(1) Rate of increase was measured for feral donkey populations in parts of northern Australia as the average exponential rate of increase, r, in a population subjected to substantial reduction. (2) The annual rate of increase was estimated to be r = 0.21. This estimate was compared with the exponential rate of increase in another recovering donkey population and found to be in close agreement. (3) Ultimate and proximate factors regulating the abundance of feral donkey populations were examined by monitoring and sampling two populations; one at or close to equilibrium density, the other below equilibrium density and recovering from reduction. (4) The size of the population at equilibrium density remained stable over the 12 months of monitoring while the size of the recovering population increased by 20 percent (r = 0.18/yr). (5) Growth and body condition were significantly depressed in the population at equilibrium density suggesting that donkey populations are limited by the food resources available to them. (6) Breeding occured over a discrete season, with births occurring between September and February. 11 (7) Fecundity was high, with more than 75 percent of mature females breeding in each year, and was independent of population density. (8) Adult and juvenile mortality were density dependent, with mortality over the first six months of life the most important demographic factor influencing rate of increase in donkey populations, and hence population abundance. (9) Implications of the estimated rate of population increase for the cost of long-term control of feral donkey populations were examined by constructing numerical models predicting the relative cost of ongoing control. (10) These models were constructed using functions to describe density dependent variation in population productivity and the cost per donkey removed. (11) The cost of removing donkeys at various population densities was estimated using predator-prey theory. The cost, measured in hours of helicopter time per removal, was found theoretically and empirically to take the form of an inverted functional response curve, with cost saturated at high donkey densities. (12) The utility of models predicting the cost of continuing pest control is illustrated by comparing the relative costs of two potential strategies for feral donkey control.

Thesis (Ph. D.)--York University, 1999. Graduate Programme in Social and Political Thought. / Typescript. Includes bibliographical references (leaves 540-580). Also available on the Internet. MODE OF ACCESS via web browser by entering the following URL: http://wwwlib.umi.com/cr/yorku/fullcit?pNQ43414.

Feral pigs (Sus scrofa) are considered to be among the world’s worst invasive species due to their successful invasion and ecological and economic impact to native and agricultural plants and animals around the world. Feral pigs are significant disturbance agents that destroy plant communities, change soil characteristics, alter nutrient cycling, and create open sites for colonization of both native and non-native plant species through their foraging behavior called rooting. In contrast to native animal disturbances, rooting is a striking feature in the landscape that varies in space, seasonal timing, frequency (number of times rooted), and intensity (depth of rooting). During this study, feral pigs rooted 7.7% of the search area, which increased to 12% when abandoned patches (baseline patches that were not rooted during this study) were included. Overall, feral pigs rooted and re-rooted habitats along roads and trails significantly more than wetlands. Rooting also varied temporally with the most rooting occurring during July-November, which also corresponds to the peak in rooting intensity. Implications to land managers include avoiding the installation of roads and trails near wet to mesic habitats or other habitats that contain species of concern in order to conserve habitat quality and recreational value. Despite less rooting activity, feral pigs still pose a significant threat to wetlands as evidenced by the large amount of abandoned patches documented. In order to conserve natural areas, effective management and development of efficient control methods is needed to keep feral pig populations in check. As a large opportunistic omnivore, feral pigs have the potential to be important vectors for endozoochorus seed dispersal of a variety of plant species. Feral pigs can travel long iv distances and have a gut retention time up to 49 hours, therefore seeds can be deposited throughout the landscape far from the parent plant. Over the course of this study, feral pigs dispersed 50 plant species from a wide range of ecological and morphological characteristics, though the majority were native, small seeded, wetland species. For most plant species, location of deposition matched their habitat preference and suggests a high probability of survival. Feral pigs disperse mainly wetland plant species, which has important implications for wetland conservation. However, feral pigs also deposited unwanted species into wetlands and predated the seeds of important wetland canopy tree species.

ABSTRACT Despite increasing evidence for the impact of feral cats Felis catus on native fauna in Australia, little is known of the ecology of cats, particularly factors that limit cat abundance. The ecology of the feral cat in Australia is represented by just 15 published studies on diet, only one of which has examined diet in relation to prey availability, and one study of home range behaviour. The red fox Vulpes vulpes is a significant pest to agriculture and native fauna in Australia and widespread fox removals have been proposed by the Vertebrate Biocontrol Cooperative Research Centre (VBCRC). However, there is concern that feral cats may increase compensatorily when fox populations are reduced, as has occurred in Western Australia, and therefore that predation pressure may not be alleviated on native fauna following fox control programs. This thesis is divided into two parts. First, the diet and home range size of cats is examined in relation to prey availability, and home range overlap and habitat use are determined. In the second part, several niche parameters (diet, home range and habitat use) that were potentially important resources for foxes and cats were quantified to assess the potential for competition. Avoidance and aggression between cats and foxes was examined using simultaneous radiotracking techniques and video observations. The hypothesis that foxes limit cats through interspecific competition (exploitation and interference) was then tested using a fox removal experiment. Finally, three further hypotheses were tested using a fox removal experiment to determine which factors limit feral cats at Burrendong. The four hypotheses tested were thus: i) Cats are limited independently of foxes through other factors such as food availability; ii) Foxes limit cats through interspecific competition (exploitation and/or interference); iii) Foxes limit cats through intraguild predation; iv) Cats benefit from the presence of foxes through facilitation. The diets and spatial use of feral cats were examined on agricultural land on the eastern shore of Lake Burrendong, New South Wales (32o40�S, 149o 10�E) between July 1994 and June 1997. The major land use for the area is water catchment under the agistment of sheep Ovis aries and cattle Bos taurus. The study area encompasses about 90 km2 of hilly terrain with undulating slopes that extend down to a flat foreshore area that has been extensively cleared of trees for grazing. The slopes are generally well timbered and dominated by white box Eucalyptus albens woodlands with some yellow box E. melliodora associations. Stands of cyprus pines Callitris spp. are also common. Feral cats and red foxes are established throughout the study area, and the European rabbit Oryctolagus cuniculus was abundant until the arrival of Rabbit Calicivirus Disease (RCD) in June 1996. The diet of feral cats was determined from the analysis of 499 scats. Rabbits were the staple prey of cats, with occurrence (O) in 81.6% of scats and comprising 68.4% by volume (V). Carrion (mostly eastern grey kangaroo Macropus giganteus and sheep) (O 21.5%, V 11.5%) was an important secondary food, particularly in winter and spring. Other mammalian prey included brushtail possums Trichosurus vulpecula (O 4.6%, V 2.4%), house mice Mus domesticus (O 6.2%, V 3.2%), black rats Rattus rattus (O 2.6%, V 1.4%) and a dunnart Sminthopsis sp. (probably S. murina) (O 0.2%, V 0.006%). Invertebrates (mostly Orthopterans) (O 41.5%, V 7.5%), vegetation (O 26.3%, V 3.6%), birds (O 4.2%, V 0.8%) and reptiles (O 3.4%, V 0.3%) were generally of minor importance in the diet. Few significant seasonal differences were found, although invertebrates contributed significantly less, and possums more, to the mean scat volume in winter and summer respectively. A significant dietary response was found for changes in rabbit abundance, but not for the other prey groups. Cats continued to prey heavily on rabbits after the arrival of Rabbit Calicivirus Disease, despite the relatively low numbers of rabbits. Ten months post-RCD, house mice increased in importance in the diet. However, it was not known whether this represented prey switching sensu stricto or opportunistic predation on an increased mouse population, as mouse abundance was not measured during this period. Seventy-seven cats (48 recaptures) were caught in 6762 trap nights between November 1994 and August 1996 using both cage traps and leg-hold traps. A further 18 individual cats were trapped as non-target animals by the VBCRC Fox Sterility Project and used in this study. Trapped adult cats were fitted with radio collars and their home range size, overlap and habitat use examined. Home ranges and core areas were quantified using 95% and 50% kernel utilisation distributions (KE 95 and KE 50) and minimum convex polygons (MCP 100, MCP 95, MCP 50). Four habitat types (grassland, open woodland, open forest, and mudflats) were delineated on aerial photographs and a habitat map produced using ARC/INFO. Compositional analysis was used to examine habitat preference in cats. Home range sizes of cats (n = 15, 598 fixes) in winter 1995, prior to fox removal, were similar to those reported in the only published study of cat spatial use in Australia, but larger than those recorded elsewhere. This may have reflected more dispersed food resources in Australia, although home range size was not correlated significantly with rabbit abundance. Male ranges (MCP 95 = 284 ha, n = 11) tended to be larger than females ( = 151ha, n = 4), but no differences were detected between young (1-3 years, = 271ha, n = 7) and old (>3 years, = 221ha, n = 8) cats. Cats were active both by day and night with no temporal differences being detected in range size. Both adult male and female cats tended to be solitary, although home ranges overlapped extensively. Kin groups were indicated (but not confirmed) as most inter-sexual overlap occurred between young and old cats. Habitat composition of home ranges generally reflected the availability of habitats at the study site, although cats significantly avoided mudflats. Home ranges comprised mostly open woodland and open forest habitats with smaller areas of grassland and mudflats. However, within individual home ranges, cats used grassland and open woodland habitats most often where rabbits were more abundant. Inter-individual (sex, age) or temporal (day/night) differences in habitat use were not detected. Comparison of resource use between cats and foxes indicated a large overlap in diet, home ranges and habitat use. Dietary breadths and overlaps between cats and foxes increased when rabbit availability declined in autumn and post-RCD. Dietary overlap was high overall (75%), although some resource partitioning was detected. Rabbits were more important in the diet of cats than foxes, particularly in summer, when foxes ate more grasshoppers. Carrion, invertebrates and vegetation were more important for foxes than for cats overall. Home ranges of both cats and foxes comprised mostly open woodland habitats followed by grassland, open forest and mudflats, which largely reflected their relative availabilities. However, within individual home ranges, cats showed a preference for grassland habitats. In addition, cats tended to deposit scats more often than foxes at rabbit warrens and at hollow log entrances, while foxes deposited scats more often than cats on sand plots, tracks and at dams. The large overlap in resource use between cats and foxes indicated a high potential for exploitation competition. Foxes may attempt to lessen competition by killing cats (interference competition). Three radiocollared cats were killed by foxes and aggression was observed toward cats. Home ranges overlapped extensively, but avoidance was indicated from the simultaneous radiotracking of both predators, as greater separations and lower overlaps in home ranges and core areas were recorded between species than within species. In addition, video observations suggested avoidance of carcasses by cats in the presence of foxes. The hypothesis that foxes limit feral cats through interspecific competition was then tested using a fox removal experiment. Foxes were reduced at two of the four sites from October 1995 using �1080� baiting and spotlight shooting by the VBCRC Predator-Prey project. Resource use and abundance of cats were compared before and after fox removal and between treated and untreated sites. Although no increase in cat abundance followed the removal of foxes, significant behavioural changes by cats strongly suggested interspecific competition operating via exploitation and interference. Exploitation competition was supported by the increased consumption of carrion by cats at the treated sites after fox removal, while support for interference competition came from the increased use of grassland habitats at night after fox removal. The direction of the resource shifts to more prey-rich habitats indicated asymmetry in the relationship between the two predator species. Although the null hypothesis of no limitation of cats by foxes could not be rejected, as no increase in cat abundance was recorded after fox removal, interspecific competition was considered to be the most likely mechanism limiting feral cats at Burrendong. Intraguild predation was not indicated as no cat remains were found in any of the 343 fox scats or 255 fox stomachs that were examined. In addition, minimal evidence was found for facilitation between cats and foxes, or for food limitation. The potential for foxes to limit cats, as shown in this study, indicates that cats need to be considered in future fox control operations. Integrated pest management, where foxes, cats and rabbits are controlled together, is strongly proposed if the objective is to safeguard native fauna in Australia. Further research is required to improve the effectiveness of current techniques for censusing cat populations, particularly in forested areas. This is essential for monitoring the effectiveness of control campaigns and quantifying factors that limit cat populations, and ultimately for effective protection of susceptible native fauna.

The control of feral goats (Capra hircus) and relevant aspects of their biology were studied on Aldabra Atoll, Republic of Seychelles, from October 1993 - May 1994 and November 1994 - May 1995. A total of 832 goats were killed on Aldabra using both the Judas goat technique and traditional hunting methods; a total of 28 Judas goats were used during the entire campaign. The remnant goat populations on Ile Picard (N=13) and Ile Malabar (N=19) were eradicated during the first season. On Grande Terre, a total of 798 (374 M: 424 F) goats were killed. The overall kill rate on Grande Terre was 0.37 goats killed/hour with 1.66 shots fired/goat. A total of 1,042 goats were encountered of which 26.1% escaped. Mean group size was 3.2 with a range of 1 to 20. Judas goat hunting became increasingly important over time with 18.0% (n=85) of goats killed in the first season being in the presence of Judas goats; 42.3% (n=126) of goats killed during the second season were in the presence of Judas goats. The overall kill rate for the project was almost 2 times greater for Judas goat hunting (0.61 goats killed/hr) than traditional hunting (0.32 goats killed/hr); Judas goat hunting was approximately 70% more effective than traditional hunting when compared using multiple linear regression. There was a significant relationship between Judas goat home range size and the number of conspecifics killed. Feral goats on Aldabra may be unique among feral goat populations by apparently not responding to population reductions in a density-dependent manner. For the first season, the intrinsic rate of increase (r) was 0.45; r=0.39 for the second season. Twinning rates were 30.7% and 37.5% in the first and second seasons, respectively. I subjectively estimated approximately 60-120 goats remaining on all of Grande Terre at the end of the project; 84 goats were estimated using the Leslie-Davis removal method of population estimation. / Graduation date: 1998

A telephone questionnaire was developed to collect information on pet owners, cat ownership patterns, and people's opinions about homeless pets. A 7-day observation log was also developed to gather information about free-roaming cats in Caldwell, TX. The objectives of this research were: (1) to evaluate the reliability of the telephone questionnaire, (2) to assess general cat ownership patterns, (3) to evaluate attachment level of pet owners to their pets, (4) to determine general opinions about free-roaming cats, (5) to determine if demographics were associated with opinions about free-roaming cat and dog problems and (6) to investigate free-roaming cat activity in a community. Telephone questionnaire information collected from 100 subjects was tested for reliability. Reliability was fair to good for cat level questions (sex, age, breed, length of time owned, indoor/outdoor status, litter, number of vet visits, vaccinated). Reliability was good for questions concerning subjects' knowledge of cat and dog behavior and levels of attachment to their pets. Reliability was excellent for all household level (demographic) variables. Reliability was moderate for questions regarding subjects' opinions about homeless animals. Telephone questionnaire responses collected from 441 subjects were checked for associations using exploratory logistic and linear regression models. A cat's role as a pet, vaccination status, and the length of time owned were associated with a cat's sterilization status. A cat's role as a pet was associated with the cat's indoor/outdoor status. Household size, education level and ethnicity of the owner were associated with cat ownership. Having children was associated with a negative opinion about homeless cats. Education level was associated with subjects' knowledge about dog and cat behavior. Gender, household size, and knowledge score were associated with subjects' attachment to their pets. Descriptive information on free-roaming cat activity was collected from 21 subjects using the 7-day observation log. Subjects made 382 cat sightings during the study period. Slightly more cat sightings were made during the morning than in the evening and afternoon. Most cats were spotted in neighborhoods and were resting or eating. Most of these cats that were eating were seen during the morning or evening hours.

A telephone questionnaire was developed to collect information on pet owners, cat ownership patterns, and people's opinions about homeless pets. A 7-day observation log was also developed to gather information about free-roaming cats in Caldwell, TX. The objectives of this research were: (1) to evaluate the reliability of the telephone questionnaire, (2) to assess general cat ownership patterns, (3) to evaluate attachment level of pet owners to their pets, (4) to determine general opinions about free-roaming cats, (5) to determine if demographics were associated with opinions about free-roaming cat and dog problems and (6) to investigate free-roaming cat activity in a community. Telephone questionnaire information collected from 100 subjects was tested for reliability. Reliability was fair to good for cat level questions (sex, age, breed, length of time owned, indoor/outdoor status, litter, number of vet visits, vaccinated). Reliability was good for questions concerning subjects' knowledge of cat and dog behavior and levels of attachment to their pets. Reliability was excellent for all household level (demographic) variables. Reliability was moderate for questions regarding subjects' opinions about homeless animals. Telephone questionnaire responses collected from 441 subjects were checked for associations using exploratory logistic and linear regression models. A cat's role as a pet, vaccination status, and the length of time owned were associated with a cat's sterilization status. A cat's role as a pet was associated with the cat's indoor/outdoor status. Household size, education level and ethnicity of the owner were associated with cat ownership. Having children was associated with a negative opinion about homeless cats. Education level was associated with subjects' knowledge about dog and cat behavior. Gender, household size, and knowledge score were associated with subjects' attachment to their pets. Descriptive information on free-roaming cat activity was collected from 21 subjects using the 7-day observation log. Subjects made 382 cat sightings during the study period. Slightly more cat sightings were made during the morning than in the evening and afternoon. Most cats were spotted in neighborhoods and were resting or eating. Most of these cats that were eating were seen during the morning or evening hours.

The resident feral cat (Felis catus) population on the University of KwaZulu-Natal (UKZN), Howard College campus (HCC) in Durban, South Africa was studied from March 2004 to November 2005. This study was initiated as the HCC is an registered as an urban conservancy and so should be removing alien invasive flora and fauna and conserving the indigenous biodiversity of the campus. This research was undertaken to assist with recommendations for the control and management of feral cats on the HCe. A survey to determine public perceptions and opinions regarding the feral cats was conducted among various communities on the campus. Feral cats from the resident population on the HCC were trapped and fitted with radio-collars in order that their home range sizes and distribution could be determined. Monthly census counts were also carried out in an attempt to calculate population densities of the feral cats on campus, while data on behaviour patterns was collected opportunistically throughout the study period. The survey showed that two extreme views existed on campus regarding the presence of feral cats. The university is a registered conservancy which some feel is no place for this exotic species. However, it is also situated within an urban surrounding and there are some cat enthusiasts among the public who feel that resources should be provided for the feral cats, both nutritionally and financially. While many people were unaware that the feral cats were a cause for concern on the HCC, the majority concluded that a management policy needed to be adopted to control feral cat numbers. Most were against the suggestion of eradicating the cats and strongly agreed with the implementation of a university funded feral cat IV sterilising and feeding programme. Feeding the feral cats, however, needs to be stringently controlled. In this study, the availability of an abundance of food resources was shown to be the primary influencing factor for home range size, cat distribution and population densities. It also had an overriding effect on the feral cats' behaviour patterns and activity levels. Once these had been initially established, other factors such as human activity, reproductive status and gender then came into play. Distribution of the feral cats around campus was not homogenous, and densities differed according to areas on campus. Highest cat densities were recorded in those areas on the HCC where permanent cat feeding stations had been established (usually the developed areas on campus), while no feral cats were sighted in the Msinsi Nature Reserve, a natural bush area on campus were no food resources (other than prey species) is available. Home range sizes of the feral cats were relatively small with a considerable amount of overlap between and within the sexes. There were also no seasonal differences in range sizes and diurnal ranges were only marginally smaller than nocturnal range sIzes. In terms of behaviour, the HCC feral cats were generally inactive, with passive behaviour such as lying down and sitting being most often observed. Although hunting activity was very rarely witnessed, the combined effects of feral cats supported at high densities by supplemental feeding may exert predation pressures that could be detrimental to both local prey and predator populations. Little social interactions were observed by the cats on the HCC. Other studies show that competition is greatly reduced if food is available in abundance and there is no need for territorial disputes if both food and a potential mate are located in close proximity. In the present study, this also means that immigrating feral cats from surrounding neighbourhoods are tolerated; another factor contributing to the increase in feral cat numbers on the campus. These findings suggest that the feral cat population on the HCC is being maintained at higher population densities than would be expected and management initiatives are needed to control the feral cat population at a minimum density through a sterilising and low key feeding programme so that it is acceptable to all concerned parties. However, the decisions need to favour the status of the HCC as a conservancy in an urban area as well as consider the well-being of the students and staffmembers in a public place. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2005.

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