88 The Building of the Nest 



bring disaster. Until I studied this point the 

 occurrence of exceedingly frail nests was ever a 

 matter of surprise, for it is to be remembered 

 that the same species, as a cat-bird or cardinal 

 red-bird, does not build after a uniform 

 fashion, but adapts its work to the spot 

 chosen for the nest. It would be very haz- 

 ardous to say that a nest was built by this or 

 that bird, unless the builder was seen in 

 possession. 



So difficult is it to watch a pair of birds 

 while building, that the method of their work- 

 ing is largely to be guessed at from the work 

 itself, but by means of a field-glass a good 

 deal can be learned. It would appear as if 

 a great many twigs were brought for the 

 foundation of a nest, such as a cat-bird's or 

 song-sparrow's, that were unsuitable. I have 

 occasionally seen a twig tossed aside with a 

 flirt of the head very suggestive of disap- 

 pointment. The builders do not always 

 carry with them a distindl idea of what they 

 want when hunting for material, and so labor 

 more than would be necessary if a little wiser. 

 Very funny disputes, too, often arise, and these 

 are most frequent when wrens are finishing 

 their huge structures in a box or some corner 



