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Geology topics

Mark K. Sogge

Publications and source records attributed to Mark K. Sogge.

28 records · Page 2Linked to original sources
USGS2002

Nestling sex ratios in the southwestern willow flycatcher

Using molecular-genetic techniques, we determined the gender of 202 Southwestern Willow Flycatcher ( Empidonax traillii extimus ) nestlings from 95 nests sampled over a five-year period. Overall nestling sex ratio did not vary significantly from 50:50 among years, by clutch order, or by mating strategy (monogamous vs. polygamous pairings). However, we did observe significant differences among the four sites sampled, with sex ratios biased either toward males or females at the different sites. Given the small population sizes and geographic isolation of many of the endangered subspecies' breeding populations, sex-ratio differences may have localized negative impacts.

Condor↗
USGS2001

Southwestern willow flycatchers recaptured at wintering sites in Costa Rica

An adult Southwestern Willow Flycatcher banded in summer 1998 at Ash Meadows National Wildlife Refuge, Nevada, was recaptured the following winter in Santa Cruz, Costa Rica, then relocated at Ash Meadows during the 1999 breeding season. Another Southwestern Willow Flycatcher banded in 1999 as a nestling at Roosevelt Lake, Arizona, was recaptured in January 2000 on its wintering grounds in Bolsen, Costa Rica. The bird was recaptured at Roosevelt Lake in summer 2000, returned to the same wintering site in Bolsen the following winter, and was relocated at Roosevelt Lake in summer 2001.

North American Bird Bander↗
USGS2000

Breeding season ecology: Chapter 6 in Status, ecology and conservation of the Southwestern Willow Flycatcher (RMRS-GTR-60)

The willow flycatcher ( Empidonax traillii ) breeds across much of the conterminous United States and in portions of extreme southern Canada. As might be expected in such a wide-ranging species, willow fly- catchers in different portions of the range exhibit differences in appearance, song, and ecological characteristics. The intent of this chapter is to provide information on the breeding-season ecology of the southwestern subspecies, E.t. extimus . However, most ecological studies to date have dealt with other willow flycatcher subspecies. Relatively few studies have been published on E.t. extimus , and much of what is currently known is presented in unpublished literature (e.g., agency and consulting firm reports); these sources are relied upon heavily in this chapter. This chapter does not address habitat characteristics in depth, other than for nest sites (refer to A Survey of Current Breeding Habitats for additional details). Although southwestern willow flycatchers are frequent victims of nest parasitism by brown-headed cowbirds ( Molothrus ater ), this chapter will not address the topic of parasitism and its effect on breeding ecology (refer to The Ecology of Brown-headed Cowbirds and their Effects on Southwestern Willow Flycatchers for details). Readers interested in more details of willow flycatcher biology and ecology are encouraged to read McCabe’s (1991) treatise, which is based on over a decade of willow flycatchers research in Wisconsin and includes comparisons with other populations and subspecies.

General Technical Report↗
USGS1999

Range-wide impact of brown-headed cowbird parasitism on the southwestern willow flycatcher (Empidonax traillii extimus)

We present datasets from long-term studies of brood parasitism of Southwestern Willow Flycatcher ( Empidonax traillii extimus ) populations at the South Fork Kern River (SFKR), California, the Grand Canyon, Arizona, and from other intensive flycatcher studies in Arizona. In the two main study areas, we recorded high parasitism rates for the flycatcher. We found that 75 % of Willow Flycatcher nests failed completely when parasitized and that an extremely low percentage of Willow Flycatcher eggs survived to fledging in parasitized nests (11% vs. 47% in unparasitized nests). Our data show that cowbird parasitism also delayed the fledging of young flycatchers. However, contrary to our expectations, we did not find a significant difference between the return rates of “early” versus “late” fledged birds. To evaluate how important cowbird parasitism is to the population decline of the endangered Southwestern Willow Flycatcher, we reviewed the current level of parasitism on this species throughout its range in six states using a large number of datasets from different sites. We also reviewed the historic pattern of increase in Brown-headed Cowbird ( Molothrus ater ) populations in the southwest between 1872-1997 using both nest record and egg collections and documentary evidence. Given the level of impacts to flycatcher productivity inflicted by cowbird parasitism that we observed at SFKR and Grand Canyon, it is likely that cowbirds played a role historically in reducing many local Southwestern Willow Flycatcher populations. Also, cowbirds continue to play a role in slowing or preventing the recovery of this subspecies.

Studies in Avian Biology↗
USGS1997

Status and breeding ecology of the southwestern willow flycatcher in the Grand Canyon

Ernpidonax trailIll extirnus is one of several recognized subspecies of the Willow Flycatcher (Unitt 1987, Browning 1993), a neotropical migrant that breeds across much of North America. This southwestern race is a riparian obligate, nesting in dense patches of willow ( Salix sp.), willow-cottonwood ( Populus sp.), or other similarly structured habitats. In some areas of the Southwest, it nests in dense stands of tamarisk ( Tamarix sp.). Willow Flycatchers were once widespread and locally common in the Southwest (Unitt 1987) but have declined to the point that E. t. extirnus was listed as an endangered subspecies in 1995 (USFWS 1995).

Western Birds↗
USGS1994

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↗
USGS1993

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↗
USGS1991

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↗
USGS1990

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↗