White-tailed Kites are often seen hovering above open areas, watching for small mammals, which constitute 95% of their diet. These kites usually start hunting shortly after first light, hovering 5-25 m (16-78 ft) above the ground and facing into the wind as they watch for prey movements. If no prey are captured, the kite usually hovers over another spot, finally returning to a perch after an average of 5-6 minutes. In cooler weather hunting may continue all day, but is generally limited to morning and evening at warmer temperatures (Dunk 1995).
The White-tailed Kite of the southwest United States and Middle and South America was lumped with the Black-shouldered Kite (E. caeruleus) of southwest Europe, Africa and south Asia in 1981. The brief marriage was dissolved in 1994 as the predominant ornithological trend shifted from lumping to splitting species. Two other species found in Australia complete the genus (Clark and Banks 1992, Dunk 1995, Am. Ornithol. Union 1998).
DISTRIBUTION. During the 1987-1992 field work seasons of the TBBA project, atlasers found 32 confirmed, 33 probable and 33 possible breeding sites for White-tailed Kite, with confirmed locations primarily along the Texas coast and in the lower Rio Grande valley. In addition probable and possible evidence was also obtained further inland, especially in the Post Oak Savannah and South Texas Brush Country regions (see the region map in Lockwood and Freeman ). The confirmed record in the northern Panhandle deserves further study. In Oklahoma this kite is a rare and erratic breeder (Stuart 2004).
Elsewhere this species is resident along the Pacific Coast from southwest Washington to northern Baja California, in southern Arizona, Louisiana, south Florida, at lower elevations in Mexico and Middle America. In South America, White-tailed Kites breed mostly east of the Andes, south to central Argentina and Chile. This kite has wandered widely and is apparently expanding its range (Dunk 1995, Howell and Webb 1995, Am. Ornithol. Union 1998. Corman 2005, Tweit and Orness 2005, Sauer et al. 2007, Florida Breeding Bird Atlas).
SEASONAL OCCURRENCE. White-tailed Kites are resident in Texas and throughout their range. In this state they breed from March to September, based on egg dates from March 18 to August 21 (Oberholser 1974).
BREEDING HABITAT. White-tailed Kites are resident in Texas to about 200 m (650 ft) elevation (Oberholser 1974). In North America these kites prefers open areas and savannahs at low elevations, including grasslands, agricultural habitats and wetlands (Dunk 1995). In Arizona breeding evidence was found in riparian, agricultural and grassland areas (Corman 2005). In Washington (state) in a much more humid situation, grassland is also the preferred habitat (Tweit and Orness 2005).
The nest of this kite is usually placed in a solitary tree or one at the edge of a grove or forest. The height of the tree used may vary from 3-50 m (10-165 ft) and the nest is usually placed in the upper third of the tree (Dunk (1995).
The nest, built by both sexes, in 7-28 days, is composed of sticks and lined with grass, leaves or forbs. The outside diameter is about 53 cm (21 in), inside diameter 18 cm (7 in), cup depth 9 cm (4 in) and height 21 cm (8 in). In the cup the female usually lays 4 (range 3-6) white eggs. This ground color is often wholly or largely concealed by brown markings. The eggs, laid on alternate days, are incubated by the female for 30-32 days, starting with the laying of the 1st or 2nd egg. The young birds take their first flights 4-5 weeks after hatching and remain with their parents for about another 33 days (Dunk 1995).
STATUS. White-tailed Kites are uncommon to common residents of the Coastal Prairies, southern Post Oak Savannahs and eastern South Texas Brush Country (Lockwood and Freeman 2004). Comparison of the TBBA map with that of Oberholser (1974) suggests no major range change has occurred since 1970. Breeding Bird Survey data for 1980-2006 from 9 routes in Texas suggest an annual population increase of about 10% for this period (Sauer et al. 2007).