OMNIVOROUS BIRDS AND PROTOCHORDATES 237 



moths and butterflies, including many harmful sorts, long-legged 

 Crane- Flies (Tipulida), and other pests possessed of the power of 

 flight. These birds further rid the ground of innumerable noxious 

 insect -larvae: cockchafer grubs, wire-worms, surface and other 

 caterpillars, mole -cricket larvae, &c. They also prey on field- 

 slugs and earth-worms. They can often be seen following the 

 plough in order to pick up the grubs and wire-worms which are 

 exposed. 



''As to the plant-food of crows, these birds are exceedingly 

 partial to germinating seeds, e.g. those of peas and beans, and 

 also the grains of cereals. Germinating maize is particularly 

 appreciated by them. When possible they permit the seeds, &c., 

 to remain in the ground until germination has begun, appearing to 

 know that these have then become sweeter (as the result of the 

 formation of sugar from starch, &c.). Crows also peck the grains, 

 especially when half-ripe, out of the ear . . . liking barley best. 

 Of germinating grains, next to maize, wheat and oats are pre- 

 ferred. They further rob ripening peas, and the nearly mature 

 fruit of the cherry, plum, and apricot. . . . Even potatoes, beet, 

 and mangold-wurzel are not despised by crows. Of the species 

 mentioned the raven is least addicted to seed-eating." 



The above gives a good idea of the mixed nature of the diet 

 affected by some omnivorous birds, and it will be noted that there 

 is a considerable difference between related species, the raven, for 

 instance, being fonder of animal food than the other crows, a fact 

 which may be correlated with its formidable beak. Among other 

 omnivorous members of the Crow family may be mentioned 

 magpies, jays, and choughs. The related family of Starlings 

 (see vol. i, p. 155) also includes many omnivorous members, of 

 which the Common Starling (Sturnus vulgaris) may be taken 

 as an example. 



GEESE, DUCKS, AND SWANS (ANSERES) 



Passing over the numerous remaining families of perching 

 birds, many of which include omnivorous forms (e.g. birds of 

 paradise, weaver-birds, thrushes, warblers, and larks), mention 

 may be made of GEESE, birds which feed by preference in the 

 neighbourhood of water, either on the sea-shore or inland. Some 

 of the species are practically vegetarian, as, for example, the 



