RED-EYED VIREO 337 



duced in a way to be presently described, and the gap or open side, opposite tlie 

 first-formed hanging mass, long remains open ; with the vireo, as with the oriole, 

 it is filled in last. * * * 



The most striking actions of this vireo that I noticed on the first day were as 

 follows: (1) winding silk and fine threads of bast over the forks of the twig at 

 about an inch from their junction; (2) building downward from this support 

 a loose mass of fibers — corresponding to the primary nest mass of the oriole's 

 work — perfectly secured but giving no hint of the beautiful cup-shaped structure 

 that was to appear; (3) carrying the suspension forward and downward until 

 one could recognize part of the concave wall of the future nest, or hardly more 

 than the half of a vertically divided cup; (4) finally, attempting to rest in the 

 imperfect nest and use the breast for molding long before it was physically pos- 

 sible to make such movements effective. * * * 



At four o'clock on the second day the frame of this nest was evidently com- 

 pleted. It was composed almost wholly of fine bast, bark strippings, and 

 spider's silk, the latter having been derived from the egg-cocoons of such species 

 as nest on the under side of leaves or against the clapboards of houses. * * ♦ 



In reality the work of construction lasted nearly five days, but from the close 

 of the third day until the end of the fifth, active labor gradually slowed down ; 

 the hen would sit in her nest-cup for longer and longer intervals, until June 4, 

 or the sixth day from the start, when she remained to lay her first egg, which 

 was deposited after 7 :30 o'clock in the morning. 



W. J. Erichsen (1919) says of nest building: "A peculiarity of this 

 species which I have noted both in Liberty county [Georgia] and else- 

 where is a habit the birds have of destroying partially completed nests 

 built by them. I once watched a pair remove piece bj^ piece the material 

 from a nearly completed nest, and weave it into another which they had 

 begun a few yards distant." 



Ora Willis Knight (1908) gives the measurements of a nest as "two 

 and a half inches deep outside by one and a half inside, the ex- 

 ternal diameter was three and the diameter inside two inches." 



Eggs. — [Author's note: Four eggs generally make up the set for 

 the red-eyed vireo, but sometimes only three are laid and very rarely 

 five may be found. These are mostly ovate, rarely slightly elongated. 

 They are pure lusterless white, and are usually sparingl}' marked, 

 chiefly toward the larger end, with fine dots of small spots of reddish 

 brown, or darker browns, or blackish; rarely an egg is nearly or 

 quite immaculate; an occasional set may contain eggs that show large 

 spots or small blotches of light browns, but such cases are rare. The 

 measurements of 50 eggs in the United States National Museum 

 average 20.3 by 14.5 millimeters ; the eggs showing the four extremes 

 measure 22.9 by 15.8, 21.8 by 16.3, and 18.3 by 13.2 millimeters.] 



Young. — Ora W. Knight (1908) gives the incubation period as 12 

 to 14 days. M. G. Vaiden, of Rosedale, Miss., writing to Mr. Bent 

 of nests he had studied carefully, found that the eggs hatched in 11 

 days. He began his count the day after the last egg was laid : in one 

 case it took an extra day. 



