National Geographic : 1962 Apr
can be woven into a round, cuplike nest. Stage III. The bird builds a roof and there fore needs stronger materials, namely twigs, which can be carried only in the bill. Now, after a little detective work, we say that the lovebird species of Madagascar (Stage I) are more primitive than those of Angola (Stage II), and that the most advanced species live south of Lake Victoria (Stage III). We can even predict some female lovebird behavior of the future: Stage IV probably will carry not one but several twigs in her bill. Parrot's "Aggression" Mostly Bluff Once a week Bill and the research staff meet in the observatory and discuss experi ments and new findings in related sciences. They talk of "survival value," "fear thresh olds," "redirected aggression." It is fascinat ing, and not nearly so forbidding as it sounds. Imagine parrot A stalking fiercely toward parrot B. That's aggression. Parrot B doesn't give ground, and bird A becomes frightened. 550 He has reached his fear threshold. Bird A flies off to a high perch and pecks fiercely at the perch. That's redirected aggression. Other birds, such as pigeons, fight frequent ly but are not equipped to harm each other much. The parrots, however, carry extremely powerful bills. The behavior described above - bluffing rather than fighting -keeps them from tearing each other to pieces. Therefore this behavior pattern has survival value. On Monday nights the observatory is usual ly crowded with bird lovers from all walks of life: professors, students, doctors, lawyers, and businessmen, many from neighboring towns. They hear lectures, perhaps from our new director, Dr. Olin Sewall Pettingill, Jr., on his study of penguins in the Falkland Islands,* or from our executive secretary, Dr. Sally Foresman Hoyt, on talking birds. Recently *Dr. Pettingill's account of his experiences, "People and Penguins of the Faraway Falklands," appeared in the March, 1956, NATIONAL GEOGRAPHIC.