BIRDS OF PASSAGE. SI 



swallow, observe their time of coming." The 

 regularity with which these creatures depart from, 

 and return to us, is very surprising. The same 

 pair of swallows have been known to occupy, for 

 several successive years, the same nest, and to 

 twitter, as old friends, at the same window-sill ; 

 yet these, during their absence, must have passed 

 their time a thousand miles to the south. 



That most delicious warbler, the mocking bird, 

 which spends the summer with us in Pennsylva- 

 nia, removes, at the end of autumn, into the south. 

 This bird is so constituted as to be unable to bear 

 the coldness of our winter. During the sum- 

 mer our groves and orchards are filled with 

 "feathered choristers," busily engaged in rearing 

 their young ; but no sooner is this effected, and 

 the cold winds of autumn begin to blow, than they 

 wing their way to more genial climates, again to 

 delight us by their reappearance, in spring, as the 

 harbingers of our finest seasons. These birds are 

 called summer birds of passage ; it is God who 

 teaches them their appointed times of coming and 

 going, and who guides them in their long journeys. 



Most birds, when preparing to migrate, assem- 

 ble together in great flocks. Thus we may see 

 clouds of swallows wheeling about in the air, in 

 Septen^jer, as if they were trying their strength 

 of wing before their final departure. Woodcocks, 

 turtle-doves, wild-geese, and shear-waters, do the 

 same, and are always seen travelling in company. 



There are other migratory birds, which spend 



