262 BULLETIN 2 03, UNITED STATES NATIONAL MUSEUM 



In California, there is a gradual exodus of Audubon's warblers 

 from the lowlands to the mountains during April and May. Mrs. 

 Amelia S. Allen tells me that "by the end of April they have dis- 

 appeared from the San Francisco Bay region." And Swarth (1926b) 

 says that in May, following the spring molt, "there is a gradual with- 

 drawal of the birds to the higher mountains and to more northern 

 latitudes." 



Audubon's warbler occurs abundantly on the Huachuca Mountains, 

 Ariz., but as a migrant only, during March, April, and May. Swarth 

 (1904) writes: 



Though disti"ibuted over all parts of the mountains, they were at all times 

 more abundant in the higher pine region, than elsewhere ; and on April 24, 1903, 

 I found them particularly numerous along the divide of the mountains, evidently 

 migrating. They could hardly be said to be in flocks on this occasion, for along 

 the ridge, which runs almost due north and south, there was for several miles a 

 continuous stream of Audubon Warblers travelling rapidly from tree to tree, 

 always moving in a northerly direction ; sometimes a dozen or more in one 

 pine, and sometimes only two or three, but never stopping long and all moving 

 in the same direction. Almost all that were seen on this occasion were high 

 plumaged males, hardly half a dozen females being observed for the day. 



This was about two weeks before the local breeding race {D. a. nigri- 

 frons) might be expected to arrive. 



Dr. Merrill (1888), at Fort Klamath, Oreg., found Audubon's 

 warblers "extremely abundant during the migrations. A few males 

 were seen at Modoc Point on the 8th and 9th of April, and at the Fort 

 on the 15th ; by the 20th they were quite plentiful. A second 'wave' 

 composed of both males and females, which latter had not previously 

 been seen, arrived about the 4th of May, when they suddenly became 

 more abundant than ever, bringing D. aestiva morcomi and H. lutes- 

 cens with them." 



Nesting. — The only two nests of Audubon's warbler that I have seen 

 were shown to me in Washington, near the State University at Seattle. 

 The University is located on high land at the north end of Lake 

 Washington, where the steep banks, sloping down to the lake, are 

 heavily wooded with a mixed growth of large and small firs of at 

 least two species, as well as cedars, alder trees, and maples. In the 

 more open part of the woods I was shown, on April 29, 1911, a nest of 

 this warbler placed about 30 feet from the ground on two small 

 branches and against the trunk of a tall Douglas fir beside a woodland 

 path. The other nest I saw in the previously described "prairie 

 region" near Tacoma on May 14, 1911 ; it was placed only 9 feet from 

 the ground but 10 feet out from the trunk of a dense Douglas fir grow- 

 ing in the open, and was well concealed in the thick foliage. 



These nests were evidently typical for the region, according to 

 Rathbun. He mentions in his notes two other nests. One, found 



