Animal Diversity Web

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)

• Biogeographic Regions
• palearctic
  • native

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)

• Habitat Regions
• temperate
• terrestrial

• Terrestrial Biomes
• savanna or grassland
• forest
• scrub forest
• mountains

• Other Habitat Features
• agricultural
• riparian

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)

• Other Physical Features
• endothermic
• homoiothermic
• bilateral symmetry

• 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)

• Mating System
• monogamous

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)

• Key Reproductive Features
• iteroparous
• seasonal breeding
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual
• oviparous

• 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)

• Key Behaviors
• flies
• diurnal
• motile
• migratory
• sedentary
• territorial
• social

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)

• Communication Channels
• visual
• acoustic

• Perception Channels
• visual
• tactile
• acoustic
• chemical

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)

• Primary Diet
• carnivore
  • eats terrestrial vertebrates
  • scavenger

• 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)

• Known Predators

  • northern goshawks (Accipiter gentilis)
  • humans (Homo sapiens)
  • red foxes (Vulpes vulpes)

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)

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)

• IUCN Red List

  Near Threatened
  More information

• IUCN Red List

  Near Threatened
  More information

• US Migratory Bird Act

  No special status

• US Federal List

  No special status

• CITES

  No special status

• State of Michigan List

  No special status

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 Pow­ers (ed­i­tor, in­struc­tor), Rad­ford Uni­ver­sity.

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.