^°l89o!"'] PROCEEDINGS OF THE NATIONAL MUSEUM. 471 



of tern's uests, just finished, apparently, as they were clean, but empty, 

 and the old birds continued flying above us ami screaming their re- 

 sentment. 



On July 5, 1884, at McGee's Lake, Carberry, I found the terns just 

 beginning to lay. Each nest is a mere handful of floating reeds, slightly 

 moored to others growing in the deep water, where they are found. 

 The whole structure is just on a level with the surface of the water and 

 entirely wet ; on this are the eggs, much the same color as the reeds, 

 and as wet as eggs can be. 



It is a remarkable fact that, although this species is abundant in all 

 parts of southwestern Manitoba, and 1 have often searched in various 

 lakes with a flock of terns screaming about my ears, yet I have never 

 before found either nest or eggs. On this occasion I found three eggs 

 in one nest ; several nests with two eggs ; one or two with one, and one 

 or two empty nests just completed. 



On July 9 the terns were numerous everywhere on the i)rairie. 

 Timed and counted the wing beats of several as a basis for calculating 

 their rate of flight; one made 54 beats in 9 seconds ; another, 28 beats in 

 9 seconds, a third 30 in 10 seconds. July 6, observed one make 27 beats 

 in 10 seconds. July 12, saw another make 15 beats in 5 seconds, show- 

 ing that about 3 is the average number of beats to the second. July 5 

 I had an opportunity of measuring the distance a tern covers with 8 

 beats; it was 24 yards. 



August 14 : Terns are abundant now on the open prairie ; it is a com- 

 mon sight to see this bird zigzagging about in pursuit of the large 

 dragon flies, until, at length, having secured as many as it could con- 

 veniently carry, it suddenly ceased the fantastic maneuvering for the 

 swifter beeline, and made straight for its twin nestlings in the reedy 

 expanse of some lake far away. 



To-day, I made a calculation of the speed; one bird covered 70 yards 

 with 14 beats, i. e., 5 yards i)er beat; I find they usually give 3 beats per 

 second ; this, therefore, is 15 yards per second or 31 miles per hour ; much 

 less than I expected. This black inland member of a white marine 

 family is abundant about all the weedy sloughs and lakes of the Mani- 

 toban prairie regions. It seems not to subsist on fish at all, but chiefly 

 on dragon flies and various aquatic insects. It finds both its home and 

 its food in the marshes usually, but its powers of flight are so great 

 that it may also be seen far out on the dry open plains scouring the 

 country for food at a distance of miles from its nesting ground. 



The voice of the species is a short, oft-repeated scream, and when any 

 known enemy, be it man or beast, is found intruding on the privacy of 

 their nesting ground the whole flock comes hovering and dashing about 

 his head, screaming and threatening in a most vociferous manner. 

 Under such circumstances it is the easiest thing imaginable to procure 

 as many specimens as may be desired. When one of the flock falls 

 wounded in the water, its fellows will repeatedly dart down aiul hover 



