84 The Wilson Bt'lletix — Xo. 108 



hamlets or villages of 25 or 30 nests located some distance 

 from the main colony. 



As is well known, no nest worthy of the name is made; 

 the bird makes a depression in the sand by turning round 

 and round, and in the slight hollow thus forme<l, the eggs 

 are laid. Four eggs comprise a full set, although three 

 nests were found containing five eggs and quite a number 

 containing only three. 



It is probable that the sets of three (while some of 

 them were highly incubated) were incomplete sets. 



On windy days, if the bird stays away from the nest 

 for any length of time, the nest is soon filled level full of 

 the fine shifting sand and the eggs are completely covered. 

 This may account for the smaller sets. 



One set was found containing a dwarf egg and three 

 sets containing albino or partially albinistic eggs. 



Quite a difference in size was noted; the longest egg 

 measured 2.02 and the shortest 1.55. In the short diame- 

 ter, the largest measured 1.18 and the smallest 1.14. In a 

 series of 179 eggs measured, the average long diameter is 

 1.74 and the short diameter 1.28. The dwarf egg measures 

 1.09X.83. 



Assisted by my son, I set up the blind where five nests 

 could be seen, each one of them in a different direction and 

 none of them more than ten feet from the blind. Four of 

 the birds did not return to their nests, but the fifth one 

 did; she was very nervous and during the day did not re- 

 main at the nest for any great length of time. As she set- 

 tled upon her eggs, she would utter a sort of liquid cud- 

 dling sound, somewhat similar to the clucking sound made 

 by a hen as she broods her chicks. Each time as she set- 

 tled upon the eggs, she pressed her sharp bill upon the edge 

 of the nest. This action accounts for the sharp lines in the 

 sand frequently seen radiating in all directions from the 

 nests. As the skimmer invariably faces the wind, either 

 while brooding or while standing upon the sand, in time 

 these marks point in almost every direction. 



