{"id":805,"date":"2010-10-29T16:52:36","date_gmt":"2010-10-29T22:52:36","guid":{"rendered":"http:\/\/featheredphotography.wordpress.com\/?p=805"},"modified":"2011-05-29T11:10:07","modified_gmt":"2011-05-29T17:10:07","slug":"why-grebes-eat-feathers","status":"publish","type":"post","link":"https:\/\/featheredphotography.com\/blog\/2010\/10\/29\/why-grebes-eat-feathers\/","title":{"rendered":"Why Grebes Eat Feathers"},"content":{"rendered":"

Grebes, as a group, are\u00a0known for eating feathers – usually their own.\u00a0 The obvious question is – why?\u00a0 There would be virtually no nutritional value in a feather.<\/p>\n

\u00a0<\/p>\n

\"\"<\/a><\/p>\n

Clark’s Grebe eating a feather<\/em><\/p>\n

I’ve photographed four species of\u00a0grebes – Western Grebe, Clarks Grebe (these two are very similar), Pied-billed Grebe and Eared Grebe.\u00a0 I’ve been able to document feather eating\u00a0in all but the Eared Grebe.<\/p>\n

\u00a0<\/p>\n

\u00a0\"\"<\/a><\/p>\n

Western Grebe parent feeding feather to young<\/em><\/p>\n

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.\u00a0<\/p>\n

\u00a0<\/p>\n

\u00a0<\/p>\n

\"\"<\/a><\/p>\n

Western Grebe chick reaching for a feather from its parent\u00a0<\/em><\/p>\n

Feathers are fed to the young almost immediately after hatching.\u00a0 In fact, feathers are very often the first item eaten by newly hatched chicks of many grebe species.<\/p>\n

The purpose(s) of feather eating is unproven but evidence suggests that the behavior has\u00a0these benefits for the birds.\u00a0<\/p>\n

    \n
  1. Some of the ingested feathers form\u00a0a plug in\u00a0the pylorus, between the stomach and small intestine,\u00a0which acts\u00a0as a strainer to keep fish bones in the stomach long enough to be completely digested.\u00a0<\/li>\n
  2. Most swallowed feathers end up in the stomach lumen, mixed with food.\u00a0 They eventually (along with any indigestible matter) form pellets that are ejected through the mouth.\u00a0 The continuous\u00a0passage of these pellets through the upper digestive system minimizes the buildup of a variety of parasites that are very common there and plague grebes.\u00a0<\/li>\n<\/ol>\n

    \u00a0<\/p>\n

    \"\"<\/a><\/p>\n

    Pied-billed Grebe eating a feather\u00a0<\/em><\/p>\n

    Most of the feathers grebes eat are their own, pulled out during preening.\u00a0 However, if there are many grebes on a\u00a0 pond, lots of these feathers end up floating on the water.\u00a0 When a grebe sees one of them it will very often eat it, whether or not it’s from that bird or another.\u00a0 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.\u00a0<\/p>\n

    Virtually all of the feathers are small, soft, contour feathers from their flanks – not the larger quill feathers.\u00a0 Grebes continually molt these flank feathers, probably as an adaptation that provides a constant supply of feathers for pellet formation.\u00a0<\/p>\n

    \u00a0<\/p>\n

    \"\"<\/a><\/p>\n

    Pied-billed Grebe\u00a0about to consume a feather\u00a0<\/em><\/p>\n

    In post-mortem exam, feathers may form as much as 52.5% of total stomach contents in Pied-billed Grebes, so obviously feather ingestion plays a significant role in the normal functioning of the digestive tracts of grebes.\u00a0<\/p>\n

    Ron\u00a0\u00a0<\/p>\n

    \u00a0<\/em><\/p>\n

    \u00a0Source: The Birds of North America, Online (pay site)<\/em><\/p>\n","protected":false},"excerpt":{"rendered":"

    Grebes, as a group, are\u00a0known for eating feathers – usually their own.\u00a0 The obvious question is – why?\u00a0 There would be virtually no nutritional value in a feather. \u00a0 Clark’s Grebe eating a feather I’ve photographed four species of\u00a0grebes – Western Grebe, Clarks Grebe (these two are very similar), Pied-billed Grebe and Eared Grebe.\u00a0 I’ve been able to document feather eating\u00a0in all but the Eared Grebe. \u00a0 \u00a0 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.\u00a0 \u00a0 \u00a0 Western Grebe chick reaching for a feather from its parent\u00a0 Feathers are fed to the young almost immediately after hatching.\u00a0 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\u00a0these benefits for the birds.\u00a0 Some of the ingested feathers form\u00a0a plug in\u00a0the pylorus, between the stomach and small intestine,\u00a0which acts\u00a0as a strainer to keep fish bones in the stomach long enough to be completely digested.\u00a0 Most swallowed feathers end up in the stomach lumen, mixed with food.\u00a0 They eventually (along with any indigestible matter) form pellets that are ejected through the mouth.\u00a0 The continuous\u00a0passage of these pellets through the upper digestive system minimizes the buildup of a variety of parasites that are very common there and plague grebes.\u00a0 \u00a0 Pied-billed…<\/p>\n

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