Notes on the Nesting of the Lawrence's Warbler 131 



earliest dates in southern Arizona and southern New Mexico are included 

 between April 6 and April 9, while the species appears in the northern por- 

 tion of its range in Colorado early in May. 



The last do not leave central California until the first week in October 

 and do not desert the state until after the middle of the month. 



Notes on the Nesting of the Lawrence's Warbler 



By ISAAC BILDERSEE 



ON May 15, 1903, Dr. Wm. Wiegmann observed a Lawrence's War- 

 bler [Helminthophila lawrencii) in Bronx Park, New York City, but 

 did not see the bird again that year. On May 18, 1904, he again 

 observed an individual of this species in the same locality. It was carrying 

 nesting material. On June 6, the bird was observed carrying green larvae, 

 presumably to its young. On June 8, Dr. Wiegmann and I observed the 

 bird at various times during about five hours. Its song, which is described 

 elsewhere in this article, was first heard by us on that day. 



On June 10, I remained for about seven hours near the place where we 

 had seen this rare Warbler, but I could not find our bird. I had seen a 

 female Blue -winged Warbler fly into a certain thicket of catbrier and sec- 

 ond-growth of dogwood several times during the day, and, in order to con- 

 firm suspicions that I had formed, I concealed myself among some near by 

 bushes and waited. At the end of half an hour I was rewarded by seeing 

 the Blue-winged Warbler fly in with food, accompanied by the Lawrence's 

 Warbler. The female immediately dropped to the ground, while the 

 Lawrence's Warbler stayed in the vicinity (at times less than ten feet from 

 me). After five minutes the Blue- winged Warbler flew away, the 

 Lawrence's Warbler taking her place on the ground. The Lawrence's 

 Warbler waited until the Blue-winged returned and then flew away 

 with her. It was by this time too dark for further observations. On 

 June 12, in company with Mr. Waldron Dewitt Miller, of the American 

 Museum of Natural History, I paid another visit to the vicinity. In less 

 than five minutes we found the nest, which contained six fledglings, evi- 

 dently about a week old. The young could not, at that time, be dis- 

 tinguished from the fledglings of either the Golden -winged or Blue- winged 

 Warblers. Mr. Miller and I observed the birds during the remainder of 

 the morning. The parent birds paid frequent visits to the nest, averaging 

 about five minutes between their trips. The female stayed on or near the 

 nest for about eight minutes each time, the male, or Lawrence's Warbler 

 staying only about three minutes. 



On June 13, the young were perceptibly advanced. At this time the 



