54 Bird - Lore 



method of flight by continuous beating of the wings, that normal to most birds, 

 we find four general modifications correlated with specialized methods of flying. 

 The first of these is that found among terrestrial birds like the domestic fowl , or 

 the Ruffed Grouse that seldom fly except to escape their enemies when it is 

 necessary that they should be able to rise quickly and fly very rapidly for short 

 distances. They ordinarily do not fly very far. The type of wing developed 

 among this class of birds is one that is much shorter than the average and rounder, 

 and it is moved much more rapidly. It would be a distinct disadvantage for a 

 bird that has to fly long distances to have this type of wing as it would soon 

 tire, but it is approximated in many of the Flycatchers and Hawks, like the 

 Sharp-shinned and Cooper's, that ordinarily lie in wait for their prey and dart 

 out after it. With this type of wing they are able to develop full speed almost 

 immediately. The wings of Rails are likewise of this type though, because of 

 lack of use, their breast muscles have been reduced and their flight is weak. 



The second type is very different being a large, broad, rounded wing, such 

 as is found in the Eagles, Buzzards, and larger Hawks. It is adapted for soaring, 

 and birds having this type of wing can maintain themselves in the air sometimes 

 for hours without flapping their wings, merely by taking advantage of the up- 

 ward currents of air and adjusting their wings accordingly. A third type of wing 

 found among birds, that likewise enables them to take advantage of the air- 

 currents, is the long, narrow wing, found best developed among the Albatrosses 

 but also among the Gulls and Terns and other sea-birds that are on the wing a 

 large part of the time. Among the Hawks, the Marsh Hawk and the Fish Hawk 

 have longer and narrower wings than the others and they seldom soar and never 

 lie in wait for their prey but spend their time sailing back and forth over the 

 water or over the fields, for the long, narrow wing is best adapted for what may 

 be called gliding. The fourth type is that of the pointed wing, usually broad at 

 the base and moderately long. This wing is best adapted for speed of long duration 

 and is that found among the Swallows and among the Falcons, birds that pursue 

 their prey on the wing and strike it at full speed. They need to have full control 

 of their flight at all times and to develop great speed, and the moderately long, 

 pointed wing seems best adapted for this. Thus one might go on analyzing the 

 differences among the wings of birds and perhaps find a reason for even the 

 minor differences that are known to occur, but the differences that have been 

 mentioned will suffice to make the wing of the bird in the schoolroom have some 

 meaning and perhaps start some child delving for the reasons for that which he 

 sees. — A. A. A. 



QUESTIONS 



1. What is the best way to keep a bird in the schoolroom? 



2. Why is the ordinary bird-cage unsatisfactory? 



3. What is meant by a 'terrarium'? Describe one. 



4. What are four requisites of a flying-machine? 



5. Name ten ways in which the weight of a bird is reduced. 



