Nightjar: Where you can see one of Yorkshire's most mysterious birds as it returns from Africa

The male also makes a sharp coo-ick call when he is courting before settling down to sing for the night.

The song is a strange mechanical sound, rising and falling and compared to the noise of a small, far off, motorbike.

The nightjar frequently spends the day on the ground among dead bracken and is beautifully camouflaged with its black, brown and cream feathers breaking its outline.

It also keeps its eyes half closed so that any movement can be mistaken for a leaf or other vegetation lifted by the wind and will also roost in trees stretching along a branch to be as inconspicuous as possible.

Nightjars nest on the ground, laying two blotchy eggs and the incubating bird is also perfectly camouflaged as she stretches over them.

It is obvious then that a good view of a nightjar can be hard to obtain but sometimes one can turn up in an unusual place such as one singing at the edge of a Barnsley supermarket car park a few years ago while there have been one or two recent sightings of nightjars coming in off the sea along the Yorkshire coast.

With its large eyes and large mouth, which is 4 cms across at full gape, the nightjar has a reptilian appearance which caused it to be called the flying toad in some places. Its Latin name means goatsucker because people used to believe it suckled goats's milk at night.

In Yorkshire we are fortunate to have thriving populations of nightjars in the North York Moors forests and on Thorne and Hatfield Moors, part of the vast Humberhead Peatland reserve.

In recent years they have also spread or repopulated other areas including the Washburn Valley north of Otley where the felling of mature trees has provided forest clearings, ideal for them to hunt over and sing from the surrounding trees

At one time, as heathland across England was lost to developers, the nightjar was under threat, so much so that it was one of the species included on the Birds of Conservation Concern Red List.

But , thanks to the work to provide habitats by Forestry England and others, nightjar numbers have steadily increased since the 1980s ,and it has now been moved to the less critical Amber List.