I don't know exactly what your paper is about but how about dealing with the issue that hunting the birds decreases the population and is therefore not good for the species. The counter is obviously that while unregulated hunting might be bad (in fact it almost wiped them out in North America) it was hunters (through the NWTF) that have brought them back and actually helped to expand their range. So obviously, hunting and the dollars it raises for conservation is very good for the species. You can get some good back up for this on the NWTF website.