MAMMALIA 261 



Washington, while the robins summering in northern 

 United States migrate to a winter home along the Gulf of 

 Mexico. The nighthawks, living in Alaska from May to 

 September, fly over five thousand miles to their congenial 

 winter home in Patagonia. Over fifty species of New 

 England birds winter in South America. Twenty-five 

 species from northern United States pass the winter in 

 Porto Rico, an equal number go to Cuba, and at least 

 twenty species remain during our cold season, in Jamaica. 

 Others, such as the red-eyed vireo, migrate to Central 

 America. 



Every school should keep a record of the time of the 

 appearance of each species in the spring and its departure 

 in the autumn. The pupils should be encouraged to 

 report how many birds they have coaxed to dwell in the 

 yard and garden by putting out meat bones and bread 

 crumbs in winter, and erecting nesting boxes for summer. 



19. MAMMALIA 



The mammals are distinguished from all other verte- 

 brates by their habit of providing the young with milk 

 and by the possession usually of a hairy covering. Like 

 the birds they are distributed throughout both the warm 

 and cold regions of both hemispheres. Since the habits as 

 well as the structure of the different groups vary widely 

 it will be necessary to consider the characteristics of each 

 of the eleven orders. 



Egg layers (Monotremata). The duck mole of Aus- 

 tralia is one of the three species of mammals which lay 

 eggs. It deposits hi its burrow on the bank of a stream 



