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Mark K. Sogge

Publications and source records attributed to Mark K. Sogge.

22 records · Page 2Linked to original sources

A survey protocol for the Southwestern Willow Flycatcher (Empidonax traillii extimus)

The southwestern willow flycatcher ( Empidonax traillii extimus ) is a riparian obligate neotropical migrant, nesting in cottonwood-willow associations and structurally similar riparian vegetation associations. The southwestern willow flycatcher has declined through the twentieth century, primarily due to a number of factors, including loss and fragmentation of riparian habitat, brood parasitism by brown-headed cowbirds ( Molothrus ater ), invasion of riparian habitat by the exotic tamarisk ( Tamarix sp.), and predation (Hunter et al. 1987), Unitt 1987, Hunter et al. 1988, Whitfield 1990, Harris 1991, Rosenberg et al. 1991). In 1991 the U.S. Fish and Wildlife Service (USFWS) designated the southwestern willow flycatcher as a candidate category 1 species (USFWS 1991), indicating that the USFWS had sufficient information to support listing under the Endangered Species Act of 1973, as amended (Act), but that a proposal to list was precluded by other listing actions of higher priority. In July 1993, the USFWS proposed to list E. t. extimus as an endangered species and to designate critical habitat under the Act (USFWS 1993). The states of Arizona, New Mexico, and California comprise most of the southwestern willow flycatcher's historic and current range. Each of these states lists the species as endangered [Arizona Game and Fish Department (AGFD) 1988, New Mexico Department of Game and Fish (NMDGF) 1988, California Department of Game and Fish 1991]. Because of the precarious status of the southwestern willow flycatcher (Unitt 1987, USFWS 1993), there is a need to identify as many remaining breeding locations as possible. This survey protocol was developed to facilitate and standardize breeding surveys, and is based primarily on extensive 1992 and 1993 field surveys. It was developed at the request of the Arizona Partners in flight, and organization of Federal and State agencies, nongovernmental organizations, and individuals. This protocol is intended to be useful throughout the range of the southwestern willow flycatcher. The authors welcome any suggestions on refining this protocol.

Report

Nests and nest sites of the San Miguel Island Song Sparrow

Nests and nest sites of the San Miguel Island ( SMI ) Song Sparrow ( Melospiza melodia micronyx ) are described; nests are compared with those of 16 other races of Song Sparrows. Bush lupins ( Lupinus albifrons ), coyote brush ( Baccharis pilularis ) and golden bush ( Haplopappus venetus ) were the shrubs used most commonly as nest sites by Song Sparrows on SMI. As a result of its location, the nest was effectively concealed from gray foxes ( Urocyon littoralis ), the major predator of this sparrow. Nest and nest site also moderated the combined chilling effects of cool air temperatures and strong northwesterly winds on the eggs and nestlings. Even in the absence of these moderating effects of the nest site, the energetic cost of incubation, estimated at 41-53% of the sparrow's resting metabolic rate, was modest. Twenty-nine percent of the canopy above the nest was open and as much as 73% of the nest cup was in the sun at midday, a time when surface temperatures of foliage, nest and nestlings sometimes exceeded 40 C. Whereas this exposure did not apparently reduce fledging success, it may explain why the incidence of addled eggs was so high in this population of Song Sparrows compared to others. Significant differences existed among races of Song Sparrows in the size, porosity and insulation of the nest. In most cases, these differences were not related to the latitude of the races' nesting areas.

California

Growth and development of thermoregulation in nestling San Miguel Island Song Sparrows

Patterns of growth (reviewed by Ricklefs 1968, 1969; O'Connor 1984) and the development of endothermy (reviewed by Dawson and Hudson 1970, Dunn 1975, Hill and Beaver 1982) have been well-studied in altricial wild birds, especially passerines. But few studies compare grown and thermogenesis in separate populations of the same species. Results of such studies with emberizids varied among species. King and Hubbard (1981), for example, found that nestlings from subarctic, subalpine, and low-altitude montane populations of White-crowned Sparrows ( Zonotrichia leucophrys gambelii ) grew at similar rates. In contrast, Rogers (1985) reported that the growth rates of nestlings in different populations of Savannah Sparrows ( Passerculus sandwichensis ) varied in response to the different environmental constraints of the localities in which they were reared. Nice (1937) and Smith et al. (1982) documented patterns of nestling growth in mainland (Ohio) and insular (Mandarte Island, British Columbia, Canada) populations of Song Sparrows ( Melospiza melodia ), respectively, and found that they were similar to those reported for most other passerines by Ricklefs (1968, 1969) and O'Connor (1984). In 1985-1986, we had the opportunity to examine the growth of nestlings from a third race of Song Sparrows, M. m. micronyx , which is endemic to San Miguel Island near Santa Barbara, California. We also studied the development of endothermy in these young birds, a process not hitherto described for nestling Song Sparrows. We report both in this paper.

California

Water-vapor pressure in nests of the San Miguel Island Song Sparrow

The water-vapor pressure (P N ) in nests of the San Miguel Island race of Song Sparrows ( Melospiza melodia micronyx ) averaged 16 torr, but varied considerable between nests and within individual nests during successive days of incubation. Large daily fluctuations occurred throughout the incubation period and did not parallel concurrent changes in ambien vapor pressure (P 1 ). Daily rates of water loss from nest eggs (M H 2 O ) averaged 28 mg day -1 , but also varied considerable within and between nests and did not correlate with changes in P 1 . M H 2 O increased 6-33% after the third day of incubation. P N was significantly higher and M H 2 O significantly lower in nests located in sheltered gullies than in nests from a windswept slope. These data suggest that Song Sparrows do not regulate P N to achieve hatching success.

California