I studied a population of Cooper's hawks (Accipiter cooperii) nesting in the metropolitan city of Tucson, Arizona, from 1994 to 1997. I identified 51 Cooper's hawk territories distributed across Tucson with pockets of nesting density as great as 1 pair/64.7 ha. Eucalyptus (Eucalyptus spp.) (70.8%), aleppo pine (Pinus halepensis ) (25.0%), and cottonwood trees (Populus fremontii) (4.2%) were used as nesting structures more frequently than expected based on availability. Nest trees were primarily located in residential yards (48.3%) and high-use recreational areas (28.3%). Nest sites had a greater basal area, canopy cover, stem density, and number of trees >10 m tall than random sites. I compared the breeding ecology of urban Cooper's hawks with those in exurban areas. Urban pairs tended to have larger clutches (urban x̄ = 3.64: exurban x̄ = 3.20) (P = 0.085) and more nestlings (urban x̄ = 3.11; exurban x̄ = 2.78) (P = 0.145) than exurban pairs. Nestling mortality, however, was greater among urban nests (51%) than exurban nests (5%). The primary cause of death among urban nestlings was trichomoniasis (80%), a disease caused by the parasitic protozoan Trichomonas gallinae ; the disease was not a mortality factor among exurban nests. Raptors develop the disease by eating infected prey. Doves (Columbidae) are hosts for the protozoan and accounted for 83% and 10% of the diet of urban and exurban Cooper's hawks, respectively. Breeding age Cooper's hawks were 99% free of infection independent of nesting area. Infection rates were greater among urban nestlings than exurban nestlings (P < 0.0001). Breeding urban Cooper's hawks have high probabilities of survival (0.792) and recapture (0.947), but the estimated juvenile survivorship is low (0.199). Age-specific fecundity and survival suggests the urban population is declining by 8% annually, but has the capacity to increase by at least 2% annually. Paradoxically, the population appears to be stable or increasing, probably due to immigration of Cooper's hawks from outside the study area. Population sinks in human altered landscapes have been described as "ecological traps" because animals are attracted to them but suffer from low productivity or high mortality once they are there. My results suggest Tucson may be an ecological trap for Cooper's hawks.

The influence of the herbicides sulfometuron and simazine on the establishment of 8 species of tree seedlings was studied in northern Israel. The experiment included three treatments and a control. The first treatment applied simazine at a rate of 5 kg/ha, and second treatment applied simazine at a rate of 5 kg/ha and sulfometuron at a rate of 0.03 kg/ha. Sulfometuron was applied alone at a rate of 0.03 kg/ha in the third treatment. Statistical analyses showed significant effects on the survival of some species treated with sulfometuron. To ensure earlier season survival, the rate of sulfometuron applied should be kept at a minimum level to allow both weed control and adequate establishment of seedling. Low-rate applications are particularly important in arid and semi-arid areas.

I examined movements and habitat use by desert mule deer (Odocoileus hemionus crooki) and collared peccary (Dicotyles tajacu) in the Rincon Mountain District of Saguaro National Monument (SNM) from February 1988 through December 1989. Movements and habitat use by mule deer were closely associated with the distribution of free-standing water during the driest seasons of the year. Deer responded to losses of ephemeral water sources in SNM by leaving the monument to obtain water. Four of 5 peccary herds supplemented their natural diet by visiting houses and/or restaurants on a daily or twice daily basis. The addition of water and supplemental food sources was a deliberate effort by homeowners to attract wildlife onto their property. The current pattern of habitat islands interspersed with low density housing (1 house/2-4 ha) is an effective and highly desirable buffer zone between the monument and the more heavily developed urban areas 3.2 km west of the park.

The Hayden-Rhodes Aqueduct (HRA) extends from Lake Havasu along the California and Arizona border to 40 km northeast of Phoenix, Arizona. The Bureau of Reclamation established water catchments for wildlife, and wildlife bridges to provide access for wildlife across the HRA. I investigated the effectiveness of these mitigations for desert mule deer (Odocoileus hemionus crooki) from July 1989 to July 1990. I examined deer use of wildlife bridges, concrete overchutes, and water catchments; the quality of deer habitat at crossings; and the influence of mountain lions (Felis concolor) on deer at water catchments. All water catchments were used by deer. There was very little use of wildlife crossings by deer. Deer habitat on the north side of the HRA received more use by deer than habitats south of the HRA. I could not determine if mountain lions capture prey more often near water catchments than in other areas.

I sought to determine if brown tree snakes (Boiga irregularis) raised in captivity showed annual and/or subsidiary growth marks corresponding to feeding or shedding events. I injected 25 brown tree snakes with a fluorescent bone marker (calcein or alizarin red) and raised them for one year under constant conditions. Growth marks beyond the fluorescent marker were correlated with shedding events but not with years or feeding events. Shedding events have not previously been identified as a correlate of growth marks in bone. I do not know if the correlation occurs in other species, as growth cycles have not previously been studied in tropical snakes. The correlation between growth marks and shedding events may allow the study of ecdysis in free-ranging snakes, and shedding events may be the cause of the secondary growth marks found in many reptiles.

Measurements of tree characteristics were used as indicators of overstory structure on four oak woodland sites in southeastern Arizona. Three areas harvested at different times and intensities were compared with an undisturbed area to assess effects of harvesting on various structural attributes of woodland overstories. Structural vegetation changes affect habitat quality and thus wildlife populations in modified areas. Significant differences were found for some woodland structural characteristics between harvested areas and an undisturbed area. Structural changes persist, as prolific coppice sprouting produces shrub-like trees, which appear to take a relatively long time to reach mature height and form. Managers might be able to moderate impacts of harvests on woodland structure by adjusting harvest intensity, and multiple-use management objectives for some species of wildlife still might be met.

I examined the relationship between exotic and native cavity-nesting birds in the Sonoran desert near Tucson, Arizona during 1988 and 1989. I attempted to limit cavity availability in 1989 by plugging cavities that were unused, or used by exotics, in 1988 with rubber test tube stoppers. Numbers of nests of any species did not significantly change between 1988 and 1989. Control plots showed similar results. I found no significant negative correlations between number of nests of European starlings (Sturnus vulgaris) and any other cavity-nesting species. Of the cavity characteristics examined, species only differed in size of cavity openings. My data indicate that exotic and native cavity-nesting birds were not competing for nest cavities. An excess of available nest cavities is the probable reason for this lack of competition. Temporal differences in cavity use among species may have helped contribute to the abundance of cavities.

Habitat use of Merriam's turkey (Meleagris gallopavo merriami) was characterized in the Prescott National Forest, Arizona, between March 1991 and August 1992. Roost sites were generally found in canyons or on hillsides, and contained a large number of ponderosa pine trees, and Gambel oak seedlings and trees. Turkeys fed on juniper berries, generally in small groups of large juniper trees within ponderosa pine stands. Turkeys fed on acorns in stands of Gambel oak on hillsides. Turkeys feeding on grass/forb vegetation tended to be on flat areas with a large amount of forb and grass cover. Turkeys loafed under Gambel oak, in areas with large amounts of Gambel oak growth near openings, on hillsides or in canyons. Turkeys also loafed under juniper trees; these areas had a large basal area of alligator juniper and high numbers of Gambel oak seedlings.

In 1992, I surveyed 359 National Park Service units to determine the presence of coyotes and to assess problems and management activities. Coyotes were reported in 42% of all parks in 1992. Management activities for coyotes varied, but in general coyotes were not a management problem. I examined the annual, seasonal, and daily movements of coyotes (Canis latrans) near the Rincon Mountain District of Saguaro National Monument from December 1991 through December 1992. I estimated annual and seasonal home-range areas and daily movements using minimum convex polygon (MCP) and harmonic mean (60% isopleth) estimates from 1,412 point relocations and 432 continuous relocations of 9 coyotes (6 M and 3 F). The average annual MCP home range estimate was 15.7 km2 and harmonic mean was 2.3 km2 Annual and seasonal home range areas did not differ (P > 0.05) between suburban and rural areas or between males and females. Daily average MCP estimate was 1.5 km2 and harmonic mean was 0.5 km2 Daily movements of coyotes also did not differ (P > 0.05) between study areas or sexes.

This study was conducted to determine if suburban development adjacent to Saguaro National Monument (SNM) affected coyote (Canis latrans) populations. I estimated density, described grouping behaviors, and analyzed the diets of coyotes living near the interface of SNM and Tucson, Arizona from November 1991 to December 1992. I used a mark-resighting method to estimate the density of coyotes in a 13 km² area. Seven territorial groups (n = 48 coyotes) lived in the 13 km² area. Group size varied among behavioral seasons. I compared diets of coyotes between 2 areas: suburban and rural. Coyote scats from the suburban area contained less (P < 0.05) plant material annually, and less mammal material during coyote breeding and gestation periods than the scats from the rural area. Dog food, bread, and other human related items comprised 35% of the coyotes' annual diets in the suburban area. Supplemental sources of food in the suburban area helped support high densities of coyotes.