Abstract

Waterbirds have vexed Louisiana crayfish farmers since the industry’s earliest days. Large flocks are regularly encountered. High densities of crayfish predators and competitors would appear to be detrimental to production. As yet, no definitive studies have determined whether or not “perceived” problems are “real”. However, “perceived” problems cause concern among crayfish farmers and should be of concern to those charged with addressing wildlife damage complaints. Conflicts between farmers and conservationists are exacerbated because of the clear value of the Louisiana’s 67,000 ha of crayfish impoundments to over 100 species of waterbirds. Concern about waterbirds involves several issues. Direct predation on crayfish is a clear concern. Birds are also competitors for crayfish food resources, including invertebrates, small vertebrate animals, and un-harvested seeds. Birds impact harvesting by removing cut fish bait and/or crayfish from traps, as well as dislodging traps permitting crayfish to escape. Finally, some birds hasten destruction of emergent vegetation that provides crayfish with protective cover, reduces absolute density per unit area and affords access to the surface during periods of low dissolved oxygen. Specific bird groups include: grebes, pelicans, cormorants, egrets, herons, night-herons, ibises, spoonbills, storks, geese, dabbling ducks, diving ducks, coots, shorebirds, gulls and terns. Information about control methods for dispersing birds, including non-lethal harassment, ex-closures, management of water depth and vegetative cover, and crayfish trap modification will be presented. The seasonality of “problem” birds varies and will be discussed.

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