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I I 1\ I I I I a I I I t I I I I I ,1 I BIOLOGICAL OPINION Status of the Species preclude a complete description of this subspecies' former distribution and abundance. However, the more than 600 egg, nest, and specimen records available from museums throughout the U.S. in combination with State, county, and local faunal accounts from the fIrst half of the 20th Centur y indicate that, historically, the southwestern willow flycatcher was more widespread and, at least, locally abundant. Phillips (1948) first described E.t, extimus from a specimen collected by Gale Monson on the lower San Pedro River near Feldman, AZ (Pinal Co.). The taxonomic validity of E,t. extimus was subsequently reviewed by Hubbard (1987), Unitt (1987), and Browning (1993), and has been accepted by most authors (e. g., Aldrich 1951, Behle and Higgins 1959, Phillips et al. 1964, Oberholser 1974, Monson and Phillips 1981, Harris et al. 1987, Schlorff 1990, Harris 1991). Unitt (1987) reviewed historical and contemporary records of E.t. extimus throughout its range, determining that it had II declined precipitously. . . II and that, "although the data reveal no trend in the past few years, the population is clearly much smaller now than 50 years ago, and no change in the factors responsible for the decline seem likely. " Overall, Unitt (1987) documented the loss of more than 70 breeding locations rangewide, including locations along the periphery and within core drainages that form this subspecies' range. Unitt estimated that, rangewide, the southwestern willow flycatcher population probably was comprised of 500 to 1000 pairs. Because more recent rangewide survey data was not available at the time of Unitt's review, he did not evaluate potential dispersal and recolonization that may have occurred following extirpation. Data presented below, however, indicates that after four years of rangewide surveys fewer than 500 southwestern willow flycatchers have been documented. Below is a State-by-State comparison of historic and current data. Since 1992 more than 800 historic and new locations have been surveyed rangewide to document the status of the southwestern willow flycatcher (some sites in southern California have been surveyed since the late 1980s). Survey efforts in most States were done under the auspices of the Partners In Flight program, which served as the coordinating body for survey training sessions and review and synthesis of data. The extensive and, in some case, intensive nature of these efforts have provided a critical baseline on current distribution, abundance, and reproductive success rangewide. California The historic range of E,t. extimus in California apparently included all lowland riparian areas in the southern third of the State. It was considered a common breeder where suitable habitat existed (Wheelock 1912, Willett 1912, 1933, Grinnell and Miller 1944). Unitt (1984, 1987) concluded that it was once common in the Los Angeles basin, the San Bernardino/Riverside area, and San Diego County. Specimen and egg/nest collections confirm its former distribution in all coastal 59