birds' nests. 129 



manner which may well answer to our own childhood; possessing by nature 

 first, and by the tuition of his parents and practice afterwards, most 

 of the acquirements which are necessary for his support. Thus it is 

 no uncommon sight, and a very pretty one, to see a pair of old birds 

 instructing their young in flight, fluttering round them, waiting on them, 

 and encouraging them to try their own powers. 



The development of these powers varies very much in different species; 

 thus, all the water-birds are clothed only with a kind of down for a 

 considerable period after their exclusion from the egg; the reason of this 

 is manifest, for flight is not their primary qualification, but onlv an 

 auxiliary to swimming or wading, which they can exercise almost from the 

 moment they are hatched. Again, those birds which are essentially fliers 

 have their feathers already in progress of growth at their birth, and in a 

 surprisingly short period use their wings for many hours during the sum- 

 mer day. There are others, such as the gallinaceous, or fowl and pheasant 

 tribe, which trust more to their legs, and are for a considerable period 

 imperfect on the wing. Thus we may trace in this as in every other 

 stage of animal life, the wonderful and perfect adaptation of the means 

 to the necessities of the individual. But before they can arrive at their 

 first anniversary they must encounter many and great dangers, which their 

 inefficiency in motion and experience renders them peculiarly liable to. 

 Among these not the least is migration, which is no mean undertaking, 

 and with some, such as the Swift, must take place in about five weeks 

 only from the time the young are produced. What an extraordinary 

 reflection is this, that creatures so helpless as these appear to be, should, 

 in so brief a space, be traversing the fields of air over the vast ocean to 

 realms which they are to visit for the first time, and which, if they are 

 accidentally separated from the rest of the flock, a thing very likely 

 to occur, they can only reach by that wonderful instinct which is such 

 a necessary guide. This reflection has, I know, been before made, but 

 it must strike the most unobservant with astonishment. 



If this is likely with regard to such powerful fliers as these, how much 

 more with the summer birds of passage; in fact, as I have elsewhere observed,, 

 the waste which takes place by contingencies is generally found to bring the 

 numbers which arrive pretty nearly even every spring. And now begins the 

 bird's real entrance into the actual business of life. With our own kinds 

 the latter end of February usually sees all (except such as are polygamous, 

 which are gallinaceous birds,) arranged in pairs. In my article on "The 

 Effects of Spring," I have touched upon this part of the subject to observe 

 what a difference of manner this mode of life produces, softening and 

 lomesticating to a certain degree even the wildest. The migratory birds 

 are seen in pairs immediately on their arrival, and I am inclined to think 



