Vol. 29 No. 2 (1998)

The Mad River Ranger District (MRRD) of the Six Rivers National Forest (SRNF) is located in northwestern California (Figure 1). We compiled data on the status and distribution of the birds of this area for three primary reasons.

The Sacramento Valley forms the northern reach of California's Central Valley, one of the most intensively farmed regions in North America. Over 90% of the Central Valley's wetlands and riparian habitats have been lost or degraded through agricultural and urban development since the early 1900s.

Tomales Bay, on the Marin County coast, is one of California's largest and least disturbed estuaries, yet little has been published on the status of its waterbirds or their vulnerability to environmental threats.

During the winters of 1994–95 and 1995–96, over a dozen Cliff Swallow (Petrochelidon pyrrhonota) nests on the campus of California Polytechnic State University, San Luis Obispo, California, were totally destroyed.

From 4 to 16 September 1997, two of us (Winker and Dickerman), representing the University of Alaska Museum and with the cooperation of the Alaska Maritime National Wildlife Refuge and the U.S. Coast Guard, conducted an intensive survey of the early fall avifauna in the Massacre Bay area of Attu Island, the westernmost of the Aleutian Islands, Alaska.

On 23 May 1997, we found and photographed a gray-plumaged cuckoo of the genus Cuculus on Midway Atoll, constituting the first record of this genus in the Hawaiian Islands and in the central Pacific Ocean east of Palau. We suspect it was a Common Cuckoo of the southeastern subspecies (C. canorus telephonus), but cannot eliminate the Oriental Cuckoo (C. saturatus) at this time.

This is the second edition of a book first published in 1983, from which the present work differs mainly in its additional treatment of all hummingbird species found south to the Isthmus of Tehuantepec in southern Mexico, thus widening the definition of North America to a biogeographic rather than political boundary.

California's fourth breeding atlas—and the first for southern California—this volume reports on data collected from 1985 to 1990, plus selected records through 1994. Dividing the county into 5 x 5-km squares yielded 61 full and 50 partial blocks, a respectable 79 percent of which Gallagher deems to have been covered to a "good" or "excellent" degree. Because the Santa Ana Mountains account for most of the area afforded "poor" to "marginal" coverage, I expect that exciting discoveries still lurk in this poorly known range.

In 1995, following Greenlaw (1993), the AOU split the Sharp-tailed Sparrow into two species: the Saltmarsh (Ammodramus caudacutus) and Nelson's (A. nelsoni) Sharp-tailed Sparrows.