62 BIRDS ORGANIZATION DIAGRAM 4. 



They always hare the neck stretched out, and the beak open, 

 and it is all that their parents can do to provide food for this 

 voracious family, and the quantities of insects which they then 

 destroy long ago caused it to be said "that there was not a single 

 species of injurious birds in spring." For the rest, there is 

 always a very good means of ascertaining if certain birds are 

 useful or injurious to agriculturists, and this is to kill one or 

 two occasionally at different seasons of the year, and to notice 

 what food they have in their stomach ; if corn, the bird is 

 mischievous, but if it is remains of insects or grubs, the bird is 

 useful. This is the best method of judging of the merits of 

 such birds as rooks, which are alternatively regarded as useful or 

 mischievous. But it will not suffice to limit ourselves to 

 examining what the bird eats once in the course of the year ; it 

 will be necessary to begin again at different seasons, because a 

 bird which eats corn at harvest-time or seed-time for instance, 

 destroys insects all the rest of the year ; and the farmer must 

 then calculate whether the injury done by the bird in eating his 

 corn, is counterbalanced or not by the advantage of seeing them 

 destroy his true enemies i.e., insects. In a general way we may 

 say that all birds live on insects in spring, corn in summer, and 

 berries in winter. But it must be remembered that many birds 

 migrate during this last season. 



There are, in reality, a great number of birds which are 

 accustomed to change their country according to the season, and 

 to make what is called a migration every year. Thus, when 

 insects begin to disappear at the first cold weather, all the 

 swallows depart for Africa, from whence they return in the 

 spring of the following year. These long journeys are very 

 common among birds. The cold drives them all towards the 

 South. Those of the North come to us during the winter in 

 search of water which is still unfrozen, and our own birds 

 migrate to the South in search of warmth and insects. On 

 crossing the Mediterranean Sea from France to Algeria, it is 

 common to see flocks of small birds alight on the masts of ships, 



