26 INTRODUCTION. 



twenty-four hours, according to the temperature 

 of the atmosphere. Heat accelerates — cokl retards 

 it. The young remain in the nest till they are able 

 to fly a little, but not sufficiently to protect them 

 from danger. At that time the parents may 

 be seen, leading them into covert ; and, if an 

 enemy appears, the old birds instantly give the 

 alarm, which the young perfectly understand, and 

 they keep quiet. How old birds know their 

 own young, and young birds their own parents, 

 amongst so many of the same species, is, and per- 

 haps ever will remain, a mystery to us. Birds 

 continue to feed their brood after they have left 

 their nest, till the young are able to feed them- 

 selves, and v/hich they generally can do in about 

 three weeks or a month ; — then the tie between 

 the parent and the young, in some species, is 

 broken. Others continue in small flocks of pa- 

 rents and their brood, till they migrate and leave 

 the island together. Some species, that remain 

 with us all the yeai', also keep in brood-flocks 

 through the winter, as the stare ; while others, as 

 the linnet, redpoles, &c. congregate in great num- 

 bers, and form large flocks, each flock being form- 

 ed of many brood-flocks joined together; and 



