Guy McCaskie and Kimball L. Garrett, Regional Editors
With a bird list of 623 species, Southern California boasts nearly unmatched biodiversity, habitat complexity, and topographic extremes. A human population of nearly 25 million, though translating to massive environmental modification, includes substantial numbers of birders and field-oriented academic and amateur ornithologists, with an important record stretching back beyond the mid-1800s to globally significant Pleistocene and early Holocene fossil sites.
The highest point in the Lower 48 (Mt. Whitney) lies in the southern Sierra Nevada along the region’s far northern border, a mere 135 kilometers from the lowest point in Death Valley. Coast, Transverse and Peninsular ranges, some exceeding 3,000 meters in elevation, span the region, creating a rain shadow with varied deserts (the high Great Basin and Mojave to the low Colorado) dominating the eastern half of the region. The imperiled Salton Sea and surrounding agricultural areas in the southeast constitute a unique set of bird habitats.
The offshore Pacific includes warm deep waters beyond the continental shelf and cooler inshore currents with significant upwelling, plus eight Channel Islands (and the endemic Island Scrub-Jay). Coastlines, though heavily impacted by human activities, may be steep and rocky or broad and sandy, and important estuaries and protected bays remain. West of the deserts, scrublands (coastal sage, chaparral), remnant grasslands, oak woodlands, coniferous forests, and highly modified urban habitats dominate in the region’s Mediterranean climate of warm to hot, dry summers and cool to mild and variably wet winters.
The avifauna matches the geographical diversity, e. g., 45 species of wood-warblers, 26 gulls, 18 woodpeckers, 14 hummingbirds, 14 alcids, 12 vireos, 10 storm-petrels, and 9 mimids. Impressive annual migrations of seabirds off the coast, passerines through the deserts and coastal foothills, and shorebirds in coastal estuaries and interior wetlands entertain the legions of birders. And finally, Southern California is the go-to region for such species as Allen’s Hummingbird, Scripps’s (and related) Murrelets, Yellow-footed Gull, Elegant Tern, Black-vented Shearwater, California Gnatcatcher, Lawrence’s Goldfinch, the iconic California Condor, and scores of others.