Vireos 739 



THE VIREOS 



(Family Vireonida) 



The Vireos, or Greenlets, as they are often and perhaps more appropriately 

 called, constitute a small group of upward of a hundred species and subspecies 

 disposed in some eight genera. They are confined exclusively to the New 

 World, having their maximum development in the tropics, whence they range 

 in gradually decreasing numbers throughout practically all of the temperate 

 regions. They are small, active, arboreal birds with a dentirostral bill which 

 is notched in both mandibles, a variable wing, which, however, is always longer 

 than the tail and in which the outer primary is very short or sometimes rudi- 

 mentary and concealed (then practically nine-primaried), while the nostrils 

 are partly exposed and the rictal bristles usually inconspicuous. As additional 

 characters it may be mentioned that the tail is usually rather short and composed 

 of rather narrow feathers, the tarsus short and robust, and distinctly scutellated 

 in front, while there is a considerable amount of cohesion of the front toes. 

 The coloration is somewhat variable, though they are never streaked, spotted, 

 or barred, the prevailing hues being plain olive, olive-green or gray above, and 

 plain whitish or yellowish below. The wings are often white-banded, and 

 there is sometimes bright green and yellow, rarely blue, on the head. A white 

 or yellow orbital ring occurs in certain forms, and others are marked by the 

 possession of white, red, or yellow eyes. The Vireos are preeminently birds of 

 the open forest, but they also frequent the trees in parks and along village streets, 

 swamps, and the taller undergrowth along streams, going about in pairs or more 

 often singly and keeping mainly to the upper branches, where they hunt indus- 

 triously for their food or gambol about in their play. As a rule they are fair 

 songsters, though, as Mr. Ridgway says, "some species are distinguished by 

 the oddity rather than the melody of their notes," and, within certain limitations, 

 each kind has its own musical accomplishment. They are mainly insectivorous, 

 though feeding to some extent on fruits and berries. So far as known they all 

 build one style of nest, and this a "rather slight and thin-walled, but neat and 

 compact, pensile cup-like structure, suspended from the fork of a twig," some- 

 times but a few feet from the ground, at others high up in a tree. The 

 eggs are uniformly white with a few dark specks. 



As regards the affinities of the Vireonidce there are some differences of opinion. 

 Largely on account of the stout-hooked and notched bill they were formerly 

 included with the Shrikes (Laniidce) ; but all things considered, they seem best 

 placed near the Waxwings (Ampelidce). 



Red-eyed Vireo and Relatives. Although several generic names have been 

 in use at various times, it has been the custom in recent years to include 

 the majority of the forms in the genus Vireo, but in his revision of the 

 North and Middle American forms Mr. Ridgway has found it expedient to 

 recognize three genera. Of these Vireosylva may be first mentioned, its 

 members being small or medium-sized Vireos, with the tenth primary 



