Cuckoo in a Nest (image) The City University of New York Share Print E-Mail Caption Common cuckoos are parasitic -- they are raised in the nests of other species. As adults, male cuckoos recognize their familiar neighbors and aggressively attack passing by stranger cuckoos: a phenomenon known as the Dear Enemy Effect. Credit Csaba Moskat Usage Restrictions None Share Print E-Mail Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.