160 CITIZEN BIRD 



strands which held the nest firmly in the crotch of the 

 elder stem. 



"What is that soft stuff?" whispered Dodo. 



" It is wool scraped from the stalks of young ferns," 

 said the Doctor ; " the soft brown wool that is wrapped 

 round the leaves to keep them warm in their winter 

 sleep until they stretch out of the ground and feel the 

 warmth of the sun. The little Warblers gather it in 

 their beaks and mat it into a sort of felt." 



" There is something else in the nest-lining that looks 

 like feathers," said Nat. 



"That is dandelion down." 



" Don't you think, Doctor, that this nest is very thick 

 underneath? " asked Rap. " It is twice as high as the 

 one they built here last summer." 



The Doctor felt of the bottom of the nest very gently 

 with one finger and said, " I thought so ! You have 

 sharp eyes, Rap ; it is very thick, and for a good rea- 

 son — it is a two-storied nest ! " 



" A two-storied nest ! Are there such things ? " 

 clamored the children together. 



" The mother-bird is worrying ; come over under the 

 mulberry tree and I will tell you about this wonderful 

 nest. 



"There are some very ill-mannered shiftless Citizens 

 in Birdland, called Cowbirds," began the Doctor; "you 

 will learn about them when we come to the family to 

 which they belong. They build no nests, but have the 

 habit of laying their eggs in the nests of other birds, 

 just as the equally bad-behaved Cuckoos do in Europe. 

 Some birds do not seem to know the difference between 

 these strange eggs and their own, and so let them re- 



