Grebes Eating Feathers (including two graphic images)

Grebes eat feathers.  Lots of them.  They do it intentionally and for good reason.

 

pied-billed grebe 8923 ron dudley 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.

 

 

pied-billed-grebe-1436 ron dudley I cropped this image tightly so that the feather in the mouth could more easily be seen.

 

 

western-grebe-8385 Other grebe species also eat feathers, including Western and Clark’s Grebes.

 

 

western-grebe-1224-ron-dudleyFeathers 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.

  1. 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.
  2. 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.

 

 

western-grebe-1021-ron-dudley

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.

 

Recently Linda Sackman, Health Staff Manager at Pasadena Humane Society, sent me the following images taken during the necropsy of a Western Grebe with a severely injured neck which required the bird to be euthanized.  The bird was necropsied to give the staff additional experience and insight into the unique physiology of grebes.  Linda was kind enough to send me multiple photos of that necropsy that related to feather eating in grebes and I’ve included two of them below.

Caution:  These two images are graphic.  If you are disturbed by such images please scroll no further.  You have now been warned twice so please, no complaints about them if you decide to proceed.  I have left extra space below this warning so it could be read without having already scrolled to the point where you would see them.

 

 

 

 

 

   

 

 

western grebe ingested feathers 4577

 Copyright Linda Sackman.  Image used by permission. 

This is a mass of swallowed feathers that had been swallowed by the grebe.  The feathers were stained green by bile.  Linda said that she was “completely dumfounded at the volume of bile colored feathers ingested” and that the mass was “rock hard”.  At first she thought the mass might be “pathological” (which it was not).

 

 

 western grebe ingested feathers 4578 ron dudley

  Copyright Linda Sackman.  Image used by permission. 

Here some of the feathers have been teased away from the tight mass on the right.

I applaud Linda and her staff for making the extra effort to learn more about grebe anatomy by doing the necropsy and then searching the net where she found my earlier post on feather eating in grebes which explained the feather mass she found. As she says, it’s all about “education” and “the next time I x-ray a grebe with “obstruction” I will certainly wait for a feather pellet before making any judgment calls”.  Linda also browsed through many of my other bird photos and said that they “reminded me that not all birds are broken beyond repair… which is how I usually see them”.  It must be very difficult for folks like Linda who have an obvious love for “critters” but see so many of them in pain and despair.

Kudos to her and all others who do such work.  Humane Societies and wildlife rehabilitators have my admiration and respect and I believe they deserve the support of all of us.

Ron

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East Canyon Red-tailed Hawk

I spent yesterday morning in the Wasatch Mountains looking for raptors and other birds.  I had my best luck with Red-tailed Hawks…

 

red-tailed hawk 9399 ron dudley

 1/2500, f/6.3, ISO 500, Canon 7D, Canon EF500mm f/4L IS II USM +1.4 tc, not baited, set up or called in

including this one near East Canyon Reservoir.  The hawk was perched above me and I don’t much like this angle on the subject unless the bird takes off, which it did.  The sky color in these shots is intensely blue but that’s often the case at these elevations (6000′) in the morning.

 

 

red-tailed hawk 9402 ron dudley

   1/2000, f/6.3, ISO 500, Canon 7D, Canon EF500mm f/4L IS II USM +1.4 tc, not baited, set up or called in

The wing position in these first two images…

 

 

red-tailed hawk 9404 ron dudley

   1/2000, f/6.3, ISO 500, Canon 7D, Canon EF500mm f/4L IS II USM +1.4 tc, not baited, set up or called in

is almost identical but the bird has moved forward almost two feet in the interim.  I find that the frame rate of my 7D is very often perfectly timed with the wing-beat speed of buteos as they take off.  I wonder if I’ll get a little more variety in wing position when I get the new Cannon 7D Mark ll when it is released in a few days (Canon has moved up the release date from November 29 to October 30 and mine has been on order for weeks).  The Mark ll has a burst rate of 10 frames/sec as opposed to 8 frames/sec for the older 7D.

 

 

red-tailed hawk 9405 ron dudley

   1/2000, f/6.3, ISO 500, Canon 7D, Canon EF500mm f/4L IS II USM +1.4 tc, not baited, set up or called in

 I did get one image I liked with the wings down.

 

 

red-tailed hawk 9406 ron dudley

  1/2000, f/6.3, ISO 500, Canon 7D, Canon EF500mm f/4L IS II USM +1.4 tc, not baited, set up or called in

 I cropped this one vertically to include the sagebrush at the bottom of the frame.  The hawk then circled above me a couple of times…

 

 

red-tailed hawk 9427 ron dudley

 1/2000, f/6.3, ISO 500, Canon 7D, Canon EF500mm f/4L IS II USM +1.4 tc, not baited, set up or called in

and then landed at the top of the hill again but this time much further away.  Here the bird is just about to fold its wings after touch down.

Ron

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