1276 U.S. NATIONAL MUSEUM BULLETIN 23 7 part 3 



May 6, 1962, was recaptured 1,500 miles to the north at Battle 

 Harbor, Labrador, on June 12, having averaged 40 miles per day. 



The rapid northward surge of this species results in "a high fidelity 

 of timing" as Cortopassi and Mewaldt put it — 94 percent of the birds 

 pass through 1,000 miles of the northeast's most populous countryside 

 between May 2 and 18, with May 11 the median date for banding 

 migrants in this region. Milton B. Trautman (1956) gives the princi- 

 pal movement at Buckeye Lake, Ohio, as May 8 to 20. In a letter to 

 Ralph K, Bell, Gordon Wilson of Bowling Green, Ky., who has 

 chronicled the birds of his region for 45 years, gives average departure 

 as May 10, with May 28 as a late date. 



The only evidence of physiographically-con trolled spring migration 

 I have seen is a letter from Clark S. Beardslee to Mr. Bent in 1951. 

 reporting that in spring northbound white-crowns move eastward 

 through Ontario, cross into New York State in the Buffalo-Niagara 

 isthmus, then presumably circle eastward around the south side of 

 Lake Ontario before moving northward into Quebec. Harold D. 

 Mitchell has kindly confirmed these observations for me. 



Dispersal into the subarctic breeding grounds on the interior 

 Quebec-Labrador plateaus normally occurs during the last week of 

 May, though late ice and snow may sometimes delay arrival a whole 

 week. I was impressed by the influence of seasonal conditions when 

 I arrived at Knob Lake in interior Quebec on May 18, 1957. A 

 raging blizzard made it plain that winter's grip was still firm. Re- 

 turning to within 15 miles of the St. Lawrence above Seven Islands, 

 I found white-crowns abundant and obviously "dammed up" by 

 weather, for they were occupying all sorts of habitats that are not 

 usual for them. They sang softly while awaiting better conditions 

 for concluding their migration. The first birds arrived at Knob 

 Lake on May 23 that year, but even so, they had to spend several 

 days feeding along plowed roadsides until the snow melted from the 

 territories they were to occupy. Harrison F. Lewis' notes show 

 that conditions were even more severe a decade earlier; his June 4, 

 1947 journal entry records that this "was an abnormally cold, late 

 spring, with consequent heavy loss of life among small migrant 

 passerines." He recorded 120 obviously delayed migrant white- 

 crowns at Seven Islands, south and west of the breeding range. 



Territory. — Territorial behavior has not yet been described for this 

 race of the white-crown. I have twice seen fights in early June in 

 the Knob Lake region, the birds facing each other breast to breast, 

 then jumping, clawing, and flying at each other. Such jousts are 

 usually short-lived. 



The white-crown does best in "hybrid" habitats, where disturbance 

 of the surface by fire or mechanical means has increased diversity 



