INCUBATION OF DOUBLE-CRESTED CORMORANT EGGS (PHALACROCORAX-AURITUS)

Double-crested Cormorant (Phalacrocorax auritus) eggs were successfull y hatched with incubation conditions of 37.2 degrees C and 60-64% rela tive humidity. Eggs were positioned horizontally automatically rotated every two hours, and manually rotated 180 degrees about their long ax is once a day. Over 70% of cormorant eggs incubated according to these procedures successfully hatched. Variations in egg position, rotation , and length of storage were also assessed. None of the eggs incubated with their blunt end up hatched and only 54% of eggs receiving no man ual rotation hatched. Of the eggs held at room temperature for two, th ree, or five days from the time they were collected in the field, 83 a nd 76% of the eggs held for two and three days, respectively, were sti ll viable after 14 days of incubation. Only 13% of the eggs set five d ays after collection were viable when assessed at 14 days of incubatio n.