Important Birds from Blue Point Cottonwoods, Maricopa County, Arizona

Abstract

The Salt River currently consists of four basic divisions: deeply channeled river from Roosevelt Lake upstream, irrigation reservoirs from that point downstream to Stewart Mountain Dam, dry river channel from Granite Reef Dam downstream to the confluence with the Gila River, and the fourth area, a short segment from Stewart Mountain Dam to Granite Reef Diversion Dam (about 10 miles long) representing what little remains of the native river. During the 1970's this portion is scheduled to be inundated by Orme Reservoir, part of the Central Arizona Project. Blue Point Cottonwoods, located approximately 2 miles upstream from the confluence of the Verde with the Salt River, is the only large stand of mature cottonwoods (Populus fremontii), with its attendant mesquite (Prosopis juliflora) understory, left on the entire Salt River. These cottonwoods will be covered by Orme Lake, thus virtually completing the extirpation of native riparian groves along the Salt River. This virgin grove extends for nearly a mile along the north side of the river. A narrow marsh of open water approximately one-half mile long, edged with arrowweed (Pluchea sericea) and salt-cedar (Tamarix sp.), and containing several dense stands of cattails (Typha domingensis) contributes to the diversity of the habitat. Azolla sp., a water fern unrecorded for central Arizona, grows profusely with duckweed (Lemna sp. ) in the marsh. Field work at Blue Point Cottonwoods has contributed much to our knowledge of birds in the central lowlands of Arizona. In the past, many important specimens and records were obtained from the area by Lyndon L. Hargrave, Allan R. Phillips, and Lewis D. Yaeger. Some of the more important records for the Salt River Valley include: the only specimens of the Ferruginous Owl (Glaucidium brasilianum) during this century (Hargrave; Phillips); the only specimen of the Common Crow (Corvus brachyrhynchos) (Phillips); the only Red-breasted Nuthatch (Sitta canadensis) specimens (Phillips and Yeager); the only nesting record of the Bewick's Wren (Thryomanes bewickii) (Phillips and Yeager); and the only Hutton's Vireo (Vireo huttoni) specimens (Phillips; Johnson and Simpson). The northernmost specimen for the Tropical Kingbird (Tyrannus melancholicus) was collected here by Simpson and Werner (Condor 60:68, 1958). While the following species nest at one or two other localities in the Salt River Valley, Blue Point Cottonwoods and the nearby river is the only area left that is both large enough and stable enough to support them all: Green Heron (Butorides virescens), Yellowbilled Cuckoo (Coccyzus americanus), Bell's Vireo (Vireo bellii), Yellow Warbler (Dendroica petechia), Yellowthroat (Goethlypis trichas), Summer Tanager (Piranga rubra), and Blue Grosbeak (Guiraca caerulea). Considering the ephemeral nature of the other habitats, the loss of Blue Point Cottonwoods may also mean the loss of most or all these species as breeding birds in the Salt River Valley. Our recent field work in this area has resulted in several additional distributional records of some interest. All specimens mentioned in the following species accounts are in the Johnson-Simpson-Werner (JSW) collection, now housed at Prescott College, Prescott, Arizona. Our thanks to Lyndon L. Hargrave and Allan R. Phillips for critical reading of the manuscript. Least Bittern. Ixobrychus exilis. According to Phillips, Marshall, and Monson (The birds of Arizona. Univ. Arizona Press, Tucson. 1964. p. 7), the only previously documented nesting of this species in Arizona was by Simpson and Werner (loc. cit.). Our specimen (JSW no. 925) was collected on 9 July 1969 in a dense stand of cattails in the marsh. It is a juvenile female with down on the legs, wings, neck, and head, and was accompanied by one or two other juveniles, presumably nest mates, and at least one adult. At least one additional adult was seen. The nest was secured on 20 July 1969 and is the first nest from Arizona for this species. Groove-billed Ani. Crotophaga sulcirostris. A female? (gonads shot), collected on 20 July 1969 (JSW no. 879) showed no fat and no molt. This is the second known extant specimen from the state (see Phillips et al., loc. cit.:46). Later, Bernard Roer informed us that he found another Groove-billed Ani at his bird farm in Phoenix on 11 July 1969 and donated it to the Phoenix Zoo. SHORT COMMUNICATIONS 379