Plain-pouched Hornbill’s eyelashes

posted in: Hornbills, Morphology-Develop. | 1

A post on eyelashes in birds way back in March 2007 brought a comment by Nardia Thompson recently:

“I can tell you for a fact that there are several different types of birds that have eyelashes. When I was a tot we went to a petting zoo. Atop a pile of rocks was a solid black bird with a very long black beak. This bird had “showgirl” eyelashes. I noticed them from afar. I asked the keeper if I could pet the bird and he said “You can try…” and to a kid that sounds like “Sure! Go ahead!” I climbed the pile of rocks and had a good look at the bird and petted him. The eyelashes were unbelievably thick and long. This raised a number of questions in my young mind because I had never seen a bird with eyelashes before (not that I had noticed anyway) and I wasn’t sure they were even real. This made me wonder ‘Just how bored does a petting zoo keeper have to get to glue eyelashes on a bird, and what sort of glue did he use?’

“Ever since I have been on a quest to find out exactly WHAT these eyelashes were (are they the same as hairs? What makes them different from hair exactly, etc.) and what they were for. The keeper told me that the bird was probably from Africa, but he wasn’t sure. I have never seen this bird pictured anywhere and would love to know what kind of bird it was. I am so glad that I am not the only person who has noticed eyelashes on birds.”

Forest Ang had an encounter with a rescued Plain-pouched Hornbill (Rhyticeros subruficollis) in Malaysia recently. Of the many images he submitted, one shows the long eyelashes of this hornbill as showcased above.

These eyelashes are highly specialised contour feathers where the rachis or feather shaft lacks barbs. Such bristles are found at the base of the bill. Ornithologists term these rictal bristles. And rictal bristles are seen in many species of birds that catch insects, like nightjars, flycatchers, owls, swallows and hawks.

There appears to be consensus that these eyelashes protect the eyes from flying insects and other debris, especially when the bird catches large scaly insects like butterflies and moths. Rictal bristles also help the bird to detect movements of insects held in the bill, just like the whiskers of some mammals.

Image by Forest Ang.

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