Populations of mesopredators (mid-sized mammalian carnivores) are expanding in size and range amid declining apex predator populations and ever-growing human presence, leading to significant ecological impacts. Despite their obvious importance, population dynamics have scarcely been studied for most mesopredator species. Information on basic population parameters and processes under a range of conditions is necessary for managing these species. Here we investigate survival, recruitment, and population growth rate of a widely distributed and abundant mesopredator, the northern raccoon (Procyon lotor), using Pradel's temporal symmetry models and >6 years of monthly capture-mark-recapture data collected in a protected area. Monthly apparent survival probability was higher for females (0.949, 95% CI = 0.936-0.960) than for males (0.908, 95% CI = 0.893-0.920), while monthly recruitment rate was higher for males (0.091, 95% CI = 0.078-0.106) than for females (0.054, 95% CI = 0.042-0.067). Finally, monthly realized population growth rate was 1.000 (95% CI = 0.996-1.004), indicating that our study population has reached a stable equilibrium in this relatively undisturbed habitat. There was little evidence for substantial temporal variation in population growth rate or its components. Our study is one of the first to quantify survival, recruitment, and realized population growth rate of raccoons using long-term data and rigorous statistical models.

Mesopredators play an increasingly important role in ecosystems where apex predators have been eliminated, but population ecology of these midsized mammalian carnivores remains poorly understood. We applied Pradel's temporal symmetry models to > 6 years of monthly capture mark recapture data and investigated factors influencing apparent survival, recruitment, and realized population growth rate of the Virginia opossum (Didelphis virginiana), an important mesopredator with unique life-history characteristics. Apparent survival did not vary temporally; monthly survival probabilities were 0.86 +/- 0.01 (SE) for females and 0.76 +/- 0.02 for males. Recruitment rate varied monthly, with the highest recruitment in December (0.32 +/- 0.12 for females and 0.57 +/- 0.22 for males). Realized population growth rate varied monthly and was also highest in December (1.30 +/- 0.17). Both recruitment and population growth rate were positively influenced by the monthly coefficient of variation of precipitation. There was no evidence of density-dependent influences on opossum population dynamics, nor was there evidence of competition from the raccoon (Procyon lotor), a sympatric and abundant mesopredator. Our study is the 1st to simultaneously report survival, recruitment, and population growth rate of Virginia opossums and to investigate factors influencing these rates. In doing so, we provide important insights into the population dynamics of an increasingly influential mesopredator.

The loss and fragmentation of substantial areas of forest habitat, in combination with rampant hunting, has pushed many of Southeast Asia's megafauna species to the verge of extinction. However, the extent of these declines is rarely quantified, thereby weakening lessons learned and species-based management. This need not be the case as a proliferation of camera trap surveys for large-bodied mammals across Southeast Asia, which use a standardized sampling technique, presents a rich yet under-utilized wildlife data set. Furthermore, advances in statistical techniques for assessing species distribution provide new opportunities for conducting comparative regional analyses. Here, we focus on one of Southeast Asia's least known species of megafauna, the Endangered Asian tapir (Tapirus indicus), to investigate the performance of a camera trap-based spatial modeling approach in conducting a range-wide species assessment. Detection data were collectively collated from 52,904 trap days and 1,128 camera traps located across 19 study areas drawn from the Asian tapir's entire range. Considerable variation in tapir occurrence was found between study areas in: Malaysia (0.52-0.77); Sumatra, Indonesia (0.12-0.90); Thailand (0.00-0.65); and, Myanmar (0.00-0.26), with generally good levels of estimate precision. Although tapirs were widespread (recorded in 17 of the 19 study areas), their occurrence was significantly and negatively correlated with human disturbance. Thus, this study extends the previously known applicability of camera traps to include a threatened and cryptic species by identifying where and how tapirs persist (including new records of occurrence), where future surveys should be conducted and providing a benchmark for measuring future conservation management efforts. (C) 2013 Elsevier Ltd. All rights reserved.

Large ungulates across South-east Asia have been experiencing a rapid decline in recent decades because of overexploitation by humans. An absence of reliable data on the abundance and distribution of ungulates makes it difficult to assess the effectiveness of conservation efforts to recover their populations. As the principal prey for Endangered tigers Panthera tigris, depletion of wild ungulates is a major threat to the species' persistence and recovery across its range. This study estimated abundance and distribution of five ungulate taxa using a grid-based occupancy survey across a 3,000 km(2) core zone within the 5,950 km(2) Nam Et-Phou Louey National Protected Area in northern Lao. The results show an abundance index of 5.29 +/- 0.30 ungulates per km(2), with muntjac Munticus spp. and wild pig Sus spp. being most common, moderate levels of serow Capricornis milneedwardsii and sambar Cervus unicolor but few gaur Bos gaurus. This low abundance of medium- and large-sized ungulates at the site strongly suggests that strict control of hunting of these ungulates is important for securing their long-term survival as well as that of the tiger population that depends on them, which is currently the only known breeding population remaining in Indochina.

AbstractThe potential conservation value of fragmented or countryside landscapes in the tropics is being increasingly recognized. However, the degree to which fragmented landscapes can support species and the key patch and landscape features that promote population persistence remain poorly understood for elusive species such as ground-dwelling birds. We examined the presence/absence of seven species of galliforms and tinamous in 50 forest patches of 2.9–445 ha in northern Guatemala using camera traps and audiovisual surveying. After accounting for differences in detectability among species we found great variation in patterns of vulnerability of these species to habitat loss and fragmentation, with the three largest species being the most vulnerable. Distribution patterns of species among patches was influenced more strongly by measures of landscape context, such as the amount and configuration of habitat in the surrounding landscape, than within-patch variation in vegetation structure or disturbance. Our results indicate that large-bodied game birds may be particularly sensitive to habitat loss and fragmentation and emphasize that management efforts for these species need to go beyond consideration of local, within-patch factors to consider the impact of processes in the surrounding landscape. Our findings also demonstrate the utility of camera traps as a methodology for surveying large terrestrial bird species in fragmented landscapes.

We performed stable isotope analysis on eight mammalian species: pig-tailed macaque (Macaca nemestrina), long-tailed macaque (M. fascicularis), dusky leaf monkey (Trachypithecus obscurus), brush-tailed porcupine (Atherurus macrourus), wild boar (Sus scrofa), lesser mouse-deer (Tragulus javanicus), greater mouse-deer (T. napu), and barking deer (Muntiacus muntjac), to test the hypothesis that the differences in diet and habitat types among species, guilds and foraging strategies are refl ected in the δ 15 N and δ 13 C signatures of their tissues. Whereas the isotopic ratios differed among taxa, the four major isotopic groups observed were: mouse-deer species, primate species, brush-tailed porcupine, and wild boar. The brush-tailed porcupine showed the most divergent isotopic signatures, depleted in both δ 15

Understanding the influence of large and small-scale heterogeneity on species distribution and abundance is one of the major foci of landscape ecology research in fragmented environments. Although a large number of studies have addressed this issue individually, little effort has been made to synthesize the vast amount of literature published in the last decade. We reviewed 122 focal patch studies on 954 species published between 1998 and 2009 to determine the probability of species responding significantly to landscape, patch, and within-patch variables. We assessed the influence of taxonomic, life history, and methodological variables on probability of response to these 3 levels. Species in diverse taxa responded at high rates to factors at all three levels, suggesting that a multi-level approach is often necessary for understanding species response in patchy systems. Mammals responded at particularly high rates to landscape variables and therefore may benefit more than other taxa from landscape-level conservation efforts in fragmented environments. The probability of detecting a species response to landscape context, patch, and within-patch factors was influenced by a variety of methodological aspects of the studies such as type of landscape metric used, type of response variable, and sample size. Study design issues rarely are discussed by authors as reasons why a particular study did not find an effect of a variable, but should be given more consideration in future studies.

The relative influence of habitat loss vs. habitat fragmentation per se (the breaking apart of habitat) on species distribution and abundance is a topic of debate. Although some theoretical studies predict a strong negative effect of fragmentation, consensus from empirical studies is that habitat fragmentation has weak effects compared with habitat loss and that these effects are as likely to be positive as negative. However, few empirical investigations of this issue have been conducted on tropical or wide-ranging species that may be strongly influenced by changes in patch size and edge that occur with increasing fragmentation. We tested the relative influence of habitat loss and fragmentation by examining occupancy of forest patches by 20 mid- and large-sized Neotropical mammal species in a fragmented landscape of northern Guatemala. We related patch occupancy of mammals to measures of habitat loss and fragmentation and compared the influence of these two factors while controlling for patch-level variables. Species responded strongly to both fragmentation and loss, and response to fragmentation generally was negative. Our findings support previous assumptions that conservation of large mammals in the tropics will require conservation strategies that go beyond prevention of habitat loss to also consider forest cohesion or other aspects of landscape configuration.

Abstract: Accurately estimating change in wild turkey (Meleagris gallopavo) abundance is paramount for harvest management and for quantifying the effect of environmental factors, but unfortunately there is no widely accepted method to monitor wild turkey numbers. We tested a monitoring method used by the Florida Fish and Wildlife Conservation Commission that utilizes a grid of baited camera‐traps. We marked Osceola wild turkeys (M. gallopavo osceola) at 2 sites in Florida to estimate detection rates and home range sizes over 3 yr. The number of banded birds for both areas was estimated using capture—mark—recapture models. Detection and resight rates differed between areas and among seasons. Estimates of population size varied by season. Area or sex parameters did not seem to effect population size estimates. We used linear regression to analyze the relationship between the estimated wild turkey density on each area and the number of wild turkey photographs from the surveys. Radiotelemetry techniques were used to estimate home range size. Differences in home range sizes and response to camera traps were observed between the 2 areas. We found no consistent relationship between the number of birds photographed and the estimated population. We concluded baited camera‐traps are of limited use to reliably estimate wild turkey abundance.

Anthropogenic habitat fragmentation poses a serious threat to conservation of large carnivores, due to their extensive movements and potential conflicts with humans. We studied the population ecology of Florida black bears (Ursus americanus floridanus) for 6years in two study areas in north-central Florida: Ocala National Forest (ONF), a contiguous forested habitat, and an adjacent residential community of Lynne, a fragmented habitat with substantial human activities. We estimated age-specific survival and fecundity rates of bears using data from radio-collared bears, and parameterized and analyzed stage-structured matrix population models for the two study sites and also for data pooled from both sites. Annual survival rates of adult females were lower in Lynne (0.776±0.074) than in ONF (0.966±0.023). While cub survival rates were higher in Lynne (0.507±0.135) than in ONF (0.282±0.109), the rates at both sites were substantially lower than those reported for other black bear populations. Age-specific fecundities did not vary between sites. The asymptotic population growth rate for ONF was greater than one, whereas that for Lynne was less than one. Our results suggest that anthropogenic influences (primarily road density and vehicular traffic, through their effect on adult survival) can substantially affect the population dynamics of Florida black bears and other large carnivores with large home ranges. We recommend efforts such as constructing highway underpasses, which could reduce road-related mortalities, to ensure long-term persistence of Florida black bears facing threats from rapidly increasing human influences.

Multi-faceted field sampling in a mosaic landscape in Venezuela generated insights on how topographical characteristics, forest composition, degree of habitat interspersion, and paleoecology influenced the abundance and distribution of vertebrates. Physical heterogeneity resulted in distinct vegetation types and a very uneven distribution of medium to large-sized vertebrates. Variations in forest composition resulted in dramatic contrasts in primate densities. White-tailed deer densities varied an order of magnitude between vegetation types. Yellow-knobbed curassow densities peaked in moist forest. Similar chachalaca densities were encountered in dry forest. Although there was spatial overlap between jaguars and pumas, from a large-scale perspective pumas made more use of drier habitats. In select habitats the abundance and biomass of red-footed tortoises exceeded that of multiple species of large native mammals combined. This variation in animal abundance highlights the significance of scale in the interpretation of ecological data.

12 2008 33 4737 Received 3.3.2007 ; a cepted 7.8.2008 Copyright © 8 MSJ Introduction Tropical rainforests of Southeast Asia are home to a rich diversity of lesser known carnivores, including the Asiatic golden cat (Catopuma temminckii) and dhole (Cuon alpinus). These medium-sized carnivores are found primarily in South and Southeast Asia and, while their distribution status is yet to be fully determined for some countries, over much of their range they appear to be sympatric (Sunquist and Sunquist 2002; Durbin et al. 2004). For both species, their populations in Peninsular Malaysia represent the southernmost extent of the continental distribution. The Asiatic golden cat and the dhole are listed, respectively, as Vulnerable and Endangered by the IUCN Red List of Threatened Species (Sunquist and Sunquist 2002; Durbin et al. 2004), as well as Appendix I and II species by the Convention on International Trade in Endangered Species on Wild Fauna and Flora (CITES 2007), respectively. Adult Asiatic golden cats weigh about 8–16 kg (Sunquist and Sunquist 2002). In Malaysia, the average weight was 8.1 kg for females (n = 3) and 9.0 kg for males (n = 3) (Lim 2002). They are solitary hunters and primarily terrestrial, but they are able to climb trees if needed. Their diet mainly consists of small vertebrates such as birds, lizards, snakes, rodents and other mammals up to the size of small deer (Lekagul and McNeely 1977; Lim 2002), but there is a record of one cat killing a buffalo (Bubalus bubalis) calf (Pocock 1939). Dholes are slightly larger than Asiatic golden cats; females weigh 10–13 kg and males 15–20 kg (Durbin et al. 2004). They are strictly terrestrial, communal hunters, primarily preying on vertebrate prey, with a preference of medium to large ungulates. In India, dholes prey on medium-sized (31–175 kg) ungulates, including young gaur (Bos gaurus) (Karanth and Sunquist 1995; Andheria et al. 2007). The size class of prey taken by dholes in Thailand was also similar (Grassman et al. 2005). Nothing is known about the ecology of dholes in Malaysia to the extent that until recently (Durbin et al. 2004) even the species’ presence was questionable (Stewart 1993). This paper presents the first information on diet and activity patterns of two threatened but lesser known medium-sized sympatric carnivores from a primary rainforest in Peninsular Malaysia.

WEC-215, a 3-page illustrated fact sheet by Kimberly M. Annis, Melvin E. Sunquist, and William M. Giuliano, describes the Florida black bear, its distribution, and the foraging behaviors that bring it in contact with humans, how to prevent nuisance problems with bears when in bear country, and what to do if you encounter a bear. Published by the UF Department of Wildlife Ecology and Conservation, February 2007.

Wildlife MonographsVolume 158, Issue 1 p. 1-41 Ecology of Florida Black Bears in the Okefenokee-Osceola Ecosystem STEVEN DOBEY, STEVEN DOBEY Department of Forestry, Wildlife, and Fisheries, 274 Ellington Plant Sciences Building, University of Tennessee, Knoxville, TN 37996, USASearch for more papers by this authorDARRIN V. MASTERS, DARRIN V. MASTERS Department of Wildlife Ecology and Conservation, University of Florida, Gainesville, FL 32611, USA Hoopa Tribal Forestry, P.O. Box 368, Hoopa, CA 95546.Search for more papers by this authorBRIAN K. SCHEICK, BRIAN K. SCHEICK Department of Wildlife Ecology and Conservation, University of Florida, Gainesville, FL 32611, USA Florida Fish and Wildlife Conservation Commission, 1526 Kelvin Avenue, Deltona, FL 32738.Search for more papers by this authorJOSEPH D. CLARK, Corresponding Author JOSEPH D. CLARK United States Geological Survey, Southern Appalachian Field Laboratory, 274 Ellington Plant Sciences Building, University of Tennessee, Knoxville, TN 37996, USAjclark1@utk.edu.Search for more papers by this authorMICHAEL R. PELTON, MICHAEL R. PELTON Department of Forestry, Wildlife, and Fisheries, 274 Ellington Plant Sciences Building, University of Tennessee, Knoxville, TN 37996, USASearch for more papers by this authorMELVIN E. SUNQUIST, MELVIN E. SUNQUIST Department of Wildlife Ecology and Conservation, University of Florida, Gainesville, FL 32611, USASearch for more papers by this author STEVEN DOBEY, STEVEN DOBEY Department of Forestry, Wildlife, and Fisheries, 274 Ellington Plant Sciences Building, University of Tennessee, Knoxville, TN 37996, USASearch for more papers by this authorDARRIN V. MASTERS, DARRIN V. MASTERS Department of Wildlife Ecology and Conservation, University of Florida, Gainesville, FL 32611, USA Hoopa Tribal Forestry, P.O. Box 368, Hoopa, CA 95546.Search for more papers by this authorBRIAN K. SCHEICK, BRIAN K. SCHEICK Department of Wildlife Ecology and Conservation, University of Florida, Gainesville, FL 32611, USA Florida Fish and Wildlife Conservation Commission, 1526 Kelvin Avenue, Deltona, FL 32738.Search for more papers by this authorJOSEPH D. CLARK, Corresponding Author JOSEPH D. CLARK United States Geological Survey, Southern Appalachian Field Laboratory, 274 Ellington Plant Sciences Building, University of Tennessee, Knoxville, TN 37996, USAjclark1@utk.edu.Search for more papers by this authorMICHAEL R. PELTON, MICHAEL R. PELTON Department of Forestry, Wildlife, and Fisheries, 274 Ellington Plant Sciences Building, University of Tennessee, Knoxville, TN 37996, USASearch for more papers by this authorMELVIN E. SUNQUIST, MELVIN E. SUNQUIST Department of Wildlife Ecology and Conservation, University of Florida, Gainesville, FL 32611, USASearch for more papers by this author First published: 13 December 2010 https://doi.org/10.2193/0084-0173(2005)158[1:EOFBBI]2.0.CO;2Citations: 12 AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Abstract Abstract: The population status of the Florida black bear (Ursus americanus floridanus) is problematic within many portions of its range and its potential listing as a federally threatened species has been the subject of legal debate. We studied Florida black bears in 2 areas in the Okefenokee-Osceola ecosystem in southeast Georgia (i.e., Okefenokee) and north Florida (i.e., Osceola) from 1995 to 1999 to evaluate relationships between population characteristics, habitat conditions, and human activities. Bears in Okefenokee were hunted and those in Osceola were not. We captured 205 different black bears (124M:81F) 345 times from June 1995 to September 1998. We obtained 13,573 radiolocations from 87 (16M:71F) individual bears during the study. In Okefenokee, black gum (Nyssa sylvatica) and saw palmetto (Serenoa repens) fruits were the most important foods for bears based on scat analysis. In Osceola, corn from white-tailed deer (Odocoileus virginianus) feeders was the most stable food source but saw palmetto was heavily used when available. Corn from deer feeders was not available in Okefenokee. Adult bears in Osceola were 29% heavier than those in Okefenokee (t82 = 3.55, P < 0.001). The mean annual home-range size for Osceola females (x = 30.3 km2 ± 4.0 [SE], n = 53) varied little seasonally or annually and was almost half that of Okefenokee females (55.9 km2 ± 6.9, n = 69; Z = −2.47, P = 0.014). In contrast, radiocollared females in Okefenokee expanded their home ranges during years of poor black gum production. That expansion was most apparent between autumn 1998 and 1999, when mean home-range size for Okefenokee females increased from 14.5 km2 to 78.4 km2, respectively, and included a larger proportion of upland areas open to sport hunting. As a result, 5 females were harvested in the Okefenokee study area during the 1999 bear hunting season compared with only 7 harvested from 1996 to 1998. Home ranges of adult female bears were located in areas with disproportionately high loblolly bay (Gordonia lasianthus) and gum-bay-cypress (Taxodium spp.) vegetation associations in Okefenokee and gum-bay-cypress associations in Osceola. The pine vegetation association ranked lower than most other associations within the home ranges of bears in both study areas even though much of the summer and autumn diets of bears included food items found almost exclusively in pine. Sixteen mortalities of radiocollared bears were documented in Okefenokee; hunting accounted for 11 (68.8%) of these deaths. The annual survival rate of radiocollared males in Okefenokee was 0.71 (95% CI = 0.53-0.88) whereas survival of females in Okefenokee was higher (Z = 18.87, P < 0.001) at 0.89 (95% CI = 0.83-0.95). The survival rate for females in Osceola was 0.97 (95% CI = 0.92-1.00). Overall, 67 bears (51M:16F) were killed by hunters in the Okefenokee study area from 1995 to 1999. Based on all radiocollared bears in Okefenokee, many of which resided within areas closed to hunting, we estimated an annual harvest rate of 0.22 (95% CI = 0.03-0.37) for males and 0.07 (95% CI = 0.01-0.12) for females. When we excluded those bears that were not in areas open to hunting, however, the annual harvest rate rose to 0.37 (95% CI = 0.07-0.58) for males and 0.39 (95% CI = 0.09-0.58) for females. Following a black gum shortage in autumn 1995, only 1 of 15 radiocollared females in Okefenokee produced cubs in winter 1996. That low reproductive rate was in contrast to winter 1997, which followed heavy black gum production, when 21 of 22 radiocollared females produced cubs. Reproductive output was more consistent in the Osceola study area, with 46 cubs being produced from 8, 5, and 9 litters in 1997, 1998, and 1999, respectively. To estimate population size, we maintained 88 and 94 barbed-wire hair traps during 1999 in the Okefenokee and Osceola study areas, respectively. Using DNA collected at the hair traps, mark-recapture models produced estimates of 71 bears (95% CI = 59–91) in Okefenokee and 44 bears (95% CI = 40–57) in the Osceola study area during 1999. The estimated densities in the Okefenokee and Osceola study areas were 0.12 and 0.14 bears/km2, respectively. Alternative density estimates based on the amount of time bears spent within study area boundaries were similar (0.11 and 0.14 bears/km2 on Okefenokee and Osceola, respectively). We used a population model to estimate the effect of harvest in the Okefenokee bear population. Excluding harvest, bears at Osceola experienced higher average annual population growth (Λ = 1.184 ± 0.002) than those at Okefenokee (1.064 ± 0.002; t18 = 3.93, P = 0.001), most likely due to protection from hunting and higher recruitment. Including the effects of emigration and immigration, we estimated an average annual sustainable harvest at Okefenokee of approximately 9 bears (12.6%), which was slightly less than the average 1995–1999 annual harvest of 9.4. That level of hunting in Okefenokee is sustainable but likely represents the highest exploitation rate in the region. Our mark-recapture data from Osceola suggest a high dispersal rate by subadult bears, and our population modeling data support this hypothesis; we documented bears in Okefenokee that originated from Osceola but not the reverse. We speculate that bears from the interior of the Okefenokee National Wildlife Refuge (ONWR), and to some extent northern Florida, served as a source to the population sink caused by hunting mortality in Okefenokee and in the surrounding Georgia counties. Corn from deer feeders was the most probable reason for smaller home-range sizes and greater body masses and reproductive output at Osceola. Changes in management to eliminate or reduce baiting for deer with corn would negatively affect the Osceola bear population. On Okefenokee, sporadic black gum and palmetto production influenced harvest rates and cub production and, thus, governed bear population dynamics. The U.S. Fish and Wildlife Service (USFWS) concluded in 1998 that listing the Florida black bear as threatened under the Endangered Species Act of 1973 was not warranted. That decision was largely based on the stability and protection afforded to a few subpopulations within the range of the subspecies, which includes the Okefenokee-Osceola subpopulation; our results support that conclusion. However, we suggest that metapopulation processes among the various subpopulations be given greater consideration, with the ultimate goal of managing the subspecies as a unit rather than as an assemblage of independent components. Our study illustrates the importance of travel corridors for maintaining metapopulation processes. Citing Literature Volume158, Issue1January 2005Pages 1-41 RelatedInformation

A male Florida black bear (Ursus americanus floridanus) traveled a minimum of 507 km from Eglin Air Force Base (Eglin AFB), Florida, to Baton Rouge, Louisiana, between 28 May and 1 July 1996. The bear moved at an average rate of 14.9 km/day (range =1-123 km/day) and crossed a minimum of 4 interstate highways and 22 other major highways. Occasional long-distance movements by black bears may help explain the persistence of some disjunct populations and the potential for connecting other isolated bear populations in the Southeastern Coastal Plain.

We used compositional analysis to determine seasonal and annual habitat use by black bears (Ursus americanus floridanus) on Eglin Air Force Base (Eglin AFB), Florida, 1994-1996. Habitat use was nonrandom for annual (P = 0.0027), summer (P = 0.0002), and fall (P = 0.0006) periods. Riparian zones had the highest annual use followed by swamps, pine plantations, sandhills, and open areas. Annual use of riparian zones and swamps differed (P = 0.025), and each showed greater use than the remaining habitat associations. Riparian zones and swamps also ranked highest for summer and fall. Sandhills received their highest rank, third, in the fall. The high use of riparian zones demonstrates the importance of habitats associated with rivers and streams to black bears on Eglin AFB.

A population of white-tailed deer (Odocoileus virginianus seminolus) was studied in the eastern Everglades National Park from 1987 to 1992. The data for the interval January 1987 to June 1991 are summarized in this publication. During this interval, from 35 to 40 deer were monitored annually. Deer were captured utilizing a shoulder-held gun projecting a net, and fired from a helicopter. Captured deer were fitted with a radio collar and, thereafter, located by telemetry from both the ground and a fixed wing aircraft. Aerial locations were logged to a recognizable hectare square. Minimum convex polygons of deer home range use then were determined. Individual females occupied ranges of approximately 37 ha and males 113 ha, but seasonal differences in range use indicated that some males may have an annual range exceeding 12 km2. There was considerable overlap of home ranges, especially among individual females and their presumptive offspring. The population density was estimated to be 0.68 deer/km2. Adult females produce a single young; twinning was not recorded. During the course of this study, recruitment into the population was low. Mortality rates varied from year to year, especially for young fawns. The population appeared to be stable. During the course of the study, the panther (Puma concolor) was present. Deer comprised 57 percent of 99 identified panther kills in the eastern Everglades National Park and adjacent areas. Adult bucks with a mean age of 5.5 years were the dominant age/sex class killed (47% of all deer). We conclude that, although densities of both deer and panthers are low in the eastern Everglades National Park, they were normal and near carrying capacity or stable.

A two-year experimental field study was conducted simultaneously in Venezuela and Florida to test the hypothesis that in polygynous mammals offspring sex ratio is affected by maternal capacity for reproductive investment. Female common opossums (Didelphis manupialis) and Virginia opossums (D. virginiana) were used as model animals. At each study site three groups of adult virgin females (10/group/year) were trapped prior to the breeding season, weighed, radiocollared and released. Females were randomly assigned to Control, Provisioned, or Delayed Reproductive groups. Provisioned females were located at daytime rest sites and provisioned with about a 125 gm mixture of sardines and cat food at 2-day intervals from at least three weeks prior to conception until the end of the breeding season. Delayed Reproductives were those whose embryonic young were removed repeatedly from the pouch to assess the potential reproductive cost to females who conceived but lactated for only a brief time. All females were recaptured at monthly intervals for weighing and to record the sex and size of pouch young or, in the case of Delayed Reproductives, to remove any new pouch young. In both Florida and Venezuela, reproduction was highly seasonal and most (> 90%) females in the population produced two litters per year. The mean litter size (mode=7) for both sites did not differ significantly between the first and second litters, nor was there any effect of treatment on litter size. The interval between the birth of the first and second litters was of similar duration for Provisioned and Control females. Length of lactation was also similar for Provisioned and Control females, although the length of lactation for the second litter was 1-2 weeks longer in both Florida and Venezuela. There was no differential investment in male or female offspring during the teat-attachment phase, but Provisioned females exhibited greater parental investment. The weight at weaning of young from Provisioned females was significantly higher than young of Control females. Provisioned females invested disproportionately in males by producing male-biased sex ratios and by producing a higher percentage of litters that were male biased. Females, whether provisioned or not, that were in good condition tended to produce more male-biased litters. A drought in Florida in 1985 disrupted the feeding program, consequently few females received their dietary supplement and a small percentage of litters were male biased. In Venezuela, male offspring of Provisioned females were recaptured post-weaning significantly more often than males of Control females, although the comparison was not significant for the Florida data. Females who were denied the stress of lactation tended to survive longer, the difference in survivorship approached significance in Venezuela. The extended survivorship of Delayed Reproductives was not biologically significant as few lived more than two years, and mean longevity for all groups was less than two years. Opossums of both species appear to be geared to perform a maximum reproductive effort in the year following their birth.