At the time of my visit to the Park August 21 to 24, 1961, all young had recently left the nests and were able to fly. However, their behavior was so much different from that of the adults that a reliable ratio could not be obtained. The fledglings tended to remain in the nest tree, or to make relatively short flights near it, while the adults occupied with catching of prey for themselves and their young, spent much of their time aloft. The adults were hence far more conspicuous than the fledglings. However, it is my impression that the fledglings were from one-third to one-fourth as numerous as the adults. If this ratio is correct, and if all adults had bred, from two-thirds to three-fourths of the eggs and/or nestlings must have been destroyed. This rate of loss seems reasonable in view of the known histories of nests observed in June and again in July, and of the fates of birds' nests in general.
Summary
Mississippi kites were studied in southwestern Kansas in the summer of 1961, at various localities, especially at Meade State Park. At this locality, near the northwestern limit of the breeding range, the kite thrives in typical High Plains habitat dominated by a short-grass type of vegetation, but availability of trees suitable for nests is a limiting factor. Since maturing of extensive groves of cottonwoods and other trees planted at Meade State Park, the colony of kites has increased tremendously and the breeding population probably exceeded 100 in 1961.
The kites are social in all their activities and do not maintain territories. The sexes differ little in appearance, but males are slightly smaller than females and have paler heads. Food consists almost entirely of flying insects, and these are usually eaten while the kite is in flight. Kites that are feeding nestlings may travel up to two miles from the nest or perhaps considerably farther in the course of their foraging. For 148 feedings of nestlings the observed intervals averaged 10.7 minutes. Most published references to the food habits mention predation on small vertebrates, especially lizards, but including also snakes, toads, rodents, and even rabbits. In my study a total of 205 pellets were collected and 453 insects were tentatively identified but the total number of insects in the pellets was much larger. No vertebrates were identified from this sample and among 358 prey items identified from kite stomachs collected in Oklahoma, by Sutton, vertebrae of a small fish were the only vertebrate remains. Further verification of predation on mammals, reptiles and amphibians by this species is needed. Of the insects distinguished in pellets, beetles including carabids, cicindelids, hydrophilids, scarabaeids, and silphids were most numerous (270) and grasshoppers (164) were second; also there were 16 cicadas and three moths.
Kites arrive in Kansas about the second week in May. Often old nests are repaired and used over again. Hatching is about mid-June. Normally there are two eggs per clutch. By mid-August the fledglings are learning to fly. By the latter part of August they are learning to capture their insect prey, and in early September southward movement of the entire population begins.
Eggs and/or young in many nests are destroyed by hail or high wind in the sudden violent storms that are characteristic of the High Plains. Mississippi kites are often shot by misguided persons, and benefit little from the protection supposedly provided by Federal law. However, the adults probably have few natural enemies. The high ratio of older adults to yearlings indicates that the life expectancy is long. Through their second summer the kites retain their barred immature plumage, and can be readily distinguished from adults. Only ten per cent of the kites recorded in 108 June sight records at the Park were in juvenile plumage.
Literature Cited
Audubon, J. J.
1840. The birds of America. Philadelphia, pp. xv + 246.