92 THE SENSES OF ANIMALS 



as barbels which are themselves sensitive to dissolved chemi- 

 cals. The Barbel, a noteworthy fish to be found in many 

 of our British rivers, derives its name from these, and under 

 very muddy water conditions these fish rootle among the 

 debris on the bed of the streams using these organs to find 

 food. 



Birds have already been mentioned in connection with 

 their ability, or lack of ability, to smell ; and this poses a 

 pretty problem. It is generally considered that the power 

 of scent is confined to geese, ducks, and some sea birds; and 

 that the majority of birds, being well endowed with keen 

 hearing and sight, use these senses in their search for and 

 taking in of food. It can be argued that they do not require 

 a sense of smell because they have no use for it. Then againt 

 there are birds such as snipe and woodcock and curlew that 

 feed on invertebrate animals which live out of sight in mud 

 and boggy places. These birds, however, locate food items 

 by means of a localized sense of touch which will be referred 

 to later on. 



There is an old idea, which dies very hard, that vultures 

 can scent their prey (carrion) from great heights in the air. 

 This has no foundation in fact for, as pointed out earlier, 

 these great birds have the most acute vision and can 

 with ease see a prospective meal from hundreds of feet 

 up. 



I, myself, have always been interested in parrots; and 

 there have been few periods in my life when there was not 

 a parrot in the house. I have more than once wondered 

 whether parrots possess some fair degree of the sense of 

 smell. Though cheese is not a food to be given frequently 

 to parrots, a little now and then does no harm. Now it is 

 obvious that if some item of food is offered to a parrot by 

 hand it can see it well, and usually the bird will take it into 

 its beak at once ; but before nibbling at it, the item will be 

 carefully tested with the tongue, thus showing the ability 

 to taste. However, what has puzzled me — and still does — 

 is how a parrot recognizes cheese in the mass when it is on 

 the table. It is easy to see how a small piece of cheese or 

 rind can be recognized when held close to the bird, but 

 such a morsel must look very different from a pound of cheese 



