558 BULLETIN 2 03, UNITED STATES NATIONAL MUSEUM 



the Washington Monument. There was a slight mist enveloping the 

 top of the shaft and the wind velocity was 8 to 10 miles an hour. 

 Mr. Overing identified 189 Maryland yellowthroats and other sub- 

 species of Geothlypis trichas. 



W. E. Saunders (1930) writes of the great loss of bird life at Long 

 Point lighthouse, Ontario, during certain nights of September 1929. 

 Out of 2,060 birds killed on September 7, 9, and 21^29, 254 of them 

 were Maryland yellowthroats, this being the most frequent victim 

 of the 55 species reported. 



A. M. Frazar (1881) reports a great destruction of birds on April 2, 

 1881, during a sea trip from Texas to Mobile, Ala. Land birds in- 

 cluding a great number of Maryland yellowthroats were seen to 

 perish. Even those that came aboard the boat were washed into 

 the sea again. 



The yellowthroat is a frequent victim of parasitism by the cowbird. 

 L. E. Hicks (1934) reports that out of 41 nests of the northern yellow- 

 throat he has found 19, or 41 percent, that were parasitized by the 

 cowbird. Dr. Friedmann (1929) states that at Ithaca, N. Y., the 

 yellowthroat stands seventh in order of the birds most frequently 

 imposed upon by the cowbird. There are many instances on record 

 where the cowbird has been successful in having the yellowthroat 

 accept its eggs and of rearing the young to maturity. However, some 

 circumvent the intrusion by building a second nest over the first 

 containing the ^gg of the cowbird, a method frequentl}^ employed by 

 the yellow warbler. A. W. Butler (1898) writes of a 3-story nest 

 of the yellowthroat as follows : "Mr. E. R. Quick has in his collection 

 a three-story nest of this bird, taken near Brookville, Ind. Two ad- 

 ditional nests were built upon the original structure, burying beneath 

 each the egg of the cowbird {Molothrus ater). Thus it outwitted 

 the detestable parasite, and in the third nest deposited her comple- 

 ment of eggs. Similar nests have been found elsewhere, showing that 

 this is not an individual peculiarity, but others of its kind had ex- 

 perimented along the same line." 



The northern yellowthroat is host to a number of external para- 

 sites of which Harold S. Peters (1936) has identified the louse Ricinus 

 vallens (Kellogg) and the two flies Ornynoica confluenta Say and 

 Ornithoniyia andiineuria Speiser. 



Fall. — There are so many breeding birds on the migration range 

 of the yellowthroat that it is not easy to mark the beginning of the 

 southward migration in the autumn. The bulk of the birds leave 

 their northern breeding grounds in September, but even in these 

 northern sections many birds linger well into October, a few as late 

 as November. Indeed there are a number of records of birds seen 

 throughout the winter months. 



