thither upon the 10th of March. Two of them alwayf 

 appeared a day or two before, hovering in the air, thert 

 they went away 5 and speedily returned, with the whole 

 flock. 



The following seems to he a very rational account 

 of most of those that are really birds of passage. 



When by. the approach of our winter their food 

 fails, birds of passage arc taught by instinct to seek 

 it elsewhere. Want of food seems to be the chief rea- 

 son of their migration. The length of their wings 

 enables them to catch the flying insects, with which 

 the air is stored during the warm months. And most 

 summer birds of passage, feed on the wing upon 

 such insects, as are seen no more when winter 

 comes, If it be considered, how much of tho globe 

 still remains unknown, it is no wonder wo are not 

 yet acquainted with the places to which they retire, 

 rrobably they lie nearly in the same latitude in the 

 southern hemisphere, as those from whence they de- 

 part. 



As swallows cannot bear so much cold. as some other 

 birds of passage, they arc constrained to visit us 

 somewhat later, and to depart somewhat sooner. Some 

 stay a month after them. Probably many of them 

 perform their long journies chiefly in the night. Lying 

 on the deck of a sloop vn the north-side of Cuba, I 

 and the company with me heard three nights succes* 

 &ively, flights of rice-birds (their notes being plainly 

 distinguishable) passing over our heads northerly, 

 which is their direct vvay from the southern con* 

 tiuent of America, from whence they go yearly when. 

 the rice begins to ripen, and after growing fat,' return 

 back. 



There are also winter birds of passage, which ar* 

 rive here in autumn and go away in spring, name- 

 ly the fieldfare, redwing, woodcock, and snipe. 

 JJut the two letter sometimes spend the whole year 

 here.. Whereas the two former, constantly at thQ 

 " 



