Individual study: Impact of treatment with carbachol on carrion crow Corvus corone predation of decoy eggs in a heronry at Garzaia di Villarasca Nature Reserve, Lombardia, Italy
Bogliani G. & Bellinato F. (1998) Conditioned aversion as a tool to protect eggs from avian predators in heron colonies. Colonial Waterbirds, 21, 69-72
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Use aversive conditioning to reduce nest predation by avian predators
A controlled, replicated before-and-after study at a heronry in northern Italy in 1994 (Bogliani & Bellinato 1998) found that the percentage of greenish-brown hens’ eggs predated by hooded crows Corvus cornix was significantly lower than blue hens’ eggs when they were treated with Carbachol. There was no difference in predation rates either before or after the 12 day treatment period (before treatment: 100% of both blue and brown eggs consumed within one day, n = 40; treatment: 61% of untreated blue eggs consumed vs. 38% of treated brown eggs, n = 480; after treatment: 90% of both blue and brown eggs consumed, n = 40). During the conditioning period, consumption rates were similar until the tenth day and then only a single brown egg was consumed over three days.