1612 U.S. NATIONAL MUSEUM BULLETIN 237 paet 3 



intruder returned promptly and struck the feeding bird. This initi- 

 ated new threat posturing with the birds crouching low and spreading 

 their wings slightly. 



As the females continue to arrive in increasing numbers and dis- 

 perse over the tundra, the attention of the males is attracted more and 

 more toward them. Courtship flights are common, and two or three 

 males are frequently involved in chases of an individual female. 

 The male pursues the female in frequently lengthy and circuitous 

 flights and finally lands a few feet from her. Common behavior 

 during these pauses is for the male to peck at the ground and move 

 closer to the female until she flies up to the top of a tussock thus 

 initiating a new flight. His actions seem to indicate that he is 

 physiologically predisposed to copulation and is so motivated by the 

 female's presence. When her response is not one soliciting copula- 

 tion, his actions may be carried over into the displacement activity 

 of pecking. Later, as the female becomes motivated toward breed- 

 ing, probably largely due to the persistence of the chasing male, she 

 may react by reciprocal chasing. 



Drury (1961) states that: 



Pursuit flights were obviously mutual affairs and, I believe, closely associated 

 with pair formation. They were longer, slower, and with less zigzagging than 

 territorial skirmishes. If the male caught up, there was a burst of rapid zigzagging 

 but if he fell far behiud, the female slowed down until he overtook her. We saw 

 these flights before any displays on the ground, and throughout the period of 

 ground displaying. Male No. 6, displaying to his female, ran across in front of 

 her or up to her side, standing at about a 60° angle to the horizontal, with his 

 breast feathers fluffed out, head held high and bill pointed slightly up, wings 

 about half spread, drooped and quivering. While he ran in this way he was 

 singing his regular flight song. The female ran slowly ahead of him, crouched 

 in a horizontal position with her head partly lowered, wings partly spread, tail 

 cocked just above horizontal, calling zeep, zeep. * * * She and the male often 

 pecked stiffly at the ground. * * * The chestnut nape emphasized the stiff 

 bow by the male. The female ran around and ahead of him; then flew; if he 

 did not follow, she came back and repeated her actions until he did chase. During 

 the chases she landed several times, ran along the ground, then flew again, fast 

 and darting, or slowly and on quivering wings. During the period of pursuits, 

 because their attention was on the females, males sang less often and chiefly 

 on the ground. 



In the presence of a female the advertising and/or territorial song 

 flight was seen to be modified into a courtship display. The male 

 performed this flight in the usual manner, with the tail spread and 

 wings near the horizontal in a gliding path. The entire flight is only 

 a few feet in length; it is performed only a short distance above the 

 ground a few feet from the female, and the male often carries nest 

 material, apparently sedge or grass, in his bill. The chases, both 

 aerial and on the ground, together with the modified display flights 



