Скачать или смотреть Risk factors for bird damage in fruit and mitigation strategies

Our work in New York, Michigan, and the Pacific Northwest from 2012-2014 suggest two Bird Management Principles. Principle One: when there is less fruit in a given area, there will be a higher percent loss compared to areas with more fruit. Thus, expect a higher proportion of damage in: 1) low­yield years, 2) early-ripening varieties (birds will have few alternatives), and 3) blocks that abut non-fruit land-cover types. Principle Two: blocks near resources important to birds are at higher risk for damage. When/where to expect higher bird damage: 1) blocks under wires, 2) edges of blocks, 3) near night roosting sites, and 4) isolated blocks with little human activity. Whether and how much to invest in bird management in a given year will depend on the costs of bird management versus anticipated fruit losses. Although percent damage for sweet cherries and 'Honeycrisp' apples in New York and Michigan was much lower in 2014 compared to 2012, a small percent loss of a large crop could be worth enough to warrant management strategies. However, our results also suggest that bird deterrent techniques like various types of scare devices may have little impact when yields are large.