The Song Sparrows 



Taken in Seattle 



north of us — viz., morph- 

 na, whose range ex- 

 tends from the Columbia 

 River to southernmost 

 Alaska; and r ufi n a , 

 which occupies the 

 southeastern coastal 

 strip of Alaska north to 

 Cross Sound — intergrade 

 so perfectly that some 

 authorities, Grinnell, for 

 example, decline to sepa- 

 rate them at all. But 

 the final test of differ- 

 ence may prove to be 

 other than somatic. The 

 degree of participation 

 in migration may help to 

 determine the difference 

 between hypothetical 

 morphna and rufina. All 

 we know so far is that 

 the Song Sparrows of 

 western Washington, 

 morphna, are partially 

 sedentary, perhaps 

 wholly so in the south- 

 ern portion of their 

 range; whereas rufina 

 forsakes the northern 

 portions of its range, — 

 the Cross Sound and 

 Sitka districts — out- 

 right. The probabilities 

 are that the migratory 

 movement of morphna- 

 rufina is, therefore, high- 

 ly composite, that the 

 southern extreme is stable, while the northern end is forced down by a 

 telescoping motion which projects now one element and now another of 

 the composite mass into northern California. The variable character of 

 the material taken in winter in California supports this hypothesis, while 



340 



Photo by the A uthor 



"A BIRD OF MODEST MIEN" 



