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.

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.

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.

I studied bat use of 3 isolated water developments on the Cabeza Prieta National Wildlife Refuge in southwestern Arizona between May 1995 and August 1997. I recorded bat echolocation calls to measure overall activity, videotaped bat behavior and identified aquatic insects to determine whether bats were feeding or drinking, mist netted to assess visitation patterns with respect to season, sex, and reproductive condition for each of 4 species captured, studied movements of banded individuals, and monitored roosts of the California leaf-nosed bat (Macrotus californicus) in nearby mines. Echolocation activity was much higher at water than in nearby dry desert washes and was greater in dry washes than at random sites away from water. Bats visited water in all seasons, visiting primarily to drink, not to feed on insects. The California leaf-nosed bat constituted 41% of more than 1,000 captures. I concluded that in my study area this species made extensive use of water developments for drinking, particularly during lactation.

A study was done on a rocky intertidal community in Puerto Penasco, Sonora, Mexico in the summers of 1997--1999 in order to determine if the ENSO of 1997--1998 had an effect on population densities of selected macroinvertebrates. Two replicate transects were laid perpendicular to the sea edge and a census of 21 macroinvertebrate species was taken in the summers of 1997, 1998 and 1999. A significant decrease of species densities occurred in 1998 when the mean sea surface temperature (SST) was more than 2°C warmer than in 1997 due to the 1997--1998 ENSO event. A phenomenon was also observed in 1998 where some species changed, compared to 1997, their vertical distribution in the intertidal from shallow to deeper waters, with a subsequent return to a more expected distribution in 1999. Also a comparison of 1997 and 1976 densities showed an increase in 1997 in abundances of those species with southern geographic ranges and a decrease of those with northern geographic ranges. This was correlated with an increase of mean SST of 1.9°C between the 1970's and the 1990's.

<p> Being sprayed by the oil produced by the anal glands of the striped skunk (<i>Mephitis mephitis</i>) is known to be strongly aversive to potential predators, which quickly learn to not attack in the future. However, many trap lures use oil from skunk anal glands as an ingredient intended to attract carnivores. This paradoxical nature of skunk oil being both attractive and aversive to potential predators has yet to be investigated, leaving a gap in the understanding of how predators respond to the visual aposematic warning signal of the skunk&rsquo;s pelt in combination with the possibly attractive chemical components of its oil. In this study, camera traps with baited models with either black-and-white or brown pelage, either with or without skunk oil, were deployed in natural areas around Southern California. Results suggest despite its previous use as an attractant for carnivores, the skunk&rsquo;s oil acts as a long distance deterrent while pelt coloration functions as a short distance warning signal.</p>

A family of repetitive DNA sequences which comprise up to 15% of the genome of some waterfowl have previously been described. These sequences (RBMI sequences) were originally cloned from the redbreasted merganser: the species with the highest copy number. RBMI sequences are present in restriction enzyme digests as sets of fragments of discrete lengths indicating populations of various restriction morphs. Fragment sizes are conserved between related species and have been used to infer phylogenetic relationships. / In this study several major EcoRI restriction size classes of RBMI sequences were cloned and sequenced (2.6, 2.0, 1.7, and 0.6 kb fragments). The sequence elements present have several characteristics of retroposons; open reading frames, poly-A addition signals, and A-rich tails. The four clone types have overlapping regions of homology. In all 6 regions (A-F) are defined which are fragment size specific or are solely responsible for hybridization to a specific genomic restriction fragment. Probes for regions A-F were hybridized to Southern blots of DNA from related species. The organization of these sub-fragments is similar in the seven species tested. The genomic organization of these unique regions was investigated by Southern hybridization using probes for regions A-F against a time course of restriction enzyme digestion. Higher order structures were found in partial digests which indicate association of these sequences in larger discrete repeat units in the genome. Finally, partial MboI digest clones, containing RBMI sequences, were mapped with restriction enzymes, probes A-F, and total repetitive DNA. These studies indicate that regions A-F are present in the genome in several different organizations, some are flanked by unique DNA sequences, and that repetitive sequences other than regions A-F are present in these RBMI clusters. It is proposed that these sequences are of retropseudogene origin which were subsequently amplified as retroposons or as tandem repeats by recombination and/or slippage replication. / Source: Dissertation Abstracts International, Volume: 55-04, Section: B, page: 1305. / Director: Siwo R. deKloet. / Thesis (Ph.D.)--The Florida State University, 1994.

Since its introduction to the U.S., the South American fire ant Solenopsis invicta has displaced its native congener S. geminata from many habitats. Repeated censusing indicates that the distribution of these ants in the northern Apalachicola National Forest is stable, with S. invicta monopolizing pond margins, both species occupying roadsides, and S. geminata found alone in the woods. A series of investigations revealed a number of differences between S. invicta and S. geminata that may play a role in determining the distribution of the two species. Attributes of S. invicta which have likely contributed to its displacement of S. geminata include: larger colony size, quicker colony growth facilitated by brood raiding, reproduction earlier in the year, and freedom from mermithid nematode parasitism. In the woods of the Apalachicola National Forest, the advantages enjoyed by S. invicta appear to be counteracted by a greater ability of S. geminata newly mated queens to survive the colony founding period. / Comparisons of the reproductive biology of S. invicta and S. geminata indicate striking differences. All mature S. invicta colonies are reproductively active during late spring and early summer, when mating flight activity is at its peak. Subsequently, the number of active colonies and the number of ants participating in mating flights gradually declines. The reproductive system of S. geminata is more complex, with colonies pursuing three different strategies. Two-thirds of the S. geminata colonies are reproductively active only in the late spring and early summer. About one-fifth are active only in the fall. A small number of colonies release alates in the spring/summer and again in the fall. The gynes of S. geminata exhibit a distinct dimorphism: those produced in spring and summer are larger, heavier, and fatter than gynes produced in fall. Both types are successful at becoming the sole queens of mature colonies, although several lines of evidence indicate that microgynes from fall mating flights do not found colonies independently. / Source: Dissertation Abstracts International, Volume: 55-04, Section: B, page: 1269. / Major Professor: Walter R. Tschinkel. / Thesis (Ph.D.)--The Florida State University, 1994.