1920 ] Wetmore, Birds of Lake Burford, N. Mex. 243 



but in a less exaggerated manner, simply jerking the head up and down. 

 The whistling noise that accompanies the start in flight with these birds 

 is made apparently as they gain momentum by beating the sharply pointed 

 wings rapidly after their first spring from the water. 



15. Marila americana (Eyton). Redhead. — The Redhead was a 

 common breeding bird at Lake Burford and 30 pairs were located that 

 seemed settled for the summer. These birds were found mainly in the 

 small bays in the southern part of the Lake where they swam in the open 

 water or rested and slept on shore. Small flocks were seen standing on 

 the open beaches about sandy points every morning sunning themselves 

 or preening their feathers. It was interesting to note that, while the shal- 

 low water ducks paid no attention to me unless I came near, the Redheads 

 always waddled into the water and swam out into the open as soon as I 

 appeared even though I might be half a mile away. 



The peculiar mating display of these birds seen on several occasions was 

 observed to advantage on June 4. A party of four males and three females 

 were swimming in open water, two of the birds apparently being mated. 

 Suddenly one of the females began to display, approaching one of the 

 males with her head held high, sometimes jerking it up and down and 

 again holding it erect, and at intervals calling quek que-e-ek, the last a 

 peculiar rattling note. The male chosen extended his neck, holding his 

 head erect, frequently whirling quickly to show the female his back, or 

 again sank down with his head drawn in while the female bowed before 

 him. At short intervals she opened her mouth and bit at him gently or, 

 if he was swimming, sprang quickly in front of him with her head erect and 

 back partly submerged. She transferred her attentions from one male 

 to another in turn, even approaching the one who apparently was mated. 

 The males showed considerable jealously over these favors and drove 

 each other about in fierce rushes. At intervals they called, the note being 

 a curious drawn out groaning call, resembling the syllables whee ough given 

 in a high tone. As it was given the male sometimes raised his breast, 

 elevated his head and erected his crest. Again he threw his head straight 

 back so that it touched his dorsum above the rump, with the throat up and 

 the bill pointing toward the tail. The bill was then thrown up and head 

 brought again to the erect position as the call was made. The curious 

 actions of the male in calling continued after he was mated, and the strange 

 call note was heard often. Mated males were seen driving savagely at 

 their mates and biting at them while they escaped by diving. 



On June 4, a nest containing eight eggs was found in a mass of dead 

 Scirpus stems in a clump of tules below the cabin. On June 13 this nest 

 contained 14 eggs and the female had added a considerable amount of 

 down to it. The mate of this bird remained in the open water from a hun- 

 dred yards to a quarter of a mile from the nest-site but was never seen to 

 go near the nest. The female, who left the nest whenever she heard my 

 boat approaching, always flew out to join him. He remained with her 



