We made a May 18th run up to the migrant traps of the northwest Mojave and southern Kern County recently. It was probably a bit early for such a trip, but there wasn’t much going on down in Orange County, and you never know what you will find up there. We left at an ungodly hour and arrived at Butterbredt Spring, the Audubon California Kern River Preserve, shortly after dawn. It wasn’t a great day for it: the wind was whipping along at a steady 25 mph with much stronger gusts, but even on the road in from Jawbone Canyon, we could see lots of birds on the move. Despite the blow, there were flycatchers, Swainson’s Thrushes and Wilson’s Warblers crossing the road in droves before and behind us, staying low to the ground, contour flying out over the open desert hills. The preserve itself was simply alive with birds. We saw 5 species of warbler, 9 species of flycatcher and assorted passerines, including quite a few Lazuli Buntings and Black-headed Grosbeaks. One great thing about a morning like this is the chance to study difficult species like the (Empidonax) flycatchers, and to compare and contrast them in terms of their structural differences. We saw 5 species of Empids on the day, with Pacific-slope and Willow Flycatchers being the most common, but a few individuals of Hammond’s, Dusky and a single Gray Flycatcher were all observed. We also had great looks at Olive-sided Flycatchers and Western Wood-Pewees (photo) together. Being able to compare these similar species side-by-side was really helpful, making the structural differences between them much easier to see. Listening to them talk, particularly the two commonest Empid species, was also a pleasure.
From Butterbredt Spring, we drove to the next migrant trap: Central Park in California City. Like Butterbredt, this site offers a combination of water and trees to birds migrating over the desert, and it draws rare birds in frequently. We were disturbed to find the main entrance gate to the park closed and locked, but we knew that by driving around to the back side, we’d still be able to walk in among the ponds. The presence of cattail-lined ponds meant that we added quite a few common birds to our day list, but most of the migrants were the same, with the exception of a Plumbeous Vireo that was difficult to get good views of. By far, the flashiest of the pond birds were the Yellow-headed Blackbirds, a small colony of which breeds on the site. This male kept displaying and singing his distinctive raspy song. No great beauty that song, but what a handsome guy!
Our last migrant trap destination on the day was the resort at Galileo Hill. Once again, the birds here were dominated by flycatchers, especially the common Empids and Western Wood-Pewees. Swainson’s Thrushes were everywhere, looking incongruous hopping about on the lawns like robins. Wilson’s Warblers were legion too, but a careful search among the ponds revealed a few new things. At least half a dozen Spotted Sandpipers cavorted around the various water features. Perhaps the biggest surprise birds were a pair of Fox Sparrows, comprising two different sub-species. The first was a Thick-billed Fox Sparrow, showing a strong contrast between the grayish head and rusty upperparts, and of course, that great honking bill! Later, we came across a smaller-billed individual that proved to be a Sooty Fox Sparrow, showing much more rust color overall, and almost no contrast between the head, nape and upper parts. This Acorn Woodpecker (photo) seemed out of place here, in a location with no oaks!
The other pleasant surprise wasn’t avian. Groundskeepers alerted us to the presence of a young Pacific gopher snake (Pituophis catenifer). This snake was about 3 feet long, and quite beautifully marked, but rather ill-tempered. It struck multiple times and bloodied one hand, taking quite a while to calm down after I picked it up to get a look at it. This snake seemed to us to be considerably paler and more washed out in color than the individuals we see on the coastal plain, an adaptation to desert life, perhaps? I soon released it into thicker scrub away from the lawns of the resort, where it might have come to grief at the hands of some of the resort guests. It was very happy to be let go!