This paper describes a two-part study of small predators in New Zealand forests. First, during 12 days of live-trapping, 31 wild ship rats were captured, tagged and released: 9 were handled while anaesthetised using halothane and 22 were handled while conscious using gloves. There was a significant difference between the two groups of ship rats in live-recapture rate: 4 out of 9 rats that had been handled while anaesthetised were recaptured alive, compared with 0 of 22 that were handled while conscious. Second, during 12 days of removal-trapping, 23 ship rats were killed, of which 6 were tagged, including 4 of the 9 that had been previously handled while anaesthetised (2 of which had also been recaptured alive during the live-trapping) and 2 that had previously been handled while conscious. These observations have implications for the statistical estimation of population density from capture-mark-recapture data and for the development of protocols for minimising stress in captured animals, especially nocturnal species released from traps in daylight.

Our objective in this study was to determine the density of the jaguar Panthera onca from camera-trap data, using an open population model, in a private protected natural area, the Northern Jaguar Reserve, and 10 adjoining cattle ranches in the state of Sonora, Mexico. The region is considered a long–term jaguar conservation unit. As well as being the most northerly recorded reproductive population of the jaguar, the arid habitat of this region is atypical for the species. During 16 months of sampling we identified 10 individual jaguars and the data met the three main assumptions of open population models. The estimated mean density was 1.05±SE 0.4 individuals per 100 km2, with a constant survival probability of 0.94 and capture probability of 0.23. This estimate of density is lower than reported in studies of the jaguar from more southerly locations in Mexico, Belize, Costa Rica, Bolivia and Brazil but cannot be attributed to a single factor even though in general there is an apparent relationship between jaguar density and precipitation. The main objectives of the management of the Northern Jaguar Reserve are to reduce the impact of cattle and restore jaguar habitat, with strategies focused on water retention, removal of invasive grass, reforestation and environmental education. Livestock have been gradually excluded since 2003 and, combined with the protection provided under the agreements with the surrounding ranches, the area is now a suitable place for long-term studies of the jaguar.

In April–May 1986, 180 male and 218 female Glossina morsitans morsitans Westwood, each less than 1 day old, were marked uniquely and released unfed on Redcliff Island, Lake Kariba, Zimbabwe. Flies were recaptured on ox fly-rounds carried out twice daily for 6 months; marks were recorded and the flies released. For females, 56% were recaptured at leastonce; the capture probability for a given 9-day period changed with age, falling from 0.32 after birth to 0.16 by 30 days and rising above 0.5 by 80 days. For males, 57% were recaptured; the probability was 0.21 for age less than 9 days, but > 0.77 for all older flies. The capture probabilities and fly-round catches were used to estimate the change with age in the daily mortality. Female mortality was 6.8% shortly after emergence, < 1% for ages 20–50 days and rose to 5% by 130 days—a pattern similar to that for laboratory reared tsetse. Male daily mortality was 8.3% after emergence, fellto 5.5% by 9 days, then rose continuously to more than 10% by 30 days. The mortality changes are related to age rather than climate. Tsetse caught on ox fly-rounds from a natural population were aged using ovarian dissection and wing-fray analysis. The age distribution (corrected using the capture probabilities from Redcliff) was consistent with the idea that, here too, mortality increased with age.