Wednesday, September 26, 2007
While on a site visit to Sycamore Canyon yesterday, I observed several spreadwing damselflies along the stream (photo). They were a grayish lavender color, and appeared to be either the California spreadwing (Archilestes californica) or the great spreadwing (A. grandis).
Thanks to the recent publication of illustrated field guides, dragonflies and damselflies ("odonates" collectively) have joined butterflies as a group of insects that may be identified readily through binoculars. Consequently, we are quickly gaining a much clearer picture of the status and distribution of these varied creatures throughout the state (and the U.S.).
Only a handful of odonate species have been identified in the Puente Hills, and this genus, an autumn emerger, may have been missed by previous surveyors working in the spring and summer.
Posted by Dan Cooper at 9:07 PM
Monday, September 17, 2007
While doing a websearch this morning for birds of the Puente Hills, I came across a fascinating tidbit buried in a 1929 issue of the journal The Condor ("Some results of bird banding in 1928" by John McB. Robertson):
"Nestling Long-eared Owl no. 543281 banded April 10, 1928, at Rancho de los Tres Hermanos, in the Puente Hills of southeastern Los Angeles County, was taken four miles from Lancaster, California, between December 29, 1928 and January 3, 1929, a distance of about fifty miles."
Old journal articles were notoriously vaguely-worded, and as this is no exception, I missed this reference entirely in previous literature searches of birds of the Puente-Chino Hills. This note is significant for several reasons. First, it provides evidence that this scarce owl (a California Bird Species of Special Concern, pictured here) once occurred and even nested in the Puente Hills. This species, once common in ranches and riverbottoms throughout the region, is now nearly extirpated from all of southern California, with only a handful of nesting pairs known from interior valleys, remote mountain ranges, and desert oases.
Also, it illustrates the importance of the hills as a nesting area for raptors that may disperse widely for the winter and return to breed in the spring. The article also mentions a Red-tailed nestling from Carbon Canyon found (in a coyote trap!) in Madera County in the Central Valley (the fact that both these birds flew north, rather than south, for the winter is also interesting).
Finally, it suggests that scarce species like the Long-eared Owl may yet be holding out in some of the more remote canyons and properties of the Puente Hills, awaiting discovery. This ranchland is still there, visible from Grand Ave. as it crosses from Diamond Bar into Chino Hills. As the surrounding area developed in the past 80 years, maybe the owls left at some point - but maybe they've been there all along...
Posted by Dan Cooper at 12:31 PM
Thursday, September 13, 2007
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??
Posted by Dan Cooper at 2:40 PM
Friday, September 7, 2007
This is a Nutmeg Mannakin, a goldfinch-sized bird from southeast Asia that has become established in parts of the Los Angeles area in the past 15 years. They are most often found in wet, weedy patches, but will also visit bird feeders. I had one fly overhead (calling) at the head of Arroyo Pescadero just west of Colima yesterday, and today, I saw one perched just upstream of Murphy Ranch Park near the Whittier/La Habra Heights border.
Posted by Dan Cooper at 5:34 PM
Not much of a name, but there you have it. The scrub oak (Quercus berberidifolia) is found in chaparral from Humboldt Co. into northern Baja Calif., Mexico (like many chaparral plants and animals). In the Los Angeles area, it is generally found in the foothills of the San Gabriel Mtns. and in the Santa Monicas where other chaparral species are present, such as chamise, mountain-mahogany and Ceanothus. It is scarce or absent at lower elevations and along the immediate coast such as Palos Verdes, the Baldwin Hills and the Montebello/Repetto Hills, where coastal sage scrub - dominated by sages, sagebrush and buckwheat - tends to replace the higher, thicker chaparral.
In the Puente Hills, typical chaparral occurs only east of Powder Canyon, from the open space south of Rowland Heights east and north into Diamond Bar. West of here, tall shrubland tends to be dominated by sumacs and toyon, and has been called "sumac scrub". It is possible that the scrub oak and other chaparral species were burned out of the Whittier Hills over the years, or were eliminated by early brush clearance and grazing. Or, there exists a mysterious ecological barrier that has prevented their expansion west.
While conducting fieldwork here in 1997, I noticed a couple scraggly-looking scrub oaks along the Edison powerline right-of-way west of Colima Rd., growing between a steep slope and a chain-link fence, and thus protected from fire and brush-clearance. The plants were still there when I collected a sample this week (photographed), and may be the only ones in the western Puente Hills.
Posted by Dan Cooper at 5:06 PM