Bird scourge

I have been managing a volunteer cormorant scare/cull program on an island in Lake Simcoe, Ont., since 2011 (“Land of hope and guano,” Ontario, July 2019). Cormorants were historically never seen on Lake Simcoe. They first arrived shortly a er zebra mussels became established in the mid-1990s. Fish-eating cormorants are visual feeders. It is my belief that they have benefited from the invasive mussels that have vastly increased water clarity and, thereby, the effectiveness of their feeding. This translates to healthier birds, and more and healthier chick survival. Because of this, the cormorant population has increased exponentially. Our island saw an estimated 20,000 cormorants migrate and roost along a 1.5-km stretch of the shoreline each fall. The effects were devastating to the shore

vegetation, the adjacent water quality and almost all other shoreline life. Our operations have not ended the fall migration to this island, but what it has done is moved the birds out more quickly. We have found they are increasingly smart birds and move out quickly once the shooting starts, and each year they seem to move more quickly. We now see the positive impacts of fewer birds on the island. The trees are fully foliated, a large number of birds including great blue herons have returned and we even see bald eagles. Our highly strategic, sitespecific program is nothing like the open-season approach currently being proposed in Ontario. The spring effort is very successful in limiting nesting, which was previously devastating to the shoreline. Humans have impacted every habitat and ecosystem. It behooves us to try to manage and mitigate our effects when we have reasonable, dedicated and costeffective means to do so. Larry Wickett, Beaverton, Ont.