150 CLASS AVES. 



battle, or disperse in light squadrons. The earth and its cli- 

 mates have less influence on them than on quadrupeds, because 

 they almost always live in similar degrees of temperature, pass- 

 ing the Avinter in hot climates, and the summer in cold. This 

 continual interchange of birds establishes a sort of communi- 

 cation between all countries, and keeps up a sort of equilibrium 

 of life. The bird, passing in summer from the equinoctial 

 climates to the cold regions of the north, and again in winter from 

 the poles towards the equator, knows, by an admirable instinct, 

 the winds and the weather which are favourable to his voyage. 

 He can long foresee the approaches of frost, or the return of 

 spring, and learns the science of meteorology from the element 

 in which he almost continually lives. He needs no compass 

 to direct his course through the empire of the cloud, the 

 thunder, and the tempest ; and while man and beast are creep- 

 ing on the earth, he breathes the pure air of heaven, and soars 

 upwards nearer to the spring of day. He arrives at the term 

 of his voyage, and touches the hospitable land of his destina- 

 tion. He finds there his subsistence prepared by the hand of 

 Providence, and a safe asylum in the grove, the forest, or the 

 mountain, where he revisits the habitation he had tenanted 

 before, the scene of his former delights, the cradle of his in- 

 fancy. The stork resumes his ancient tower, the nightingale 

 the solitary thicket, the swallow his old window, and the red- 

 breast the mossy trunk of the same oak in which he formerly 

 nestled *. 



All the volatile species which disappear in the winter do not, 

 therefore, change their climate. Some retire into remote 

 places, to some desert cave, some savage rock, or ancient 

 forest. Such are many of the starling kind, the loriots, the 



* Linnaeus tells us, that a starling- came regularly to lay during eight 

 years, in tlie same trunk of an alder, although it emigrated every winter. 

 Spallanzani having attached a red thread to the legs of the swallows which 

 nestled under his windows, beheld them return for many years in suc- 

 cession. 



