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Pectinate Claw – Large-tailed Nightjar

on 17th September 2017

NightjarLT-pectinate claw [AmarSingh] 1

“Our ‘resident’ male Large-tailed Nightjar (Caprimulgus macrurus bimaculatus) has been with us for 3 months (‘Clockwork’). I have posted a very small number of the images and videos we have taken, although we largely leave the bird alone apart from an intermittent ‘hello’.

NightjarLT-pectinate claw [AmarSingh] 2

“Nightjars have an unusual serrated middle claw which they use to preen their feathers. Frank B. Gill. Ornithology. 3rd Edition 2007 states: ‘Herons, nightjars, and barn owls have miniature combs on their middle toe claws that are used in grooming‘. Good images can be found in an article entitled ‘Looking Good, Part I — Pectinate Claws (Avian Edition) by Curious Sengi, 2016’ LINK. The author states ‘the pectinate claw combs out all those nasty ectoparasites (i.e. external parasites), especially the feather lice that eat precious down feathers’. The article also states ‘the appearance of the pectinate claw was variable among individuals’. Clayton 2010 (Clayton, et al. ‘How Birds Combat Ectoparasites.’  The Open Ornithology Journal 3: 41–71) states: ‘The efficiency of scratching for ectoparasite control may be enhanced by the presence of a comb-like pectinate claw on the middle toes of some birds’. ‘The removal of ectoparasites is most widely believed to be the function of pectinate claws, but alternative hypotheses include roles in feeding, removing powder down, or straightening rictal bristles of the face’. The article describes that a review of 118 bird families found that only 17 possessed pectinate claws; these included herons, nightjars, owls, frigatebirds, terns, grebes, and cormorants.

NightjarLT-pectinate claw [AmarSingh] 3

“The function of pectinate claws is as yet uncertain and may have little to do with ectoparasite control. The Large-tailed Nightjar has a pectinate claw on the middle digit. It is generally not easy to see when resting on the ground or a low perch. We have seen it a number of times, especially when there is rain and the bird in our garden perches on a higher vantage point. Even then views are limited as the feet may be hidden in the plumage and light is usually low. The pectinate claws are longer than the others and tend to ‘stick out’ occasionally.

NightjarLT-pectinate claw [AmarSingh] 4

“I have attempted numerous videos to try and ‘catch’ the bird preening to determine if the pectinate claw is used. But it is very shy of cameras/tripods and often remains immobile if any are set up. A number of preening events observed covertly have yet to reveal any use of this specialised claw. The claw is used to scratch the face, but I find nothing unusual about that, having seen similar activity in birds without a pectinate claw.

“The 4 images attempt to show this unique claw.”

 

Dato’ Dr Amar-Singh HSS
Ipoh, Perak, Malaysia
June – September 2017

Location: Ipoh, Perak, Malaysia
Habitat: Wild urban garden

If you like this post please tap on the Like button at the left bottom of page. Any views and opinions expressed in this article are solely those of the authors/contributors, and are not endorsed by the Lee Kong Chian Natural History Museum (LKCNHM, NUS) or its affiliated institutions. Readers are encouraged to use their discretion before making any decisions or judgements based on the information presented.

YC Wee

Dr Wee played a significant role as a green advocate in Singapore through his extensive involvement in various organizations and committees: as Secretary and Chairman for the Malayan Nature Society (Singapore Branch), and with the Nature Society (Singapore) as founding President (1978-1995). He has also served in the Nature Reserve Board (1987-1989), Nature Reserves Committee (1990-1996), National Council on the Environment/Singapore Environment Council (1992-1996), Work-Group on Nature Conservation (1992) and Inter-Varsity Council on the Environment (1995-1997). He is Patron of the Singapore Gardening Society and was appointed Honorary Museum Associate of the Lee Kong Chian Natural History Museum (LKCNHM) in 2012. In 2005, Dr Wee started the Bird Ecology Study Group. With more than 6,000 entries, the website has become a valuable resource consulted by students, birdwatchers and researchers locally and internationally. The views and opinions expressed in this article are his own, and do not represent those of LKCNHM, the National University of Singapore or its affiliated institutions.

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