TREE SWALLOW. 



614. Iridoprocne bicolor. Q inches. 



Male, steely blue or greenish above; female, duller 

 and often plain gray above, but both sexes always en- 

 tirely white below. 



These Swallows are also abundant about farmyards; 

 except when they are skimming over ponds, they are 

 almost always scouring the air above buildings or 

 fields, at higher elevations than the Barn Swallows. 

 When weary they' roost on dead twigs or telephone 

 wires, hundreds often being seen in rows on the latter. 

 Like the Martins, these birds frequently nest in bird 

 boxes, but usually not more than one or two pairs in 

 a single house. 



Notes. A twittering like that of the other Swal- 

 lows. 



Nest. Of grass, lined with feathers, in hollow trees 

 on the border of water or in orchards, or in bird boxes 

 erected for their use; eggs white (.75 x .52). 



Range. Breeds in the northern half of the U. S. 

 and northward to Labrador and Alaska ; winters in 

 southern U. S. and southward. 

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