping their heads under the water before they dived. We also saw a number of herring gulls and a couple of great black-backed gulls, but, curiously, no waders. Watching all these birds going about their daily business was very rewarding, but after a while my feet slowly lost sensation from standing in the cold, and we made our way back to the road.
We then drove round a couple of intervening headlands to a vantage point overlooking our next survey section, which was just west of the narrows under the magnificent road bridge between Kylesku and Kylestrome.
A sudden shower happily coincided with a break for lunch, which was eaten inside a warm car. Back out on to the cliff-top soon afterwards, we were quickly rewarded by large numbers of razorbills close in. It is unusual to see so many in coastal waters in the winter, since they normally come inshore only during the breeding season; recent easterly gales could be the reason.
We saw two shags standing on the rocks nearby, spreading their wings out to dry, a bit like badly shaped clothes hangers. Apparently this is because the feathers are less water repellent than those of most other water birds. There were also two cormorants further out on the sea.
Mottled rocks exposed by the low tide were scattered along the shore. However, what at first glance seemed to be a paler area of rock was in fact a common seal lying very still just below us. A couple of great black-backed gulls were, again, patrolling the sky above us, together with numbers of herring gulls. Close to, great black-backs are really large, approaching the size of geese. A heron stood elegantly poised on the adjacent shore waiting patiently for the next meal, and we finally had some waders, a couple of oystercatchers.
Later in the week, I completed the BTO surveys for the area with the help of a friend, visiting two rugged sections of wooded cliff on the edge of Trust ground, between those already mentioned. It was low tide by the time we reached the shore and we enjoyed our lunch looking out over the sea, accompanied by the sound of coal tits, great tits and the occasional wren.
Six oystercatchers were working seaweed-strewn boulders and further along we came across obvious signs of both badger and otter. The plaintive cry of a curlew echoed in the hush of the late afternoon.
Moving on, we spotted a small seabird alone quite near the shore. It was a little auk, very unusual so close in, but the RSPB had reported, on 7 January, unprecedented numbers of this species along Scotland’s coastline. Strong easterly winds may, again, have blown them from their usual wintering grounds on the east coast of the British Isles. This bird looked fine and hopefully will have survived, but it is worrying to think of them so far off course. The unusually large numbers of common guillemots and razorbills seen in Loch a’ Chairn Bhain were probably also sheltering from recent gales.
Taking part in this wintering waterbirds survey was a great experience. It took me to places I might not otherwise have visited, at least in the winter, and improved my bird recognition skills. What I really enjoyed was watching the birds going about their daily business, realising that what at first seemed to be aimless bobbing about on the water was in fact a focussed search for food; the everyday struggle that is vital for their survival.
With the help of 11 volunteers, the Assynt Field Club successfully surveyed 73 sections out of the 75 into which the coastline of the parish had been divided; the other two were offshore islands. They logged 3,687 birds from 63 species, the commonest being herring gulls (1,229), followed by common guillemots (665) and shags (469).