Parasitic Nesting Habits. In the bird world there are a few species whose members are determined to get something for nothing, and to avoid all labor in the rearing of their offspring. This bad habit is known of the Old World cuckoos, the American cow- birds, the South American rice grackle (_Cassidix_), and suspected in the pin-tail whydah (_Vidua serena_). It seems to reach its highest point in the cuckoos. It is believed that individuals lay their eggs only in the nests of species whose eggs resemble their own. Apparently much skill and intelligence is required for introducing parasitic eggs at the most favorable moment. This is equally true of other parasites. Curator Crandall has taken several eggs and young of the rice birds from nests of two species of giant caciques in Costa Rica, but never saw an adult _Cassidix._ It is considered a very rare species, but probably is more sly than scarce. Young cuckoos eject unwelcome nestlings shortly after hatching. Daily contact with a large and varied collection of birds great and small, gathered from every section of the habitable regions of the earth, naturally produces in time a long series of interesting cases of intelligence and behavior. Out of our total occurrences and observations I will offer two that reveal original thought. Good Sense of the Wedge-Tailed Eagle. In discussing bird intelligence with Mr. Herbert D. Atkin, keeper of our Eagles Aviary and the cranes and water birds in the Flying Cage, he called to my attention two species of birds which had very much impressed him. Afterward he showed me all that he described. Keeper Atkin regards the wedge-tailed eagle, of Australia, as the wisest species with which he has to deal. In the first place, all four of the birds in that flock recognize the fact that he is a good friend, not an enemy, and each day they receive him in their midst with cheerful confidence and friendship. In the fall when the time comes to catch them, crate them and wheel them half a mile to their winter quarters in the Ostrich House, they do not become frightened, nor fight against being handled, and submit with commendable sense and appreciation. The one thing on which the wedge-tailed eagle really insists when in his summer quarters, is his daily spray bath from a hose. When his keeper goes in to give the daily morning wash to the cage, the eagles perch close above his head and screech and scream until the spray is turned upon them. Then they spread their wings, to get it thoroughly, and come out thoroughly soaked. When the spray is merely turned upon their log instead of upon the birds as they sit higher up, they fly down and get into the current wherever it may be.