An experimental procedure was set up to test if Carrion Crow (Corvus corone) predation on Little Tern (Sterna albifrons) eggs could be decreased by conditioned taste aversion. The experiment started with a control period, during which 30 artificial Little Tern nests were maintained with quail eggs for 6 days at two study sites. The rate of egg predation was assessed through daily visits and observations of crow behavior. During the treatment period (following 6 days), 15 nests were supplied with eggs pre-treated with methiocarb, an ill-inducing compound, while the other 15 nests were maintained with non-treated eggs. The treatment period was extended by a further period of eight days, during which only treated eggs were deployed at 15 nests. Carrion Crows did not develop any aversive response to the eggs. All treated and untreated eggs were taken by crows from the nests and broken in less than 24 h after delivery. However, treated eggs were apparently not consumed by crows, which suggests that they were able to identify the egg content prior to consumption. The lack of success of our study calls into question the general applicability and effectiveness of this method.