Grebes eat feathers. Lots of them. They do it intentionally and for good reason.
I photographed this Pied-billed Grebe eating a small feather nine days ago at Farmington Bay. Following are some older images that show the same behavior.
I cropped this image tightly so that the feather in the mouth could more easily be seen.
Other grebe species also eat feathers, including Western and Clark’s Grebes.
Feathers are fed to the young almost immediately after hatching. In fact, feathers are very often the first item eaten by newly hatched chicks of many grebe species. The purpose(s) of feather eating is unproven but evidence suggests that the behavior has these benefits for the birds.
- Some of the ingested feathers form a plug in the pylorus, between the stomach and small intestine, which acts as a strainer to keep fish bones in the stomach long enough to be completely digested.
- Most swallowed feathers end up in the stomach lumen, mixed with food. They eventually (along with other indigestible matter) form pellets that are ejected through the mouth. The continuous passage of these pellets through the upper digestive system minimizes the buildup of a variety of parasites that are very common there and plague grebes.
Young grebes have an intense interest in feathers floating on the water. This Western Grebe chick tried to swallow this one but eventually it was rejected, probably because it was too large. Most of the feathers grebes eat are their own, pulled out during preening. However, if there are many grebes on a pond, lots of these feathers end up floating on the water. When a grebe sees one of them it will very often eat it, whether or not it’s from that bird or another. In my experience, whenever a grebe notices one of these feathers slowly floating by it invariably plucks it out of the water and gobbles it down. Virtually all of the feathers are small, soft, contour feathers from their flanks – not the larger quill feathers. Grebes continually molt these flank feathers, probably as an adaptation that provides a constant supply of feathers for pellet formation.
Note: Originally this post contained two images of a Western Grebe necropsy that showed a large mass of feathers that had been swallowed by the grebe. Due to a misunderstanding between the person who sent them to me (and mistakenly gave me permission to use them) and her employer who owned copyright to the images I deleted those images today, 1-27-16.
Apologies for the inconvenience, especially to all those who commented on those images and to those who visited here expecting to see them.
Ron
Ron:
Very interesting. I haven’t observed this behavior but we only have Pied-billed Grebes here seasonally. I need to spend more time watching them but I may need to travel a little to do so. I want to look for the sinking dive you photographed too.
Dave
Amazing shots and interesting information Ron!
Charlotte
Amazing shots and interesting information Ron!
Charlotte
If I hadn’t seen all the great behavioral photos you’ve been posting of things I’d never heard of birds doing (like playing with cow pies to name just one) I’d have said you were making this stuff up! I had no idea this was something Grebes did commonly. One big thing I did notice immediately after beginning to do some telephoto digital bird photography was how many more very subtle postures, habits and mannerisms became more obvious. One can see a lot with binocs but the ability to catch bursts of subtle behaviors as a series of stills reveals a surprising amount more. This is great stuff.
“the ability to catch bursts of subtle behaviors as a series of stills reveals a surprising amount more”.
Exactly, James! You really do “get it”. That’s a big part of why I love bird photography so much and why I usually shoot at such high shutter speeds – to catch those behaviors which usually happen very fast.
fascinating read, Ron … and of course wonderful photography as always … love the shot of the little guy on mom’s back reaching for the feather!!! very cool!!!
Thanks very much, Lois.
I find necropsies fascinating – it’s good to be familiar with what’s normal so that when you see something abnormal, it is recognizable. And thanks for the kind words for rehabilitators! Your photos and text are, as always, a pleasure.
Rehabilitators like you folks at Cascades Raptor Center do wonderful work, Louise. You deserve the “kind words”, and more…
Hello Ron, Great article! It reminds me why I like your site so much – great photos and very informative. Keep it up, you have quite the fan club! -Pierre
I appreciate the encouragement, Pierre.
No problem for me either. But thank you for being so cautious.
I did not know. Very very interesting.
Thank you for the lesson.
Thank you, Jorge.
I learned something today, and all images are gorgeous. Fascinating, Thank you Ron.
Learning’s a great thing, isn’t it, Susan. I learn a lot writing this blog and getting feedback from my readers (including Linda Sackman).
Photos taken during surgeries or in this case, necropsy, are for education and learning. Graphic to me, are photos for sensationalism or purposely trying to make a negative statement. These were for learning. Thanks Ron!
I agree, Karen. Intention makes a difference with photos like these.
Very educational, and that little one is precious. I’m not sure what to conclude about the necropsied grebe: was the feather mass pathological or not? From the description I would conclude that it was, but it sounds like it might have been normal? Maybe I’m just not awake enough to get the point here.
Susan, No, the mass was not pathological. I appreciate the heads up that it wasn’t clear in my original text and have rectified that.
Kudos to you, wonderful educational review of Grebe behavior!
I had seen this behavior, thought it might have something to do with digestion or help with what they eat or nutrition. But, have to admit I didn’t go beyond that mulling in my mind.
Much appreciate this lesson and the graphic pictures.
Thanks, Dick. Graphic photos like this don’t bother me when they serve an educational function and are not gratuitous but I know some others who don’t appreciate them in any context.
Your warning about graphic photos to follow was well done. The space you left was ample for my laptop. My training was in pathology, so no problem for me, but I appreciate that you were sensitive to people of varied experiences. I’m in London still and have been seeing this feather feeding behavior with the Great Crested Grebes here and wondered what it was about. This makes sense to me now. Thank you for the very interesting post.
Thanks for the feedback about the “warning”, Johanna – much appreciated. I’m glad you found the post interesting.
Wow, I had no idea! That is fascinating… Sort of like the way land-based birds use stones… Great photos, too. Thank you for sharing these.
Thank you, Mary.
Fascinating how the feathers serve as an acquired strainer. And I, too, am grateful to Linda Sackman and her colleagues for performing this difficult work. I remember cleaning ducks following an oil spill in Florida in 1969, when I was a college student, and that simple restorative procedure was difficult enough.
That is interesting, isn’t it, Alison? Fish bones in the intestines would not be a good thing…
Graphic, yes, but so very educational. Thank you for sharing all of these pictures. Of course the one I loved the most was of the chick.
Arwen, As you can probably tell, I was a bit nervous about including those last two images. Thanks for the feedback.