LIFE IN WINTER NIGHTS 307 



ground is covered with hard-frozen snow is their chief time 

 for attacking the bark of young trees. 



In autumn the cries and calls of migrating birds often 

 stream downward by night from the upper air, especially in 

 foggy weather, when the birds become confused and restless. 

 In midwinter these cries are heard seldom ; and the great 

 passages of birds which often follow a sharp spell of frost 

 about Christmas take place by daylight. But certain kinds 

 of water-fowl and game-birds feed by night ; we hear their 

 notes on lakes and from the wide harbour flats, and see the 

 holes dibbled by their bills in the mire. Mallard, teal, and 

 wigeon are habitual night-feeders ; the intense whistle of the 

 wigeon travels a great way over the water in the hush of the 

 darkness, and draws attention to the lower quacking of the 

 mallard. Geese seem by nature to be day-feeders ; and the 

 ducks also have the small eye which distinguishes day-birds 

 from those which feed by twilight or night. But geese as 

 well as ducks have become partly nocturnal for protection, 

 where their feeding-grounds are too exposed by day. Grey 

 geese flight over to the inland fields before sunrise, so as to 

 take up a safe position under cover of the dawn ; and mallard 

 pass to their favourite feeding-grounds at dusk. Snipe and 

 woodcock are more purely nocturnal, and have the large 

 nocturnal eye. Both feed chiefly after dusk, and the 

 woodcock almost exclusively so. Snipe in hard weather can 

 sometimes be seen feeding by day ; but both they and the 

 woodcock are birds which learnt self-protection by conceal- 

 ment in order to escape such foes as foxes and the larger 

 hawks, and are confirmed in the same habits by the persecu- 

 tion of man. 



Winged insect life is rare in the winter nights ; and the 

 bats which prey on it in summer are all hibernating in 

 houses, and caves, and hollow trees. The pipistrelle our 



