Publications

Executive Summary We used stable hydrogen isotopes (?D) to investigate both temporal and spatial patterns during spring migration for three warbler species, Wilson's Warbler (Wilsonia pusilla), MacGillivray's Warbler (Oporornis tolmiei), and Nashville Warbler (Vermivora ruficapilla), across multiple migration routes in southwest North America. A strong correlation between stable hydrogen...

The fossil and sub-fossil plant macrofossils and pollen grains found in packrat middens can serve as important proxies for climate and vegetation change in the arid Southwestern United States. A new application for packrat midden research is in understanding post-settlement vegetation changes caused by the grazing of domesticated animals. This work examines a series of 27 middens from...

As part of the National Park Service Inventory and Monitoring Program in the Mojave Network, we conducted an inventory of amphibians and reptiles at Death Valley National Park in 2002-04. Objectives for this inventory were to: 1) Inventory and document the occurrence of reptile and amphibian species occurring at DEVA, primarily within priority sampling areas, with the goal of documenting...

We conducted a baseline inventory for amphibians and reptiles at Manzanar National Historic Site (MANZ), Inyo County, California, in 2002-3. Objectives for this inventory were to: 1) inventory and document the occurrence of reptile and amphibian species at MANZ, with the goal of documenting at least 90% of the species present; 2) provide one voucher specimen for each species identified...

No abstract available.

In November 2004, an experimental high flow release of water from Glen Canyon Dam into the Colorado River through Grand Canyon National Park in Arizona was conducted. The goal of the experiment was to evaluate the use of high flow events as a management tool for the preservation and restoration of natural resources in the Colorado River below Glen Canyon Dam. The U.S. Geological Survey...

In fiscal year 2000, the National Park Service (NPS) initiated a nationwide program to inventory vertebrates andvascular plants within the National Parks, and an inventory plan was developed for the 19 park units in the Southern Colorado Plateau Inventory & Monitoring Network. We surveyed 12 parks in this network for reptiles and amphibians between 2001 and 2003. The overall goals of our...

Arizona is home to 11 species of rattlesnakes. As rapidly growing Arizona communities move into formerly undeveloped landscapes, encounters between people and rattlesnakes increase. As a result, the management of nuisance snakes, or snakes found in areas where people do not want them, is increasingly important. Since 1994, the U.S. Geological Survey (USGS) has conducted research on the...

The narrow-headed garter snake is a harmless, nonvenomous snake that is distinguished by its elongated, triangular-shaped head and the red or dark spots on its olive to tan body. Today, the narrow-headed garter snake is a species of special concern in the United States because of its decline over much of its historic range. Arizona's Oak Creek has historically contained the largest...

Like the saguaro cactus (Carnegia gigantea) and the rattlesnake, the Gila monster is emblematic of the desert Southwest. The Gila monster is not only the largest lizard native to the United States, but also one of only two known species of venomous lizard in the Americas. This stout-bodied lizard can grow to 50 cm (20 in) and is covered with black and pink or orange markings and bead...

The Arizona black rattlesnake makes its home at higher elevations in Arizona and far western New Mexico. The snake's use of high-altitude habitat and its black coloration as an adult distinguishes it from other subspecies of the western rattlesnake (Crotalus viridis), which prefer lower elevations and range from tan to reddish in color as adults. These physical and habitat differences...

We studied home range and habitat use of radio-tagged Great Gray Owls (Strix nebulosa) in Yosemite, California. From 1986–90 we made 5338 relocations on nine adult and three juvenile owls. Home-range size was not correlated with number of locations and was significantly different between breeding and nonbreeding periods. Breeding female summer home range averaged 61.47 ha and during the...