Last year UK ringers caught over 230 Nightjars to try and find out more about their fantastic migration and demography. This species is believed to winter in tropical and South Africa. So far we have received recoveries from various countries including The Netherlands, Spain, France, Morocco and Algeria but there is much more we don't know yet.
Interestingly the notes in a Nightjars 'jar' or 'churr' are emitted at a rate of 30 or 40 per second and ringers can also testify to an interesting 'hiss' that is given by birds in the hand. This could be used to 'see off' any would be attackers by mimicking a snake.
Rebecca Nesbit has posted a clip on Youtube (below) which shows Mike Gould going through the process of Nightjar ringing.