MAY 155 



XXXVII 



A correspondent, a watchful observer of wild life, 

 asks me whether there is any cause known Nightin- 

 for the preference shown by nightingales for gales 

 oak woods as compared with beech. He has noticed 

 that the song of nightingales is never heard among 

 the beech groves near his residence in Surrey, but 

 that they abound among the oaks there. Probably 

 in food supply, the dominant motive in all bird move- 

 ments, is to be found the true reason. Nightingales 

 are wholly insectivorous, picking up most of their food 

 on the ground, and are believed to feed their young 

 entirely on caterpillars; moreover, there is very little 

 undergrowth in a beech wood. Oaks, on the other 

 hand, are the favourite nurseries of numerous larvae, 

 and their shade is not hurtful to plants of humbler 

 growth, which afford food for caterpillars of various 

 species. It does not seem difficult, therefore, to solve 

 the mystery of the attraction which oaks possess for 

 nightingales. 



