White-tailed Kites: Nesting

The nest is made from small sticks and twigs, and lined with grass, weed or straw type material (3), and construction takes between seven (3) and twenty-eight days (3). Twigs are gripped using the beak or feet, and a bird may flap or jump or move up and down to apply sufficient force to snap a twig from a tree (3). In some instances, both sexes are involved in nest construction, but in most cases, the female builds the nest (8). The construction of the nest is a part of the courtship and territorial display of the monogamous kite pair. When establishing a territory, a male may fly from tree to tree, with or without a twig in his beak. The female may also behave in this manner, but in this case the kite is usually occupied with nest building. (8). In California, nest building can start as early as January and last through August (3). Waian (8) found that while a particular nest may be used more than once, the same nest was never used consecutively from one year to the next.

Once the nesting displays and activities of the kite pair begin, the male performs most of the hunting, thus supplying the female with food from the time of egg laying until the hatchlings are ready to leave the nest (8). The male transfers prey to the female or to young fledglings (8) either in the air or when perched, with about equal occurrence (3). In the aerial mode, the recipient flies under the hovering male kite and seizes the prey from behind (3). In the second method, the female or fledgling uses its beak to take the prey from the male while the birds are perched. The aerial method is also used before egg-laying, as a courtship ritual between the male and the female. In this more spectacular display, the female flies under the male kite and turns upside down to seize the prey with the feet, with both birds calling “eegrack” at various moments. (3)

Kites typically lay four eggs (3), but the number may range from three to six (2), laid on alternate days (8). Most eggs are probably laid within the first month of spring (3). The color of the eggs may vary from white or creamy-white, with very little to a great deal of additional coloring in the form of blotches or spots in shades of brown, purple or red-brown (3). Incubation of the eggs is done by the female and takes between thirty and thirty-two days (3). Waian (8) found that after hatching, the young are covered with a yellow-hued down, replaced within seven days by a grayish down. The different sizes of the hatchlings when still young, are a result of the different intervals between the laying of the eggs (8).

Both parents are involved in the cleaning of the nest, removing uneaten prey and the regurgitated castings of bone and fur, although the cleaning may not be done in the most routine manner. The parents repair the nest with additional sticks and grass during the nesting period. (8).