568 BULLETIN 2 3, UNITED STATES NATIONAL MUSEUM 



Eggs. — Most of the sets of eggs are four in number but a few with 

 five eggs have been reported. The color and markings of the eggs are 

 similar to those of the Maryland yellowthroat. The measurements 

 of 29 eggs average 17.7 by 13.4 millimeters ; the eggs showing the four 

 extremes measure 19.2 by 13.5, 18.6 by 14.0, and 16.1 by 12.4 millimeters. 



Food. — The yellowthroat is said to be a very beneficial insect-eating 

 bird in Florida, in regions where tomatoes and other vegetable produce 

 is reared. But like the other subspecies of yellowthroats the majority 

 of the birds occupy habitats where the destruction of insects is of less 

 importance to agriculture. 



The contents of the stomachs of seven yellowthroats collected in 

 Florida were found by the United States Biological Survey to consist 

 mainly of insects, with a few spiders and small mollusks and a small 

 number of seeds of the sweetgale. Of the insects eaten, Orthoptera 

 (chiefly grasshoppers) and crickets comprise the largest amount, with 

 Hymenoptera (ants, wasps, bees) next in importance. Other forms 

 well represented were beetles, bugs, flies, and caterpillars. 



Voice. — The song of the yellowthroat as it is heard in Florida is full 

 and strong, and while having the same characteristics, is nevertheless 

 recognizably different from that of the northern yellowthroat we hear 

 in New England. The song has been interpreted as witcher-cheree.^ 

 witcher-cheree., witcher-cheree., but there is considerable individual 

 variation in the renditions. The song may be heard throughout the 

 spring and summer but in spring it seems to be more spirited and 

 perhaps more elaborate. 



The flight song begins as the singer launches forth from his thicket, 

 reaches a climax at a height of 15 or 20 feet, when the head is thrown 

 back as when singing at rest, and gradually dies away as the bird sinks 

 down with rapidly vibrating wings. The flight song resembles the 

 following: Ghee., chee., chee^ chee^ Che-witchery.^ witchery^ witchery .^ 

 witchery. 



Enemies. — The Florida yellowthroat like that of its near relatives 

 is subject to parasitism by the cowbird. It is seldom that the young of 

 the yellowthroat survive more than a few days before they are starved 

 or suffocated to death by the much larger and more aggressive cow- 

 bird. 



Various observers have reported that it frequently falls prey to 

 snakes, turtles, and even fish. This might reasonably be expected of 

 individuals that frequent the swamps and marshlands of semitrop- 

 ical Florida where such enemies are abundant. 



Harold S. Peters (1936) has found the tick, Eaemaphysalis leporis- 

 palustrus Packard a parasite of the Florida yellowthroat. It is of in- 

 terest that he found no ticks infesting either the Maryland or the 

 northern yellowthroats. 



