92 BIRD BEHAVIOUR 



seed-eating Finches, that they have practically no 

 stomach, the dilatation of the digestive canal where 

 this ought to be being so slight as easily to escape 

 notice, so as to give the food a straight run through. 



As an opposite example of a small passerine bird 

 with remarkable powers of digestion I may cite 

 the Hedge-Sparrow, which, though not a Sparrow 

 nor any sort of Finch, being an insectivorous bird 

 by structure and relationships, has a curious fond- 

 ness for seed, preferring it, when caged, to soft 

 food, and swallows it whole, digesting even hemp- 

 seed husk and all ; moreover, with such an able 

 digestion it has a vigorous appetite, eating continu- 

 ally and voiding a corresponding amount. It will 

 be noticed that, although seldom seen to pick up a 

 morsel of perceptible size, this little bird is almost 

 continually employed in eating when observed at 

 liberty. 



The most perfectly organized digestive organs 

 are found in the Pigeons, in which the crop, an 

 enlargement of the gullet where the food is stored 

 and macerated, is particularly large, and double, 

 whereas in many birds it hardly exists, or is merely 

 a temporary dilatation ; in passerine birds which 

 possess it, such as Finches, it appears when full as 

 a bulge at the base of the neck above, not below 

 as usual, and in birds of prey is most conspicuous, 

 as it swells out through the feathers. Pigeons also 

 have the posterior or grinding part of the stomach 

 the gizzard which in many birds is not differ- 

 entiated from the soft anterior or digestive portion, 



