Number of eggs.—Clutch-size at Concordia, Cloud County, is 4 eggs (3.7, 3-5; 48); in northeastern Kansas mean clutch-size is 3.7 eggs (3-5; 46). For the total sample, mean clutch-size in May is 4.0 eggs, in June, 3.7 eggs, and in July, 3.3 eggs.
Nests are placed about four feet high (one to nine feet) in willow, cattail, sedge, grass, elm, exotic conifer, elderberry, coralberry, buttonbrush, honeysuckle, smartweed, ash, osage orange, and yellow clover.
In central Kansas red-wings are host to the Brown-headed Cowbird in a frequency of one parasitized nest out of nine; in northeastern Kansas the ratio is 1:25.
Table 18.—Occurrence in Time of Summer Resident Icterids in Kansas
| Species | Arrival | Departure | ||
| Range | Median | Range | Median | |
| Bobolink | May 4-May 21 | May 11 | Aug. 28-Oct. 1 | Sept. 12 |
| Yellow-headed Blackbird | Mar. 31-Apr. 29 | Apr. 19 | Sept. 19-Oct. 18 | Sept. 24 |
| Orchard Oriole | Apr. 25-May 14 | May 4 | Aug. 5-Sept. 15 | Aug. 9 |
| Baltimore Oriole | Apr. 24-May 5 | Apr. 29 | Sept. 6-Sept. 29 | Sept. 10 |
| Common Grackle | Mar. 2-Mar. 27 | Mar. 17 | Oct. 15-Nov. 14 | Oct. 31 |
Orchard Oriole: Icterus spurius (Linnaeus).—This summer resident is common in parkland, woodland, and old second-growth. Temporal occurrence is indicated in [Table 18].
Breeding schedule.—The 118 records of breeding span the period May 11 to August 10 ([Fig. 8]); the modal date for completion of clutches is June 5, and 45 per cent of all eggs are laid in the first ten days of June.
Number of eggs.—Clutch-size is 4 eggs (4.1, 3-6; 41). Clutches laid at the peak of the season average 4.3 eggs (3-6; 26), and replacement clutches average 3.8 eggs (3-4; 9). Nests are hung about 15 feet high (ranging from six to 55 feet) in elm, cottonwood, hackberry, locust, catalpa, willow, alder, osage orange, walnut, pear, linden, and ash.
Baltimore Oriole: Icterus galbula (Linnaeus).—This common summer resident is most numerous in the east, in woodland and riparian timber. The species hybridizes freely with the Bullock Oriole in western Kansas, and individuals morphologically typical of Baltimore Orioles are rare west of the 100th meridian. Evidence of such hybridization can be found in specimens taken in eastern Kansas, but the linear nature of distribution along water-courses to the west restricts gene-flow, and evident hybrids are not yet conspicuous. Temporal occurrence is indicated in [Table 18].
Breeding schedule.—Eighty-three records of breeding span the period May 11 to July 10 ([Fig. 8]); the modal date of egg-laying is June 5, and 66 per cent of all eggs are laid between May 21 and June 10.