A rare and strange condition found in a Sooty Tern

Adult Sooty Tern with its tongue protruding from he underneath of its bill, a condition known as a sub-lingual fistula (Photo: Chris Feare)

During an evening search for ringed Sooty Terns in the Bird Island colony on 8 June, the youngest member of our team, Dylan Savy, found an incubating adult with its tongue extending below the lower mandible, having pierced the skin and other tissues in the bottom of the mouth. This condition is called a sub-lingual fistula. This is the first time that we have seen it on Bird Island, despite the handling of tens of thousands of Sooty Terns here over the past almost 50 years.

It has been found very rarely in birds. First reported in a New Zealand Stitchbird (local name Hihi), the condition has subsequently been recorded in a Masked Booby on Ascension Island (south Atlantic) and in some adult Sooty Terns, also on Ascension.

Neither the cause of the condition, nor its effect on the feeding abilities of the affected birds, are known. Any reports of this condition in any species are requested by Jim Reynolds, University of Birmingham, UK (https://ornithologyexchange.org/forums/topic/29310-seeking-records-of-birds-with-bill-abnormality/)


Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

This site uses Akismet to reduce spam. Learn how your comment data is processed.