Varying widely in color, the Fringillidæ all agree in possessing stout, conical bills, which are of service to them in crushing the seeds on which they feed so largely.
The streaked, brownish Sparrows, often so difficult of identification, are usually inhabitants of plains, fields, or marshes, where they are rendered inconspicuous by their dull colors. The more gayly attired Grosbeaks, Buntings, Cardinals etc., frequent trees or bushy growths, where their plumage either harmonizes with their surroundings or where they have the protection afforded by the vegetation.
Most of the members of this family are good singers, some of them indeed being noted for their powers of song. They are less migratory than insect-eating birds and some species are with us at all seasons. Their abundance, musical gifts, and constant presence render them, from the field student's point of view, highly important members of the great class Aves.
From an economic standpoint the Fringillidæ are no less deserving of our esteem. Some species are of incalculable value as destroyers of the seeds of noxious weeds. Fifteen hundred seeds have been found in the stomach of one Snowflake or Snowbunting, and it has been estimated by Professor Beal, of the Biological Survey of the United States Department of Agriculture, that during the winter season, in the single State of Iowa, where his studies were made, Tree Sparrows devour no less than 875 tons of weed seeds, chiefly of the ragweed.
The Tanagers, (Family Tanagridæ) are found only in the New World, where they are most numerously represented in the tropics. As a family they are remarkable for the brilliancy of their colors; the common, but mistaken idea that most tropical birds are brightly clad being in no small part due to the abundance of Tanagers and beauty of their plumage.
Only five of the some three hundred and fifty known species reach the United States and these are migratory, coming to us in the spring and returning to the tropics in the fall. Tanagers, as a rule, are not possessed of much vocal ability, our species ranking high in their family as songsters, the notes of many species being far less musical.
Like most gaily costumed birds the plumages of many Tanagers undergo striking changes in color with age and season. The male of our Scarlet Tanager, for example, is olive-green with black wing-coverts during his first winter, the scarlet plumage not being acquired until the following spring. It is worn, however, only during the nesting season after which the less conspicuous olive-green dress is again acquired, the wings and tail, however, remaining black.
Swallows, (Family Hirundinidæ) are of world-wide distribution, and as might be expected in birds possessing such remarkable powers of flight, many of the species have unusually extended ranges. Our Barn Swallow, for example, is found throughout North America in summer, and in the winter it migrates as far south as southern Brazil.
Birds of the air, the aërial habits of Swallows are reflected in their long wings and small, weak feet; while their small bills and broad, widely opening mouths indicate their manner of feeding.
In spite of their poor equipment of tools, Swallows take high rank as nest builders, and it is interesting to observe that although the birds are structurally much alike, their nests often differ widely in character. Compare for instance, the mud-made dwellings of the Barn and Cliff Swallows with the tunneled hole of the Bank Swallow and one realizes how little the character of a bird's home may depend on the structure of it's builder.