mjm@oliven.olivetti.com (Michael Mammoser) (11/03/88)
I went out last Saturday with a couple of friends to the grassland- covered rolling hills near Livermore, on the east side of San Francisco Bay. I was accompanied by Grant Hoyt, a director of the local Audubon chapter, and his wife Karen. Our purpose was to find raptors, as this is a typical winter- ing and year-round resident area for many of our local species. The trip started off with a bang. As we headed east on interstate 580, Karen noticed something alongside the freeway and we hit the next exit and headed back along the frontage road. There, between the freeway and the frontage road, about 50 yards away, was a beautiful adult Golden Eagle feeding on a jackrabbit on the ground. It had the brightest, straw-colored nape that I had ever seen on a Golden Eagle. We weren't even outside the city limits of Livermore on our way to the target area and had already gotten the best look at this species that any of us had ever had. This was the start of what was the best Golden Eagle outing I've had, culminating in a total of 8 for the day. As we continued, Ferruginous Hawks popped up quite often, being less numerous only to the Red-Tailed Hawks. Other than a few sitting on telephone poles, Ferruginous tend to be found perched on the ground. The ubiquitous Red-Tailed Hawks also added to the day's experiences, with looks at every morphological race that this highly variable buteo produces in the local area; light-phase morph, dark-phase morph, rufous-phase morph, and even immature plumage. American Kestrels abounded. A fly-over by a single Prairie Falcon was our only sighting of this magnificent bird. It flew steadfastly across the fields, about 20 ft. above the ground, raising flocks of blackbirds which scattered in frenzied panic. Turkey Vultures, a bird that we thought might be the most numerous, made their appearances later in the day, and turned out to be scarcer than we expected (quite a relief, actually). Unfortunately, 2 of our target species went undetected; Rough-Legged Hawk and Burrowing Owl. Not all the birds of prey were raptors either. As we drove along a back road, we noticed a small bird flying laboriously along close to the ground. It turned out to be a Loggerhead Shrike carrying a House Finch that was fully half its size. As it struggled to reach the fence row along the road, it was forced to drop its prey only yards from its destination by a single swoop of an American Kestrel. As the kestrel flew off with its "hard- won" prize, the shrike sat on the fence panting from the exertion. We scanned through flocks of blackbirds looking for cowbirds, or any other interesting specimens. The flocks were composed of Brewer's, Tricolored, and Red-Winged (the "bicolored" variety). We debated how to tell the normal Red-Winged Blackbird from the "Bicolored" race and the impossibility of telling female "Bicolored" from female Tricolored. Our return was along a small canyon road east of the Diablo Mts. and the non-raptor birding was excellent. A telephone wire lined with a flock of Tree Swallows; a few Long-Billed Curlews feeding in a field miles from the nearest water; a couple of Lewis' Woodpeckers in a known breeding area; a flock of about 150 Western Bluebirds; a juvenile Cooper's Hawk; Yellow-Billed Magpies; a small pool of standing water at a corral that attracted, among others, Lawrence's Goldfinch, Rock Wren, Purple Finch, Phainopepla, Western Bluebird, Nutall's Woodpecker, Dark-Eyed Junco, Ruby-Crowned Kinglet, and House Finch; a pond that yielded Mallard, American Wigeon, Northern Pintail, Gadwall, Green-Winged Teal, Northern Shoveler, Ruddy Duck, Cinnamon Teal, Canvasback, and Bufflehead. No, this wasn't chasing vagrant eastern warblers or asian stints along the coast, but a better day of birding couldn't be had. Mike