CONDITIONED AVERSION AS A TOOL TO PROTECT EGGS FROM AVIAN PREDATORS IN HERON COLONIES

We used the cholinergic-agonist carbamyl choline chloride (Carbachol) to induce conditioned aversion to rare eggs in predators. We used chic ken (Gallus gallus) eggs for the experiment, dyeing treated eggs green ish-brown and dyeing untreated eggs light blue to simulate the eggs of the Night Heron (Nycticorax nycticorax) and the Little Egret (Egretta garzetta), the main species breeding in the study heronry. After ten days from the beginning of the experiment, treated eggs were significa ntly less preyed upon than untreated eggs; and by the 12th day no trea ted eggs were preyed upon, while control eggs still were. This techniq ue may be used to protect the eggs of uncommon birds, aiding their sur vival and increasing small local populations. We suggest some guide-li nes to successfully induce adverse conditioning in similar environment al situations.