I evaluated the effects of simulated noise from low-flying jet aircraft on the behavior and physiology of 6 captive desert mule deer (Odocoileus hemionus crooki) and 5 captive mountain sheep (Ovis canadensis mexicana). I measured heart rate, body temperature, ambient temperature, and behavior related to the number of overflights/day, and decibel levels (dB) animals were exposed to (range = 92-112). I recorded heart rate and body temperatures from transmitters implanted into the body cavity of animals. Ambient temperature was recorded in the pens and behavior was described from visual observations. I compared heart rates during simulated overflights by jet aircraft (N = 112/season) of sheep and deer to data collected prior to and following treatments. I documented differences between heart rates, species, dB levels, and number of overflights/day within and between seasons. All animals became habituated to aircraft noise. Although heart rates increased during overflights, they returned to the resting heart rate in ≤ 2 minutes.

I measured digestible protein consumed by 4 (2 M, 2 F) captive desert mule deer (Odocoileus hemionus crooki). Deer were fed native forage collected from the Belmont Mountains, Arizona. Intake of forage differed significantly (P < 0.05) between sexes in every season. Intake of digestible protein for both sexes was highest in fall, lowest in the spring and summer for males and females, respectively. Significant (P < 0.05) differences of forage biomass were recorded among all vegetation associations and seasons in the Belmont Mountains. The most forage biomass was available in winter, the least in spring. Desert mule deer in the Belmont Mountains are close to the nutritional carrying capacity of the range. Other efforts to increase the deer population may not be effective if the forage base is not increased.

Average specific gravity of Emory oak (Quercus emoryi) estimated from 115 increment cores was 0.567 ± 0.011 (95 percent confidence interval). Increment core specific gravity is a predictor of average tree specific gravity. Diameter breast height (dbh) and diameter root collar (drc) were correlated with increment core specific gravity, but the correlations were too low to be valuable for predictive purposes. Estimated physical properties of Emory oak wood were lower than those reported for Gambel oak (Quercus gambelii) but higher than those reported for alligator juniper (Juniperus deppeana).

I designed and tested experimental enclosures with 1-way exits for the study of emigration in house mice. Rapid emigration from barren enclosures supported the contention that all mice can find and use the exits if conditions in the enclosures are unsuitable for them. Invariable residency in resource-rich enclosures during the spring, summer and fall revealed that resident animals will not cross the exits during routine behaviors. The enclosures and exits permitted normal emigratory and residency behavior. In experiments on the role of emigration in population regulation, the number of resident mice was consistent in enclosures with fixed levels of resources. The number of residents was about double in enclosures with twice the resources. The first male and few females added in each trial usually became resident, and mice added subsequently usually emigrated. My data suggest that mice were regulating their numbers to available resources through spacing and emigration.

Management strategies are needed to reduce the rate at which brown-headed cowbirds (Molothrus ater) parasitize their hosts. I investigated whether vegetation management could be used to reduce parasitism by seeking differences in nest-site microhabitats of hosts in a riparian area of central Arizona. During 1993 and 1994, I quantified vegetation characteristics in 0.04 ha plots centered on 128 nests of 4 commonly parasitized species and 4 infrequently parasitized species. I compared characteristics between (1) parasitized and unparasitized nests of common hosts, and (2) nests of common and infrequent hosts. Factors associated with outcome of parasitism were vegetation volume at nest, size of nest substrate, distance from nest to visual obstruction below nest, and presence of large trees near the nest. Whether nests belonged to common hosts or infrequent hosts was best predicted by nest height. My results indicate riparian areas should be managed for large trees and numerous shrubs when the goal is to reduce parasitism.

Whitebark pine (Pinus albicaulis Engelm.) tree-ring chronologies of 700 to greater than 1,000 years in length were developed for four sites in the Sawtooth-Salmon River region, central Idaho. These ring-width chronologies are used to (1) assess the dendrochronological characteristics of this species, (2) detect annual mortality dates of whitebark pine attributed to a widespread mountain pine beetle (Dendroctonus ponderosae Hopk.) epidemic during the 1909 to 1940 period, and (3) establish the response of whitebark pine tree ring-width growth to climate variables. Crossdating of whitebark pine tree-ring width patterns was verified. Ring-width indices had low mean sensitivity (0.123-0.174) typical of high elevation conifers in western North America, and variable first order autocorrelation (0.206-0.551). Mortality of dominant whitebark pine caused by mountain pine beetle had a maxima at 1930 on all four sites. Response functions and correlation analyses with state divisional weather records indicate that above average radial growth is positively correlated with winter and spring precipitation and inversely correlated with April temperature. These correlations appear to be a response to seasonal snowpack. Whitebark pine is a promising species for dendroclimatic studies.

Determination of reproductive success in birds is important for understanding population dynamics, habitat quality, and features necessary for breeding. I incorporated behavioral observations, nest monitoring, and a reproductive ranking index (Vickery et al. 1992) to (1) categorize painted redstarts (Myioborus pictus), solitary vireos (Vireo solitarus plumbeus), and western wood-pewees (Contopus sordidulus) as breeders or nonbreeders, (2) locate nests, (3) monitor nest status, and (4) determine nest success and parasitism rates in 14 canyons of the Huachuca and Santa Rita mountains, Arizona during 1994-1995. I built logistic regression models for each species that correctly classified 58-68% of successful nesters from unsuccessful nesters, 62-85% of areas used by birds from random sites along the canyons, and at each nest, I correctly classified 39-60% of successful nest sites from unsuccessful nest sites and 87-95% of nest sites from nonoverlapping sites in areas of use. These models can be used to determine areas that would promote occupancy and successful nesting by these 3 species.

Geographic range and numbers of buff-breasted flycatchers (Empidonax fulvifrons) have decreased in Arizona. I conducted surveys to locate additional populations. Results suggested that some small populations have disappeared since 1980, but that other small populations have increased. I estimated reproductive success using an index based on adults' behavior. I measured vegetation in used areas, nest sites, and available areas. I used logistic regression to compare used to available areas and nest sites to used areas. Used vs. available comparisons indicated that buff-breasted flycatchers used areas dominated by pines, with a sparse oak understory. I found significant associations between buff-breasted flycatcher presence and vegetation type, structural stage, canopy cover, and forest patch width. I developed a habitat model to help manage this rare species. I recommend continued monitoring of buff-breasted flycatcher populations and creation of open pine forest with an open understory of oak. Fire may facilitate development of potential habitat.

With Anglo settlement of southern Arizona in the late 1800s, fire regimes were altered dramatically. Currently, desert scrub has experienced a dramatic rise in frequency and size of wildfire which may remove fire-intolerant perennials that define the community structure. On the contrary, woodlands and forests now contain excessive fuel build up and require prescribed burning to restore the system's balance. These opposing attitudes reflect the conundrum of how to manage naturally occurring fires, or where and when to initiate prescribed burning to recreate each vegetation community's "natural" fire regime. To resolve this dilemma, there is need to discern natural fire histories by collecting specific baseline data such as where, when and how the landscape has burned. This research has been focused on the design and development of a relational database, and the incorporation of a geographic information system to develop a system that can be used to fulfill this need.

Little is known about habitat selection by elf owls (Micrathene whitneyi) and western screech-owls (Otus kennicottii). From 1994 to 1996 in the Sonoran Desert, I used point counts and nest searches to examine habitat selection by both species at multiple spatial scales. The abundance of both species had a positive association with percent cover of washes and mesquite (Prosopis spp.) at the scale of the study area. At both the scale of the study area and the nesting area, elf owls selected areas with high densities of mature saguaros (Carnegiea gigantea) and saguaro cavities. Elf owls nested only in woodpecker cavities in saguaros, whereas western screech-owls nested in both saguaro cavities and in natural cavities in mesquite. Western screech-owls nested nearly exclusively in gilded flicker (Colaptes chrysoides) cavities when they nested in saguaros. Patterns of nest cavity selection by elf owls suggest they may choose cavities that provide thermoregulatory advantages. I give management recommendations based on my findings.