1658 U.S. NATIONAL MUSEUM BULLETIN 23 7 part 3 



The females at this stage are not yet sexually receptive, and rebuff 

 the males' frequent attempts to copulate. This results in the con- 

 spicuous sexual flights, in which the males chase their mates swiftly 

 both close to and high above the ground in a most dazzling manner. 

 These flights according to Tinbergen invariably follow unaccomplished 

 coition. They may continue for several weeks, but they decline 

 rapidly when the female becomes oestrously receptive. 



During this period paired birds, often one following the other, 

 explore the various niches and fissures on the territory, presumably 

 searching for nest sites. Even unpaired males on territory show 

 interest in holes by entering them. Tinbergen describes the nest 

 stage thus: 



The beginning of this new period was marked by a change in the behavior of 

 the female. She had until now shown interest in holes, but never had picked up 

 nesting materials. On a certain day, the female suddenly took some moss in 

 her bill, carried it for a few seconds or even less, and then dropped it again. On 

 this same day she did not flee when the male, as on previous days, approached 

 her, but adopted an attitude which was never seen before: she kept her back quite 

 flat and horizontal, pointed her bill upward and lifted the tail. The male mounted 

 and coition was accomplished. 



The carrying of nesting material therefore indicated, in all instances studied, 

 the beginning of the female's oestrous period. 



* * * 



After this first day the birds regularly performed coition, most frequently 

 during the early morning, between about 2 and 6 A.M., and not more than 2 to 5 

 times a day. 



Shortly after the first copulations the female started building, that is, she not 

 only collected pieces of moss, but she really carried mouthfuls of it to a hole. 

 What she did with it when she entered the hole, we were unable to see. Nesting 

 activities were most persistent immediately after coition. 



Nesting. — The female snow bunting builds the nest alone, though 

 the male often accompanies her to and from the nest site and occa- 

 sionally even picks up nesting material and offers it to her. She may 

 gather nesting material from afar, in which case the male does not 

 follow her much beyond territorial limits. Also she may start several 

 nests and abandon them before choosing the one she finishes. 



The species utilizes a variety of sites, but almost always hides the 

 nest in some hole or cranny, though sometimes only under moss. 

 The nest is often a foot or more back in a narrow rock fissure where 

 it is inaccessible. Frequently it is built under loose rocks on the 

 ground or in scree, and not infrequently in stone foundations or 

 buildings. Nests have been reported in skulls and in such artificial 

 sites as wooden boxes, metal containers, wire coils, construction 

 rubble, and other debris. Where rock or artificial sites are lacking, 

 the buntings will use cracks or holes in soft ground, especially where 

 the earth is frost-heaved into piles of mud. Nests in soft ground 



