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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Photographing Birds on Antelope Island

  My previous post was an overview of the geology of Antelope Island and its non-bird wildlife.  Here, I’ll focus on its birds.   Juvenile Loggerhead Shrike begging for food Loggerhead Shrikes are common on many parts of the island during summer.  They can be a challenge to approach but those few that nest close to the road eventually get used to traffic so if you photograph from your vehicle you can often get quite close.  Here this juvenile was begging for food that was being delivered by a parent just out of frame to the left.    Loggerhead Shrike with dragonfly  Shrikes are often called “butcher birds” for their practice of temporarily impaling their prey on thorns or other sharp projections.   This juvenile had done just that with the dragonfly but it wasn’t very good at it yet and in the end just decided to eat it instead of store it away.     Loggerhead Shrike with spider Shrikes are opportunistic carnivores known to feed on insects, spiders, amphibians, small reptiles, rodents and other birds.   This one also attempted to impale the prey before eating it.     Juvenile Burrowing Owl practicing its parallax technique on me Burrowing Owls are one of my favorite species on the island though they can be difficult to locate from year to year as they often don’t seem to nest in the same burrow the next year.  In the summer of 2009 there was an entire family of owls along the causeway to the island nesting under concrete rubble, as in the…

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Antelope Island

  Of the eight major islands in the Great Salt Lake, Antelope Island is the largest at 15 miles long and 4.5 miles wide.  Frary Peak reaches an elevation of 6596 feet.  The island has an intriguing history, interesting geology and free roaming herds of bison, bighorn sheep, mule deer and pronghorn, in addition to a variety of smaller mammal species and plentiful birds.  It is one of my very favorite photography locations – especially for birds.  In this blog post I will present an overview of the island and some of its wildlife.  My next post will deal specifically with bird photography on the island.  The north end of Antelope Island at sunrise as seen from the causeway access road There is a 7 mile long causeway road that provides the only access to the island, which is actually a peninsula when the Great Salt Lake water levels are low.  It’s common to see a variety of wildlife along this causeway including coyotes sprinting at the first sight of an early morning vehicle, American Kestrels, Northern Harriers, Burrowing Owls, Common Ravens and a variety of waterfowl and shorebirds where the water comes closer to the causeway.    Approaching the north end of Antelope Island  As you get closer to the island the water comes right up to the causeway’s edge and typically there’s hordes of waterfowl and shorebirds very close to the road.  In the photo above, several shoreline levels of ancient Lake Bonneville can be seen where wave action eroded “benches” in the sides of the…

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Bald Eagles in Utah

Every winter hundreds of Bald Eagles migrate south from Canada and Alaska and winter in Utah.  They do so because of our relatively mild winters and they are able to find sufficient food here.  Typically they begin arriving in November and leave in March when the ice begins to melt.  They can be found in many areas of the state but a large percentage of them winter on the wetlands surrounding the Great Salt Lake where there are a number of bird refuges and other suitable areas to accommodate them.  Adult Bald Eagle in flight Each year I spend many hours at some of the Great Salt Lake wetlands photographing eagles.  What attracts them to some of the refuges is fish – lots of fish,  especially carp.  Carp are a nuissance for wildlife managers because they root in the mud of the shallow impoundments which makes the water cloudy and unable to transmit light to the bottom.  This disrupts the healthy growth of desirable plant species needed by birds so some refuges “poison” the carp, usually in mid-winter, with rotenone – a non-toxic chemical that forms a film on fish gills preventing oxygen transfer from the water to the blood which kills the carp.  Then it’s feast time for the eagles. Bald Eagles and gulls on the ice It’s common to see several hundred Bald Eagles from one spot.  One refuge counted 408 eagles.   I’ve personally seen 150 – 200 birds on several occasions. Immature Bald Eagle with carp This is why they’re here – fish!  Specifically, carp.  Lots of carp…

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Weather Loach in Utah – Another Invasive Species

  On December 12, 2007 I photographed this Common Goldeneye with a fish at Farmington Bay Wildlife Management Area.  At the time I didn’t pay much attention to what kind of fish it might be and then just kind of forgot about it.  Male Common Goldeneye with unidentified (at the time) fish    The moment of capture Then, on October 2, 2008, I took some photos of a Snowy Egret fishing, also at Farmington.  Finally, I became curious about the unusual fish – noticing the atypical elongated almost eel-like body in particular. I made some casual inquiries of refuge personnel about fish species present there but didn’t get anything definitive that would match this fish.   More time went by, then I finally showed Justina Parsons-Bernstein some of the photos and asked her about the fish.  She is the Director of The Great Salt Lake Nature Center at Farmington Bay WMA and she was also curious as to what species of fish it was so she sent some of my images to a vertebrate specialist with the state of Utah.  He keyed it out as a Weather Loach. It turns out that the Weather Loach or Dojo Loach as it is also known (Misgurnus anguillicaudatus) is quite a remarkable fish.  The name Weather Loach comes from the fact that it is highly sensitive to minor changes in barometric pressure and when it perceives such a change its behaviour becomes erratic, active and animated.  Humans have kept them captive as a weather indicator for centuries.  They are a very hardy species, capable of surviving poor conditions by swallowing atmospheric…

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