176 American Birds 



Experiment shows that a baby linnet brought up by a tit- 

 lark took all the notes from that bird, and even though 

 placed in the company of other linnets later, he did not sing 

 as they sang. This law among birds that makes the earli- 

 est impressions the habits of after life would make a 

 strange bird world if revoked. If the nestlings did not 

 learn the songs from their parents, what a grand medley 

 we should have; robins singing like wrens and larks like 

 sparrows, till we could no longer tell birds by their songs. 

 It is largely this habit of imitation in the bird that 

 prompts him to adorn his nest with lichens and to build 

 a home that blends so closely with the surrounding 

 branches. Some people would have us believe that the bird 

 has reasoned it out, and builds in this way to protect his 

 nest from enemies. The rufous hummingbird is accus- 

 tomed to see the lichen-covered limbs of the trees, and 

 when it builds It collects these lichens and shingles its home 

 with them. Out of fifty nests of the rufous hummer all 

 were built after the same manner. But the black-chinned 

 hummer of southern California generally builds In the 

 sycamores and oaks. The leaves of the sycamores are 

 light-colored, and have a fine yellow down on one side. 

 The bird selects this down and builds Its home entirely 

 of it, so It is light yellow and can hardly be seen among 

 the leaves surrounding it. The two nests are very dif- 

 ferent In appearance, but the fact that both nests are pro- 

 tectively colored Is from the use of handy material rather 

 than the result of the birds seeking certain things for the 

 purpose of protection. 



The last week In April, before the trees were well leaved, 

 I heard the call of the Warbling VIreo {Fireo gilvus). 



