EASTERN OVENBIRD 461 



Eggs. — The eggs are laid during the morning, often before sunrise, 

 1 to 3 days after the nest is completed. Under normal conditions 

 an Qgg is laid each day until the set is completed. The number in 

 complete sets varies from 3 to 6 eggs. In 36 nests not disturbed by 

 cowbirds, J. P. Norris (1892) reported 6 with 3 eggs, 13 with 4, 16 

 with 5, and 1 with 6, an average of slightly more than 4 eggs per set. 

 Hann (1937) in a series of 27 nests in which the eggs were checked 

 as laid there were 2 nests with 3 eggs, 6 with 4, 18 with 5, and 1 with 6, 

 an average of about 5 eggs per nest. If the first attempt at nesting is 

 a failure the second set of eggs is generally smaller in number than 

 the first. Normally the ovenbird does not rear two broods during any 

 one season. 



The eggs have a white, slightly glossed ground color speckled and 

 spotted with hazel, lilac-gray, and reddish-brown. In the majority of 

 the eggs the markings form a wreath about the larger end. A series 

 of 50 eggs had an average length of 20.2 millimeters, the extremes being 

 18.6 and 23.2 millimeters, and an average short diameter of 15.5 milli- 

 meters, the extremes being 14.3 and 16.7 millimeters. 



Incubation. — Incubation is done entirely by the female and begins 

 the day after the last egg is laid, regardless of the size of the clutch. 

 When incubating, the bird sits with her side parallel to the opening 

 of the nest, her tail bent over her back and usually toward the front 

 of the nest. She changes her position many times during the course 

 of the day, placing her head in the opposite direction, but the axis of 

 her body is always in the same relative position. She exhibits con- 

 siderable nervousness when about to leave the nest and on leaving 

 does not fly but walks a considerable distance over the forest floor be- 

 fore taking flight. 



The ovenbird does not flush from her nest readily, and when walk- 

 ing through the woods I have unwittingly trampled on the edge of 

 the nest before she fluttered out. At this time the bird gave a splen- 

 did exhibition of feigned injury; she struggled seemingly helpless 

 along the ground with her wings and tail lowered and the feathers 

 of her crown and back uplifted in an attitude of dire distress. 

 After leading me away for a distance of about 50 feet she arose and 

 flew away triumphantly. 



The female during the period of incubation leaves the nest volun- 

 tarily for feeding from five to a dozen times during the course of the 

 day; spending from 8 to 17 percent of the total time away from the 

 nest. The first trip occurs soon after daylight, and the lightest incu- 

 bation is from that time until noon. Late in the evening there is a 

 tendency for her to leave again before settling down for the night. 

 It was found that the time off during the day was roughly propor- 

 tional to daily temperature changes. In a nest which I had under 



