The nights are drawing out

For the past two and a half months I have been pretty much nocturnal, or crepuscular at least. I am extremely fortunate that much of my paid fieldwork these days is directed towards one of my favourite birds, the Nightjar. These are truly fascinating birds. A friend once called them a bird designed by the Japanese because of all the special features! Massive mirror lens eyes (the Tapetum lucidum), a set of well-developed rictal bristle to direct moths into the extremely large gape, and even a comb on their toe to comb these bristles. Their main feature however is their amazing camouflage and an ability to nest almost completely undetected!! Despite lots of fieldwork, radio-tags, GPS geolocators and thermal imaging cameras I have managed to find a grand total of just 6 nests this year. The poor weather has been a major hinderance with activity levels well below normal but amazingly all 6 nests produced 2 chicks each. So far this year we have ringed a total of 49 Nightjars, including 12 chicks and retrapped at least a dozen birds ringed in previous years.

A Nightjar chick, capable of flight but still being fed by the adults.

At several of the breeding territories the first real proof that the birds were even attempting to nest was the appearance of fledged young, although, to be fair, these could have moved in from outside the study area. GPS tags have been fitted to 6 males this year and three of these have already been recovered. Each tag has shown a great amount of movement around the forest with the birds visiting a great range of clear-fells over the course of a few nights. One tag recorded over 1,200 GPS quality locations showing that the bird was covering most of the forest, far from the rigid territoriality that would be expected and helpful! A great example of the fact that the more information we gather the more questions it poses.

A juvenile Nightjar

Along with the tagging and nest recording, this year we have been collaborating in a large study looking at the genetics of Nightjars being conducted by a Hasselt University in Belgium. Birds caught for ringing and chicks in the nest have been buccal swabbed under licence from the BTO and these will be compared with birds caught elsewhere in this country and in Europe.

Buccal swabs air-drying before being sent off for DNA analysis at Hasselt University, Belgium

Much of the monitoring work being undertaken aims to investigate any possible effects of onshore wind farm development on Nightjar populations including the avoidance of active nests during the construction phase

The past fortnight or so has seen some lovely warm nights, great weather for Nightjarring, and it has allowed us to trap and ring a few juveniles and target a few of the birds still wearing GPS tags in the hope that we may still get the odd one back. Thankfully though, the Nightjar season (and the massive amount of driving it entails) is drawing to an end and there is a brief chance to get some quality sleep before the Golden Plovers and Woodcock return.