MOORLAND IDYLLS. 



last resort from the juices of insects. The 

 swallow and the house-martin, again, make 

 domed mud huts, and line them inside with 

 soft floating materials. Finally, the sand- 

 martin excavates with its bill the soft 

 sandstone of cliffs or roadside cuttings, 

 and strews a bed within for its callow 

 young of cotton-grass and dandelion para- 

 chutes. 



Why this curious variety among them- 

 selves, and this equally curious divergence 

 from the common practice of bird-kind in 

 general ? Clearly, thought I, it must bear 

 some definite relation to the habits and 

 manners of the birds which exhibit it. Let 

 me think what it means. Aha, aha, eureka ! 

 I have found it ! The insect-hawking birds 

 are not a natural group ; by descent they 

 have nothing at all to do with one another. 

 Closely as the swift resembles the swallow 

 in form, in flight, in shape of bill, in habits 

 and manners, we now know that the swift is 

 a specialized woodpecker, while the swallow 

 170 



