1346 U.S. NATIONAL MUSEUM BULLETIN 23 7 paht 3 



increasing number of birds in a given flock participate in the singing 

 until, on the eve of departure, one hears a chorus of song from each 

 flock headquarters. This group singing is not an act of defiance, 

 and provokes no hostile response either from other Puget Sound 

 sparrows or from the by now highly territorial Nuttall's sparrows in 

 whose areas the migrants live. I never saw either chasing, fighting, 

 or trilling and posturing in the flocks of Puget Sound sparrows win- 

 tering at Berkeley. 



Daily trapping of banded birds reveals that it takes about as long 

 for the individuals of any one flock to depart as it does the entire 

 local wintering population. The departure is spread over about two 

 weeks. Adults tend to depart earlier than young of the year. The 

 last members of a given flock to disappear are usually first-year 

 females. From departure and arrival dates for this race at the ex- 

 tremes of the range, I believe that the longest spring migration is 

 accomplished in not more than two weeks. I know nothing of the 

 behavior during this period. 



In the spring of 1936 I went to Friday Harbor, Wash., to watch 

 the arrival of birds destined to breed there. The largest influx oc- 

 curred between the evening of April 9 and the next morning. On 

 April 10 I found almost every piece of suitable ground, which only 

 the day before had been empty and silent, occupied by a male perched 

 conspicuously and singing with full volume every few seconds. Close 

 to him I often saw another, silent bird, the female. The shift from 

 the unassorted gregariousness of the wintering grounds to paired 

 isolation must have taken place either during migration or immedi- 

 ately upon arrival, for no flocks or fragments of flocks were in evidence. 

 Observations on color-banded birds by Mrs. Forrest Fuller at Friday 

 Harbor indicate that on the day of arrival the birds go directly to 

 the areas where they subsequently breed, and that they return to the 

 same spot in successive years. 



From the day after arrival both chasing and fighting were common 

 and continued unabated until the beginning of incubation about 

 three weeks later. Territorial boundaries were so fluid as to scarcely 

 deserve the name. Both sexes seemed more excited and restless 

 than NuttalPs sparrows in the corresponding stage. During a bound- 

 ary dispute neighboring males trilled vigorously and fluttered one 

 wing, and females frequently took part in pursuits. The whole 

 scene was one of confusion and unsettledness, in sharp contrast to 

 the orderly and law-abiding Nu Wall's on their mutually exclusive 

 areas during the seven weeks before the start of incubation. Even- 

 tually, however, the same result was achieved. By the first day of 

 incubation in late April and early May the fighting subsided and 



