BLUE OR METALLIC BLUE 503 



Hfest : In holes, exeavations, natural cavities, etc. ; made of grasses and 



straw ; thickly lined with feathers. 

 Eggs: 4 to 7 ; pure white. Size 0.75 X 0.53. 



Early in July the Tree Swallows begin to gather in 

 flocks ; and, from that time until they start on their 

 southern migration, innumerable multitudes of them are 

 to be seen flying over the open country. They sit in 

 crowds on telegraph wires or any available perch, gather- 

 ing late in the afternoon and, when near water, circling 

 over it in an endless game of " Follow the Leader." 

 They dip daintily, each one in turn, rise, circle, and dip 

 again, just brushing the surface with a light splashing, 

 until the shadows of evening fall and it is too dark to 

 watch them longer. In almost any section of the United 

 States they are the swallows best known, at least to 

 city folk, and are, I believe, the ones whose return 

 migration has been celebrated in the old song. 



They still adhere to the old habits of nesting in hollow 

 trees, only a small portion having been induced to try 

 the boxes put up for them by bird-lovers. Undoubtedly 

 they will in time accept this substitute and become as 

 changed in their environment as are the eave and barn 

 swallows ; but no one can wonder that they love the 

 forest best and are loath to leave it. At Lake Tahoe we 

 found them nesting in the old piles of the deserted pier, 

 in company with the Brewer blackbirds. They entered 

 the nesting cavities, which were usually two to five feet 

 above the water, by a knot-hole or crevice in the wood. 

 One nest whose brood I watched develop was so filled 

 with feathers that they waved in the doorway, calling 



