278 FACULTIES OF BIRDS. 



agitation is always greatest at night, proving, toge- 

 ther with observation, that birds generally commence 

 their flight at that time. The cause of this per- 

 vading inquietude cannot be attributed either to the 

 want of food or the increase of cold, it being expe- 

 rienced by individuals removed from the influence 

 of either, and therefore must reside in some as yet 

 mysterious warning, no doubt produced by natural 

 causes, which the Creator and Preserver of the uni- 

 verse has found necessary to the safety of his 

 creatures. 



It may seem strange that birds, such as the quail 

 and land-rail, remarkable for their limited powers of 

 flight, should be able to perform so extensive a jour- 

 ney as that from England to Egypt; but doubtless 

 these, and many species of small birds, instead of 

 flying continuously, proceed at intervals only, jour- 

 neying by night and resting by day. The celerity 

 with which swallows fly renders any exploit by them 

 on the wing credible enough ; and the steady flight 

 of gannets, geese, and ducks, is obviously capable of 

 carrying them over a very large space in a short 

 time. The flight of birds generally may be esti- 

 mated at from fifty to one hundred and twenty miles 

 an hour; and if we take the mean of this, we shall 

 find it sufficient to enable the migratory birds to per- 

 form the most extended journeys. The wonder is 

 not in the flight itself, but in the impulse and instinct 

 by which it is commenced and carried on. 



Pennant finds no difficulty in accounting for the 

 motive of migrations : a defect of food at certain 

 seasons, or the want of a secure asylum from the 

 persecutions of man during the time of courtship, 

 incubation, and nutrition. He considers that most of 

 the birds which leave us in spring to spend the sum- 

 mer elsewhere have been traced to Lapland, a country 

 of lakes, rivers, swamps, and alps covered with thick 



