HOMEWARD MIGRATION 



may be many days and hundreds of miles. But only the time and the miles 

 of travel are different; the appetites within the hen on her wintering 

 grounds are in the same category as those sensed by the nesting duck on 

 her loafing bar. In some females, like Mallards that winter and also nest in 

 Missouri or Colorado, there are few barriers between drive and goal. In 

 others there may be two thousand miles or more between the first sexual 

 appetite for the home range and the arrival there. The barriers are in direct 

 ratio to the distance traveled. Temperature, wind, snow, and rain are factors 

 in the schedule of travel to the breeding place, the birds staying back in the 

 face of severe adversities, surging onward in favorable weather. Weather, 

 however, must be a secondary influence on spring migration, incidental 

 rather than fundamental. 



There are two possible exceptions to this sexual nature of spring migra- 

 tion of waterfowl to the breeding grounds. In geese and swans, for one ex- 

 ample, nesting does not take place the first spring, so that in yearlings the 

 home is not the sexual goal in the same sense as it is in adults. The family 

 bond is strong enough, however, to carry the young along to the summer 

 home of the parents, which do travel on a sexual schedule. Once arrived 

 on their home area, there is intense sexual behavior in these yearlings, even 

 though it does not attain reproduction (Balham, 1953). There are also some 

 ducks, such as Bufflehead and the two Golden-eyes, which do not breed 

 until they are more than one year old. Unlike the geese, the yearlings of 

 these have no family ties. However, there is evidence that some arrive at 

 the breeding grounds independently ( Munro, 1942), and we are not entirely 

 sure that, despite the lack of breeding, there is not some sexual awakening. 

 At Delta I have seen yearling American Golden-eyes examining nesting 

 boxes; and for the yearling Barrow's Golden-eye, Munro (1939:272) says 

 that "there is some manifestation of sexual excitement amongst them and 

 they go through various performances which in the adults form part of the 

 reproductive process." Homeward travel for these birds might possibly be 

 classified as a sexual movement even though reproduction does not follow. 



I must not let this discussion end without brief mention of some of the 

 other migrants. The sweep of spring migration cannot escape the knowledge 

 of the most casual citizen in Manitoba's April countryside, for the rush of 

 travelers into this nearly birdless world of winter is a daily reminder of 

 spring's arrival on the northern prairies. In the latitude of southern Mani- 

 toba in late April and May, there are less than four hours of darkness com- 



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