RSPB Conservation Scientist, Nick Wilkinson, tells us about fieldwork and searching for ring ouzels near the Cairngorms.
Rain, rain, and more rain (with the odd snow and hail shower thrown in for good measure); probably not quite the summer jaunt that some people envisage when they hear that you’re departing the confines of office life for a few months of fieldwork near the Cairngorms. More frustration than fieldwork just at the moment. And I’m sure this adder found earlier in the week is none too impressed just now either. At 450m may be one of Britain’s highest altitude adders?
We’re ten days in to the second and final field season of a research study on ring ouzels, also known as the mountain blackbird. They’ve recently returned from spending the winter in the juniper forests of North Africa and we’re trying to find out why there are many fewer ouzels arriving back in the uplands of the UK these days than 20 or so years ago. Specifically, we’re testing whether a shortage of food during the summer may be reducing the number of chicks fledging in good condition. We know from previous work that the survival of young (first-year) ouzels in general is quite low, but that fatter, heavier chicks at fledging time tend to have higher survival subsequently. So we’ll be dividing the pairs of ouzels in to two groups and providing one group with extra food during the period of chick rearing but not the other group. Then we’ll weigh the chicks at fledging time and measure their survival over the following weeks, having fitted some of them with miniature radio tags, and compare the two groups. Simple, on paper anyway.
Photo: Andy Hay
First, find your ouzels - a blackbird with a striking white crescent at the top of the breast should be pretty easy to find, especially when the males are singing their distinctive, slightly mournful tri-syllabic song. But when you are scanning amongst the patchy, snow-covered hillsides strewn with dark heather, crags and scree, and you’ve still to get your ‘eye-in’, many a small rock with a bit of snow or pale lichen far off in the distance can look convincingly ring ouzel-like. And still he sings, taunting your senses to pinpoint him. Most importantly, has he found a mate, or is he still singing to attract one? Is he one of the birds that have been colour ringed previously, allowing us to identify him individually?
Ring ouzels easily blend in to this wintry landscape.
So far we’ve found quite a few pairs in the glen but also a good number of seemingly single males. Consequently, there have been a fair few scraps when these males check out neighbouring territories until being booted out by the resident male or pair. Some females have started nest building, closely guarded by their mate, and it looks like one female is using a nest site used last year by a different pair. A few of the same adults are back again, though with different mates, along with several of last year’s chicks, most of which are from late season nests. This is more than we might have expected so they clearly haven’t been paying attention to the ouzel rulebook! But for many birds we’ve still to get a good enough glimpse of their legs to check whether they’re ringed or not, let alone the opportunity to record the sequence of coloured rings on both legs. Maybe tomorrow when the weather improves, or next week, but certainly by the time they’re nesting....
Find out more about the ring ouzel project here.