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Archive for the ‘Raptors’ Category

Last week, on my birthday, I went out to bird along the Clarksberg Branchline Trail in West Sacramento, Ca. I was out on the trail at 6:30 just before dawn and wandered around for about an hour. The section of the trail that I was birding is really close to my condo and as such is a spot that I bird pretty frequently. This morning was one of those mornings that reminded me of why it so special, and important, to get out to places close to where you live and see what is happening in the world.

It was a great morning of birding. I saw a Red-breasted Sapsucker searching for food high in a oak, found many Varied Thrushes foraging in the leaf litter for insects and worms, watched a pair of Red-shouldered Hawks as they flew screaming across an open field straight towards me to land in a tree right over my head, and found a White-throated Sparrow (an unusual winter visitor to the west coast and my favorite member of the genus Zonotrichia) hanging out with a group of Golden-crowned Sparrows! The birds were wonderful, and I was right around the corner from my house, and only there for an hour! You do not need to work hard for great birding.

These small, local birding explorations are not grand adventures. They are not exhilarating chases to see some incredibly rare species. They do not generally produce stupendously high species totals. But what they are is the bread and butter of birding experiences. They keep us in touch with the movements and pulses of the natural world right around where we live. Pulses that can go unnoticed all too easily in our modern busy lives. These local explorations give us the one-the-ground knowledge of what creatures are living next door, of how the environment changes from season to season and year to year, of exactly where a given bird can be found and what they like in a habitat. This is not knowledge that can be obtained easily, and it is knowledge that can be of great import. So get out to visit the local spots that are close to you and keep an eye on what is going on. you never know what you are going to find!

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I was walking along the edge of a plowed field along the Clarksberg Branchline Trail in West Sacramento a couple of days ago when I saw a hatch year Northern Harrier quartering back and forth, low over the ploughed earth. The raptor was not very far from the edge where I stood, so I was able to get a really great view as I watched it coursing along and staring at the ground intently as it hunted for its breakfast. Suddenly, it made a sharp turn, almost flipping over itself, and dove for the ground. It landed on something and after a moment standing on the ground, it took off. As it did so, I saw a small, brown object in its talons. I assumed at first that it was a small mammal, and that the Harrier had made a successful hunt, but when the bird was about 20 feet off the ground, it dropped the brown object. As the thing dropped back to the earth, I was able to see that it was not an animal at all, but was actually a clod of dirt.

What had happened here? Did the Harrier make a mistake and attack a mouse-shaped bit of dirt thinking that it was, in fact, the makings of a meal? Given how amazingly keen the eyesight that raptors possess this seems unlikely. And it seems especially unlikely given that the bird was only about 20 or 30 feet off the ground when it started the dive. Making that big a mistake at that close a range is hard to believe. So what was the hawk doing? Was it practicing? This was a young Harrier. Perhaps, not seeing any actual voles or mice at that moment, it decided to do a little target practice. I don’t think of raptors needing practice, but of course that is probably kind of silly. Young songbirds need to practice their song, and often sound amusingly bad at first. However, of the course of a few weeks, they practice and hone their vocal abilities and end up producing songs that sound like the other adults of the species. So, raptors practicing their hunting skills seems pretty understandable. The amount of skill required to be a predator is rather impressive, and even when you consider that many of these skills are hard-wired instinct, that still leaves a lot of room for learning and improvement: practice. Here was a raptor that, perhaps, just picked a particular earth clod on the ground and wanted to see if it could hit it at high speed, just to see if it could. It did, so that practice run was successful! Practice does make perfect!

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HMANA Press release – October 14, 2014

Over One Million Migrating Hawks Counted during International Hawk Migration Week

Hancock, NH – The Hawk Migration Association of North America (HMANA) celebrated its first annual International Hawk Migration Week (IHMW) September 20-28, 2014 by tallying over 1.2 million migrating hawks, eagles and vultures at 100 sites throughout Canada, the United States, and Mexico.

Each year hundreds of thousands of hawks, eagles and vultures make their journey from Canada and the United States through Mexico to wintering areas as far as South America. Dedicated counters at hawk watch sites document this movement starting as early as 1 August and continuing daily into December. Their daily numbers are reported to HMANA’s online database, HawkCount.org. This particular week in late September was chosen due to the sheer number of hawks that are counted across North America.

One hundred watch sites from 33 states and provinces across the continent counted an astounding 1,203,067 raptors during September 20-28. Twenty-nine species were tallied, the vast majority being broad-winged hawks (1,125,597) – since IHMW took place during their peak migration. Other high counts included 24,899 Sharp-shinned Hawks, 8,909 Mississippi Kites, 8,724 Turkey Vultures and 7,192 American Kestrels.

Raptors tend to follow topographic features during fall migration such as north to south running ridgelines, coastlines, and river valleys. As they move further south, there’s a funneling effect as they approach the southern US. The majority of hawks choose to avoid long water crossings so are then squeezed along the coast of the Gulf of Mexico and on through Mexico. This is why the Veracruz, Mexico watch sites counted more than any other at 812,949 during IHMW. Corpus Christi, Texas located on the US Gulf coast tallied 226,224 raptors. Other counts across the continent included 15,862 at Hawk Ridge Bird Observatory, MN; 4,151 Holiday Beach Conservation Area, ON; 4,811 at the Goshute Mountains, NM and 2,777 at the Florida Keys Hawk Watch, FL.

In addition to submitting their daily migration counts to HMANA’s HawkCount.org database, sites celebrated across the map with hawk watching festivals, identification workshops and live bird of prey events. Dr. Laurie Goodrich of Hawk Mountain Sanctuary, Kempton, PA (the oldest hawk watch site in the western hemisphere) said: “IHMW is a fantastic demonstration of the popularity of hawk watching and the value of raptors in the environment.”

About HMANA

HMANA (www.hmana.org) is a non-profit organization with a mission to advance scientific knowledge and promote conservation of raptor populations through the study, enjoyment, and appreciation of raptor migration. It oversees the online database, Hawkcount.org, an archive of count data with a wealth of information for birdwatchers and general public alike, including maps and directions to sites, average counts, population status and migration timing by species.
HMANA partners with Hawk Mountain Sanctuary PA (www.hawkmountain.org), Hawk Watch International (based in Utah: http://www.hawkwatch.org), and Bird Studies Canada (in Ontario: http://www.bsc-eoc.org) in the Raptor Population Index program, which aims to track changes in hawk populations for conservation purposes.
For directions and contact information for hawk watch sites near you, visit http://www.hawkcount.org.

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On the morning of the 19th, I was out birding in the early morning along the Clarksberg Branchline Trail in West Sacramento. I was poking around the section of trail just north of Lake Washington Blvd. from about 6:20am to 7:30am. It was one of those morning where I decided to not worry about covering a lot of ground. Instead, I wanted to take my time, relax, and covered the ground thoroughly really investigating each bird I heard or saw and taking my time to enjoy it. I was rewarded by some lovely views and fun finds. My species list is at the end.

Right as I started my walk, I saw a long, slim animal run out from the edge of the blackberry tangle along the trail ahead of me. It stopped out in the open for a short moment and then continued on towards the large pond just east of the trail. To my surprise, I realized that it was a Mink! I have seen River Otters at this location before, but never a Mink. What was it doing here? As I scanned the pond, there were no birds swimming in the water except three domestic ducks that were probably dumped here to become feral. As I stood by the water’s edge, I head several birds in one of the willows that grow right on the bank. I walked that way, and found a Marsh Wren singing in the cattails and my first White-crowned Sparrow of the fall for West Sacramento! It was a really good looking  adult bird that was sitting in, and calling from, that willow. Soon the Central Valley will be covered in millions of White-crowned Sparrows back from their breeding grounds in Canada and Alaska to spend a comparatively warm winter in lovely California.

As the sun rose, beautifully tinged blood red by the smoke from the King Fire that is burning just east of Sacramento, I stumbled my way into a mixed insectivore flock. At this time of year, with migrants and vagrants wandering all over the country, mixed insectivore flocks are always worth spending some time with. Often, many birds will come together to forage, and this can attract individuals of species that you might not get to see otherwise. In this case, the bulk of the birds were Bushtits, maybe 25 of them, which were streaming from oak tree to oak tree giving their high pitched contact calls as they told each other where they were. As I watched these tinny birds, I started to notice the other species in the flock. A Western Scrub-Jay, a coupe of Northern Mockingbirds, and a lovely pair of Black-throated Gray Warblers which came low in some small trees and afforded me some great looks! The day ended with a total of 5 of these warblers which is a lot compared to what I am used to seeing in winter, which is just one or two.

After I left the mixed flock, I walked out into an open field that had been mowed and tilled. As I walked along the line of tree that marks the edge of this field I was treated to a fast triple-raptor encounter. First, a Swainson’s Hawk took off from one of the tree tops and doove down into the field. It pulled up before landing, apparently the prey animal it had seen got under cover in time to avoid becoming breakfast for the hawk, and returned to its perch. right after that a Red-tailed Hawk came barreling of the line of trees and cruised over the field and away. As I was watching the Red-tail, a Red-shouldered Hawk started calling behind me. It was circling at about tree top level and proclaiming dominion over this patch of ground. The Red-shouldered Hawk is a resident bird that I see almost every time I bird this area. The Swainson’s Hawk breeds nearby somewhere, but then leaves, with the rest of it’s species members, to head south in winter which is something that will be happening soon. The Red-tail could go either way in that it could be a resident or a migrant just here for the summer. How these different hawks interact and adjust to one another is a question that has long interested me. Take the Red-shoulder, for instance. It has a territory that it defends year-round. Suddenly, in mid-March this Swainson’s Hawk shows up trying to find a place to settle and nest. How does the Red-shoulder respond? Does it simply move out of the larger hawks way? Do the birds compete and adjust their territory boundaries to one another? Do these birds eat different enough foods that they don’t really care about each other? And then, how does the Red-tailed Hawk fit into all this? How resident birds adjust to the comings and goings of migrants is not something that has gotten a lot of attention and I think could make for a really cool research project.

Looking at the open field with the naked eye, I did not see anything out there, but just on a whim I decided to give it a scan with my binoculars. As I looked slowly across the field I saw no less than 15 Killdeer scattered about foraging. So much an empty field! It reminded me that a lot can be hiding and go unnoticed when only a cursory inspection is done.

This was a really nice morning birding. I saw some beautiful birds that got me thinking about interesting ideas and taught me a thing or two all at the same time.

Double-crested Cormorant (1)

Turkey Vulture (1)

Canada Goose (12)

Red-shouldered Hawk (1)

Red-tailed Hawk (1)

Swainson’s Hawk (1)

Killdeer (15)

Western Gull (3)

Rock Pigeon (70)

Mourning Dove (20)

Anna’s Hummingbird (3)

Belted Kingfisher (1)

Nuttall’s Woodpecker (4)

Black Phoebe (3)

Western Scrub-Jay (11)

American Crow (12)

Oak Titmouse (4)

Bushtit (25)

Bewick’s Wren (3)

Marsh Wren (1)

Blue-gray Gnatcatcher (1)

American Robin (5)

Northern Mockingbird (2)

European Starling (30)

Cedar Waxwing (8)

Orange-crowned Warbler (5)

Black-throated Gray Warbler (5)

Spotted Towhee (2)

California Towhee (1)

White-crowned Sparrow (1)

Red-winged Blackbird (30)

Mink (1)

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You are walking down a trail in a city park right here in the city of Berkeley. As it winds its way between huge boulders and beneath overhanging bushes, your attention is drawn up into a nearby tree by the sound of scratching. There, a squirrel is scrabbling up the trunk of a tree. As it ascends you notice a thick mat of sticks higher in the tree, way up near the tree’s crown. Is it the squirrel’s nest? The squirrel climbs higher, and then moves beneath the lower edge of the stick platform and then up around the side. As the squirrel begins to get on top of the mass of sticks, it is met with the oncoming rush of the beak and talons of a female Cooper’s Hawk. The mass of sticks is not squirrel’s home, it is the Hawk’s. The squirrel is in full retreat now, and the Cooper’s Hawk in full pursuit. The squirrel begins racing in the direction in which it can go the fastest, strait down the tree trunk. The Cooper’s Hawk immediately drops after it, skimming strait down along the bark of the tree. As the hawk gains, the squirrel jumps, letting go of the tree completely and free-falling into the bushes below. It is only then that the hawk gives up the chase and returns to her nest.

What you just witnessed was the defense of one of about a dozen Cooper’s Hawk nests in Berkeley and Albany. Cooper’s Hawks in Berkeley? That’s right. These roughly crow-sized predatory birds get along quite well with humans and the cities humans live in. They eat birds and small mammals which they often capture by ambushing their prey in dense vegetation and then chasing it down in a burst of speed. They are superbly adapted to this style of hunting with short rounded wings which give the speed while not getting hung up on foliage and a long tail which acts and a rudder allowing them to turn and twist through thick undergrowth and not lose their prey.

The ability to live well with humans is unusual for a predator. Most birds of prey are too sensitive to disturbance to live in such close contact with humans or need larger areas of open spaces in which to hunt than are available within such a human-dominated landscape as downtown Berkeley, but Cooper’s Hawks find a way. They are so tolerant in fact, that in Berkeley and Albany, more Cooper’s Hawk nests can be found per square mile than in any other recorded area in North America. They nest in mature trees in almost any kind of habitat from quiet city parks to busy city intersections. And Berkeley in not alone in being an urban area that has nesting Cooper’s Hawks. In California, most urban areas have populations. Outside of the state, populations that have been studied in some detail include urban areas of Arizona, Illinois, and Vancouver, Canada.

Beginning about 15 years ago, a group of dedicated volunteers have been keeping tabs each year on the levels of Cooper’s Hawk activity in Berkeley. The group, the Cooper’s Hawk Intensive Nest Survey (CHINS), has divided the 10.4 square miles of Berkeley into smaller units. Each volunteer takes responsibility for one of these units, and searches it to locate and track the presents of Cooper’s Hawks. Searching begins in late January when the hawks first arrive in the area back from their wintering grounds, and continue all through the breeding season until the adults and a new generation of young Cooper’s Hawks depart to return south in August. In between, many observations are made and recorded such as when the hawks arrive, when nest building begins and ends, how many young hatch and when, how many young fledge and when, what they are eating and how much, and finally when the adults and young disperse.

Some the information that CHINS has found is that while Cooper’s Hawks nest in greater density in Berkeley than elsewhere.Also, they are eating a lower number of species then in more rural areas, and of these fewer species a large portion (~33%) are Rock Pigeon, European Starling, and other species that are not native to California. On this limited diet, the hawks are able to breed just fine with most nests fledging 3-4 young each year.

The CHINS project is a branch of the Golden Gate Raptor Observatory, and both are examples of scientific studies made possible by volunteers from the community working to monitor and record raptor populations. Cooper’s Hawks, and birds of prey as a whole, can function as indicators of ecosystem health and stability. This makes them especially important and useful to study, and the fact that individuals from the community are able and willing act as citizen scientists and devote their time and energies to such an endeavor show both that such work can be done and that there is interest and support that such work be done.

To find out more about the CHINS Contact Allen Fish at (415) 331-0730 and find out how you can help protect your raptorial neighbors.

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On our way up into the Sierra foothills for a few days my wife and I got to see something amazing! We were driving along a beautiful curving stretch of forested road when we saw movement off to our right. Up off the side of the road, two Turkey Vultures took flight. There was a deer carcass in the ditch that they had both been feeding on until they were disturbed by our passing car. One of the Turkey Vultures flew away from the road farther into the trees. The other decided to fly across the road, directly in front of our car! This startled us, and apparently did worse to the bird, because this is when the amazing thing happened. The Turkey Vulture threw up!

This is a behavior that many New World Vultures do, and may have several functions. One is called defensive vomiting and is used in predator deterrence. If a vulture feels threatened by a predator it may vomit onto the predator, coating it with smelly, partially digested carrion. I can imagine that being a very unpleasant experience, and wanting to leave as quickly as possible, and apparently many predators agree. A competing hypothesis is that the vultures vomit is a decoy. They give the predator something that it may want to eat, the vulture’s partially digested food, and while the predator is busy with that the vulture gets away. I have not found a lot of support for this hypothesis, but it is out there and has not been well investigated. A third reason that vultures vomit is to become lighter. Vultures are somewhat boom-and-bust feeders in that they cannot count on finding a carcass every day. This means that when they do find one, they eat a lot so that they have energy to see them through until the next carcass find. The down side of eating a lot of meat is that it is heavy which makes a fast take-off rather difficult. If a full vulture is startled, and needs to get off the ground and up into the air and out of reach quickly, one fast way to lighten the load is to empty their stomach! This is exactly what I think the vulture we saw was doing. On suddenly finding itself in front of our oncoming car, and wanting to gain altitude as fast as it could, it threw up the deer meat it had just eaten, and thereby made itself lighter. Actually quite ingenious!

What made me especially excited about this whole thing was that I had never actually seen this behavior before! I had read about it and heard other people talk about, but I had never witnessed it myself! I felt so lucky. It was one of the high points of my day!

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My wife, young daughter, and I just got back from a road trip up to Seattle, WA with a stop in Ashland, OR on the way back. As we drove and drove, we had the good fortune to see eagles on a number of occasions and they were especially spectacular in the behaviors we got to witness.

Our first eagle encounter was just as we drove past Ashland, OR on our way north. My wife spotted two birds that seemed to be struggling, mid-air. They were two Golden Eagles, and as we watched they opened their wings and began to spiral downwards, feet locked together in a talon grapple! The drop was spectacular as they spun around each other and plummeted towards the earth. As we drove closer, they came to the end of the fall and let go of each other. Both huge, adult birds then flew right over our car.

After our visit in Seattle, we decided to hit the road quite early. This meant that I was driving south on I-5 as dawn was spreading her rose-red fingers across the sky. As the day brightened in central western Washington, I got to watch several Bald Eagles fishing in the various waterways we passed over. It was a truly beautiful sight with the morning light just touching the tree tops and these large, dark birds circling over the sky-reflecting water and dropping low to strafe the surface for fish.

Our final eagle encounter was back in the Ashland area. We took a side trip out to the little town of Jacksonville and on our way back stopped at a gas station. As we waited by the pump, a Golden Eagle started circling overhead. It was a very nice look, as the bird was not too high and there were no trees blocking our view. The sight got even better when the eagle climbed in altitude and then began a series of dramatic pendulum flights! Pendulum flights are where the bird flies in a number of roller-coaster-like arching dives, one right after another. At the top of each arch, the eagle would close its wings and dive, picking up speed. At the bottom of the dive, it opened its wings and used its momentum to coast up to the top of the next dive. A wonderful show, indeed!

So, for eagle watching, I would highly recommend the I-5 corridor! We certainly had a great trip!

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