Pied-billed Grebe: Podilymbus podiceps podiceps (Linnaeus).—This is a common but local summer resident, in and on ponds, marshes, streams, ditches, and lakes. The species can be seen in the State at any time, but usually arrives in the period March 1 to April 13 (the median is March 21), and departs southward in the period October 13 to November 18 (the median is October 24).
Breeding schedule.—Nineteen records of breeding span the period May 1 to June 30; the modal date for egg-laying is May 15.
Number of eggs.—Clutch-size is 4 to 10 eggs.
Nests are floating masses of marsh vegetation (cattail, smartweed, duckweed, filamentous green algae, and the like), kept green on top by addition of fresh material, in or at the edge of emergent marsh vegetation.
Double-crested Cormorant: Phalacrocorax auritus auritus (Lesson).—This is a transient, but has been found nesting on one occasion in Barton County (Tordoff, 1956:311).
Breeding schedule.—Eggs were laid in July and August in the one known nesting effort.
Number of eggs.—Clutch-size is 2 to 4 eggs (Davie, 1898).
Great Blue Heron: Ardea herodias Linnaeus.—This common summer resident nests in tall trees along rivers, streams, and marshes. The sector of greatest abundance is the Flint Hills. A. h. herodias Linnaeus occurs in extreme northeastern Kansas, A. h. wardi Ridgway breeds in southeastern Kansas, and A. h. treganzai Court breeds in western Kansas; specimens showing intermediate morphology have been taken from the central part of the State. Occurrence in time, exclusive of the few that overwinter in Kansas, is shown in [Table 10].
Breeding schedule.—Seventy-seven records of breeding span the period March 1 to April 30 ([Fig. 3]); the modal date of egg-laying is April 5.
Number of eggs.—Clutch-size is 4 eggs (4.4, 3-6; 36).