BIRDS AND THE WEB OF LIFE 405 



species." It is evident, then, that considerable importance 

 may be attached to the fauna and flora of birds' feet. 



Another linkage is seen in the poUination of flowers 

 by birds. What insects do as a rule, birds do occasionally. 

 Mr. John H. Lovell (1920, p. 76), writing of North America, 

 says : " Our wild columbine {Aquilegia canadensis) has 

 scarlet flowers which are yellow inside, or rarely all over, 

 and is chiefly visited by humming-birds. Other native 

 humming-bird flowers are the cardinal flower, the trumpet- 

 honeysuckle, the painted cup, and the trumpet-flower ; 

 but bird-flowers are not common in North America, although 

 abundant in tropical South America." 



Mr. Lovell calls attention (1920, p. 136) to the frequent 

 redness of edible berries, and notes that bird-flowers are 

 almost invariably fire-red or scarlet. " In tropical America, 

 where there are more than five hundred species of humming- 

 birds, there are scores of scarlet bird-flowers, such as scarlet 

 sages, fuchsias, and abutilons ; while in Europe, as Kerner 

 points out, where neither the humming-birds of America 

 nor the sun-birds of Africa nor the honeysuckers of Australia 

 are found, scarlet blossoms are noticeably absent. It is 

 difficult not to believe that anthophilous birds have learned 

 to associate bright red colours with the presence of an 

 ample food-supply of nectar and small insects." 



§ 4. Parasites of Birds 



Like other animals, birds have a large number of parasitic 

 retainers, varying from microscopic blood-parasites to long 

 tapeworms. Some of these parasites keep to the outer 

 surface, and work hard among the feathers and scales, 

 especially when these become foul or when the bird gets 

 out of condition. The most important of these ecto- 

 parasites are (i) the biting-lice or Mallophaga which feed 

 on the delicate portions of the feathers ; (2) the unrelated 

 true lice (belonging to the order Hemiptera) which suck 

 blood ; and (3) the skin-mites and scale-mites which are 



