Breeding schedule.—Ten records of breeding span the period May 10 to June 30; the modal date for egg-laying is June 10. The present sample is not adequate to indicate extreme or modal dates with reasonable accuracy.
Number of eggs.—Clutch-size is 4 eggs (3.6, 3-4; 5).
Nests are placed relatively low in forks in trees and shrubs.
Bell Vireo: Vireo bellii bellii Audubon.—This summer resident is common in riparian thickets and second-growth scrub. Temporal occurrence is indicated in [Table 16].
Breeding schedule.—Sixty-six records of breeding span the period May 1 to July 20 ([Fig. 7]); the modal date for egg-laying is May 25, and a little under 40 per cent of all eggs are laid in the period May 21-31. Renesting following disruption of first nests is regular, and the small peak in the histogram in the period June 11-20 is representative of this.
Number of eggs.—Clutch-size is 4 eggs (4.6, 3-6; 21). Clutches in May have an average of 3.7 eggs, and those in June and July 3.6 eggs.
Nests are placed about two feet high (ranging from one to five feet) in terminal or lateral forks of small branches in elm, hackberry, osage orange, coralberry, dogwood, plum, honey locust, mulberry, willow, cottonwood, and box elder.
Yellow-throated Vireo: Vireo flavifrons Vieillot.—This is a rare and local summer resident in deciduous forest and woodland in eastern Kansas. Stations of breeding occurrence fall east of Shawnee and Woodson counties. Temporal occurrence is indicated in [Table 16].
Breeding schedule.—Eggs are laid at least in May.
Number of eggs.—Clutch-size is about 4 eggs.