Monday, August 3, 2015

Post #31 - A potential North American first - GRAY THRASHER!!

Well, I might have ticked my first life bird of 2015 this weekend! I say might, because, as I'll discuss, there is at least some amount of uncertainty about the origin of the Gray thrasher that appeared in San Diego this weekend. 

As I was readying myself for a Sunday afternoon of general, Orange County birding, I received a phone call from a friend informing me that a Gray thrasher had been found at Famosa Slough in downtown San Diego. I will admit that Gray thrasher was not on my radar at that precise moment, but a quick internet search revealed that this otherwise Mexican endemic is confined exclusively to the Baja Peninsula. Despite the fact that this species usually ranges to within ~150 miles of the US-Mexico border, it had never been recorded in the United States before Sunday. I decided this mega-rarity would my first dedicated California bird chase since moving here 4 months ago. It certainly felt weird chasing a bird down I-5 in a car. Last year I rode my bike along this exact route as I chased a Yellow-green vireo on Point Loma. That bird required 90 miles of riding to tick. I was the last person to see that particular bird!


Gray thrasher range

I arrived at the thrasher spot at 4:30pm. There were ~30 people present at that hour. As I joined the crowd, the bird popped out of an area of dense scrub and began foraging 20 feet in front of us. Everyone was silent - save for the clicks of cameras - as the bird spent the next 5 minutes rummaging through dead leaves and foraging in traditional thrasher style. The bird eventually disappeared into the thicket from which it emerged. I was soon informed that it had not made a single appearance in the last 2 hours. My timing was perfect! Most folks hung around for a few more hours, hoping for more glimpses and photos. By the time I departed at 6:30, the bird had made at least 3 more appearances, the last one of which lasted for a full 15 minutes. It was during this stint that I managed a few particularly nice photos. Without further ado....

Gray thrasher - Toxostoma cinereum
Canon 500mm f/4 IS v1 + 1.4x III on EOS 1D Mark IV
1/800 at f/5.6, ISO 1600, Manual mode

1/640 at f/5.6, ISO 1600, Manual mode

This species is non-migratory and generally sticks to specific types of habitat on the Baja Peninsula. On one hand it is a bit surprising that this bird made it to San Diego. On the other, its such a short distance that it is totally plausible from a physiological standpoint; It's not as though this land bird was forced to cross an ocean, for example. Anyway, debate has already started as to whether this is a truly wild individual. For those unfamiliar with this consideration, if this bird was known to be an escaped, once-caged bird it would not be countable. The problem is that we will NEVER know for sure which is why a debate will occur. There California Rare Bird Records Committee will certainly have its hands full with this deliberation. My sighting of Red-legged honeycreeper from Texas last year is also under review, so I could end up with 0, 1, or 2 still-provisional birds added to my North American life list (which now stands at 696). 

A portion of the gallery


There are many points that have been brought up for and against this being a wild bird. For those that want to read the finer point of the discussion, I will point folks towards the ABA San Diego bird list for a full conversation. Gary Nunn's SD birding blog is also worth a visit for information on the bird and more general information on birding in the area.  Anyway, here are a few of the points that have been brought up.

 - This species, like many other non-migratory birds (Nuttall's woodpecker, California towhee, e.g.) generally doesn't wander from its range. But hey's, there's a first time for everything, right? 

-  There has been some wetter weather around here this year. The Angels were rained out at home for the first time in 20 years two weeks ago), so maybe the still-building El Nino helped move the bird north. After all, it's only 150 miles, nothing by vagrant standards.

-  This species, like seemingly every other species that occurs there, has been observed caged in Mexican towns by visiting birders. So, there is a precedent for caged thrashers. What this says about this bird is left to be determined. 

-  Feather wear seems within the acceptable range. A recently caged thrasher might be expected to have more wear on its tail fathers from clanking around the cage. This is a ground dwelling species so some amount of tail wear is normal.

-  The bird had a spot of something on its uppertail. Some that this was bird poop that might have come from being caged with another bird. Alternatively, it is possible that a wild bird pooped onto this wild bids tail. Most observers seem to think that the spot was actually mud which would render the above "poop-gate" theories moot. 

- It foraged close to us, but did so in a completely wild-type manner.

- The bird appears to be of the northern subspecies, the one we might expect to show up in SoCal.

- The bird was missing a claw - who knows what the hell that means?!?!!?

Anyway, you get the idea. No one consideration seemed to fully support or refute the "wildness" of the bird. The appointed folks will certainly have a lot to consider during their eventual deliberations. Who knows when that will even happen?!?! Regardless it was a nice afternoon out, and it permitted me to reconnect with a few people I met last year and introduce myself to a few new ones as well. As for the bird, whatever will be, will be, right?

2 comments:

  1. Dorian - the Texas honeycreeper was a Green Honeycreeper no? Or did you see a Red-legged Honeycreeper too?

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    1. It was a Red-legged. It was a female so it was green though!

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