78 



FRIENDS OF OUR FORESTS 



warblers go only to the West Indies. The 

 worm-eating, myrtle, magnolia, chestnut- 

 sided, black-throated green, hooded, blue- 

 winged, Nashville, orange -crowned, pa- 

 rula, palm, and Wilson's warblers, and 

 the chat, go no farther than Central 

 America, while many species spend the 

 winter in South America, including some 

 or all the individuals of the black and 

 white, prothonotary, golden-winged, Ten- 

 nessee, yellow, cerulean, bay-breasted, 

 black-poll, Blacklnirnian, Kentucky, Con- 

 necticut, mourning, and Canada warb- 

 lers, the redstart, oven-bird, and both the 

 water-thrushes. Nearly all the warblers 

 of the western United States spend the 

 winter in Mexico and the contiguous por- 

 tions of Central America." 



V.AST NUMBERS SUCCUilC 



The northward journey in spring, away 

 from the land of sunshine and plenty to 

 the land of uncertain spring weather, is 

 another matter. Probably if all birds 

 that habitually abandon the north and 

 winter in the south were to nest there, 

 their quota, added to the number resident 

 in the tropics, would be too great for the 

 means of subsistence. 



Nevertheless, birds are not forced away 

 from their winter quarters by inclement 

 weather or impending famine, but by the 

 subtle physiological change which warns 

 them of the approach of the mating sea- 

 son and fills them with new desires, 

 among which is the compelling one of a 

 return to the spot where they first saw 

 the light, or where they reared last sea- 

 son's brood. 



Whatever the cause, the birds are not 

 discouraged by the many and great perils 

 that attend migration, and vast numbers 

 every year succumb to them. Storms, 

 especially off-shore storms, constitute the 

 gravest peril, and there is abundant evi- 

 dence that millions of birds are annually 

 blown out to sea to find watery graves. 

 Perhaps no family sufi:ers more in the 

 aggregate than the warblers. Thinly 

 feathered, delicately organized, highly in- 

 sectivorous, they are exposed to unusual 

 dangers while birds of passage to and 

 from their nesting grounds. 



It is a matter of common observation 

 that every few years in some given lo- 



cality, perhaps embracing a region of con- 

 siderable size, a particular species of 

 warbler or other bird suddenly becomes 

 rare where before common. After a sea- 

 son or so, though sometimes not for years, 

 the equilibrium is reestablished and the 

 numbers are as before. These changes 

 very probably are the visible signs of 

 migration catastrophes, the result of the 

 sweeping away of a migration wave, com- 

 posed of one or of many species, in the 

 path of some sudden storm. 



Again, many of us have witnessed the 

 dire effects of a prolonged rain and sleet 

 storm in spring, when thousands of luck- 

 less migrants find only too late that they 

 have prematurely left the warmth and 

 plenty of their tropical winter refuges. 

 Under such circumstances thousands of 

 migrants perish from the combined efi:'ects 

 of cold and starvation, and among them 

 are sure to be great numbers of warblers. 



ECONOMIC V.AEUE OF WARBLERS 



From the esthetic point of view, our 

 warblers, as a group, occupy a high and 

 unique position. They also occupy no 

 uncertain place in the list of our useful 

 birds. Preeminently insectivorous, they 

 spend their lives in the active pursuit of 

 insects. They begin with the eggs, prey- 

 ing upon them whenever and wherever 

 found, and continue the good work when 

 the egg becomes tlie larva and when the 

 larva becomes the perfect insect. 



They are especially valuable in this re- 

 spect because of the protection they lend 

 to forest trees, the trunk, bark, and foli- 

 age of which they search with tireless 

 energy. Their efficiency is vastly in- 

 creased because the many different spe- 

 cies pursue the quest for food in very 

 different wavs. While some confine their 

 search chiefiv to the trunks and large 

 branches and examine each crack and 

 crevice in the bark for eggs or larvas, 

 others devote their energies to the twigs 

 and foliage, scanning each leaf and stem 

 with eager eyes. Still others descend to 

 the ground and examine the rubbish and 

 grass for hidden prey, while nearly all 

 are adept at catching insects on the wing. 



Each species, however, has a method 

 of its own, more or less unlike that of its 

 fellows, and each excels in some specialty. 

 Not only does the group as a whole spe- 



