A comparison of coyote ecology after 25 years: 1978 versus 2003

Most ecological studies of coyotes are of short duration and studies are generally never repeated, thus the opportunity to compare changes in coyote (Canis latrans Say, 1823) ecology over time is rare. We compared coyote home ranges, activity patterns, age, and diet at the Welder Wildlife Refuge in south Texas between 1978-1979 and 2003-2004 (25 years later). The Minta index of overlap between 1978 and 2003 home ranges was 51.7 ± 7.0 (n = 7), much greater than the Minta index value based on randomized tests (28.7 ± 8.6), indicating similar spatial patterns between time periods. The Minta index was 12.3 ± 6.2 (n = 7) for core areas, whereas the Minta index value based on randomized tests was 4.0 ± 3.0. Although overall diets were similar between 1978 and 2003, we detected some differences in prey species consumed. Activity patterns were similar between the two study periods, with peaks in movement occurring around sunrise and sunset. There was no difference in the mean age between the two populations (P = 0.44, n = 68, t [66] = 2.00). Our findings suggest that population features, such as home-range position and age structure, are similar between extended time periods, while individual-level patterns, such as the prey species consumed and distribution of locations within a home range, are dynamic and may reflect changes in the local environment

A comparison of coyote ecology after 25 years: 1978 versus 2003

Most ecological studies of coyotes are of short duration and studies are generally never repeated, thus the opportunity to compare changes in coyote (Canis latrans Say, 1823) ecology over time is rare. We compared coyote home ranges, activity patterns, age, and diet at the Welder Wildlife Refuge in south Texas between 1978-1979 and 2003-2004 (25 years later). The Minta index of overlap between 1978 and 2003 home ranges was 51.7 ± 7.0 (n = 7), much greater than the Minta index value based on randomized tests (28.7 ± 8.6), indicating similar spatial patterns between time periods. The Minta index was 12.3 ± 6.2 (n = 7) for core areas, whereas the Minta index value based on randomized tests was 4.0 ± 3.0. Although overall diets were similar between 1978 and 2003, we detected some differences in prey species consumed. Activity patterns were similar between the two study periods, with peaks in movement occurring around sunrise and sunset. There was no difference in the mean age between the two populations (P = 0.44, n = 68, t [66] = 2.00). Our findings suggest that population features, such as home-range position and age structure, are similar between extended time periods, while individual-level patterns, such as the prey species consumed and distribution of locations within a home range, are dynamic and may reflect changes in the local environment

Effectiveness of Twenty, Twenty-Five Diazacholesterol, Avian Gonadotropin-Releasing Hormone, and Chicken Riboflavin Carrier Protein for Inhibiting Reproduction in Coturnix Quail

Contraception may provide a useful nonlethal management tool when it is desirable to reduce populations of birds. We tested the efficacy of 20,25 diazacholesterol, and immunization with avian gonadotropin-releasing hormone (AGnRH-I) and chicken riboflavin carrier protein (cRCP) as contraceptives and investigated their modes of action in Coturnix quail (Coturnix coturnix japonica). Females that were paired with males treated with 20,25 diazacholesterol produced lower percentages of eggs that were fertile and hatched. Females treated with 20,25 diazacholesterol and paired with control males laid fewer eggs, and lower percentages of their eggs were fertile and hatched. Treatment with 20,25 diazacholesterol reduced testosterone levels in males and progesterone levels in females. Nonesterified cholesterol levels were reduced, whereas desmosterol levels increased in birds treated with 20,25 diazacholesterol. Treatment with AGnRH-I and cRCP immunocontraceptive vaccines did not decrease average egg production and hatchability or hormone levels, but this failure might have been due to the vaccination protocol. If registered, wildlife managers may be able to use 20,25 diazacholesterol when other methods, such as lethal control, are undesirable for reducing damage caused by specific breeding behaviors such as the building of nests

Estimating brown hyaena occupancyusing baited camera traps

Conservation and management of brown hyaenas (Hyaena brunnea) is hampered by a lack ofinformation on abundance and distribution, which is difficult and labour-intensive to obtain.However, occupancy surveys offer a potentially efficient and robust means of assessingbrown hyaena populations. We evaluate the efficacy of camera trapping for estimatingbrown hyaena occupancy, and the effect of environmental variables and lures on detectionprobability. We estimated population density in Pilanesberg National Park, South Africa, at2.8/100 km2, occupancy at 1.0 and model-averaged detection probability at 0.1. Using a fishlure increased detection probability to 0.2 and significantly increased encounter rates. Wealso found that brown hyaenas are more likely to be detected in areas of scrub or woodlandrather than grassland. Our results suggest that 13 camera sites would be needed to achievean occupancy estimate with S.E. of 0.05, and a minimum of 16–34 sampling occasions (withand without the fish lure) should be used in comparable study areas. We conclude thatcamera trapping is a viable method of estimating brown hyaena occupancy at local andlandscape scales and capture–recapture analysis is also possible at a local scale

Terrestrial carnivores and human food production: impact and management

1. The production of food for human consumption has led to an historical and global conflict with terrestrial carnivores, which in turn has resulted in the extinction or extirpation of many species, although some have benefited. At present, carnivores affect food production by: (i) killing human producers; killing and/or eating (ii) fish/shellfish; (iii) game/wildfowl; (iv) livestock; (v) damaging crops; (vi) transmitting diseases; and (vii) through trophic interactions with other species in agricultural landscapes. Conversely, carnivores can themselves be a source of dietary protein (bushmeat). 2. Globally, the major areas of conflict are predation on livestock and the transmission of rabies. At a broad scale, livestock predation is a customary problem where predators are present and has been quantified for a broad range of carnivore species, although the veracity of these estimates is equivocal. Typically, but not always, losses are small relative to the numbers held, but can be a significant proportion of total livestock mortality. Losses experienced by producers are often highly variable, indicating that factors such as husbandry practices and predator behaviour may significantly affect the relative vulnerability of properties in the wider landscape. Within livestock herds, juvenile animals are particularly vulnerable. 3. Proactive and reactive culling are widely practised as a means to limit predation on livestock and game. Historic changes in species' distributions and abundance illustrate that culling programmes can be very effective at reducing predator density, although such substantive impacts are generally considered undesirable for native predators. However, despite their prevalence, the effectiveness, efficiency and the benefit:cost ratio of culling programmes have been poorly studied. 4. A wide range of non-lethal methods to limit predation has been studied. However, many of these have their practical limitations and are unlikely to be widely applicable. 5. Lethal approaches are likely to dominate the management of terrestrial carnivores for the foreseeable future, but animal welfare considerations are increasingly likely to influence management strategies. The adoption of non-lethal approaches will depend upon proof of their effectiveness and the willingness of stakeholders to implement them, and, in some cases, appropriate licensing and legislation. 6. Overall, it is apparent that we still understand relatively little about the importance of factors affecting predation on livestock and how to manage this conflict effectively. We consider the following avenues of research to be essential: (i) quantified assessments of the loss of viable livestock; (ii) landscape-level studies of contiguous properties to quantify losses associated with variables such as different husbandry practices; (iii) replicated experimental manipulations to identify the relative benefit of particular management practices, incorporating (iv) techniques to identify individual predators killing stock; and (v) economic analyses of different management approaches to quantify optimal production strategies