246 BULLETIN 2 03, UNITED STATES NATIONAL MUSEUM 



tails, obvious in the primary coverts, but the differences are not abso- 

 lute." In the female, "the first nuptial plumage is assumed by a 

 restricted moult, leaving behind many brown feathers. The brown 

 feathers of the lores and auriculars are assumed by moult." 



The adult winter plumage is acquired by a complete postnuptial 

 molt, beginning late in July. In the male, this "differs little from 

 the first winter dress, but the wings and tail are blacker with brighter 

 gray edgings, noticeable especially in the primary coverts. The back 

 is usually grayer and the lower parts whiter, with broader streakings 

 above and below." In the female there are similar differences, the 

 adult winter female resembling the young male at that season. Adults 

 have a complete postnuptial molt in July and a prenuptial molt as 

 in the young birds. 



Food. — Forbush (1929) sums up the food of this warbler very 

 well as follows : 



The Myrtle Warbler is one of the few warblers that can subsist for long 

 periods upon berries and seeds, although undoubtedly it prefers insects when 

 it can get them. Along the coast during the milder winters there are many 

 flies rising from the seaweed in sheltered spots on mild days even in January, 

 and there are eggs of plant-lice and some hibernating insects to be found on 

 the trees, but the principal food of the Myrtle Warbler in New England during 

 the inclement season is the bayberry. They can exist, however, on the berries 

 of the Virginia juniper or red cedar and these seem to form their principal 

 food when wintering in the interior ; berries of the Virginia creeper or wood- 

 bine, those of viburnums, honeysuckle, mountain ash, poison ivy, spikenard 

 and dogwoods also serve to eke out the birds' bill of fare. In the maple sugar 

 orchards in early spring they occasionally drink sweet sap from the trees. 

 In the southern Atlantic states they take palmetto berries. North and south 

 they also eat some seeds, particularly those of sunflower and goldenrod. Dur- 

 ing spring and summer they destroy thousands of caterpillars, small grubs and 

 the larvae of saw-flies and various insects, leaf-beetles, dark-beetles, weevils, 

 wood-borers, ants, scale insects, plant-lice and their eggs, including the woolly 

 apple-tree aphis and the the common apple-leaf plant-louse, also grasshoppers 

 and locusts, bugs, house-flies and other flies including caddice-flies, crane- 

 flies, calcid-flies, ichneumon-flies and gnats, also spiders. 



To the above comprehensive list there is little to be added, although 

 wild cranberries and the berries of the poison sumac might have been 

 included. Myrtle warblers are doubtless instrumental in spreading 

 the seeds of poisonous species of Rhus^ w^hich is not to their credit ; 

 they also help to disseminate the red cedar, as they digest only the 

 outer covering of these three and the bayberries. These warblers 

 are often seen on the beaches and sand dunes eating the seeds of 

 the beachgrass, or in open fields feeding on grass seed and doubtless 

 various weed seeds. They frequent the fresh holes bored by sap- 

 suckers to drink the flowing sap and eat the insects that are attracted 

 to it. In Florida, in winter, they drink the juice of fallen oranges 

 in the groves and even the broken oranges on the trees. 



