Milvus milvusred kite

Geographic Range

Milvus milvus is endemic to the western Palearctic region in Europe and northwest Africa. Formerly, these birds of prey also occurred in northern Iran. They are rare kites that are resident in western Europe and northwest Africa. Red kites from northeastern and central Europe migrate further south and west, reaching south to Turkey for the winter season. Vagrant birds have been recorded as far north as Finland and south in Israel and Libya. (Newton, et al., 1996; Snow and Perrins, 1998)

Habitat

Red kites are a wide-ranging species with a wide habitat tolerance. Their only requirements are large, mature trees in which to build nests. Generally these nests are built 10 to 15 m above ground. Sometimes red kites take over an old crow or buzzard nest. Red kites can be very protective of their nesting area, but are not highly territorial of their entire breeding territory. Most red kites nest within 20 km of where they were reared. (Mougeot, 2000; Newton, et al., 1996)

Physical Description

Red kites are brownish-chestnut in color with a mix of orange/buff and darker brown or black streaking. The main wing feathers (secondaries and primaries) are dark brown, which contrast with white patches under the wings. They have pale grey heads which are streaked with black. The bright yellow legs and feet can often be seen in flight. They have hooked beaks which are very sharp and designed for tearing meat. Females are generally larger ranging from 1000 to 1300 g in weight, males are 800 to 1200 g. Their wingspan ranges from 175 to 195 cm and body length from 60 to 66 cm. (Snow and Perrins, 1998)

  • Sexual Dimorphism
  • female larger
  • Range mass
    800 to 1300 g
    28.19 to 45.81 oz
  • Range length
    60 to 66 cm
    23.62 to 25.98 in
  • Range wingspan
    175 to 195 cm
    68.90 to 76.77 in

Reproduction

Red kites are monogamous and pair-bond for life, usually staying with each other year-round. Courtship each year renews the bond the pair already have. Mated pairs are more successful in reproduction with experience.

Courtship begins for established pairs in March. The birds play courtship games, such as flying towards each other and then turning and twisting away from each other at the last moment. They also have mock talon grappling fights, spinning in mid air, spiraling toward the ground, parting at tree level. Occasionally pairs courting this way fail to release each other in time and die. (Mougeot, 2000)

Red kites reach maturity between 2 and 4 years of age. These birds normally pair for life, although, in winter they may spend time apart or in communal roosts. Winter is the best time for viewing kites because it minimizes disturbance to breeding kites. They are notorious for being easily disturbed at the nest.

One to three eggs are normally laid in April, produced at 3 day intervals. This ensures that there will be a dominant chick who will likely outlive his siblings. Incubation time is 31 to 32 days with an extra 3 days per additional egg.

Fledging can take 7 to 9 weeks, depending on food availability. At around 6 weeks the chicks will move away from the nest to exercise their wings. Even after their first flight, young do not move far from their nests as parents continue to feed them around the nest for several weeks. Young attain adult plumage at around 1 year and will breed at about 3 years. (Mougeot, 2000; Newton, et al., 1996)

  • Breeding interval
    Red kites breed once yearly.
  • Breeding season
    Nest-building usually begins during March, but first-time breeders may not start until April. Eggs are usually laid in early April.
  • Range eggs per season
    1 to 3
  • Range time to hatching
    31 to 35 days
  • Range fledging age
    7 to 9 weeks
  • Average time to independence
    1 years
  • Average age at sexual or reproductive maturity (female)
    3 years
  • Average age at sexual or reproductive maturity (male)
    3 years

Both parents assist in nest-building, usually in hardwood trees. Red kites are protective of the nest area, but not of the entire breeding territory. The female carries out the majority of incubation with relief from the male for several 20-minute breaks during the day for feeding and exercise. The parents stay alert for nest predators, such as crows and ravens. When the chicks hatch, the male bird brings food to the nest for the female to tear into small pieces to feed them. Parents will continue to feed the young a few weeks past the fledgling stage. (Mougeot, 2000; Newton, et al., 1996)

  • Parental Investment
  • altricial
  • pre-fertilization
    • provisioning
    • protecting
      • female
  • pre-hatching/birth
    • provisioning
      • female
    • protecting
      • male
      • female
  • pre-weaning/fledging
    • provisioning
      • male
      • female
    • protecting
      • male
      • female
  • pre-independence
    • provisioning
      • male
      • female
    • protecting
      • male
      • female

Lifespan/Longevity

Captive red kites are known to have lived 26 years in captivity. Wild records are unavailable, but related Milvus migrans have been recorded living up to 24 years in the wild. (Richards, 1998)

  • Range lifespan
    Status: captivity
    26 (high) years

Behavior

Red kites nest in trees, often close to other kites. In the winter, many kites roost together. Red kites are social in winter and mate for life, so occur in pairs during the breeding season. Some red kite populations are migratory; others that occur in milder regions are sedentary. Those that do migrate remain on the same continent, and often return to their natal grounds to breed. (Carter and Grice, 2000; Mougeot, 2000)

Home Range

Red kite home-ranges generally consists of their nesting and hunting area. Average home range size is poorly defined and highly variable, as kites may hunt 2 to 25 km from their nest. (Richards, 1998)

Communication and Perception

Red kites, like other carrion birds, feed on widely dispersed food sources, so they may communicate at roost sites. Individuals tend to find food for themselves or by following another. (Richards, 1998)

Food Habits

Red kites are primarily scavengers, but they are also predators, especially during the breeding season when they must feed their young. They eat a wide variety of live prey, primarily small mammals such as rabbits, voles, and field mice, but also including birds, worms, and invertebrate prey. Red kites glide lower than their usual soaring height to hunt live prey, visually searching for movements on the ground. They then dive quickly and grab prey in their talons. (Snow and Perrins, 1998)

  • Animal Foods
  • birds
  • mammals
  • amphibians
  • reptiles
  • fish
  • carrion
  • insects
  • terrestrial non-insect arthropods
  • terrestrial worms

Predation

Goshawks (Accipiter gentilis) are the only known natural predators of adult red kites. The main threat is from human activity. Red kites have been targeted by egg thieves and illegal use of poisoned baits in carcasses, even though they are not set specifically for red kites. Nestlings and eggs are also vulnerable to nest predators, although both parents actively defend the nest. At signs of predators females signal to her fledglings who "play dead," even to the extent that a fox will believe them to be dead and leave, thinking it can return to eat them later. (Richards, 1998; Snow and Perrins, 1998)

Ecosystem Roles

Red kites are important predators and scavengers in the ecosystems they inhabit. Parasites found on these birds include: an acanthocephalan (Centrorhynchus milvus) and a trematode (Phagicola ascolonga). (Kuntz and Chandler, 1956; Schmidt, 1975)

Commensal/Parasitic Species
  • acanthocephalan (Centrorhynchus milvus)
  • trematode (Phagicola ascolonga)

Economic Importance for Humans: Positive

Red kites prey on rabbits and other rodents that act as agricultural pests. They also help by removing dead carcasses that could spread disease. (Richards, 1998)

  • Positive Impacts
  • controls pest population

Economic Importance for Humans: Negative

There are no known adverse effects of Milvus milvus on humans.

Conservation Status

Red kites are directly persecuted by poachers, forestry workers, tourists, and others. Habitat destruction, shortage of food, over-use of pesticides and other chemicals, over-exploitation, collisions, and petroleum and oil pollution are all indirect threats to Milvus milvus. They are considered near-threatened by the IUCN. Populations are in decline in areas that were previously considered strongholds of this species, including Germany, Spain, and France. (Richards, 1998)

Other Comments

The closest relative of red kites are black kites (Milvus migrans). Red and black kites co-occur in countries like Spain and occasionally hybridize.

Contributors

Tanya Dewey (editor), Animal Diversity Web.

Beth Meyer (author), Radford University, Karen Francl (editor, instructor), Radford University.

Glossary

Palearctic

living in the northern part of the Old World. In otherwords, Europe and Asia and northern Africa.

World Map

acoustic

uses sound to communicate

agricultural

living in landscapes dominated by human agriculture.

altricial

young are born in a relatively underdeveloped state; they are unable to feed or care for themselves or locomote independently for a period of time after birth/hatching. In birds, naked and helpless after hatching.

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

carnivore

an animal that mainly eats meat

carrion

flesh of dead animals.

chemical

uses smells or other chemicals to communicate

diurnal
  1. active during the day, 2. lasting for one day.
endothermic

animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.

forest

forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.

iteroparous

offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

migratory

makes seasonal movements between breeding and wintering grounds

monogamous

Having one mate at a time.

motile

having the capacity to move from one place to another.

mountains

This terrestrial biome includes summits of high mountains, either without vegetation or covered by low, tundra-like vegetation.

native range

the area in which the animal is naturally found, the region in which it is endemic.

oviparous

reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.

riparian

Referring to something living or located adjacent to a waterbody (usually, but not always, a river or stream).

scavenger

an animal that mainly eats dead animals

scrub forest

scrub forests develop in areas that experience dry seasons.

seasonal breeding

breeding is confined to a particular season

sedentary

remains in the same area

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

social

associates with others of its species; forms social groups.

tactile

uses touch to communicate

temperate

that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).

terrestrial

Living on the ground.

territorial

defends an area within the home range, occupied by a single animals or group of animals of the same species and held through overt defense, display, or advertisement

tropical savanna and grassland

A terrestrial biome. Savannas are grasslands with scattered individual trees that do not form a closed canopy. Extensive savannas are found in parts of subtropical and tropical Africa and South America, and in Australia.

savanna

A grassland with scattered trees or scattered clumps of trees, a type of community intermediate between grassland and forest. See also Tropical savanna and grassland biome.

temperate grassland

A terrestrial biome found in temperate latitudes (>23.5° N or S latitude). Vegetation is made up mostly of grasses, the height and species diversity of which depend largely on the amount of moisture available. Fire and grazing are important in the long-term maintenance of grasslands.

visual

uses sight to communicate

References

Bent, A. 1954. Life Hisotries of North American Birds of Prey. New York, New York: Dover Publications Inc..

Carter, I., P. Grice. 2000. Studies of re-established Red Kites in England. British Birds, 93: 304-322.

Evans, I., R. Dennis, D. Orr-Ewing, N. Kjellin, P. Anderson. 1997. The re-establishment of Red Kite breeding populations in Scotland and England. British Birds, 90: 123-138.

Kuntz, R., A. Chandler. 1956. Studies on Egyptian Trematodes with Special Reference to the Heterophyids of Mammals. I. Adult Flukes, with Descriptions of Phagicola longicollis n. sp., Cynodiplostomum namrui n. sp., and a Stephanoprora from Cats. The Journal of Parasitology, 42/4: 445-459.

Mougeot, F. 2000. Territorial intrusions and copulation patterns in red kites, Milvus milvus, in realtion to breeding density. Animal Behaviour, 59: 633-642.

Newton, I., P. Davis, D. Moss. 1996. Distribution and Breeding of Red Kites Milvus milvus in Relation to Afforestation and Other Land-use in Wales. The Journal of Applied Ecology, 33: 210-224.

Pain, D., I. Carter, A. Sainsbury, R. Shore, P. Eden. 2007. Lead contamination and associated disease in captive and reintroduced red kites Milvus milvus in England. Science of the Total Environment, 376: 116-127.

Peterson, R., G. Mountfort, P. Hollom. 1953. A Field Guide To the Birds of Britain and Europe. London: Collins Clear-Type Press.

Richards, A. 1998. Birds of Prey: Hunters of the Sky. Philadelphia, Pennsylvania: Courage Books.

Schmidt, G. 1975. Sphaerirostris wertheimae sp. n., and Other Acanthocephala from Vertebrates of Israel. The Journal of Parasitology, 61/2: 298-300.

Snow, D., C. Perrins. 1998. The Birds of the Western Palearctic Concise Edition. Oxford Oxfordshire: Oxford University Press.

Veiga, J., F. Hiraldo. 1990. Food Habits and the Survival and Growth of Nestlings in Two Sympatric Kites (Milvus milvus and Milvus migrans). Holarctic Ecology, 13: 62-71.

Winfiled, I. 1990. Predation pressure from above: observations on the activities of piscivorous birds at a shallow eutrophic lake. Hydrobiologia, 191: 223-231.