THE YELLOW-THROATED VIREO. 



{Vireo fiavifrons.) 



There are many illustrations of that 

 wonderful plan of the Creator by which 

 the equilibrium of Nature is kept con- 

 stant. LefJ tojierself and not changed 

 by the ever active influence of the inven- 

 tive mind of man, Nature would always 

 be in balance. No species would pre- 

 dominate over all life, yet those which 

 are the best fitted for life in their envi- 

 ronment would survive. Every form of 

 life seems to have enemies which prey 

 upon it. There is a constant fight for 

 existence, and "among us and about us, 

 animals and plants as well as men bring 

 to their aid every means which will in 

 any way secure advantages to them- 

 selves and their posterity." In nature 

 these advantages are secured by gradual 

 development ; those individuals surviv- 

 ing which are protected by some peculiar 

 characteristic which is retained and fur- 

 ther developed in their offspring until 

 after many generations, the species 

 becomes almost immune from the attacks 

 of their worst enemies. 



Probably no division of animal life 

 would upset the balance of life more 

 quickly than the insects, for as a whole 

 they develop rapidly and their progeny 

 are exceedingly numerous. It has been 

 estimated that they comprise four-fifths 

 of all animal life, and that there are now 

 quite 250,000 species to which names 

 have been given. These insects have 

 enemies among their own kind, among 

 the fish, the reptiles, the mammals and 

 above all, among the birds. The insect- 

 eating birds form one of the best illus- 

 trations of how Nature's balance is 

 retained. They are always around about 

 us, and their song and appearance influ- 

 ence us to note their habits. The fly- 

 catchers chiefly catch their insect food 

 while on the wing ; the warblers flit 

 through the foliage picking an insect 

 here and there; the Vireos "patiently 



glean their food from the under surface 

 of leaves, crevices in the bark, etc." In 

 various ways other groups of birds prey 

 upon insects. 



The Vireos, of which there are about 

 fifty species, are especially interesting to 

 us, for they are American birds though 

 the larger number of them are confined 

 to arboreal and shrubby districts of the 

 tropical regions of Central and South 

 America. All are musical and some of 

 them are gifted singers. But it is not 

 their melodious song alone which 

 attracts our fancy, for they are also 

 clothed with a beautiful plumage and 

 they build a most interesting home. This 

 home is a nest of great architectural 

 beauty, and shows remarkable ingenuity 

 in its construction. In form, the Vireo's 

 nest is always a deep cup, "about two- 

 thirds of a sphere in its form, and trun- 

 cated at the top. It is usually suspended 

 from the fork of two, and even more, 

 converging twigs, the margin being very 

 neatly overwoven so as to embrace and 

 cover them." The nests are generally so 

 placed that they are well concealed by 

 thick foliage, especially from above. The 

 habits, too, of all the Vireos are interest- 

 ing. While some of the species do not 

 always shun the habitations of man and 

 will build their nests on the pendant 

 branches of the trees of gardens, road- 

 sides, parks and public squares, most of 

 the Vireos are unknown excepting to the 

 close students of nature. Searching the 

 crevices in the bark and the under sur- 

 face of leaves for their food, these birds 

 are quite hidden from view. Then, too, 

 many of the species frequent only the 

 larger growths of forests. But they are 

 happy in their work and sing or utter 

 their call-notes quite throughout the day. 

 Of one of the Vireos the poet has writ- 

 ten : 



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