Breeding Ecology of the Mississippi Kite in Arizona

Abstract

The Mississippi Kite (Ictinia mississippiensis) recently has extended its breeding range into the southwestern United States and was first recorded nesting in Arizona in 1970. Approximately 25 regularly active nesting sites occur in Arizona in riparian forest-scrubland habitat along the tributaries of the Gila River. Nesting habitat consisted of a structurally diverse (patchy) arrangement of cottonwood (Populus fremontii) trees and salt cedar (Tamarix chinensis) understory. Cicadas, the principal prey of the kites studied, were captured frequently (41% of all prey captures) by hawking from cottonwood perches within 150 m of nests. Vegetation patchiness facilitated foraging and accounted for 71% of the variation in reproduction. Increased vegetation diversity in the more traditional breeding areas of the Great Plains and in migration and wintering habitats may have enhanced foraging, reproduction, and survival of kites, and may help to explain the recent population increase. Most nest sites were distributed among four groups. No movement between groups was noted during any one nesting season. Most adult kites attempted to nest, but up to 52% of all nesting attempts failed during courtship and nestbuilding (44% of all failures), incubation (40%), and nestling (16%) stages. Reproductive success was 0.60 fledglings per nesting attempt, similar to that estimated for kites in the Great Plains. Apparently, reproduction at a nest was not enhanced by close proximity to another active kite nest. The Mississippi Kite (Ictinia mississippiensis) nests in North America from Florida and South Carolina westward through the Great Plains south of Nebraska and, recently, into Arizona, New Mexico and Colorado. It has been reported during spring and summer irregularly from California to Massachusetts (Parker and Ogden 1979). Migration and wintering records for the neotropical region are scarce but show that most individuals may winter in tropical regions (Eisenmann 1963, Parker 1977). Levy (1971) first recorded the Mississippi Kite in southeastern Arizona in 1970 and estimated that as many as 10 pairs nested along the lower San Pedro River. Observations of Mississippi Kites and possible breeding activity along the Verde River in central Arizona during 1970 and 1973 were reported by Johnson and Carothers (1976). In this paper we examine the breeding ecology of the Mississippi Kite in Arizona and discuss the ecological relationships that influence the presence of this species in the southwestern United States.