| White-tailed kite | |
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| White-tailed kite with prey. | |
Scientific classification | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Aves |
| Order: | Accipitriformes |
| Family: | Accipitridae |
| Genus: | Elanus |
| Species: | E. leucurus |
| Binomial name | |
| Elanus leucurus (Vieillot, 1818) | |
| Subspecies[2] | |
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| Synonyms | |
Elanus caeruleus leucurus | |
Thewhite-tailed kite (Elanus leucurus) is a smallraptor found in westernNorth America and parts ofSouth America. It replaces the related Old Worldblack-winged kite in its native range.
The white-tailed kite wasdescribed in 1818 by the French ornithologist, someone who studies birds,Louis Pierre Vieillot under thebinomial nameMilvus leucurus with thetype locality as Paraguay.[3] It is now one of four species in thegenusElanus which was introduced in 1809 by the French zoologistJules-César Savigny.[4] The wordElanus is fromAncient Greekelanos for a "kite". The specific epithetleucurus is from the Ancient Greekleukouros for "white-tailed":leukos is "white" andoura is "tail".[5]
For some recent decades, it was lumped with theblack-winged kite ofEurope andAfrica asElanus caeruleus and was collectively calledblack-shouldered kite.[4] However, the American Ornithologists' Union accepted a more recent argument that the white-tailed kite differed from the Old-World species in size, shape, plumage, and behavior, and that these differences were sufficient to warrant full species status.[5] Thus, the white-tailed kite was returned to its original name. Meanwhile, theOld WorldE. caeruleus is once again called black-winged kite, while the nameblack-shouldered kite is now reserved for anAustralian species,Elanus axillaris, which had also been lumped intoE. caeruleus but is now regarded as separate again.
The coloration of the white-tailed kite isgull-like, but its shape and flight is falcon-like, with a rounded tail. While it has white faces and white underparts, it has black wingtips, beaks, and shoulders. Contrastingly, the white-tailed kite has deep red eyes that stand out at night.[6] A mid-sized kite, it measures 35–43 cm (14–17 in) in length, spans 88–102 cm (35–40 in) across the wings and weighs 250–380 g (8.8–13.4 oz). Both the wings and tail are relatively elongated, and thetarsus measures around 3.6 cm (1.4 in).[7]
The white-tailed kite was rendered almost extinct inCalifornia in the 1930s and 1940s due to shooting andegg-collecting, but they are now common again. Their distribution is patchy, however. They can be found inCentral Valley and southern coastal areas, open land aroundGoleta including the Ellwood Mesa Open Space, marshes in Humboldt County, and also around theSan Francisco Bay. Elsewhere in California, they are still rare or absent. Although they are not migratory birds, they are also found from southernTexas and easternMexico to theBaja California Peninsula and through Central and South America to central Argentina and Chile. Globally, they are not considered threatened species by theIUCN.[1] On rare occasions the bird can be found far outside its usual range. At different times, two had been sighted inNew England as of 2010.[n 1]
White-tailed kites typically nest at the top of trees, usually around 20 to 50 feet above ground level. These nests can be in open-country trees growing in isolation, or at the edge of or within a forest. Their nests are built from medium-sized sticks and twigs, grasses, weeds, hay, and moss and are measured about 21 inches across with a cup that is around 7 inches across and 4 inches deep.[9]
The white-tailed kite is famously known for "kiting," hovering in a position by facing into the wind and fluttering its wings. Although it may seem like irrelevant behavior at first, it does serve a purpose for hunting. While hovering around 80 feet in the air, it tips its head down to look for small mammals moving in the grass below. When prey is spotted, it dives down, quickly grabs the animal with its talons, and flies back up to eat.[10]
White-tailed kites feed principally onrodents (as well as smallopossums,shrews,reptiles,amphibians and largeinsects),[11] and they are readily seen patrolling or hovering over lowland scrub or grassland. They rarely if ever eat otherbirds, and even in opencerrado,mixed-species feeding flocks will generally ignore them.[12] Most of the hunted insects are consumed on the wing while flying. This means that instead of returning to a perch to feed, these birds transfer the prey from their talons to their beaks while flying to eat. In the case of larger prey such as rodents and lizards, they will fly to a perch to pluck and eat.[13]
Outside the breeding season during the winter, they roost, congregate or settle to rest at night, communally in groups of up to 100. However, once mating formally begins with the construction of nests by both males and females in mid-February, the female kite abstains from hunting for the time being and stays in the nest to incubate the eggs while the male brings food back to the nest for the female and children.[14] This incubation period lasts around 26-32 days and they lay around 4 to 5 eggs at a time. Their eggs are cream-colored with splotches of light and dark brown. Once they have hatched, it takes them around 35-40 days to develop the proper feathers and start learning how to fly.[15]
White-tailed kites have been observed in aerial combat at the margins of territories, locking talons in a behavior described as "grappling".[16] This is most often done during mating season as an act of dominance when the male Kite patrols the nest. They will typically slash and peck at intruding birds until one of the birds backs down or falls.
Their predators are primarily other birds like red-tailed hawks, peregrine falcons, prairie falcons, and great-horned owls. Meanwhile, smaller birds like American crows, common ravens, and small to medium-sized carnivores will go for the eggs of white-tailed kites.[17]
Deforestation and urban expansions have caused the number of white-tailed kites to decrease as they lose suitable places to live and truly thrive. Climate change also impacts the white-tailed kite population as heat waves in the spring put young birds at risk as their bodies are not developed enough to properly regulate their body temperature and can die from dehydration.
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