378 BULLETIN 17 9, UNITED STATES NATIONAL MUSEUM 



the preceding species [tree swallow]. A number of pairs of the 

 Northern Violet-green Swallow were found in possession of a lumber 

 yard in town and were nesting inside large, square piles of board 

 lumber that was loosely cross-laid so as to leave space for circulation 

 of air for drying purposes." 



Eggs. — The violet-green swallow generally lays four or five eggs 

 to a set, but sets of six are not very rare, and as many as seven have 

 been recorded. The eggs are usually ovate and pure dead white, 

 without markings. The measurements of 50 eggs average 18.7 by 

 13.1 millimeters; the eggs showing the four extremes measure 20.8 

 by 12.7, 17.3 by 13.7, 16.3 by 12.7, and 17.3 by 12.2 millimeters. 



Young. — Mr. Rathbun tells me that the incubation period is 13 

 or 14 days, and that the young are on the wing within 23 days; 

 they remain near the nest for a few days and then disappear from 

 the locality, to be seen only occasionally thereafter. During the first 

 few days after they leave the nest they make only short flights, but 

 as the birds become stronger these aerial excursions become more 

 extended. When at rest on some favorite perch, such as a telephone 

 wire, the young are constantly calling to their parents and are fed 

 by them from time to time. Frequently one launches itself into the 

 air to meet its parent and take its food while on the wing, a graceful 

 performance. 



Leon Kelso (1939) made some observations in Colorado on the 

 feeding of young violet-green swallows. "The female secured most 

 of the food for the young; the male brought something only occas- 

 ionally. When returning with food they would sweep about the 

 nest in wide arcs, then, coming to a point about 50 ft. or more in 

 front of it, would fly directly to and in the entrance." He noted 

 that food was brought at frequent but widely varying intervals; 

 during the first afternoon the "visits came at 1 to 30 second intervals." 

 On another day, August 1, the intervals varied from 20 seconds to 

 four minutes, considerably over a minute intervening in most cases. 

 Periods spent in the nest between feedings varied from one second to 

 over two minutes. 



Mr. Shirling (1935) noted on two occasions that more than one 

 female attended a brood of young, entered the nest and apparently 

 fed them : 



One male bird stood guard and rarely entered the nest. He was kept 

 busy chasing other male swallows away, but did not seem to object to either 

 of the females coming. [At another nest] there was more than one female 

 swallow interested in the nest. At one time three female birds and one male 

 were at the nest. The male, keeping guard, paid little attention to the other 

 birds unless it was a bird of some other species that arrived, or a male Violet- 

 green Swallow. * * * 



Female No. 1 seemed to have priority of claim to the nest. She often 

 remained with her head at the doorway and pecked at intruders. She was also 



