Friday, November 4, 2016

Le Conte's Thrasher at Borrego Springs

Four-and-a-half miles east of Christmas Circle roundabout in Borrego Springs, on Palm Canyon Road, is a sharp left curve that marks the beginning of Peg Leg Road. It is here that you turn right on to Dump Road. At a sharp right turn are signs for the Old Springs Road Open Space Preserve off to the east. Park along the road here and walk east. (Am I the only one that gets my internal compass mixed up here? I have to fight to keep from feeling east is south and west is north in Borrego Valley.)

The desert here is right on the edge of sand dunes with Fonts Point to the east. Walk that direction. The widely--and evenly--spaced creosote bushes along the road give way after a few hundred feet to what I believe are scattered big saltbush (see photo below). You are now in prime Le Conte's Thrasher habitat. As Sibley describes it: "Uncommon, local, and secretive on extremely arid and sparsely vegetated plains with saltbush and creosote bush and lots of bare sandy ground. Solitary; most often seen running across the ground from one bush to another."--Sibley Guide to Birds: second edition (2014).

Old Springs Road Open Space Preserve
Dawn at Old Springs Road Open Space Preserve looking east toward Fonts Point on the right. October 30, 2016.
I have visited this location 7 times over the past two-and-a-half years and found Le Conte's Thrasher only twice. In fact, the total number of species I've found here is 9--mostly fly-overs--this is very barren land! In almost 45 years of birding I have only observed this bird 4 times. No wonder--it's preferred habitat is barren and otherwise birdless! [One of my seven visits produced no birds whatsoever in 20 minutes of walking!] No birder would go there except to find this one species.

One thing that may have led to my success in finding the Le Conte's when I did was arriving as close to sunrise as I could. Also, in both cases, I heard the thrasher singing first. It was a brief musical warble with an up and down pattern, similar to House Finches (which are also present), but without any scratchy notes. Singing, yes, but very softly. Some call it a whisper song, others a subsong. This most recent singing was the end of October, the other time late December, well before the breeding and main singing season. As such, the song was very soft and first given when I was very close to the bird (20-35 feet)! I thought I was hearing a bird hundreds of feet away, but a few steps and the song moved to come from a dense bush I was walking past. It was almost as though the bird was singing as a nervous response to my close presence. [You may dismiss this idea, but American Robins on their nest squeak when you walk by--giving them away, when if they had remained silent they would have gone unnoticed.]

Why would they be singing at this time of year? Do they set up winter territories and defend them from others of their kind? Is it a response to the recording I played 5 minutes earlier on the December occasion? Or do they sing throughout the year? [According to the San Diego County Bird Atlas (Unitt, 2004) egg laying is documented in San Diego from 22 February to 25 April, and notes an early record for nearby Palm Springs, Riverside County, as early as 22 January. So late December could be the start of a normal breeding season singing period.]

Le Conte's Thrasher
A sneaky Le Conte's Thrasher running away. Borrego Springs, California. October 30, 2016. Greg Gillson.
I saw a shadow move and circled the bush just in time to see the bird running away at a rapid pace, holding its tail high. I snapped off a quick picture. Don't blink, don't look down to watch your step, and pay attention to your peripheral vision. Does the bird watch your eyes and run off when you're not looking in its direction? It seems so to me.

After the thrasher ran away I walked on in the direction it had disappeared, not knowing how I would find it again now that it had fled from me. But in a moment I heard light singing again and scanned ahead. There it is--singing from an exposed perch. I shield my advance behind one large bush ahead, then peer our carefully with my camera to get photos. It's a bit far, but there are no bushes for me to hide behind in order to sneak closer. In the low light most of the photos are a bit blurry--even with image stabilization. But this one turns out pretty well...

Le Conte's Thrasher
Le Conte's Thrasher perched up and singing softly. Borrego Springs, California. October 30, 2016. Greg Gillson.
Then, oh I missed it! The bird disappeared again when I momentarily looked away. Goodbye until next time, then.