| dc.description.abstract | Between 39-57 million pheasants (Phasianus colchicus) are reared and released into the UK each year to accommodate recreational shooting. When carried out well, the associated land management can be very positive for the environment. However, releases at high densities can cause significant detrimental impacts for the wildlife around release sites. To improve the environmental sustainability of the shooting industry, methods must be found to; reduce the numbers of birds released without adversely affecting the shooting industry, increase knowledge and understanding of the impacts of pheasant releases on wildlife, and ensure that methods of monitoring pheasant populations are robust and reliable. I showed that two separate rearing enhancements can be combined within a commercial rearing system and lead to greater pheasant harvests while still releasing the same numbers, so future release sizes can be reduced while harvest rates are maintained. This was achieved by the provisioning of perching material and providing an improved diet during rearing that resulted in improved pheasant survival post-release, enabling more to contribute to the harvest. Enhanced pheasants were harvested at rates 16-17% higher than Control pheasants on shoots releasing <601 or >2000 pheasants but 6% lower on shoots releasing 601-2000 pheasants. When release date was considered and not release size, shoots that released prior to August 22nd shot proportionately more Enhanced birds while shoots that released after shot proportionally more Control. Enhanced Rearing was cost-effective, only increasing the average cost per pheasant by 2.6%. Enhanced pheasants also flew higher, had larger hearts, larger breast muscles, thicker tarsi, gained weight more slowly over time, and impact invertebrates and habitats in and around the release pen no more than traditionally reared pheasants. Higher flying pheasants were shot at higher rates early in the shooting season but lower rates by the end. The overall flight performance of the pheasant population as a whole does not change over the course of the shooting season. Releasing pheasants can lower total invertebrate biomass, slug counts, and detritivore counts within the release pen by 4 weeks post-release when overall invertebrate abundance is high, but this effect is removed by 9 weeks post-release. Conversely, when overall invertebrate abundance is low, there is little effect of releasing pheasants on invertebrates within release pens 4 weeks post-release, but by 9 weeks post-release, pen interiors can have higher total invertebrate biomass, total invertebrate counts, slug counts, and beetle counts. Releasing pheasants at higher stocking densities in one year can, prior to releases in following years, reduce the invertebrate biomass within the release pen, reduced detritivore counts both inside and outside of the pen, and increase slug counts both inside and outside of the pen. I created a correction factor that accounts for the deterioration rate of the Multi-Tag patagial wing tag which is widely used for marking gamebirds. This allows past and future datasets using this tag to increase the accuracy of their findings. Even with the correction factor, I recommend that Multi-Tags not be used for long-term (>1 year) studies. I improved the accuracy of aging pheasants using proximal primary feather features by 1.3% by adding feather mass as an additional variable to length and diameter. I also found that machine learning may be overall less effective at aging pheasants via the proximal primary method alone. Finally, I discussed the implications of my findings and how they could impact wildlife conservation, pheasant and shoot management, and monitoring gamebird populations. I also identified several areas for potential future study. | en_GB |
