The slender-billed kite is a slaty gray kite with broad, rounded wings and a short, square tail. The species ranges from 36 to 41 centimeters in length and possesses a wingspan of 80–90 centimeters. There is no sexual plumage dimorphism within the species; however, females tend to be larger than the males, weighing between 367 and 485 grams while males weigh between 377 and 448 grams. Their characteristically sharp black beak is hooked, matched by sharp, black talons. Their eyes are yellowish, and their face and legs are orange-red. Juveniles resemble adults, but have brownish eyes and three narrow white bands in the tail. Both sexes resemble the male
snail kite, and the slender-billed kite has often been included in the same genus,
Rostrhamus. Adults are distinguished by their yellow, rather than red, eyes and a noticeably shorter tail. Their primary call is a nasal
kee-ee-aay-aay-aay that begins with a sharp increase in frequency followed by a steady decline. This call is often heard in-flight or in response to predators. Their second call is a repeating
ker-ah with oscillating frequency (sometimes followed by repeating
ah-ahs) heard as they approach their mate in the nest. ==Diet==