ALASKA LONGSPUR 1611 



those of longspurs moving through the interior. Irving has taken 

 latitude 50° N. and longitude 134° W. as representing the north- 

 western sector of the wintering area and points out that from that 

 locality migration extends 20° north and 14° west to the eastern 

 border of the breeding range in Mackenzie, while to the west in the 

 Aleutian Islands, migration extends 67°, but represents only a 4° 

 northward advance. The average arrival time for four years at 

 Atlin, British Columbia was April 22 (Swarth, 1936). This station 

 is located in the path of large migratory flights moving westward 

 to Alaska and from whence the general sequence of northward 

 movement may be traced (Irving, 1961). 



Arrival in western and northern Alaska varies from the last of 

 April until mid-May with an average arrival date of about May 10. 

 The consistent arrival in April in southeastern and south-central 

 Alaska and the Aleutian Islands indicates a coastal migration inde- 

 pendent of the major movements of birds through the interior. 



The first flocks are entirely or preponderantly comprised of males, 

 and these are followed in a few days by flocks that are preponderantly 

 females. Arrival of the longspurs coincides with the rapidly retreating 

 snow cover and the increasing availability of nesting habitat. Late 

 snowfall, especially in the arctic, is not uncommon and the weather is 

 characteristically unsettled when the birds appear. 



Courtship. — Courtship and pair formation take place after the birds 

 have arrived on the nesting ground. Scattered males take up resi- 

 dency on the tundra and show signs of increasing territoriality. At 

 this time, usually mid-May, small groups of males continue to remain 

 together quietly feeding, and intermittent stormy weather may cause 

 others to leave the newly established or forming territories and re- 

 group temporarily in sheltered areas such as willow-clad stream bot- 

 toms. Singing on the wing, or less commonly from more elevated 

 parts of the territory such as sedge tussocks, commences rather 

 abruptly after the males arrive. Territorial disputes, including 

 spirited chasing of neighboring males at the borders of the territories, 

 and alternate singing with adjacent males are commonplace. Some 

 of the chases are long-lived with the pursuing male seemingly within 

 inches of the fleeing adversary, and maneuvering adroitly to remain 

 there as they are lost from view. 



Actual contact between rival males is not uncommon and one 

 intruder was seen to land on the back of a silently feeding male, thus 

 initiating a prolonged and erratic chase during which he was routed. 

 On another occasion two males approached to within a foot of one 

 another on the ground; both crouched down in a throat posture for a 

 moment, whereupon the intruder flew off a short distance and the 

 remaining bird resumed his feeding between the tussocks. The 



