AMEllICAN OnNITIIOLOGY. 



357 



night and at a great height. The day time is passed in rest or in feed- 

 ing about the marshes that they pass on their way South. In the Fall 

 and Spring they are a great deal more common along the coasts than 

 during the breeding season. They are very strong fliers and are fre- 

 quently met with in the middle of the ocean. 



Except during migrations they do not usually fly at a great eleva- 

 tion. Their movements while on the wing are the equal of those of 

 any others of the family, as is shown by their scientific name of Hydro- 

 chelidon, which signifies "Water Swallow". Their movements on the 

 land are graceful although they do not do much walking, trusting to 

 their wings rather than their feet in moving from place to place. Their 

 head is carried well down on the shoulders and the body is horizontal 

 with the wings well up on the back. They live chiefly on insects, 

 worms and young fish and frogs, which they catch on land or by dip- 

 ping their heads into the water, rarely swimming except from necessity. 



NEST AND[EGGS OF BLACK TERN. 



Phoio by P. B. Peabody. 



