Thursday, September 13, 2007

Trouble for Cactus Wren (and cactus?)

The Puente Hills supports one of the largest coastal-slope populations of the Cactus Wren, a large, mockingbird-like member of the wren family that is completely dependent on large clumps of cactus for nesting and foraging.

Coastal populations are restricted to southern California (Ventura Co.) south into Baja Calif., Mexico, and are geographically and genetically isolated from birds in the desert.

When I was surveying the Puente-Chino Hills for birds in the late 1990s, they seemed to be more widespread, but now are gone from many of their former haunts. I've been revisting cactus patches over the past few weeks, and have either found many fewer or have found them gone entirely.

The cactus patches themselves also appear to be in trouble - the pads withered, with large dead areas within the patches. A colleague of mine has noticed the same thing in southern Orange Co. - sickly looking cactus patches devoid of Cactus Wrens. This is especially troubling because these patches hold several distinctive plant and animal species (not just Cactus Wrens), and can serve as refugia when fires whip through an area, protecting the soil.

Today, I checked the extensive cactus on the south-facing slope just south of Sycamore Canyon above Hellman Park in Whittier, basically the top of Rideout St. I didn't hear a single one. I'm working on a chart of extant populations, but it looks grim - Sycamore Canyon seems to have most of the birds, with small numbers in upper Turnbull Cyn. (north of T.C. Rd.), along Colima Rd. (in 2002) and just east of Hacienda Dr. near Skyline Trail. Birds appear to be gone from Schabaurum Park and possibly from the slopes above Whittier.

Does anyone know of additional populations, and if so, where??

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