TRUMPETER SWAN". 87 



southern Iowa, on the average, March 19; at Heron Lake, Minn., the 

 average date of arrival is April 4, earliest March 21, 1889 (a very 

 early spring); other average dates are: Nebraska, March 16; South 

 Dakota, April 2; North Dakota, April 15; Saskatchewan, April 16; 

 British Columbia about April 20. All these dates are later than those 

 which mark the arrival in these districts of the early ducks and geese. 

 Fall migration. — The trumpeter begins to move south early in Sep- 

 tember, crosses into the United States the last of that month, and 

 reaches the Gulf of Mexico in Texas about the middle of November. 

 The last remain on the breeding grounds until October, when they are 

 forced away by the gathering ice. 



