BUILDING NEW TRADITIONS 



ger (1941:105) says "it may be stated in general that the Crow was dis- 

 tributed sparsely in the State prior to 1855, became common in the south- 

 ern portion by 1875, and abundant by 1890." As the land changed, pioneer- 

 ing Crows and Meadowlarks, Robins and Song Sparrows moved in to take 

 residence in country their kind had never occupied before, migrating to 

 and from these new places and delivering the traditions to their progeny,* 

 so that now these regions are firmly established within the natural ranges 

 of the species. 



When the Arkansas Kingbird moved into Manitoba, it extended its mi- 

 gratory range northward by at least two hundred miles, to such an outpost 

 as Lake St. Martin, f Even though this bird was not a member of the native 

 fauna, it is now among the most regular of spring and fall migrants. Here, 

 within the span of a few years, we have the evolution of a migration carry- 

 ing many individuals hundreds of miles into land their race never used be- 

 fore. The urge of these Arkansas Kingbirds to migrate must be sexual and 

 inborn, regardless of the newness of the places to which they migrate. The 

 recent origin of the migration, however, seems to give further evidence 

 that the route is learned ; the short time these kingbirds have lived in Man- 

 itoba cannot have been sufficient to permit the establishment of inborn ties 

 to their new geographic locations. This same thing, as suggested by Mayr 

 and Meise (1930), must have taken place in response to the ecological 

 changes in the wake of receding glaciers. As Allen (1880) wrote, "Such mi- 

 gration must have been at first 'incipient and gradual,' extending and 

 strengthening as the cold-wave Ice Age receded and opened up a wider 

 area within which existence in summer became possible." There is strong 

 evidence, then, that the length of migrations was extended by ecological 

 changes following the recession of glaciers in the same way as new migra- 

 tions accompanied the changes wrought by man. In the first instance, the 

 pioneerings of birds must have been slow; in the modern example of the 

 Arkansas Kingbird, the deep advance into new migratory range has been 

 accomplished in a twinkling of history. Probably both slow and rapid 

 pioneerings became established in the same way, as the actions of experi- 



We must point out that there are some species, of limited number to be sure, that 

 seem to have no ties to the land, birds that pioneer to new breeding places one year, never to 

 appear there again for many seasons, wanderers such as the Pine Siskin, the crossbills, and the 

 Evening Grosbeak, which, as Roberts (1932:365) points out, are possessed of a "gypsy-like 

 wanderlust" that takes them "now here, now there and only irregularly and seemingly by 

 chance back again to the same locality." These "eccentric creatures" are pioneers leaving be- 

 hind no followers, explorers delivering no traditions except of wandering. 



t A. G. Lawrence, in "Chicadee Notes," Winnipeg Free Press, May 29, 1953. 



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