This is a question that I’ve only recently thought about, but do birds yawn?
The other day, I was sat under a tree eating my lunch. I was watching and photographing 13 pied cormorants who were sat in the branches above taking a post-lunch siesta. I decided to hang around to see what their plan for the afternoon was. Halfway through my sandwiches one of the birds lifted its head, eyes half open, stretched its neck and opened its beak wide. I was anticipating some sort of call, but nothing came. Was this a yawn? Or was it simply a stretch?
Birds jaw-stretching can be observed both with held breath and with inhalation and exhalation. Jaw-stretching whilst inhaling and exhaling is considered a yawn. In fact, some of the earliest observed confirmed bird yawns were in shags, (the Brandt’s Cormorant and the Pelagic Cormorant). Shags in general are also known for their courting displays. These involve stretching their neck and repeated yawning like movements. They are even often referred to as “yawning displays”, although they are not true yawns.
Are birds stretching, yawning, putting on a display, trying to intimidate or otherwise when they open their beak? To tell, not only will you have to observe the beak opening, but you also need to note whether the bird is breathing at the same time. To complicate matters further, the physiological definition of a yawn is still under debate. This is largely because we don’t know the reasons why we yawn, so it’s hard to define what a yawn actually is.
Are any of these birds yawning?
The cormorants in the tree that sparked this question in my mind slowly woke up over the next half an hour. As each bird awoke, it stretched in some way, most often its neck. To be fair, if I slept with my head under my arm I think I’d need to stretch out my cricked neck too. Some stretched their beaks like the first cormorant had done and there was one that you could just tell had been out late the previous night.
I’ve seen other birds opening their beaks without making a sound that probably can’t be attributed to a yawn. But for me that afternoon with the cormorants was conclusive, birds do yawn!
What do you think? Have you ever seen a bird yawn?
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