If you go up to Mutter’s Moor or on to Aylesbeare Common as it gets dark at this time of year, you might hear an eerie churring and clicking sound. The RSPB describes it as like a strange clockwork toy unwinding. If you look up at the darkening sky you might see the silhouette of bird with pointed wings and a long tail, a Nightjar.
Nightjars are summer migrants arriving from their winter home in the scrub grasslands of the Democratic Republic of Congo in late April or May. One of their favoured breeding areas is heathland, but also moorland and they have taken to nesting in recently cleared conifer plantations.
They nest on the ground where their mottled brown and grey plumage is perfect camouflage. One of our group was on Woodbury Common last week and he almost trod on an adult sat on its nest, presumably brooding eggs. Luckily he noticed the bird at the last minute and took this picture. The bird didn’t move.
Nightjars can have two broods in a summer, they usually lay two eggs which are incubated by both the male and female. The downy chicks hatch after about 18 days and fledge when they are 17-18 days old, all this depends on how much food is available.
The main food is large flying insects especially moths and beetles. As has been said so often, our insect populations have fallen in the last few decades and so has the number of Nightjars, although recent work to improve heathland habitats across southern England has helped to stabilise the population of Nightjars.
We are lucky to have the RSPB and Clinton Devon Estates working hard to make our remaining areas of heathland optimal locations for these enigmatic birds. One particularly useful strategy is grazing areas of heath with ponies and cattle. This not only promotes good ground conditions for the nests, but the animal poo is great for dung beetles and flies which the birds can catch.
Close up, Nightjars are strange looking birds with large eyes and a huge gape on their beak, both adaptations for catching insects in the gloom of dusk. This appearance along with their nocturnal habit, strange call and magical appearance and disappearance wreathed them in mystery in times gone by.
One strange story is calling the Nightjar the Goat Sucker. There is an old myth that Nightjars would creep up to resting goats and suck their milk. The goat’s udders would then shrivel, become diseased and the goat would die. The myth was taken forward by Linnaeus when he assigned the scientific name Caprimulgus in 1758 from the Latin Capra for ‘nanny goat’ and mulgere ‘to milk’. If a Nightjar ever did go near goats it was probably to eat the dung beetles.
If you want to experience the thrill of hearing this strange bird over the darkening heath, or perhaps seeing one, then you only have a few weeks left. They are one of the last migrants to arrive in late spring, and one of the first to fly south, most have gone by mid-August, all part of their mystery.
Ed Dolphin
Image by Charles Sinclair
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