Tag: grebes

Grebe Panic

These aren’t great images technically but I thought they documented a fascinating phenomenon well enough. Yesterday there were thousands of these grebes at the first bridge along the Antelope Island causeway.  They were actively feeding at the current boundary where the water coming under the bridge met the still water in the north arm of the Great Salt Lake so they were bunched up in incredibly thick masses.  Several species of gulls were also present.   Each time a gull would pass over the grebes, those directly underneath the gulls would panic and dive into the very shallow water in front of the gull which would create quite the stir in the water.  Those grebes just a few inches to either side didn’t react which created a dramatic visual phenomenon as the frothy splash moved in front of and directly beneath the gull.     Those times the gulls flew along the length of the mass of grebes the “splash” would travel exactly the same speed as the gull for perhaps 75 yards.  This was one of the few times when shooting birds that I wish I’d practiced more with the video capabilities of my Canon 7D.  That would be a video that I’d like to see many times as it was quite the spectacle to watch. Ron

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Why Grebes Eat Feathers

Grebes, as a group, are known for eating feathers – usually their own.  The obvious question is – why?  There would be virtually no nutritional value in a feather.   Clark’s Grebe eating a feather I’ve photographed four species of grebes – Western Grebe, Clarks Grebe (these two are very similar), Pied-billed Grebe and Eared Grebe.  I’ve been able to document feather eating in all but the Eared Grebe.     Western Grebe parent feeding feather to young Over a period of perhaps a half hour I watched this adult feed several feathers to the chicks, who seemed almost as eager to consume the feathers as they did the fish provided by the parents.      Western Grebe chick reaching for a feather from its parent  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 any 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.    Pied-billed…

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