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…
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
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…
Red-winged Blackbird With a Crossed Bill
This morning while out photographing birds at a local wildlife refuge I came across this Red-winged Blackbird with a strongly crossed bill, which of course is not typical of the species. I’ve seen a few mildly crossed bills in this and other species in the past but never one quite this pronounced in a species where it isn’t “normal”. Red-winged Blackbird with a crossed bill, perched on curley dock There are species of birds in North America that have crossed bills as a species trait – the Red Crossbill and the White-winged Crossbill. Their crossed bills are an adaptation for extracting seeds from cones. Seeing this RWBB with a crossed bill naturally got me thinking about evolution. Variations occur throughout nature since each individual inherits a different combination of genes from its parents. This particular variation would likely be selected against in RWBB’s and would not persist since they do not typically pry seeds from cones. However, one can see how this same variation in the ancestors of todays crossbills would be the genetic fuel for the crossed bill trait they all exhibit today. Ron
Great Horned Owls on the Farm
For perhaps twenty years now there has been at least one pair of nesting Great Horned Owls on the farm where I grew up near Cut Bank, Montana. They were never there when I was a kid but they’ve sure taken to it since. This farm still seems like home to me and I return to it at least once every year for a visit with family and of course to check up on the owls. It’s the perfect place for these birds as it’s isolated, there are many old barns and granaries for the owls to find sanctuary and mice, voles and the ubiquitous Richardson’s Ground Squirrels (gophers) are everywhere. Both the owls and I love the place! Great Horned Owl in a barn cutout Most often I prefer my birds on natural perches but there’s just something about owls and old barn wood that appeals to me. I think owls, particularly Barn Owls and Great Horned Owls, often just seem to “fit” in many rustic settings. In the image above, I like the warm tones of the bird contrasting with the cooler tones of the black background and some of the wood. Juvenile (no “horns” yet) in warm, early morning light The youngster above was sitting in an east facing cutout in an old granary just as the sun came up. The effect of the warm light on both bird and wood is fairly dramatic (no saturation added). This juvenile is wet from the dew, thus the “spikiness” on the top of the head. They look very different from the…
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……
A Bitter Lesson in Depth of Field
I have spent many hours photographing Burrowing Owls over the past two summers but it’s a real challenge to get clear shots of them as they typically stay on the ground and are usually at least partially obscured by vegetation. For me it’s a real coup to get one on an elevated, natural perch in good light. Last week I had a wonderful opportunity with them and simply blew it. As we approached our “owl spot” we noticed that there were three of them perched up high on a sagebrush in beautiful early morning light. I maneuvered my pickup for the best light angle I could get and to obtain separation of the owls from each other. Everything perfect. And all three birds gave us a variety of interesting poses for several minutes. I had noticed that the owl on the left was perhaps a foot (or slightly less) closer to us than the other two birds so I was concerned about depth of field. I seldom shoot multiple subjects and typically with only one bird I’m shooting at f/6.1 – f/8 depending on the situation. Knowing I needed more DOF here I dialed in f/13 thinking that would be plenty to get all three birds sharp. The image below is typical of the results I got. Burrowing Owl – Canon 7D, 500 f/4, 1.4 tc, 1/200, f/13, ISO 500, cropped to 77% of original image The owl on the left is noticeably soft. That is quite apparent at a larger image size, say 1200 pixels, though not quite so obvious at this…
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…
How I Photograph Birds
Tripod shooting at the Great Salt Lake wetlands Tripod shooting is certainly not my typical method of photographing birds. My best estimate is that less than 10% of my bird photography is from a tripod. When circumstances demand it however there’s simply no substitute for a sturdy but relatively lightweight tripod and a gimbal style head, especially for shooting birds in flight with my large, heavy lens. Some folks are able to hand hold this lens for hours on end and get spectacular results. I can’t, partly due to back problems. Lens Cart Because of back problems I can’t carry my heavy lens, camera body, tripod and associated gear further than about a mile. To help solve that problem I came up with this lens cart. It’s a pull-type golf cart that I modified to be able to carry my heavy 500mm lens with attached body in the pack and my tripod with Wimberly head attaches under the “tongue” of the cart. There’s room in the pack for other assorted gear and I often hang a water bottle and extra body with my 100-400mm zoom to the pack. It’s very light and pulls effortlessly. The wheels are large enough to handle fairly rough terrain. The main limitation of this outfit is that it can’t negotiate tall vegetation or narrow paths between trees. Without this cart some of my favorite birding spots would be unavailable to me. My typical method of photographing birds This is how I do most of my shooting – from…
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…