10 June 2011

Nightjars and Lightbugs

Nightjars are now returning to the Forestry Commission's Thetford Forest and are pairing up ready to start nesting. Thetford Forest Ringing Group members were out on Thursday night in order to catch these birds to understand more about their movements on migration and particularly in their wintering quarters, as surprising little is currently known about this species. A first catch of four birds was a marvellous start to this new BTO/Biotrack project, supported by Shoreham & District Ornithological Society.

Unlike the Cuckoo, previously reported, the Nightjar is too small to have a Satellite transmitter fitted. Geolocator tags are an excellent alternative but we have to catch the birds again next year to download the information on their movements. These tags, known as Lightbugs, collect data on day length and time, which is used to calculate the bird’s global position to within 100km, each day. These daily locations will help reveal migration routes and wintering locations within Africa.

Just when you thought a near perfect night couldn't get any better, one of the females was discovered to be already ringed, RP01170. She was originally caught on migration, 171km away at Icklesham, Sussex on 15 September 1999 and we had not seen her since she was caught in the forest in 2008.

RP01170 has now broken the previous British and Irish longevity record, which stood at 11 years and 10 days, by 257 days. Amazingly, Brian Cresswell who helped fit the Lightbug to RP01170, originally caught the previous oldest Nightjar, in Dorset, back in 1992! So, quite a privilege to have handled the two oldest Nightjars in Britain and Ireland.

Thanks to Brian Cresswell and Forestry Commission for their valuable help and to Kate Risely for the photo (Lee Barber on left and Brian Cresswell on right).

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