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Archive for December, 2012

Yesterday I, my wife, and our ten-day-old daughter went out to bird the area south of Davis, CA. as part of the Winter Raptor Survey that has been started by the Hawk Migration Association of North America (HMANA).  I am on the HMANA board of directors and have been helping to organize this winter raptor survey.  We are hoping it will grow into a nation-wide monitoring system of the raptors that spend the winter months anywhere in North America.  To run a survey route all that is need is a bit of local raptor knowledge and four days a year.  Each volunteer sets up their own route in an area, and then drives that route one day in November, one day in December, one day in January, and one day in February.  After driving the route (which should be between 30 and 100 miles long), and identifying all the raptors seen, the results are entered into an online database and compiled.  Repeatedly surveying the same route several times each winter gives a better measurement of how many individuals and species are using a particular area, and will result in a more accurate overall population estimate.

The route that I am running was established by a former graduate student in the Avian Sciences Graduate Group at U.C. Davis that he used for his masters research (he established many routes throughout California, so if anyone wants to run an established route, contact me).  This route works its way through an area land that is used for crops, orchards, and cattle and sheep range land.  It is about 40 miles long and took us about 4 hours to run (12 to 4). The day was a bright and sunny one with no clouds and a cold wind out of the northwest.

It was a wonderful day of birding, and my daughter’s first birding outing!  She slept in her car seat the whole time except when we stopped to feed her and change her diaper.   In total, we saw 96 raptors of 10 species.  The species were Turkey Vulture, White-tailed Kite, Northern Harrier, Cooper’s Hawk, Red-tailed Hawk, Ferruginous Hawk (a beautifully marked adult), American Kestrel, Merlin, Peregrine Falcon, and Prairie Falcon.

Other birds we saw included Loggerhead Shrike, Savannah Sparrow, White-crowned Sparrow, Golden-crowned Sparrow, American Pipit, Least Sandpiper, Killdeer, Cattle Egret, Great Egret, Great Blue Heron, American Crow, Common Raven, Mallard, Brewer’s Blackbird, Red-winged Blackbird, Double-crested Cormorant, and European Starling.

I am already looking forward to January’s survey!

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My first memory of Rich Stallcup is actually not a bird memory at all, but rather a frog memory.  I was probably about ten years old when my mother, brother and I joined him on a bird walk.  But the very first thing he stopped to show the group were several Bullfrogs.  He got his scope on them and let us watch them breath.  He told us about how they were an invasive species and voracious predators that were eating the tadpoles and larva of other animals and so driving down their populations.  My second memory of Rich is a bird memory.  We went on a bird walk to Limantour Beach that Rich was leading that focused on gull identification.  I remember standing looking at a large flock of gulls and listening to him point out the subtle differences between different species, and the even more subtle differences between different aged birds of the same species.  I remember being amazed at the level of detail that he could notice and even more amazed by the concept that there was so much more detail out there to be noticed then I had ever realized before.

These memories, and so many more, point out what I feel were some of Rich’s greatest qualities.  He was a naturalist in the truest sense of the word.  He was the best birder I have ever known with an encyclopedic knowledge of birds, but he also knew tremendous amounts about mammals, reptiles, butterflies, and dragonflies.  He even kept a wildflower life list.  In an age of ever increasing specialization on smaller and smaller scales of knowledge, Rich went the other way and proved that a person does not have to choose between being a jack of all trades or a master of just one, but instead could master quite a few.  It is a lesson that I have tried to learn and an ideal that I continue to strive for.  And his attention to detail was incredible.  While standing watching a group of Bushtits work their way through a willow stand, he finally decided that he was not missing any other birds in the flock when he started recognizing individual Bushtits in the flock!

Of course, Rich’s professional accolades are many.  One of the prominent discoverers of the amazing natural history of Point Reyes and the fact that the outer point acts as a tremendous vagrant trap attracting unusual birds from across the continent when they are disoriented by a predator attack or a storm.  The outer point now also attracts birders from around the world.  Rich was also one of the founders of the Point Reyes Bird Observatory, an organization that is now one of the foremost international conservation NGOs.  He has written books, papers, and articles; and also led countless bird walks and pelagic birding trips, all with the aim of introducing people to nature.

I had the good fortune to be able to bird with Rich for many years.  When he and Ellen Blustein started the PRBO Youth Bird-a-thon Team in 1999, the four founding youth members were myself, my brother,and two of my best friends.  I have continued to participate in that event ever since.  Even after I got old enough that I could not count as a youth anymore, Rich seemed happy to have me stay on as a mentor to the incoming generations of youths.  When he learned that I was expecting my first child he told me that, as long as the kid was more than two days old, I should bring him or her on the Point Reyes Christmas Bird Count!  I was very happy that he was able to meet my wife a couple of times, and saddened that my child will never get the chance.

Rich Stallcup died on the 15th of December, 2012 of Leukemia.  His loved ones were at this side.  He was a naturalist who inspired me and many others with his knowledge, passion and generosity, and he will be greatly missed.

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Yesterday morning I went birding along the Clarksburg Branch Line Trail.  I started where the trail crosses Linden Rd. and walked south from there to where the trail crosses Davis Rd. and then back again.  It was a cold morning with only a small amount of cloud cover.  The whole walk started at 7:00am and ended around 8:20am.

Species seen included: Canada Goose, Common Goldeneye, Mallard, White-crowned Sparrow, Golden-crowned Sparrow, Song Sparrow, Lincoln’s Sparrow, Fox Sparrow, Western Scrub Jay, American Crow, Marsh Wren, California Towhee, Spotted Towhee, Yellow-rumped Warbler, Ruby-crowned Kinglet, Bushtit, Turkey Vulture, White-tailed Kite, Red-shouldered Hawk, Red-tailed Hawk, Ferruginous Hawk, Brewer’s Blackbird, Great-tailed Grackle, European Starling, Great Egret, Dark-eyed Junco, Black Phoebe, Anna’s Hummingbird, Northern Mockingbird, Yellow-billed Magpie, Mourning Dove, Rock Pigeon, Herring Gull, Northern Flicker, House Finch, and Nuttall’s Woodpecker.

The Ferruginous Hawk was my first of the winter.  It was a beautiful adult that was perched in a tree above the trail and watched me as I walked up the trail almost directly under it before it decided to fly off.  Even then it circled around me and gave some fantastic views.  really great bird!

The Great-tailed Grackle was a surprise.  They are getting more and more common in the California central in summer, but I have not seen one in winter before.  They have been expanding their range north across the continent, so this may become a more common sight in the coming years.

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This month marks the end of my first year serving on the board of directors of The Hawk Migration Association of North America (HMANA).  HMANA is an organization that is serving as a central clearing house of raptor migration data across the continent.  Member sites upload the count data they have collected, and HMANA sorts it and makes it open and searchable to anyone who is interested.  HMANA also analyses and presents much of the data it collects in their journal, Raptor Migration Studies.  Other than migration counts, HMANA has also been working on a project called the Raptor Population Index which is attempting to track the population status of all of North America’s raptor species.  Yet another HMANA project, and one that I have been helping with a fair bit, is the Winter Raptor Survey.  What we want to set up is a network of survey routes that are run each year and that will allow us to monitor the wintering population of birds of prey in North America.

Winter marks a poorly studied part of the annual cycle in the lives of birds of prey.  Where raptors spend the winter, how many there are, and what they are doing are all questions that have, at best, only general answers.  The studies that have been done have given some very interesting and important results.  In Argentina in the mid-1990s, there were reports large numbers of  Swainson’s Hawks being found dead at their communal roost sties.  In 1995 and 1996 some 6,000 Swainson’s Hawks were found dead at such roosts.  The cause was determined to acute pesticide toxicity.  Since Swainson’s Hawks feed largely on insects during the winter, they were being poisoned when they eat insects that had been sprayed with highly toxic chemicals, or were being sprayed directly when they were perched on the ground in crop fields being sprayed.  Specifically, an organophosphate called monocrotophos proved to be especially deadly to raptors.  This chemical had already been banned in the USA, and the deaths of the an estimated 20,000 Swainson’s Hawks led to the banning of this chemical in Argentina in 1999.  A different study on the winter ecology of raptors that was conducted here in central California found that male and female American Kestrels use different habitats to hunt.  Females generally use the more productive open grassy territories, while males are generally relegated (probably due to their smaller size) to less productive mixed shrub habitats.  Such habitat partitioning is vital to know if conservation is gong to be effective.  If a declining species displayed a similar habitat partitioning, and only one habitat type were known and conserved, the population would still decline.

So, how is the HMANA Winter Raptor Survey hoping to monitor the winter populations of birds of prey in North American?  The goal is to establish survey routes that are run once a month for the four months (November, December, January, and February).  This span of time covers the ‘winter’ months of most raptor species.  Along the routes, which are between 30 and 100 miles long, the habitat is described according to one of the categories we have established and the position and identification of all raptor species seen along the route are recorded.  This survey data is then uploaded to the WRS website.  This data can then be used to track habitat use, landscape and habitat change, raptor numbers and densities, and the interactions between any and all of the above.  So, to all the raptor-philes out there, we need your help!  Now that the fall migration is over, please lend a hand in monitoring raptors in the winter.  Set up a route!

HMANA is largely volunteer run.  Check out the HMANA webpage at http://www.hmana.org/ for general HMANA information and news, and the HMANA WRS webpage at http://wrs.hmana.org for specific details on how to set up and run routes.  While you are at these websites become a member of HMANA!  It is a great organization that is showing what citizen scientists can do on continent-wide scale.

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This is a sad follow-up to my post of 2-Oct-2012 “Why the World Needs Wolves.”  This fall was the first time wolf hunting was allowed in the state of Wyoming.  Among the dead, was 832F, the alpha female of the Lamar Canyon Pack (and possibly the most famous wolf in the world).

 

Grey Wolf - 832F

A lovely photo of 832F by TreeHugger.

 

Here is a more complete article from the New York Times.

http://www.nytimes.com/2012/12/09/science/earth/famous-wolf-is-killed-outside-yellowstone.html?partner=socialflow&smid=tw-nytnational&_r=1&

 

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The Broad-winged Hawk (Buteo platypterus) is one of North America’s smaller Buteos being about two thirds the size of a Red-tailed Hawk.  It is common and wide spread in the eastern half North America with an estimated breeding population of at least 1.7 million individuals.  It breeds throughout deciduous and mixed conifer-deciduous forests and hunts mostly small mammals and reptiles, but also includes the occasional bird, amphibian, or even more occasional insect.  Breeding densities have been estimated to range from 1 pair every 2 to 5 square kilometers.  However, breeding bird surveys appear to be inadequate at detecting Broad-winged Hawks do to how secretive they are when on their nesting territory.  Migration has proved to be a better point in their annual cycle to monitor population levels.

Along with the Swainson’s Hawk (Buteo swainsoni), the Broad-winged Hawk is one of the raptor species that migrates the longest distances between its breeding grounds and non-breeding grounds which stretch from Mexico to Brazil.  As might be expected from the combination of how common they are and this long migration distance, this species is a very common member of fall hawkwatch counts in the eastern USA and in Central America.  Numbers in the 10s of thousands are not unusual at many sites (such as Hawk Mountain PA) and several sites have counts of 100s of thousands (such as Corpus Cristi, TX) and even over 1 million (such as Vera Cruz, MX).  It is unusual for a raptor in that groups of these birds migrate in flocks frequently forming large kettles that fill the sky as they move south.  But these are all eastern sites.  Do Broad-winged Hawk occur in the western half of the continent?

Before the 1980s the answer would have generally been no, but during the 1980s something started to change.  Sightings during migration have been increasing in many western states including Idaho, Montana, Wyoming, Colorado, New Mexico, and Arizona.  This suggests that the breeding range of the Broad-winged Hawk is extending to the west into Alberta and British Columbia.  The Golden Gate Raptor Observatory (GGRO) in California have been seeing them regularly since that fall migration was first discovered in 1972.  It remains the best place to spot a Broad-winged hawk west of the Rocky Mountains.  This year was an amazing Broad-winged year at the GGRO.  Most fall seasons see between 25 and 240 Broad-winged Hawks with numbers generally concentrated in the last half of September.  But during the 2012 season (and only through the end of November, since the count season is still ongoing) hawkwatchers have counted a record-shattering  755 Broad-winged Hawks!  This total included one day which recorded a total of 295 which is higher than the previous record season total of 248!  No one is completely sure what caused this boom of Broad-wings, but one interesting facet is that of the 755 birds seen this year, about 99% of them were hatch-year birds.  This indicates that the population of Broad-winged Hawks that breed in western Canada had a very good year this past spring and summer.

The western expansion of the Broad-winged Hawk breeding range roughly matches the westward movement of the Barred Owl (Strix varia).  It also roughly matches the eastern expansion of the Evening Grosbeak (Coccothraustes vespertinus) across the same geographic area of Canada, although the Evening Grosbeaks moved east earlier than the hawk or owl moved west.  All three of these species prosper in mixed deciduous-conifer forests, and that hints at a possible explanation.  These range expansions could be the result of increasing edge habitat that results from timber harvesting in areas of what would otherwise be wide swaths of coniferous forest.  They could also be due to the increased numbers of trees that are being planted in and around cities in the great plains of Canada and the USA as wind-breaks.  Such human-induced changes to the landscape will no doubt cause changes to the distributions of other organisms, and these three species may be examples.  More investigation into these changes in range are needed before any convincing explanation is reached.

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