Tuesday, September 27, 2011

LCRV Rarity Photos

I've been promising for a while to post photos of rarities that have been seen lately in the LCRV.  The thing is, the rarities just keep coming!  I have finally caught up, for now, and I present a suite of photos of recent rarities (all photos by Lauren Harter unless otherwise stated).

First, remember the Long-tailed Jaeger from my last post?  Since that sighting, we were having continual sighting of distant jaegers identified as "probable Long-tailed".  I was getting pretty sick of jaegers after a while.  Finally, though, David managed to get some good, identifiable photos of a Long-tailed Jaeger.  Then, David and I spotted the bird sitting on the water not far off Pittsburgh Point.  It was gorging on a dead fish.  We were puzzled when it flew up into a cove and out of sight, and we couldn't refind the bird!  I scanned from a rocky ridge while David walked the shoreline, both of us trying to turn up this bird.  Eventually David gave up and started walking up the next ridge over, only to see the jaeger sitting on top of the ridge!  David having inadvertently flushed it, the bird flew back to its dead fish--and right over my head.  I mean if I had stretched out my arm I could have pet this bird's belly.  With the jaeger back at its fish, I digiscoped some better photos.

Photo by David Vander Pluym

These photos show the most important marks for Long-tailed Jaeger - lack of cinnamon tones in the plumage, bold black-and-white barring on the undertail coverts, two white primary shafts, boldly marked underwing coverts, whitish tips to upperwing coverts, and especially the two long central tail feathers.  The bill does look a little large for LTJA - remember that was one of the confusing features I mentioned in my earlier post - and just shows how important it is to note multiple features in juvenile jaeger ID!
In case anyone is wondering why I think this is the same bird I photographed before...

Photo from 15 Sept
Photo from 9 Sept
To get a bit more chronological, I'll go back to August and our great shorebird migration.  Several Sanderlings were seen, particularly in the Bill Williams Delta, where up to nine were present at a time.  This bird was photographed in the Parker Strip on the California side, at Emerald Cove Sewage Ponds, August 30.

On a county level, one of the "better" birds in the LCRV this fall is the Tricolored Heron at the north end of Lake Havasu.  If accepted by the CBRC, this will be a first county record for San Bernardino County (CA) as well as Mohave (AZ)!  Oddly enough, Tricolored Heron turns up regularly in southern Arizona, but there are few records for the LCRV, and it is rare enough to be a review species in California.  This bird is also unusual because it is an adult.  It was first spotted August 10, and as far as I know it is still around!

Sept 4, being chased by a Ring-billed Gull
Sept 12 photo by David Vander Pluym
John West has gotten some beautiful shots of this bird, which will hopefully be posted at the link above.

Back to jaegers for a moment is a single photo of our first jaeger this fall, a Parasitic.  This bird flew by us on the hill without stopping for a moment, heading north.  It came by close enough for photos, but not close enough for good photos!

Sept 6 photo by David Vander Pluym
Next up is a round of photos of Spizella sparrows.  Usually, there is little difficulty in distinguishing Clay-colored and Brewer's Sparrows.  Clay-colored is a much brighter, more distinctly marked bird, with a broad buffy supercilium and gray nape, both unmarked.  Clay-colored also has a distinct dark lateral throat-stripe and a less distinct, partial eye-ring.  Brewer's typically shows a much more muted face pattern, with short dark streaks on the supercilium and nape, a dull, indistinct lateral throat-stripe, and a bright, complete eye-ring.  Clay-colored also shows a distinct pale central crown-stripe - Brewer's can show a less distinct stripe, but this is one feature that doesn't seem to overlap.

On Sept 9, I encountered a flock of Spizellas that seemed to be mixed Clay-colored and Brewer's.  Being inexperienced with fall Clay-colors, I just started snapping photos of every bird I could get close to.  Later I examined the photos and read up on Spizella identification.  An excellent article by Peter Pyle and Steve Howell can be found in Birding 28:5 (Oct 1996), "Spizella Sparrows: Intraspecific Variation and Identification".  After reading this article and other information on Spizella ID, studying my photos and grouping photos of individuals based on individual feather patterns, I concluded that I had photographed four Clay-colored Sparrows in this flock.  As Brewer's Sparrow migration has continued, I have come to appreciate the range of variation that this species shows.  Many of the birds I encounter have gray napes and broad supercilia only slightly marked with streaks, as well as distinct dark lateral throat-stripes.  The mark that these birds do not show is the distinct pale central crown-stripe.

I would be interested in hearing comments on the four birds that follow from anyone familiar with fall Clay-colored Sparrow, as none of these birds are quite as bright as I would expect from a typical CCSP.  I have plenty more photos and full-size versions for anyone who is interested.

Bird #1 (left) with Brewer's Sparrow (?)

Bird #1, showing central crown-stripe

Bird #1, closer look at face and nape pattern
Bird #2, the most confusing individual to me.  It has a muted face pattern, although the supercilium and nape do not seem to be streaky, but it shows a distinct central crown-stripe.

Bird #2, side view.  Is this a Brewer's Sparrow with an unusually distinct central crown-stripe, or a very dull Clay-colored Sparrow?
This was bird #4, but as I went to add these photos I realized that it's the same as bird #2...

Bird #2, blurry but in better light?  Looking much more distinctly patterned...
Bird #3

Bird #3 and its central crown-stripe
The next Clay-colored Sparrow showed up September 10-11, and this bird was a beauty!  After straining my eyes looking at individual feathers on the preceding birds, it was nice to see a CCSP that was very brightly marked, and buffy on the breast.

Both photos Sept 11 by David Vander Pluym
But that's not all the CCSP observations!  At the same location, I saw one September 14.  I saw it well but briefly when I first arrived at the spot, then later I believe I got a fuzzy photo of the bird (below) - I was focusing on taking pictures so I didn't get a clear view in the field the second time I saw it.


Just for fun, I think this is one of those well-marked Brewer's Sparrows that shows a central crown-stripe.  Or maybe it's another Clay-colored...

Birding the same spot Sept 25, I saw yet another CCSP - this really seems to be a hotspot.  Finally, I have heard that David found on on the California side of the Parker Strip this morning!

Back to September 14, a day when the north end viewpoint was alive with migrants.  In addition to the Clay-colored Sparrow, I had a Virginia's Warbler and Dusky Flycatcher, both good birds in the LCRV.
Virginia's Warbler
Dusky Flycatcher.  The short primary projection and long tail are visible in the photo; it was also giving a "whit" call in the field.

Moving on to the next bird, the Bobolink.  The story of its discovery is pretty amazing, I think.  I was birding the north end viewpoint with my friend David Rankin.  While he was standing on the hill and I was birding the riparian below, I saw him suddenly look at something with binoculars, and I heard this weird soft call.  As a bird flew over his head, he took his binoculars down, pointed at it, then raised his binoculars again.  I got my binoculars on it as it flew over, calling again, "boink".  I saw a yellow bird with a few distinct streaks on the flanks.  We both agreed that this had to have been a Bobolink, but for such a rare bird in Arizona, our view was frustratingly brief.  I had to forget about it, because as I told David, there was no way we would be able to find it again - it showed no signs of stopping, and even if it did, there is plenty of potential habitat for it along the lake shore!  So we continued birding and, over an hour later, made our way to Rotary Park.  David got out of the car and started scanning the golf course--and almost immediately spotted a yellow bird among the sparrows.  I got my scope on it and, sure enough, it was the Bobolink!  It happened to land on this golf course, over 4 miles from the north end where it had flown over us, and in a place where David was able to find it again!  This was September 21, and it was still present as of yesterday (Sept 26).  It has been seen by many birders, fortunately.  Following are a few of my photos from the day it was found, but better photos can be seen here.

The next bird was very frustrating in the field.  Birding 'Ahakhav Tribal Preserve, I spent quite a bit of time in pursuit of an Empidonax flycatcher giving a "whit" call.  Typically the only two species that give such a call in the LCRV are Willow and Gray Flycatchers.  Once I got a brief view of the bird, I could see that it wasn't a Willow, and the bill wasn't right for Gray.  I tried to get a better view, thinking it may be a Dusky, a fairly rare bird in the LCRV.  Eventually the bird sat in the open for a moment, and I saw very contrasty wings, and odd tail-flicking behavior - it was flicking its tail quickly down.  Both are features of Least Flycatcher.  David and I spent the next few hours trying to get good views of the bird, and David finally managed to get some decent pictures.  It's the bill that clinches the ID - the long narrow bill with about a substantial dusky tip points to Dusky Flycatcher, not Least.  Not the rarity we would have liked, but still a good bird!

Both photos Sept 25 by David Vander Pluym.  Bill shape and pattern characteristic of Dusky Flycatcher shown well in the first photo.  Wings looked more contrasty in the field than they do in the second photo.
Birding along the state line between Arizona and California produces some interesting patterns.  One thing we have noticed is that sometimes, you see a bird that is a much more interesting record on one side of this imaginary line than the other.  Neotropic Cormorant is one example--they always seem to turn up in Arizona, but they are a Review Species in California.  Similarly, a jaeger on the California side is a good bird for the inland counties, but all three jaegers are Review Species in Arizona.  Yesterday, I saw one of these species: a Cassin's Sparrow.  While this species is common in southeastern Arizona, there are few records for the northern and western regions of the state.  Rosenberg et al. only lists one record from the LCRV, in La Paz County.  This summer, David and I found the first in Mohave County - around Peach Springs, we had several singing birds.  This was a good year for them in northern Arizona, with reports across the northern tier of the state.  Across the lake in California, Cassin's Sparrow is a Review Species.  There have been several records of singing and even breeding birds in San Bernardino County, but only in very good years.

The Cassin's Sparrow I saw yesterday was in Mohave, at the north end viewpoint.  This was a very surprising find, with the bird not only out of range but in unusual habitat.  I came around a corner to see a sparrow feeding on the edge of some dense vegetation on the lake shore.  Thinking it would be a Brewer's Sparrow, I got my binoculars on it in time to see a scaly pattern on the back and crown, and I knew it was a Cassin's Sparrow.  It disappeared into the brush as soon as it saw me, peeking out only for a moment so I could see a distinct eye-ring.  I then waited and waited, staring at the brush pile and trying to ignore all the Brewer's and Chipping Sparrows, Orange-crowned Warblers, and other birds flitting all around me.  Eventually, the Cassin's Sparrow did come out, and I managed to get some decent photos.

Note plain dark tertials with distinct white edging, scaly-striped back pattern, eye-ring, and yellow supraloral, as well as shape.

Note faintly streaked breast, yellow at bend of wing, and dull yellow supralorals
That's it for now.  Until next time!

Friday, September 9, 2011

Long-tailed? Jaeger

We've been scouring the lake lately for jaegers - those wonderful winged pirates - given all the reports coming from the inland southwest.  We were rewarded a few days ago with a flyby Parasitic that hasn't shown itself since.  What we have seen a few times is a faraway dark jaeger in flight, disappearing into the haze over California waters.  Today, arriving at my favorite lighthouse on Pittsburgh Point, I spotted a jaeger almost immediately - quite possibly that dark-looking bird that has been so distant before.  It stayed on the water a long time and I was able to digiscope some very bad photos of it.

I initially identified the bird as a Long-tailed based on proportions and shape.  This photo shows the shape best.

It looks evenly proportioned - no shrunken head look - and overall slender and delicate.  The apparent size of the bill varies among all the photos.  In the field, it looked very slim.  After noting the shape and making a tentative ID, the bird swiveled in the water and I was able to see the striking black-and-white barred undertail coverts (not shown well in this photo).  Soon after, it dunked its head underwater, slightly spreading its wings and exposing its full spread tail.  The central rects were very conspicuous, much longer than the surrounding feathers.  They looked full and rounded, quite a contrast with the quick view I had of the recent Parasitic Jaeger.  (Juvenile Parasitic Jaegers have central rects slightly longer than the others, and distinctly pointed - a feature that was easy to see even at a distance on the recent Havasu bird.)  The combination of the pattern on the undertail coverts and the shape of the central rects led me to conclude that this bird was a Long-tailed Jaeger.

These photos show how much the apparent bill size changes from photo to photo!  What is more clear is the pattern of the undertail coverts - barred black and white.  The bird faced away from me many times and I was able to note that this pattern passed across the entire undertail, unbroken.

The apparent color of the bird changes dramatically in the photos depending on the settings I was using, as well as the cloud cover, which varied during my stay there.  In flight, the bird looked very much like this - dark overall.  Even in this photo, where the bird looks much darker than it looked in the field, the black-and-white undertail coverts are visible (though it doesn't show up well on the smaller blog version).

I saw the bird in flight only twice, and never well.  When it finally left the area, it spent most of its flight flying directly away from me.  As I said above, it looked rather dark overall in flight.  One thing I noticed - which had me scratching my head - was the pattern on the upper surface of the primaries.  A Long-tailed Jaeger should show only 2 primaries with white shafts, but this bird seemed to have 5 or 6.  In active flight, I could only see one or two pale primary shafts - it was when it spread its wings completely before landing, or when it lifted its wings as it sat on the water, that it seemed to have so many pale primary shafts.  This isn't considered a good field mark, as it is subject to a lot of variables in the field that affect the apparent number of pale shafts, but it did make me scratch my head - could it be a Parasitic?

There are a few other features of this bird that don't sit right for Long-tailed.  It looks a little brown overall (in the photos as well as in the field), and the bill looks a little big in several of the photos.  In the field, I tried to judge the percent of the bill that was black (the size of the nail), and judged it to be a little less than half.  The photos seem consistent with this.  This photo shows it best:

Despite these points, I think that the pattern of the undertail coverts, the shape of the tail, and the overall shape all point to Long-tailed Jaeger.  I would love to hear opinions from others on this confusing bird.  In the mean time, David and I will certainly be out there tomorrow trying to get better looks and better photos!