The naturalist Alfred Wallace called feathers “the masterpiece of nature”. An illustration of their astonishing benefits is the ability of emperor penguins to withstand blizzard temperatures during the Antarctic winter (when the males incubate their solitary egg) of -60C. Possibly even more impressive is a feat of golden-crowned kinglets, a warbler-like mite that can survive Alaskan nights of -30C, when the differential between their core body and the ambient temperature is as much as 78C. A kinglet weighs 5gm (compared with an emperor penguin’s 30kg).
Feathers are amazing, but sometimes it’s good to give the owners a helping hand. As I look out at the snowy expanse over Lightwood at 4pm every day, I am aware how all roosting birds are effectively forced to fast in these sub-zero conditions for 16 hours until dawn. Suitable weather-proofed niches – tree hollows and dense thickets – are at a premium, so last autumn a friend and I put up a box apiece for kestrels and barn owls. Every night at present I scan the trees hoping some local raptor has taken advantage of our free accommodation.
Barn owls are on the edge of their altitudinal limit in this area and have little waterproofing in their feathers, which effectively prevents them from hunting during wet weather. However, around Hathersage, 10 miles south-west of Sheffield, my friend’s assembly of 39 owl boxes has transformed the species’ fortunes. Not only do the birds use the boxes as winter roosts, they also nest in them. Last spring, there were six breeding pairs where previously there was just one.
A key problem for owls at Lightwood is the abundance of feisty, town-dwelling jackdaws, which often out-compete them for nest holes. But our box is beautifully proofed against that outcome, because the circuitous entrance acts as a baffle and bars entry to any stick-bearing jackdaw intent on building a nest. Owls, by contrast, use no nest material. Another ingenious feature of our ready-made owl home is a sealed-off second floor. When the nest contains young the female owl forbids her partner to enter, and the lower annex, with its own access hole, serves as an additional roost site for males in times of poor weather.
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