Category: Feeding

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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Northern Harriers Fight to Survive Harsh Winters

  Typically life is good for the hundreds of Northern Harriers who spend fall and winter in the marshes and prairies surrounding the Great Salt Lake after spending breeding season up north.  Here their diet consists almost exclusively of microtine voles (small rodents resembling mice).  These voles are incredibly abundant and relatively easy prey.  It’s quite unusual to see a harrier even attempt to catch a songbird or anything else for that matter.    Harrier hunting voles near the Great Salt Lake   However the easy life takes a major turn for the worse during unusually harsh winters with intense cold and deep snow packs.  During these times the voles spend most of their time underground eating roots and dried vegetation which means the primary source of food for harriers is suddenly unavailable just when they most need nourishment for warmth.  And since most songbirds (their fall-back food source) have either migrated south or have already succumbed to the many American Kestrels in the region, simple survival for the harriers is suddenly very precarious.  Now, out of desperation,  harriers begin to go for larger prey – ducks and coots for example.     Harrier on a duck kill frozen into the ice They aren’t able to take these prey often and when they do they can’t eat them quickly like they can a vole.  The result is intense aggression – fighting fiercely over food.  Typically I see very little true aggression(other than territorial squabbles) between harriers but all that changes when food becomes scarce.  A relatively large prey item will provide multiple…

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American Avocet Feeding on Fish

  I’ve spent many, many hours watching and photographing feeding avocets and have never once seen one eat a fish or even attempt to catch one that I was aware of.  Until yesterday.   American Avocet feeding on fish at Bear River MBR   While at Bear River Migratory Bird Refuge I photographed this avocet catching, manipulating and finally swallowing a fish.  I know that this behavior is not unheard of as Birds of North America Online (BNA) states that this species sometimes eats fish and my friend Dave Sparks once posted an avocet with a fish on an online critique forum.  However, for me it was something new and unique and worthy of a post here.  Ron 

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Loggerhead Shrike Impaling Prey, revisited

  Recently on this blog I posted images of a juvenile Loggerhead Shrike impaling a dragonfly on thorns and said I hoped to get more documentation of the behavior but it would likely have to wait until next years nesting season.  I was wrong.  I witnessed and photographed this behavior again just three days ago.  This time the shrike was also a juvenile but the prey was a large spider.    Juvenile shrike with spider What happened after the capture was interesting for me.  The bird didn’t simply impale the prey and leave it (as a cache or food store)  as might be expected of an adult.  Instead, it attempted to impale the spider on different thorns multiple times, like it was practicing – learning how to do it (keep in mind, the bird is a juvenile).  In fact, at one point the shrike even seemed to be “studying” its work, as you will see (I’m sure that’s anthropomorphic of me).  Sometimes they don’t actually impale the prey, instead they wedge it into crevices or between forked branches/twigs.  This shrike tried to do both with the spider.  After what I believe was four attempts at impaling/wedging the spider on some thorny branches someone had placed in a campground fire pit, the bird had apparently had enough practice and simply ate the prey in several pieces.   Some of the  images below aren’t of the best quality but I think they do document what I saw.  As far as I could tell, the spider was dead through this whole process.    Attempting to impale…

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American Kestrels Rejecting Intestinal Tract of Prey

  Several times I have photographed American Kestrels discarding the intestinal tract of their prey.  The prey has always been a vole or mouse when I’ve seen it happen, though it may occur with small birds also.  I was surprised by this behavior.  Every time I’ve seen it happen has been during our harsh winters when I would assume every last morsel of food would be significant for their survival. Below is a series of photos where a female American Kestrel demonstrates the behavior with a vole kill. Female kestrel begins to pull small intestine out of a vole And deliberately drops it      The cecum? is discarded:  the intestine is still attached to the body and hanging down the side of the post   She pulls more intestine out of the vole   Breaks it loose from the body      And deliberately drops it to the ground   Finally, she pulls out the last of the small intestine, which she also dropped I know of others who have seen similar behaviors in other raptors – a variety of hawks and Osprey.  Several theories to explain it have been mentioned by bird photographers and others who have seen my photographs.  Among them: “These organs are filled with potentially harmful bacteria”.  Then how are many raptors, owls for example, able to consume their prey whole without harmful effect? “These organs are filled with food of low value to the kestrel (vegetative matter). Why fill up on carbs when it’s protein you need?  Begs  the question – Would they also discard intestines of insectivorous birds?  I don’t know……

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The Short-eared Owls of Red Rock Lakes National Wildlife Refuge

  Male Short-eared Owl with a vole for the family  Red Rock Lakes NWR is simply a wonderful spot on this ol’ earth.  Located in SW Montana about halfway between Yellowstone National Park on the East and Interstate 15 on the west, it lies in a beautiful high elevation valley and the setting is stunning.  It’s not for the faint of heart though as the weather holds many potentially nasty surprises and the access to the refuge is primitive at best.  But that’s one of the things I love about Red Rock.    In late June we had the place mostly to ourselves, which is ideal for me.    Coyotes howling, other  mammals  in abundance, birds plentiful, wildflowers galore, spectacular mountain scenery, amazing sunrises and sunsets, weather surprises, bad roads to limit visitation, isolation and especially those incredible Short-eared Owls.   I love this place!    Female at the nest with one of two youngsters  On our second day there we found a pair of nesting Short-eared Owls with two youngsters.  The nest was at the base of a sagebrush within a few feet of a road.  I have a (very unscientific) theory as to why these birds would make their nest so close to a road with regular traffic.   Coyotes are very common on the refuge – we heard them howling often and would see them but they were seldom close to any road.   They seem to avoid roads whenever possible.   A nest on the ground would be very vulnerable to coyote predation.  So I wonder if the choice to build…

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Loggerhead Shrikes Impaling Prey

  Shrikes have been called “butcher birds” for their habit of impaling their prey (insects, small rodents, reptiles or birds) on thorns, barbed wire or other sharp projections.   They do it for several reasons.  It helps them to tear  the flesh into bite sized pieces, they use it as a method of caching (storing) their food and it helps them to survive eating the toxic lubber grasshopper because the toxins within the insect degrade to harmless substances within a couple of days.   I had never seen or photographed this behavior, or evidence of it,  until this summer when I did both several times.                         In the first  three photos below, this juvenile Loggerhead Shrike is practicing this instinctive behavior but the bird apparently isn’t very skilled at it yet as it had some difficulty impaling the dragonfly on the short thorn just below the insect.  In the first image the bird seems to be trying to decide which of several thorns to use for this grisly task.    Preparing to impale the dragonfly      Impaling the dragonfly on a thorn        The dragonfly has been impaled, though a little off-center.   In this case the bird didn’t wait long to begin eating the prey.  Here it has torn off the head and the front part of the abdomen with one pair of wings attached and is swallowing them.  As you can see, the rest of the insect is still impaled on the thorn.   Soon after this shot was taken the shrike removed the rest of the dragonfly from the thorn, flew with…

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