46 



of birds, and often alight on their very heads or shoulders 

 — this the wild Crows, viewing from a distance, seem to 

 think is evidence of a disordered mind, and they forthwith 

 use every wile, every stratagem in their power, to entice the 

 tame birds back to their ranks. Often in summer when I 

 arrive early at the Park I surprise a company of them " hav- 

 ing it out " — the tame bird surrounded by a ring of his fel- 

 lows, who are all talking at once, and giving him no chance 

 for argument. But their trouble is the only reward for their 

 pains, for his is a life of unnumbered daily meals, not to 

 mention the opportunities for stealing and hoarding sundry 

 keys, knives, and other bright plunder — the occupation 

 dearest to a corvine heart ! 



The psychology and the growth of young birds is a field 

 as yet almost untouched by careful workers. I offer the 

 following facts which came to my notice in rearing from 

 eggs in an incubator individuals of the Common Tern [Sterna 

 hirundo), Least Tern (jS. antillarum), Laughing Gull (Larus 

 atricilla)^ Black Skimmer [Rynchops nigra) and Green Heron 

 (Butorides virescens). 



1. — The call, food and alarm notes of Common Terns, 

 Black Skimmers and Laughing Gulls are instmctive — not 

 taught by the parents nor learned by imitation. 



2. — The remarkable disparity in the length of the mandi- 

 bles in the adult Black Skimmer is foreshadowed even in the 

 embryo and in the newly -hatched bird. 



3. — My experience with a dozen terns and gulls showed 

 that these individuals prefer fresh water to salt. 



4. — There is absolutely no "instinctive" fear of man or 

 other objects which enter quietly into the environment of 

 the young birds ; but a sudden shadow or loud noise causes 

 them to perform certain acts — wholly instinctive — which 

 have for their object an escape from supposed danger. 

 Under such conditions the tern (which is not so protec- 

 tively colored as the skimmer) takes time to run to the dark- 



