HELMITHEROS VERMIVOROS (Gmelin)
WORM-EATING WARBLER
Plate [10]
HABITS
The breeding range of the worm-eating warbler covers much of the central portion of the United States east of the prairie regions. Its center of abundance seems to be in the vicinity of Pennsylvania, but it breeds less abundantly northward to southern Iowa, New York, and New England and southward to Missouri and to northern Alabama and Georgia, as well as in much of the intervening wooded region, where it is essentially a woodland bird.
The distribution, migration, and habits of this warbler were but poorly understood by the early writers on American birds, and neither Wilson nor Audubon ever saw its nest; the latter’s description of the nest, probably from hearsay, is entirely wrong. Frank L. Burns writes to me: “Bartram neglected to list this species, although he had furnished the type to Edwards 35 years earlier, and from the information furnished by the youthful Bartram it doubtless received its name, which is a misnomer perpetuated by Gmelin in his Motacilla vermivora.” Mr. Burns says further on in his notes: “I searched for 10 seasons before I found my first nest, and oddly enough it was through the parent bird carrying a ‘worm’ to its young; nevertheless I have since thought that a more fitting name for the species would have been hillside or laurel warbler.”
Hillside warbler would not be a bad name for this bird, which shows a decided preference for wooded hillsides covered with medium-sized deciduous trees and an undergrowth of saplings and small shrubbery. Often a running stream with numerous swampy places, overgrown with brier tangles and alders, bounds the base of the hill as an additional attraction. It is seldom seen outside of its favorite woods and returns year after year to the same chosen haunts.
W. E. Clyde Todd (1940) says that in western Pennsylvania “wooded slopes are its chosen abodes, the shadier and cooler the better. * * * Deep ravines, down which trickle little streams, and the slopes of which support good stands of deciduous trees, with plenty of shrubbery and bushes for cover, are favorite resorts.” In Ritchie County, W. Va., William Brewster (1875) found it “most partial to the retired thickets in the woods along water courses, and seldom or never found in the high open groves.”
Spring.—The northward movement of the worm-eating warbler evidently begins in March, as the earliest arrivals from the Bahamas, the West Indies, and Cuba reach southern Florida during the first week in April. From its main winter resorts in Central America the flight seems to be partially across the Gulf of Mexico. Professor Cooke (1904) says in part: “The time of arrival on the coasts of Louisiana and Texas is about the same as in southern Florida. * * * Houston is the southernmost point in Texas from which it has been recorded to date, and Alta Mira is the northernmost point of record in Mexico. Since the species is apparently not common west of Louisiana or north of Vera Cruz, it is probable that the principal line of migration is from Yucatan and the coast immediately west of Yucatan directly north to the northern coast of the Gulf of Mexico.” According to Williams (1945) the species is common on the coast of Texas in spring, and it probably migrates along the coast. Thence the migration proceeds northward through the Mississippi Valley and through the Atlantic Coast States east of the Alleghenies, the warblers reaching the more northern breeding grounds by the middle of May, where nesting activities begin as soon as mates have been selected.