Nesting chambers are in old burrows of Bank Swallows, Kingfishers, rodents, or in crevices remaining subsequent to decomposition of roots of plants; frequently this swallow uses a side chamber off the main tunnel, near the mouth, of a burrow abandoned or still in use by the other species mentioned above. =Cliff Swallow=: _Petrochelidon pyrrhonota pyrrhonota_ (Vieillot).--This common summer resident occurs wherever suitable sites for nests are found. Temporal occurrence is indicated in Table 14. _Breeding schedule._--The 610 records of breeding span the period May 21 to June 30 (Fig. 6); the modal date for egg-laying is June 5, and 85 per cent of all clutches are laid from May 21 to June 10. Such synchronous breeding activity is probably a function of strong coloniality with attendant "social facilitation" of breeding behavior. _Number of eggs._--Clutch-size is 5 eggs (4.9, 3-7; 7). Nests are built in mud jugs plastered to vertical rock faces, bridges, culverts, and buildings from a few feet to more than 100 feet above the ground. [Illustration: FIG. 6.--Histograms representing breeding schedules of the Horned Lark and swallows in Kansas. See legend to Figure 1 for explanation of histograms.] =Barn Swallow=: _Hirundo rustica erythrogaster_ Boddaert.--This summer resident is common in most habitats, occurring chiefly about cultivated fields and pastures. Temporal occurrence is indicated in Table 14. _Breeding schedule._--Sixty-three records of breeding in northern Kansas span the period May 1 to July 31 (Fig. 6); the modal date for completion of first clutches is May 25, and that for the second is July 5. The schedule of breeding in southern Kansas (chiefly Cowley County), to judge by 41 records, conforms to the one for northern Kansas: the season spans the period May 1 to August 10, and the modal date for first clutches is May 15. The ten-day lag in peak of first clutches of the northern over the southern sample is about what would be expected on the basis of differential inception of the biological growing season from south to north each spring. _Number of eggs._--Clutch-size does not vary geographically, to judge only from the present samples, and all are included in the listing to follow. The modal size of clutches is 5 eggs (4.7, 3-7; 43); clutches from the period May 1 to 30 show an average of 5.0 eggs, from June 1 to 20 an average of 4.9 eggs, and from June 21 to August 10, 4.4 eggs. Nests are usually placed on horizontal surfaces in barns, sheds, or other such structures; more rarely they are put on bridges, and less frequently yet on vertical walls of culverts or sheds. =Purple Martin=: _Progne subis subis_ (Linnaeus).--This summer resident is common in the east but rare in the west. The only documented colony west of the 99th meridian was in Oberlin, Decatur County (Wolfe, 1961), occupied some 50 years ago. Temporal occurrence is indicated in Table 14.