With its bill agape, I watch as the crow fans out awkwardly across the cedar shingles. Pressing the camera to my face I snap a couple photos, pleased to finally capture on film a moment I so often encounter in the field. Unlike the crow, who’s keeping a watchful eye on the sky, I’m completely taken with my admittedly creepy behavior. Until, of course, I hear the stiff “Excuse me, can I ask what you’re doing?” from the driver’s window as the homeowner’s minivan pulls up behind me.
Fortunately for me, crow curiosity isn’t hard to come by and quickly the homeowner is as taken with watching this bird as I am. “So, what is it doing up there? I see them like this on my roof all the time” he asks after I give him my credentials. It is a rather odd sight. It’s nearly 90˚ and the crows is sitting in direct sunlight, mouth open, head cocked and wings outstretched like it’s injured. Rather than escaping to shade, it’s joined by its fledgling and together they bake their bodies in the hot sun for a few minutes before gathering themselves and carrying on down to the grass to forage.
Although the specifics can vary slightly, this general kind of posture can be observed across hundreds of bird species, even those you might not expect to have much opportunity for it like owls. Often it’s used to dry wet feathers or warm up on a crisp winter morning but, given that they do it even when it modestly heat stresses them, it must have some other physiological benefits beside thermoregulation.
There are a handful of other reasons that birds may sunbathe, but the big picture is that applying intense heat to feathers is critical to maintaining them in good condition. For example, sunlight exposure has been shown to suppress feather degradation caused by the bacteria Bacillus licheniformis.1 Heat also helps control ectopatasites, possibly by making them more mobile and easier for birds to remove.2 Lastly, sunning may relieve discomfort caused by molting and promote vitamin synthesis.3
So, far from being a signal of distress or heat exhaustion, observing this posture in crows is like watching them ruffle around in a puddle. It’s a routine, and important part of their self care regimen. Plus, everyone knows a few minutes in the sun just plain feels nice.
Photo c/o Kathy Brown. Find more of her great photos on Instagram @kat2brown
Literature cited
1. Saranathan, V., and Burtt, E.H. Jr. (2007). Sunlight on feathers inhibits feather-degrading bacteria. The Wilson Journal of Ornithology 119: 239-245
2. Blem, C.R., and Blem, L.B. (1993). Do Swallows sunbathe to control ectoparasites? An experimental test. The Condor 95: 728-730
3. Potter, E.F., and Hauser, D.C. (1974) Relationship of anting and sunbathing to molting in wild birds. The Auk 91: 537-563
corvidresearch.blog 
Thanks for another enlightenment… I have often watched Great Blue Herons sit in their startling ‘Buddha’ positions, exposing their undersides to the sun….. it is often described as a cooling off mechanism, which it may well be…. but it always seemed to have more meaning…. perhaps this is one of those meanings…….
Could it have anything to do with UVB absorption and vitamin D? Vitamin D studies are in their infancy, and I have no clue what role vitamin D plays in birds and if/how they metabolize it, but I know from my own deficiency that sun exposure is crucial to human vitamin D metabolism, and that mammals and fish have all kinds of unique strategies for making it. Looking through my own second-story window at all the neighborhood rooftops I see similar antics from both crows and squirrels, and always wonder if they’re getting their vitamin D. Thanks as always for an interesting article.
Totally! I mentioned that briefly in the article but yes, there is some evidence vitamin production is also part of this behavior.
Another great article. I always wondered about this behavior. Thank you!
I love watching crows sunbathe. In the wintertime, when there is less sun, do they have more problems with the bacteria and parasites? The last photo you posted looks just like the crow we saw on UW campus. I had never seen a crow laying outstretched on the grass before, so close to a well used foot path. Thank you for the great article!
Great question, Kris. I’ll look more deeply into this since I haven’t found anything so far on seasonal differences in ectoparasites.
I think it’s especially odd that they seem to stare directly into the sun when they do this. I have observed parrots doing the same thing, and chickens!
They’re particularly vulnerable in this position so they’re keeping an eye on the sky for predators.
Great post!! I’ve never seen a bird to that, but I’ve only recently begun to pay close attention. Now I will watch for it..Thanks for the information.
I’ve seen them do this on a super busy area at a crowded beach, and people were taking pics, getting right up to him/her(I felt it my duty to tell people to not mess with him), but he seemed so very vulnerable to ‘people'(predators?) ..no one touched him, but are they deemed incapable of defending themselves while in a deep sunning? You mentioned they keep an eye to the sky, but what about heavy foot traffic/instincts?
Great article, as always, though:) really enjoyed it.
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We watched two crows on the beach today, thanks for the information.
You’re welcome!
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Hi. I live in Miami, Florida. And today under the exausting tropical sun I saw one crow stepping on grass in the open sun, its beak wide open, and its head tilted sideways. I thought it was sick at first, then another crow flew by and did just same bizzare body posture. Then I realized they are not sick, but are doing it on purpose. But what purpose is it? The
mystery left me guessing. The first guess is they must get some physical benefit from it: may be the heat does kill bacteria or burns bothering insects(however why would that require them to open the beak and tilt the head still does not explain it), another guess is it might be a form of gasping similar to the way dogs do when they are too hot ( but then the shadow is near and they need not be in the open sun, which does not explain it either), my third guess is, given the fact that crows are one of the most intelligent creatures, they tilt their head to make sure one eye can observe the sun and simply they thereby worship the sun ( animals have rituals too, not just humans). But if the latter guess is true and it is their ritual, it should not be the same way everywhere on every continent. You mentioned that your crows opened their wings wide. But the ones I saw did not open the wings, but only their beaks…..) can’t come up with another guess for now…yet I will try to load my picture below. I surely took a picture of that wonder. Hopefully, it will be able to download here……
Hi Ginseng, for what it’s worth they don’t always stretch out their wings. It’s the head tilt/open bill that are the most indicative of the behavior.
SorrySorry cant copy my image of the crow here…
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ONE MORE NOTE BELOW: I have read comments below that some people witnessed other birds do it. If many birds do it, then it is very likely due to some physical need, perhaps, related to their vision or eyesight and /or body inner temperature manipulation.
Great article
TY!
Hi this is interesting. I have been reading a magpie (pica pica) and have observed it also doing this. I wondered what it was doing. It makes sense that there are extra benefits to this than just mere drying off or sunbathing. Thanks for the article!
Rearing*
Thank you so much for your explanation; we’ve just seen this for the first time (in Wiltshire, UK)!
Hi
I’ve become more aware of crows lately while walking in the area. I noticed in the heat they have their mouths open…in your pics, the crow was lying out in the sun..I have a 10 sec video of crows standing perfectly still for longer than the video…is this sunbathing as well? Or a way of not creating more heat through movement? I’ve seen it a few times lately…
They are very still while they sunbath, yes, that’s part of why people often think they’re actually injured! They can hold the pose for an impressively long time, I’ve seen it for up to 10/15min before!
I wonder if we know whether it is the UVA/B aspect of sunlight that does the killing of the bacteria you mention, or simply the heat. I ask because I know many who keep injured Corvids indoors to get better (because they do not have the space for an outdoor setup) and the birds thus cannot access much sunlight, but they do have a heater and a UV lamp. To hear your thoughts in these scenarios would be really appreciated.
I’m not sure Chris! It’s an interesting question though. I bet someone else knows the answer.
I’ve befriended a pair of crows who visit our back yard. Since it turned hot, I’ve seen local crows with their mouths open because of the heat. I just saw one of my buds doing this up close today and there’s a thin red curving line (maybe a cut?) going from below his beak down toward his neck. He doesn’t seem concerned at all, other than in whether I’m going to give him some kibble. I’m not sure if this is an injury or something normal that becomes visible when crows have their mouths open (I could only see one side of his head). Any ideas? They just finished molting.
Hi Jackie, that’s normal. While it may look like birds are covered in feathers (the way a dog is covered in fur) the feathers only emerge from certain tracts along the body, while the rest is bare skin. When they open their mouths and stretch the skin, the featherless tracts become visible. Like any thin skin, if you shine a light through it it looks red because of the blood vessels. This will be especially obvious on younger birds.
Awesome and fascinating! Thank you for answering!
I’ve got crows that sit in my tree and have their beaks open, tilt their heads all the way back, and sit like that for several minutes. Wings are never spread out. It’s been hot for 2 weeks here in the PNW.
Isn’t it funny looking?