346 BULLETIN 2 3, UNITED STATES NATIONAL MUSEUM 



over the eye, and, especially, the flaming orange throat and breast. 

 The female in the spring and the male in the fall are similarly marked, 

 but the colors are much duller. The colors of young birds in the fall 

 are even duller, and the back is brownish, but the white outer web 

 of the basal half of the outer tail feather should indicate the species. 



Fall. — Early in August, young and old birds begin to gather into 

 flocks preparing to migrate, and before the end of that month most 

 of them have left their breeding grounds. All through August and 

 most of September, we may see them drifting through our deciduous 

 woods in mixed flocks with other species of warblers. These mi- 

 grating flocks are generally so high up in the tree tops and are so 

 active in their movements that it is not easy to identify them in their 

 dull winter plumages. 



By early October, most of the Blackburnian warblers have passed 

 beyond the United States, en route to their winter home in South 

 America. Professor Cooke (1004) says: "By the middle of October 

 the earliest migrants have reached Venezuela and Ecuador. The main 

 army of the Blackburnians pass the south end of the Alleghenies be- 

 tween September 25 and October 5, and during the first two weeks 

 of October are moving through San Jose, Costa Rica, and by early 

 in November are settled for the winter in Peru." 



Dickey and van Rossem (1838) refer to it as a "fairly common 

 fall migrant and very rare winter visitant in the Arid Lower Tropi- 

 cal Zone" in El Salvador, but "not seen in spring." 



Winter. — Dr. Alexander F. Skutcli contributes the following notes : 

 "Rarely recorded, and apparently only as a bird of passage, in Guate- 

 mala, the Blackburnian warbler is a moderately abundant winter 

 resident in Costa Rica. Here it passes the winter months on both 

 slopes of the Cordillera, from about 1,500 to 6,000 feet above sea-level, 

 but is far more abundant above than below 3,000 feet. It is found 

 in mid-winter both in heavy forest and among scattered tall trees. 

 Although the birds appear to arrive in flocks in late August or Sep- 

 tember, they soon disperse through the woodland and show slight 

 sociability. Yet one or two may at times join a mixed flock of Tennes- 

 see warblers and other small birds. Restlessly active, the Black- 

 burnian warbler forages well above the ground, where it is difficult 

 to see. I have never heard its song in Central America. 



"Early dates of fall arrival are: Guatemala — Chimoxan (Griscom), 

 October 1; Panajachel (Griscom), October 4. Costa Rica — San Jose 

 (Cherrie), September 8; San Jose (Underwood), Septem 10; La 

 Hondura (Carriker), September 19; San Isidro de Coronado, Sep- 

 tember 8, 1935 ; Vara Blanca, August 19, 1937 ; Cartago, September 

 13, 1938 ; Murcia, September 14, 1941 ; Basin of El General, September 



