The Question: I recently began heating the water in my birdbath. Yesterday 3-4 starlings were splashing and rolling in the water, having a ball. Meanwhile, freezing rain was falling from the sky, and the temperature hovered around 28 degrees F (-2 C). They only left when a grackle came down out of curiosity and filled the bath, leaving them no room. They flew off into the tree branches and fluffed out. Why don’t their feathers stick together? Does water get to their skin? Is their body temperature in danger of dropping? Submitted by: Barbara F, Rhode Island, USA |
The Short Answer: It sounds like you have a feathered polar bear club in your back yard. Maybe they just enjoy the challenge and the shock the same way people who swim in the ocean in winter do.
More likely, they’re washing up. When birds bathe, they often go through ritualized motions that seem to work to get water over most of their feathers, and down to their skin. This probably serves to clean their skin and help remove parasites such as bird lice, and it definitely helps to smooth and repair their feathers. With the temperature just below freezing at 28 degrees F (-2 C), it would take a few minutes for water droplets to freeze, and since the droplets are being heated by the bird’s body, they probably don’t get a chance to freeze and stick the feathers together at that temperature. It might be different at 0 degrees F (-18 C). (Dr. David Swanson, professor of biology at the University of South Dakota, says that he has, in fact, seen ice on birds’ feathers in very cold temperatures.) Bathing seems to be important for most birds to keep their feathers in good shape. This is important to allow the birds to fly well to escape predators. It probably also helps to maintain the insulating properties of the feathers. So the birds may be trading a little short term warmth for more long term warmth and safety. At it turns out, European starlings (Sturnus vulgaris) are particularly good at warming themselves up, so as long as they are well fed, the starlings are probably not in any danger of getting cold from bathing.
More Information: Feathers are amazing adaptations for both flight and insulation, but they don’t come without cost. In fact, one study found that across a wide range of species, birds averaged over 9% of their time preening (1). Some species spend a full quarter of their life cleaning and rearranging their feathers. A bird feather is constructed of a central shaft with lattice-like branches. Coming off the branches are short shafts with rows of barbs which interlock, something like hundreds of tiny zippers. Any time a bird’s feathers are contacted, some of the tiny zippers may shift and come undone. It probably even happens just when the bird is flying. Unless the bird rezips the feather structures several times a day, it would grow more and more ragged and the feathers would become less and less sturdy. Eventually, the bird would find it pretty hard to fly well (2). This could mean the difference between life and death to a bird trying to escape a predator. So those starlings may not be splashing around just for the fun of it.
As for the ability of European starlings to stay warm, measurements of the ability of birds to increase their metabolism when cold show that starlings are better at it than most birds their size (3). Dr. Swanson, who studies adaptations to cold and other environmental extremes, cautions that the relevant data is old and may have been gathered under less accurate standards than modern studies. Also, the data was gathered in the summer, and many cold climate birds go through seasonal changes that increase their ability to ramp up their metabolism in the winter. The difference between starlings and other birds pretty much disappears in the winter. Still, it’s something of a mystery as to why starlings might have a greater ability to increase their metabolism in the summer. Starlings have a very wide summertime range, extending into northern Canada and Alaska in North America, and well above the Arctic Circle in their native range in Europe. So maybe they are adapted to be able to deal with cold temperatures year round.
One of the ways that birds warm up, by the way, is shivering and using the heat given off when muscles contract, a trick that human Polar Bear swimmers also use. But birds like starlings have those marvelous insulating feathers to hold the heat generated by shivering. So when they take a polar bear plunge, they shake off the water and warm right back up again … unlike their human winter bathing counterparts.
Trivia: Although there is a polar bear swim in Barbara’s home state of Rhode Island, the more famous winter ocean swim there is called the Penguin Plunge.
Sources: My thanks to Dr. Swanson for his generous help.
- COTGREAVE, P., and D. CLAYTON. 1994. COMPARATIVE-ANALYSIS OF TIME SPENT GROOMING BY BIRDS IN RELATION TO PARASITE LOAD. Behaviour 131 : 171-187.
- Brilot, B., L. Asher and M. Bateson. 2009. Water bathing alters the speed-accuracy trade-off of escape flights in European starlings. Animal behaviour 78 (4): 801-807.
- Swanson, D., and T. Garland. 2009. THE EVOLUTION OF HIGH SUMMIT METABOLISM AND COLD TOLERANCE IN BIRDS AND ITS IMPACT ON PRESENT-DAY DISTRIBUTIONS. Evolution 63 (1): 184-194.Ask a Naturalist® (November 30, 2023) Birds Bathing in Winter?. Retrieved from https://askanaturalist.com/birds-bathing-in-winter/."Birds Bathing in Winter?." Ask a Naturalist® - November 30, 2023, https://askanaturalist.com/birds-bathing-in-winter/Ask a Naturalist® February 9, 2011 Birds Bathing in Winter?., viewed November 30, 2023,<https://askanaturalist.com/birds-bathing-in-winter/>Ask a Naturalist® - Birds Bathing in Winter?. [Internet]. [Accessed November 30, 2023]. Available from: https://askanaturalist.com/birds-bathing-in-winter/"Birds Bathing in Winter?." Ask a Naturalist® - Accessed November 30, 2023. https://askanaturalist.com/birds-bathing-in-winter/"Birds Bathing in Winter?." Ask a Naturalist® [Online]. Available: https://askanaturalist.com/birds-bathing-in-winter/. [Accessed: November 30, 2023]
I’m so glad to read this! I live in northeast US and just this evening a pair of starlings appeared at my bird feeder very obviously wet. They were grooming themselves and shaking. I assumed they had bathed in my year round bird bath on the other side of the house. But I couldn’t understand it because it was getting dark, a horrible wind was up, and the temps were around
25 F and prbably colder with wind chill. I thought these silly birds must have gotten confused by the relatively warm water of the bird bath, but it seems from this great website that they are actually going to be just fine. Well I’m glad I didn’t accidentally trick some poor birds to bathe!!
Its February and the NY Staten ISland Temperatures are well below freezing and going down to 2 degrees tonight. So much for Al Gore and the 100’s of millions he has made on Global warming. In any case the Starling bath in my heated bird bath in any weather sometime 4 – 6 at a time, I do not see Cardinals, blue Jays, Sparrows, wood peckers all of which feed in my yard but never seen bathing and I wonder why.
Thank you Tom!
I just observed 7 pigeon doves in my heated bird bath at twilight, just before dark, and it is 24F degrees out. I couldn’t believe my eyes. With their entire bodies in the water, they looked like people in a hot tub. Although it is now dark out, I topped the bird bath off with warm water in case they had a party planned tonight. 🙂
is it usual for a Starlin to stay with you during the day play ,eat .rest go in and out from your window then before sundown to leave and stay gone all night and return the next day ?
notify me with all feedback thanks Frank
Hi Frank, I don’t think it’s usual, but starlings are very smart and some people keep them as pets. I suppose it’s possible that you have someone’s escaped pet starling at your window. http://blogs.thatpetplace.com/thatbirdblog/2011/09/15/european-starlings-as-pets/#.WHpjT_nR-00
I just had some cardinals take a bath and it is 17 degrees here in Minnesota now.
Do grackles take a shower in cold warm or hot water
Hi Abir, Most of the water that grackles would bathe in would be the temperature of the environment. So if it’s winter, the water would be cold. If it’s summer, the water would be warm. Are you wondering about putting water out for them? If so, I’d suggest making it lukewarm, 60-80 degrees. If it’s winter, they’ll enjoy the warmth, and if it’s summer, water at that temp will feel cool. Tom at AskaNaturalist.com
We live in Shrewsbury Pa and also have a heated bird bath which is great, sometimes I add warm water to top it off when it is extremely cold and windy. Recently it was 6 degrees in the afternoon and we too had several doves using it as a hot tub, very cute. Later several grackles showed up and had a blast in the water, cleaning themselves for a few minutes, shook off and flew away. Went to refill the bath, boy was it dirty! Cleaned it and refilled, and within a minute or two we had new visitors
I was quite shocked to have starlings bathing in my heated bird bath on the coldest day of the year. Temperatures with wind chill were over ten below zero. The water was very dirty afterwards with a bunch of downy feathers floating around. This is my first year providing water. I didn’t realize I’d have to clean every day. I thought they’d take dainty little sips!
I moved to Salt Lake City, UT just over two years ago from Florida. We’re at the beginning of winter or end of fall and this is the first year out here that I have fed the local birds and provided them with the birdbath. I didn’t see them last winter so stupid me thought they might’ve migrated. Remember Floridian here. Someone recently told me that no most the birds don’t migrate that they do stay here and if I continue to feed them during the winter and provide them with water I would continue to see them throughout the winter. I decided that I was going to make sure that they had both food and water this winter. Even though I left the hose running in my birdbath last night it still froze. I thawed it out with hot water and kept it thawed all day, there were so many birds in it today bathing and having fun. I was worried because it was cold out. I didn’t even think about a heater for the birdbath until today so I will be ordering one. But I had no idea the birds would bathe in freezing temperatures. We even have quails which are the most amazing birds to watch. They usually are long gone by this time of the year. Again I thought they were gone, but with the food in the water they are still here in droves.. I didn’t realize birds were so resilient. Thank you for your post it’s giving me peace of mind
Today a very large number of starlings washed their feathers in my heated birdbath with outdoor temperature of 3.2 degrees Fahrenheit.
Large numbers of Mourning doves love to hang out around the heated birdbath. Hawks keep an eye of them too though…