Fox Sparrows and the Species Concept: Part 1

Here at BoomCha we've begun, and hope to continue, talking about some big questions in ornithology (see Gavin Leighton's recent interesting posts on the evolution of flight).  Another major question, though not at all limited to avian biology, is how to define the idea of the species.  In my experience species definitions (and similarly definitions of higher taxa - genera, family, etc) often seem arbitrary.  The constant lumping and splitting baffles the birding bystander, yet remains unquestioned.  In many cases the same taxa are lumped and then subsequently split or vise versa!

A Fox Sparrow of the thick-billed race, probably representing the subspecies brevicauda.  I would argue (and am not alone) that the four races of Fox Sparrow represent evolutionarily independent units and should be considered distinct species.

Bird watchers and birders in general may not care - though certainly many do - all that much about why species are classified the way they are or who is making those decisions.  For the purposes of birding and bird watching alone, the American Ornithologists Union (AOU) is fairly helpful in keeping a standardized checklist of birds that everyone uses in North America.  Still, every once in a while (i.e. every time a supplement to the AOU Checklist comes out), you have to ask, why ornithologists at the AOU make the decisions they make.  Why split one taxon with multiple independent populations but not others?  Indeed the duty of sorting through the current literature, and choosing what species definitions to use is a difficult one, but it is often done in a way that seems almost arbitrary.

A short hike in February with Steve Howell (author of Gulls of the Americas, A Field Guide to the Birds of  Mexico and Northern Central America, and most recently Petrels, Albatrosses & Storm-Petrels of North America among many others) on Pine Mountain in Marin county, CA to look at three of the four Fox Sparrow races (sooty, thick-billed, and slate-colored) got me thinking about the species concept.  This trip was followed by some interesting discussions with Steve on how to define species, and some major problems with the AOU.  In part one of this series I will discuss very basically about the idea of the species, and some of the ways species (at least for birds) come about.  In later posts I will discuss some of the ways that biologists delimit species, and how these ideas pertain to Fox Sparrow races (the four probably represent separate species but have not been split).  Further, I will attempt to discuss possible ways to deal with the problem of delimiting species.  I will not, however, write an in depth criticism of how the AOU Committee on Classification and Nomenclature (CCN) should do their job (I would not be authoritative on this matter, but if you are interested Steve Howell wrote a very informative commentary on the forty-first supplement to the AOU checklist that covers some examples of inconsistent decisions made by the CCN in the past and the need to standardize a system for taxonomy).

Though there is much debate in biology on how to best delimit species, most biologists agree that a species is the smallest evolutionarily independent unit.  Speciation is the evolutionary process leading to the rise of new species - a consequence of gene flow (essentially gene flow is just interbreeding between two populations; gene flow between populations means speciation won't occur), mutation, natural selection, and genetic drift (changes in gene frequencies due to random chance alone) acting on separated populations.  The most common form, known as allopatric speciation, involves geographic isolation between two populations that then diverge as the aforementioned processes act differently on each population.  Geography, ecology, and genetics all play a major role in this process.  Despite such wide agreement on how species arise and what they are in the most basic sense, there are a lot, in fact more than 25, of species concepts out there, each with a different way of classifying species.

Speciation is the evolutionary process that results in new species.  It has happened millions if not billions of times in earth's history resulting in species of all kinds such as this Mosque Swallow in west Africa (above) and this leopard, Pantera pardus, from South Africa (below).  [Photos by Lukas Musher]

The problem lies simply in the fact that delimiting species is intrinsically complex.  That is to say, since species arise from other species and microevolution is often occurring in natural populations, the point at which speciation happens is often ambiguous.  Species concepts attempt to draw the line that defines the species, and the good ones do it consistently, systematically, and in a way that is broadly applicable, corresponding to discrete entities that exist in nature.  However, no single concept is agreed upon by all biologists, and each has it's own set of problems.

Still, to most, if not all, people the basic idea of the species is not difficult to grasp.  I would argue that for the most part what a species is, is intuitive.  We know that Northern Cardinal is not the same as a Greater Roadrunner.  They look nothing alike, they make different vocalizations, they have different habits, live in different habitats, and so on.  A little more subtly, most people could tell that a Yellow Warbler is different than a Wilson's Warbler if compared next to each other.  However, more difficult, but arguably as intuitive is deciding when cryptic species are different.  We know that Willow and Alder flycatchers are not the same.  They may look the same (almost) and have awfully similar habits, but they make different vocalizations, have different DNA, and so on.

One use of bird song is to help distinguish between other species. Prothonotary Warbler, Magee Marsh, OH [Photo by Lukas Musher]

So it isn't just an evolutionary and molecular understanding that is required to identify species, it is generally something that is easy to do.  Perhaps classification is a major part of being human.  Pre-Darwinian natural historians as well as non-western native cultures have recognized most valid species that we recognize today (most, if not all, exceptions include cryptic species).  Even species can tell species apart.  Song Sparrows, among others, have been shown to be capable of distinguishing between their own and other species.  Needless to say all birds do it on a daily basis during the breeding season (sometimes unsuccessfully in the case of hybridization) with song.

In the words of the great ecologist, Ernst Mayr, species are "natural kinds."  Ultimately, though, a species in it's most basic definition is just an entity that evolved independently of other such entities.  In order to be independent, and thus for speciation to occur, they must not breed with other such entities during the course of their evolution.  In the next part of this series I will discuss some of the major ways of delimiting species in biology.

By Luke Musher

Well - It's a Shrike...Photo Quiz 3/19/12 Solution

I think it was obvious to everyone that this bird was a shrike.  Given that it was in North America, and Nebraska at that, the only options you have are Loggerhead (LOSH) and Northern Shrike (NSHR). As a friend of mine said when he answered the quiz, "you could get the answer by flipping a coin."  All of the answers I received were well thought out, but interestingly enough, they were mostly wrong.

I saw this bird near the Platte River of Nebraska in March of 2006.  There is about a one week overlap in mid-March where both shrikes are equally likely (which is about when I saw this bird) before which NSHR is more common, and after which LOSH quickly becomes more common.  Though both are still possible throughout March and early April.

Graph showing Frequency of LOSH and NSHR in March and April in the Nebraska [ebird.org]

So, don't let the snow bias your identification.  A freak blizzard hit that week making for some interesting birding (and as you can tell, poor conditions for photography!).

Alright - so if we have equal or near equal probabilities of seeing either shrike, we need to focus closely on the field marks we see in the image.  To me, on first glance I see a dark-backed, white-throated, plain gray-breasted (i.e. no barring/scaling), large/round-headed shrike with bill that is neither very short nor very long, and neither very hooked nor very unhooked.  So far the evidence is pretty good for LOSH.  A lot of people used bill shape and size to identify this bird and got it wrong for having ignored other major field marks, and assuming that factors acting against them were due to lighting issues.  Just as the bill is intermediate, the mask becomes somewhat broad posteriorly, but doesn't necessarily rule out NSHR.  Many people actually thought the mask looked too narrow for LOSH, but even though some of the mask is blocked by a twig, to me, it doesn't look overly extensive or limited enough to decide one way or the other.  Another tweener here is the supercillium.  A white supercillium is present, but to me it is indistinct, and is more supportive of LOSH than NSHR.

Even if you thought the bill was too long and hooked for LOSH, there are other, less subjective (i.e. presence-absence) field marks to use.  NSHR usually has a pale base to the mandible of the bill (though sometimes this becomes black in spring), which LOSH will not have (although I saw a photo of a fledgling that had a pale-ish base).  Similarly, NSHR almost always (or maybe always) has gray or mixed gray and black lores and nasal tuft, whereas LOSH generally has black lores and nasal tuft (less frequently gray, but variable).  The presence of these characters connects the left and right masks around the bill.  I'd like to ID this bird by just these two field marks, but it has been pointed out to me that there is some variation in NSHR bill color and LOSH lore/nasal tuft color (as I pointed out above).  However, in my opinion there is no single field mark that obviously supports NSHR over LOSH, but there are several intermediate characters and a several that point towards LOSH.  Thus, I choose LOSH, but challenge you to prove me otherwise.  Truthfully, when I originally saw this bird, I was told it was a LOSH by another birder, and now, 6 years later had to make sure that's really what it was.

Winners:
Diana Humple
Jared Feura
Gavin Leighton
Francesca Massarotto

~Luke Musher

Photo Quiz!

 Photo taken by Lukas Musher at Platte River, NE in March 2006

Not many options here - pick one by Wednesday, March 21.  Email us at boomchachalaca@gmail.com

The solution along with the names of the winners will be posted Thursday.

~Luke

The Why of Fly - The Origin and Evolution of Flight in Birds: Part 2

To read The Why of Fly - The Origin and Evolution of Flight in Birds: Part 1 by Gavin Leighton, Click here.

How flight evolved is one of the oldest and yet most uncertain questions in avian evolutionary morphology.  Below, Gavin explains some of the prominent hypotheses that may explain the evolution of flight in the context of ecology.  White Hawk, Chan Chich, Belize [Photo by Lukas Musher]

In the first post I explored some of the requisite physiological/morphological changes necessary for flight in birds.  Importantly, these physiological changes did not arise in a vacuum, and there remain the interesting questions of what selective forces could change the body plan of birds so that flight was possible.  Since flight evolved in birds millions of years ago, one can not definitively define the specific selective pressures that contributed to bird evolution.  Despite this difficulty, we still have a set of several competing hypotheses for the selective factors promoting flight.  These factors are described below in conjunction with the evidence for each hypothesis. 

The first explanation is the oldest explanation, having been proposed in 1879 by Samuel Williston.  This first explanation for flight is the cursorial hypothesis (Figure 1).  The cursorial hypothesis posits that the bipedal ancestors of modern birds would run to catch their prey.  To facilitate catching prey that was flying away (think insects), the ancestors would leap into the air to obtain the prey.  While the cursorial hypothesis seems technically possible, the theory is not parsimonious.  First, to gain sufficient ground speed for considerable ascent the ancestors of birds would have to have been faster runners than the birds today.  Second, after liftoff, the increased drag would after liftoff would have limited the ascent.  Finally, and perhaps convincingly, we don’t see this behavior in any extant birds today, suggesting that either this explanation is erroneous, or that feathers evolved according to the cursorial hypothesis and then the behavior was subsequently lost by any and all ancestral birds. 

Figure 1: The cursorial hypothesis.  Therapod dinosaurs that could achieve short bursts of lift may have been better able to catch flighted prey (i.e. insects; dinosaurs like Archeopteryx were not much larger than an American Robin), thus giving them an advantage in survival and reproduction.  Unfortunately this hypothesis is not well-supported.

One of the major hypotheses for why flight evolved capitalizes upon observations of contemporary birds.  Since many birds spend significant time in the trees, the arboreal hypothesis of flight argues that wings evolved to help birds navigate from tree to tree.  The progression of evolution begins with individuals living primarily arboreal lifestyles (i.e. foraging in trees and spending most of the time in tree canopies).  Such a lifestyle would put selection pressure on individuals to move from tree to tree without having to return to the ground first.  These observations led to the arboreal theory.

The arboreal theory is the most strongly supported theory and also provides a plausible progression of feathers.  Specifically, the first arboreal individuals would have utilized the feathers to glide from branch to branch, instead of flapping their wings.  Indeed, research indicates that many of the early feathers would not have been able to withstand the force of a downstroke during flight (Nudds and Dyke, 2010).  Since individuals could not flap their wings to take off, one would expect that the first flight, or proto-flight, took place when birds would jump from branches to reach another branch. 

The strength of the arboreal hypothesis derives from multiple sources.  The first is that the requisite physiology necessary for flight was not present in many feathered theropod dinosaurs, and thus, self-powered flight was not possible.  Therefore, climbing a tree to achieve flight would explain how flight could be achieved without all of the pieces being in place.  Second, contemporary birds are arboreal, and inhabitat almost every vertical niche one can think of.  Third, there are many other arboreal inhabitants that have evolved the ability to glide due to their arboreal lifestyle.  For example, flying squirrels and lizards with skin flaps jump from trees and use various adaptations to glide to another branch.  And finally, the arboreal hypothesis provides an argument for the extensive feathering we see on the bodies of Microraptor and Archaeopteryx (Figure 2). 

Figure 2: Many therapod dinosuars in the avian lineage, such as this Microraptor, are known to have been covered with  feathers,  including long feathers extending from both forelimbs and hindlimbs, as well as from the tail, suggesting that early birds were gliders rather than capable of powered flight.

An explanation on the periphery is that wings were primarily helpful for young birds that would climb trees to return to nests they had fallen from.  This idea, known as assisted-incline running is argued most forcefully by Ken Dial (Dial, 2003).  Dr. Dial has studied chukars (Alectoris chukar) in the lab and notice that they will pump their wings to scale inclines in the lab (Figure 3).  The fact that there is a modern bird that uses wing-inclined running makes it more attractive than the cursorial theory that is not supported among modern birds.  In contrast, the theory suffers from fossils that are incongruent with wing-assisted incline running.  Specifically, fossils such as microraptor have feathers on both the hindlimbs and tail; and the feathers in these areas would be unnecessary if used for wing-assisted incline running.   

Figure 3: One potential explanation for how flight evolved involves using wings to help scale inclines.  Although plausable and supported empirically, it probably isn't as good of an explanation as the tree-down, or arboreal hypothesis. 

Most recently, a group from Montana State University has proposed that the evolution of feathers in theropod dinosaurs was used primarily to help stabilize the predator while it was pinning it’s prey with feet (Fowler et al., 2011).  The argument is that theropod dinosaurs, like birds of prey today, would pin their prey down using both feet.  Pinning the prey was enhanced by strong legs and large talons that are used to hold prey that are large enough that they may escape.  Importantly, once the prey has been pinned, the prey may still struggle, thus causing the theropod to lose balance – since it’s legs are being used to grasp the prey.  To help stabilize the predator, the authors argue that feathers would have evolved and wing beats could be used to stabilize the predator while it consumed the prey.  Similar to the other hypotheses, this idea is plausible; however, it still does not explain the extent of the feathers on the entire bodies of many of the earliest bird ancestors. 

Similar to the diversity of birds we see today, there is a diversity of hypotheses that have been offered to explain the evolution of flight in birds.  The four hypotheses: the cursorial, arboreal, wing-assisted inclined running, and predator stabilization, all provide potential explanations for flight.  Some of these hypotheses are even reinforcing.  For example, an arboreal lifestyle would have likely favored making nests in trees, which would have then favored individuals that fell out of nests to re-ascend into the tree.  Therefore, the non-mutually exclusive arboreal and wing-assisted incline running hypotheses could complement each other.  In total, however, the main hypothesis that is still considered the most likely is the arboreal hypothesis.  The arboreal hypothesis can explain many of the phenomena we see in extant birds, and much of the physiology in ancestral birds.  Therefore, birds arguably evolved flight to glide first, and over time gained the adaptations necessary to perform powered flight.  Thus resulting in the avifauna we see today. 

Barrow's Goldeneye, Rodeo Lagoon, Marin Headlands, CA [Photo by Lukas Musher]

By Gavin Leighton


Gavin is a PhD candidate at the University of Miami studying cooperative behavior in Sociable Weavers.  To learn more about Gavin, see our Guest Writers page.

Citations:

Dial, K. (2003). Wing-Assisted Running and the Evolution of Flight.  Science. 17: 402-404

Fowler et al. (2011) The Predatory Ecology of Deinonychus and the Origin of Flapping in Birds. PLoS ONE 6(12).

Nudds, RL., Dyke, GJ. (2010). Narrow Primary Feather Rachises in Confuciusornis and Archaeopteryx Suggest Poor Flight Ability.  Science. 14: 887-889. 

Bolinas Birding

Yesterday, Dan Lipp and I went into town in Bolinas to check the lagoon and look for a Summer Tanager seen in the morning by Ryan DiGaudio.  No Summer Tanager, but there is plenty of habitat in town for one to hang out in town, so it's out there somewhere.  Not too much of note, except a very close Pelagic Cormorant on the lagoon, and lots of large flocks up on Altura Road that have potential for a vagrant (e.g. a Summer Tanager!).  

Pelagic Cormorant, Bolinas Lagoon, Bolinas, CA

Pelagic Cormorant, Bolinas Lagoon, Bolinas, CA

Golden-crowned Sparrow, Bolinas, CA

Golden-crowned Sparrow, Bolinas, CA

Golden-crowned Sparrow, Bolinas, CA

Mourning Doves, Bolinas, CA

By Luke Musher

Photo Quiz 3/9/12 Solution

This one wasn't as tough as I thought it would be, as most people got it right.  Still, the wrong answers I got were expected misidentifications, and people I talked to told me it took them some time to figure out.  Let's take a closer look at the image above:

We know this bird is in NJ, so Hooded Warbler and first summer male Orchard Oriole come to mind because of the combination black throat and yellow body.  However, on closer inspection we can see that the tail is relatively short, too short for any oriole, and the undertail coverts and underside of the rectrices are white.  This bird is clearly a warbler, not an oriole.

A short and incomplete study of this bird would undoubtedly lead you to believe that it is an adult male Hooded Warbler.  However there is a lot that just isn't right.  The black seems limited to the throat, and does not extend up the back of the face.  Still, that could be due to over exposure/poor lighting.  I'm pretty sure Hooded Warblers have pink legs, but they don't have white undertail coverts.  This bird just doesn't seem right for Hooded.  After that, we don't have many options.  If you forget about the fact that one of the most common hybrid warblers in North America is Blue-winged x Golden-winged, then you'd easily label this as a Hooded Warbler and move on (unless you saw the whole bird!).  This bird is an adult male Lawrence's backcross Blue-winged x Golden-winged hybrid.  Take another look at this bird below (I know these photos suck!).

Winners:
Steve "No Good" Howell
Dan Lipp AKA "Curly Dan" AKA "Big Boy" AKA "Tiny Dancer" AKA "Dempsey Arceneaux"
Frenchie "Wine and Drop" Massarrotto
Mark "Mad Dog" Dettling
Ryan "The TBB Delgado" DiGaudio
Conor "The Upland Manpiper" Higgins
Jared Frickin' Feura

~Luke Musher

Recent Birds at Palo and in Alameda County

The past few days have been beautiful here in the bay area, and the birding has been pretty good around Palo and elsewhere.  Birds are getting ready to move and getting ready to breed here at Palo.  We're beginning to find our first CP's (Cloaical Protuberance - male sex organ during the breeding season), and I found the first nest about two weeks ago that is still going strong.  It was an Anna's Hummingbird with two jellybelly-sized eggs, that are now two nestlings.  Dan Lipp has been hearing Red Crossbills across the Arroyo Honda almost daily, and heard a Northern Rough-winged Swallow as we were banding up on the hill a few days ago.  Tree Swallows and the occasional Violet-green Swallow have been seen as well.  Mixed feeding flocks have been found around the area as well including larger than usual numbers of Townsend's Warblers.  Less than a week ago I came across a large mixed flock of mostly Bushtits, Chestnut-backed Chickadees, and Ruby-crowned Kinglets on the nature trail.  I didn't detect a single warbler, but hopefully something interesting will turn up one of these days.  A few Hutton's Vireos, a Red-breasted Nuthatch, and several Golden-crowned Kinglets were also in the flock.  1 or 2 Fox Sparrows, and a Hermit Thrush also may have been loosely associating with the group.  A Northern Saw-whet Owl has been heard almost nightly as well.  And, just now, an Orange-crowned Warbler was heard and then seen right outside the field station library.

Red-breasted Nuthatch, PRBO Palomarin Field Station, Bolinas, CA

Chestnut-backed Chickadee, PRBO Palomarin Field Station, Bolinas, CA

Yesterday Rich Cimino graciously offered to show me around some great birding spots in Alameda county.  We hit Del Valle Park, Mines Road, and Patterson Pass among other locations.  Some highlights from the day include Prairie Falcon, Golden Eagle, Lark Sparrow, Loggerhead Shrike, Horned Lark, Mountain Bluebird, Yellow-billed Magpie, Phainopepla, Chipping Sparrow, and large numbers of Lesser Goldfinches (though we couldn't pick out any Lawrence's Goldfinch despite our best efforts).  We missed a few target birds such as Northern Pygmy-Owl, Yellow-bellied Sapsucker, and Lawrence's Goldfinch, but who could complain with all the great birds we got.  Rich is an active conservationist in the bay area doing great work to help protect birds and their habitat.  He also knows the area really well, and owns/operates a great bird tours company, Yellowbilled Tours.  If you are looking to bird in California, definitely contact him.  He also leads tours in Nome, Wisconsin, and New Mexico with more destinations possibly to come.

Lesser Goldfinch, Mines Road, Alameda county, CA

White-crowned Sparrow, Mines Rd, Alameda, County, CA

Mountain Bluebird, Patterson Pass Wind Farm, Alameda county, CA

By Luke Musher

Photo Quiz

Taken May 2006 in Lambertville, NJ by Lukas Musher (Click to Enlarge)

Identify this bird by Monday 3/12/12.  The answer along with the winners names will be posted Tuesday.   Email us at boomchachalaca@gmail.com with your answers.

~Luke and Cory

How Climate Change might affect California Birds

As birders we are ingrained with an appreciation for the beauties of the natural world, and a fear of the impending loss of them.  Biodiversity is by no means taken for granted by birders (generally speaking of course).  This is why thousands of American birders congregate in southern Texas or Florida to see hundreds of species of birds in just a few days.  Anthropogenic climate change is a looming threat to avian diversity, and has been shown by many authors to pose risks as great as extinction for many of the world’s taxa.  Still, systems for ranking threats to species have often overlooked their vulnerability to climate change despite its widely appreciated consequences.  In an effort to quantify the vulnerability of California's birds to climate change, a recent publication by PRBO Conservation Science researchers here at the Palomarin field station (Tom Gardali, Nat Seavy, and Ryan DiGaudio) in collaboration with California Fish and Game develops a new method to evaluate the effects of climate change on birds, and pin-points species and subspecies of highest concern in California.

Coastal species such as these Wandering Tattlers or Common Murres (below) are quite vulnerable to climate change likely because rising ocean levels will alter rocky shorelines, beaches, or estuaries used by many species for foraging habitat (as with the tattlers) or nesting habitat (as with the murres).

According to the publication, California birds may be sensitive to climate change in any of the following ways: 1) habitat specialization—species with narrow habitat preferences may be more sensitive to climate change than habitat generalists; 2) physiological tolerances—species with broader physiological tolerances may be less likely to be affected by climate change because they are more resilient to extreme temperatures; 3) Migratory status—migratory species may be more sensitive to climate change because the timing of their movements critically depend on climatic conditions for survival and successful reproduction; and 4) Dispersability—species with poor dispersal ability may be more sensitive to climate change because they lack the mechanisms to rapidly habitat track.

Further, climate change poses risks to species by exposing them to any of the following conditions: 1) Changes in habitat suitability—exposure to changes in habitat structure in any of a variety of ways may pose risk if habitat suitability decreases for a given species; 2) changes in food availability—exposure to changes in the availability or abundance of food sources undoubtedly affects survival and reproductive success; and 3) changes in extreme weather—extreme weather has been shown numerous times to lead to low fecundity or even nest failure in many species.

The authors scored species on all of these seven criteria and ranked vulnerability of the top 25% of scores from most vulnerable to least vulnerable to climate change.  In doing so, they added five taxa not originally listed in the California Bird Species of Special Concern monograph (BSCC; 2008), and raised the priority of ten more.  Further, it was found that 21 of California’s 29 state or federally threatened or endangered species were susceptible to the consequences of climate change.

Some results:

Studies such as this provide a salient understanding of how anthropogenic climate change will affect natural populations, and are critical to effective conservation since threats such as climate change pose risk for extinction.  For instance, alpine species with restricted temperature tolerances would be unlikely to survive long-term global warming because habitat tracking ends at the top of the mountain.  Delimiting which taxa are most vulnerable will allow conservationists and managers to prioritize species of high concern and further work to protect them in addition to their habitat requirements.  


By Luke Musher


To read the open access article visit: http://www.plosone.org/article/info:doi/10.1371/journal.pone.0029507

Gardali T, Seavy NE, DiGaudio RT, Comrack LA (2012) A Climate Change Vulnerability Assessment of California's At-Risk Birds. PLoS ONE 7(3): e29507. doi:10.1371/journal.pone.0029507

I Pick up Year birds like it's my Job

Okay.  Maybe I didn't pick up that many year birds today, but I got a few, and was able to get some good photographs on the way.  First spot I went was Las Gallinas, and finally saw the long-staying Laughing Gull.  Nothing much else of note here.  Some Cackling Geese were present, which are always nice, including both Aleutian and Minima subspecies.  Next spot I hit was Sonoma to look for the Ruff, which I'd already struck out on once.  I walked the whole pond and was disappointed to hear that it had flown off with a yellowlegs about ten minutes before I arrived.  Ugh.  Pretty standard.  Finally I stopped in Petaluma and walked around the cemetery where there's been a Palm Warbler.  Spent a lot of time looking around for it seeing Nuttall's Woodpecker, Oak Titmouse, Townsend's Warbler, Yellow-rumped Warbler, and a single Chipping Sparrow was a nice surprise.  Linda Hunn showed up and we sat for a while at the "lollipop tree" waiting for the Palm Warbler.  Luckily, our patience paid off.  The Palm Warbler showed up.

Yellow-rumped Warbler

This Purple Finch was right outside our house at Palomarin the other day.

Savannah Sparrow, Las Gallinas Valley WTA

Laughing Gull, Las Gallinas Valley WTA

California Gull, Las Gallinas Valley WTA

Horrible photo of the Petaluma Chipping Sparrow

Palm Warbler, Petaluma, CA

Male Eurasian Wigeon with the American Wigeon, Bolinas, CA

Got a little too close to these American Wigeon, I guess.

Female Eurasian Wigeon with the Americans

By Luke Musher

A Harrier and a Bobcat

Went out hoping to photograph the local Burrowing Owl yesterday, but had no luck.  There has been a second year (?) Northern Harrier at the spot every time I've been there, though.  I got some photos, although they're nothing to rave about.  On my drive back I saw a bobcat about twenty meters off the road.  I went to take some photos, and spent about twenty minutes stalking this elusive little fellow before successfully getting any photos.  Luckily one came out.

Thinking SY based on adult gray feathers along with retained brown first-winter plumage. Adventitiously molting S1 and maybe S2.

By Luke Musher