78 GLEANINGS FEOM NATURE. 



faultlessly executed and so well sustained that the tiny 

 musician may claim no mean rank in the feathered 

 choir." 



Each pair, after mating, seek some tree with a gray- 

 ish bark, usually an oak, maple or apple, and finding 

 a horizontal limb or convenient fork, they begin their 

 nest, building it principally from hair and the fine 

 fibres of various plants which they weave very closely 

 and compactly together. Finally they cover the whole 

 with a coat of lichens, fastening them on with the 

 finest of wool or the silk of spiders' webs. This 

 lichen covering serves the useful purpose of a mask, 

 rendering the color of the nest almost exactly that of 

 the bark of the tree on which it is built ; thus hiding 

 it from the keen eye of the young oologist walking 

 beneath, or the keener eye of the crow or hawk flying 

 above. But there is one eye sharp enough to detect 

 it. For no matter how deep and dark the ravine in 

 which a nest is hidden away ; no matter what aid of 

 nature has been called into use in rendering it incon- 

 spicuous to the view of other animals, necessity seems 

 to lend a preternatural sharpness to the vision of the 

 female cow-bird, enabling her to discover, whenever 

 needed, a safe place of deposit for an" egg, destined to 

 become at no distant day an orphan which will be a 

 heavy burden to its foster parents. 



The nest of the blue-gray gnat-catcher when com- 

 pleted, is usually very small, and is cylindrical in form, 

 not hemispherical, like that of most other birds. One 

 which contained five eggs, taken on the 2nd of last 

 May, was but 5| inches in circumference by 2f inches 

 in length, and weighed only 3.7 grams. But the cow- 



