Birdwatcher’s Diary No.190

Published on: 30 Jun, 2019
Updated on: 30 Jun, 2019

By Malcolm Fincham. This report focusing on summer migrant the nightjar.

The nightjar is one of our most fascinating summer migrants that come to visit and breed on our Surrey heathlands.

Our European nightjar has a flat, wide head, small bill and large eyes. It has a long, slender body, short legs, long, narrow wings and a long tail. Click on pictures to enlarge.

Short-staying visitors, they arrive mid to late May, breed here, then leave by mid-August.

Until recent years little was known about their migration and wintering sites, but through modern technology, tagging and tracking work, we have been able to learn much about these delightful critters, and now know they winter in southern Africa.

Nightjar on Whitmoor Common.

They favour heathland areas to breed of which Surrey still has its fair share. Thanks to conservation and management, they have been among a few birds that have actually increased slightly in recent years. However, they remain amber listed. A lack of available breeding habitat is thought to be a major issue for the species.

Inadvertent disturbance can also be an issue. Being ground-nesting birds their main predators are snakes, owls and red foxes. Though with encroachment of housing close to such heathlands, we can now add wandering cats, unleashed dogs and even humans to the mix.

Due to their elusive nocturnal habits, not much is known to the general public about nightjars. They have also been the basis for many myths and legends over the centuries.

In many European countries, where they also breed, the nightjar is known as a ‘goatsucker’ after its Latin name. This is because they were believed to feed from goats due to the fact that they were often found in close proximity to livestock. We now know that the attraction is the invertebrates associated with livestock.

Nightjar spotted in a day-time roost on Whitmoor Common.

While you may be lucky to see a nightjar silhouetted against the sky at dusk as it searches for insects, you are much more likely to hear one. The male has a unique ‘churring’ call which can contain up to 1,900 notes a minute!

Click here for audio clip of nightjars recorded by David Rose on Whitmoor Common

It remains well camouflaged during daylight hours due to its brown and black tree-bark-like plumage, fading into the background. It often takes a “keen-eye” and a lot of luck, to pick one out, perched up, incognito and motionless, in its daytime roost.

Their plumage is especially important for the female, as they are a ground-nesting bird that don’t make nests, just laying their eggs on bare soil, to incubate.

Two nightjars perched on wires.

Adults have a flat, wide head and large eyes that aid their sight at night. In flight, they have obviously long wings and tails. Male nightjars can be differentiated from females by their white wing and tail patches.

Results from surveys on nightjar breeding success are as follows:

“There was a significant relationship between nest failure and disturbance. Failure being more likely in nests sites closer to paths.

“Failed nests also had poorer cover, being surrounded by short vegetation. Predation of eggs is the major cause of nest failure.

“The most likely mechanism for nest failure is that the incubating nightjar is flushed from the nest during daylight, leaving eggs exposed and vulnerable to avian predators, notably corvids.

“Nightjars display a very low frequency of flushing, only recorded in daylight, but it requires only one untimely flushing event for nest failure to occur through predation. Flushing agents included dogs. Recommendations are made for management measures to minimize the effects of walkers and their dogs.”

Some of the best places to watch nightjars in Surrey can be found on this link.

Male nightjar in flight on Whitmoor Common.

On my “local” heathland, just to the north of Guildford, I have only witnessed two pair, this year. I have encountered more pairs in previous decades, while the footfall of dog walkers I have noticed has increased in recent years. And heathland fires have no doubt hindered their success.

Hopefully we can sustain the population of these little known about though truly marvellous critters for future generations to enjoy.