BIRDS. 179 



duction is almost demonstrable ; but the instinctive feeling which 

 guides them without compass across seas and continents, and 

 enables them to migrate at certain periods, corresponding with 

 the production of their food in distant countries, can only be re- 

 ferred to one Great Source. 



Who bade the stork, Columbus-like, explore 

 Heavens not his own, and worlds unknown before ? 

 Who calls the council, states the certain day ? 

 Who forms the phalanx, and who points the way ? 



The flights of migratory birds have been noticed from the 

 earliest periods ; " The stork in the Heaven knoweth her ap- 

 pointed times, and the turtle and the crane and the swallow 

 observe the time of their coming." And, as if their passage 

 through the air or the structure of their bodies made them 

 sooner perceive the incipient changes of weather, the appear- 

 ance and cries of birds have long been considered to afford pre- 

 sages of the coming storm or the cessation of the tempest. The 

 institution of a College of Augurs at Rome may therefore be con- 

 ceived to have reference to something better than mere supersti- 

 tion ; and though the flight of particular species might, in the 

 hands of interested individuals, be made to presage the wished- 

 for result of a battle, or direct a march already determined on, 

 yet, in the absence of the barometer and thermometer, the ap- 

 pearance or disappearance and cries of birds were the signals for 

 the husbandman to sow his fields or to secure his crop. 



Jam veris praenuncia venit hirundo. Ovid. 

 Now comes the swallow, harbinger of spring. 



Turn cornix plena pluvium vocat improba voce. Virg. 

 The crow with clamorous cries the shower demands Dryd. 



In this country the great migrations of birds take place in 

 spring and autumn. Those which arrive in spring come from 

 warmer climates, and after incubation leave us in autumn ; and 

 another host, chiefly Palmipedes, from the arctic regions, ar- 

 rive in autumn, pass the winter on our lakes and shores, and 

 depart again in the spring. Each species has a particular 

 mode of flight in these annual journeys, and a certain period 

 of arrival and departure. Assembled in large flocks the cranes 

 cleave the air in the form of a long triangle ; wild-geese fly in 

 angular lines ; and the smaller birds associate in less numerous 

 families, and reach their destination by less continued flights. 



