Yellow-billed kite

Yellow-billed kite
Adult in Limpopo, South Africa
Juvenile in the Kruger Park, South Africa
Scientific classification Edit this classification
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Accipitriformes
Family: Accipitridae
Genus: Milvus
Species:
M. aegyptius
Binomial name
Milvus aegyptius
(Gmelin, JF, 1788)
Subspecies[2]
  • M. a. aegyptius - (Gmelin, JF, 1788)
  • M. a. parasitus - (Daudin, 1800)
Milvus aegyptius range (light green)

The yellow-billed kite (Milvus aegyptius) is the Afrotropical counterpart of the black kite (Milvus migrans), of which it is most often considered a subspecies. However, DNA studies suggest that the yellow-billed kite differs significantly from black kites in the Eurasian clade, and should be considered as a separate, allopatric species.

Taxonomy

The yellow-billed kite was formally described in 1788 by the German naturalist Johann Friedrich Gmelin in his revised and expanded edition of Carl Linnaeus's Systema Naturae. He specified that the bird was found in Egypt, placed it with the eagles, falcons and relatives in the genus Falco and coined the binomial name Falco aegyptius. Unusually, Gmelin did not cite a source for his information.[3] The yellow-billed kite is now one of three kites placed in the genus Milvus that was introduced in 1799 by the French naturalist Bernard Germain de Lacépède.[4][5]

There are two subspecies:

Image Subspecies Distribution
M. a. parasitus (Daudin, 1800) found throughout most of Sub-Saharan Africa (including Madagascar), except for the Congo Basin (with intra-African migrations)
M. a. aegyptius (Gmelin, JF, 1788) Egypt, southwestern Arabia and the Horn of Africa (which disperses south during the non-breeding season).[5]

The yellow-billed kite was formerly considered as conspecific with the black kite (Milvus migrans).[6] A molecular phylogenetic study published in 2005 compared DNA sequences of two mitochondrial loci of the red, black and yellow-billed kites. It found that there was significant divergence between the three species, but unexpectedly, the two clades corresponding to the M. a. aegyptius and M. a. parasitus subspecies did not form a monophyletic group.[7]

Description

The yellow-billed kite is a medium-sized, opportunistic raptor, with recorded measurements for an adult male including a weight of 550 g, a wingspan of 398 mm, and a tail length of 255 mm.[8][9] As suggested by its name, the yellow-billed kite is easily recognized by its entirely yellow bill, unlike that of the black kite (which is present in Africa as a visitor during the North Hemisphere winter). However, immature yellow-billed kites resemble the black kites of the corresponding age.

Behaviour

The yellow-billed kite is generally gregarious during both its breeding and non-breeding periods, although individual breeding pairs are not. [10] They are described as facultative colonial species. [11][9]. Research conducted in the Albert Falls region of KwaZulu-Natal (KZN), South Africa, found that nesting density increased significantly in proximity to reliable, surplus food sources (specifically crocodile farms) which effectively resulted in the formation of colonies. [9]

Habitat and feeding

They are found in almost all habitats, including parks in suburbia, but rare in the arid Namib and Karoo. While adaptable, the species is more abundant in higher rainfall regions in addition to woodlands, especially those with dense rural human habitation compared to grasslands and desert areas.[12] Research conducted in KZN, South Africa, found that yellow-billed kites specifically preferred riparian areas characterized by dense vegetation and tall trees (such as the Eucalyptus camaldulensis) for nesting, while consistently avoiding cultivated land and open woodlands.[9]

The yellow-billed kite highly commensal with humans and thrives in human-dominated environments by exploiting an increased food supply from human refuse and reliable scavenging opportunities at specialized facilities [13][14][9][12]. In the Albert Falls region of South Africa, the presence of crocodile farms has historically attracted thousands of kites to the area to exploit surplus meat. [9]

They feed on a wide range of small vertebrates and insects, much of which is scavenged. In addition to scavenging, the yellow-billed kite is an active hunter that utilizes elevated perches within thickets as strategic vantage points to prey on small animals [15][8]. While they avoid cultivated land for nesting, telemetry data acquired from tracking a yellow-billed kite showed that their diurnal activity can be flexible, frequently using croplands and grasslands for foraging. [8]

Migration

A nine-year study conducted at a communal roost near Pietermaritzburg, South Africa, identified high interannual synchrony in the post breeding migratory departure of yellow billed kites.[16] Over the study from 2016 to 2024, the birds were found to depart almost exclusively within a narrow window between March 20th and 26th each year.[16] This consistent timing suggests that migration is driven by endogenous cues, such as hormonal changes triggered by decreasing day length (photoperiod) rather than external environmental factors.[16] Researchers concluded that cues like food availability were not the primary drivers because the kites departed on schedule despite the presence of a reliable and abundant food supply at a nearby crocodile farm.[16]

Status

It is mostly an intra-African breeding migrant, present in Southern Africa July–March and sometimes as late as May. It is generally common. There are no threats to this species as stated by the IUCN.

References

  1. ^ BirdLife International (2021). "Milvus aegyptius". IUCN Red List of Threatened Species. 2021 e.T22734928A197335248. doi:10.2305/IUCN.UK.2021-3.RLTS.T22734928A197335248.en. Retrieved 20 February 2022.
  2. ^ Gill F, D Donsker & P Rasmussen (Eds). 2020. IOC World Bird List (v10.2). doi : 10.14344/IOC.ML.10.2.
  3. ^ Gmelin, Johann Friedrich (1788). Systema naturae per regna tria naturae: secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis (in Latin). Vol. 1, Part 1 (13th ed.). Lipsiae [Leipzig]: Georg. Emanuel. Beer. p. 261.
  4. ^ Lacépède, Bernard Germain de (1799). "Tableau des sous-classes, divisions, sous-division, ordres et genres des oiseux". Discours d'ouverture et de clôture du cours d'histoire naturelle (in French). Paris: Plassan. p. 4. Page numbering starts at one for each of the three sections.
  5. ^ a b Gill, Frank; Donsker, David; Rasmussen, Pamela, eds. (August 2022). "Hoatzin, New World vultures, Secretarybird, raptors". IOC World Bird List Version 12.2. International Ornithologists' Union. Retrieved 6 December 2022.
  6. ^ Mayr, Ernst; Cottrell, G. William, eds. (1979). Check-List of Birds of the World. Vol. 1 (2nd ed.). Cambridge, Massachusetts: Museum of Comparative Zoology. p. 297.
  7. ^ Johnson, J.A.; Watson, R.T.; Mindell, D.P. (2005). "Prioritizing species conservation: does the Cape Verde kite exist?". Proceedings of the Royal Society B: Biological Sciences. 272 (1570): 1365–1371. doi:10.1098/rspb.2005.3098. PMC 1560339. PMID 16006325.
  8. ^ a b c Ehlers Smith, D.A., Ehlers Smith, Y.C., Hoffman, B. and Downs, C.T., 2021. Home range, landscape use and a migration event by a non‐breeding yellow‐billed kite Milvus migrans parasitus. African Journal of Ecology, 59(4).
  9. ^ a b c d e f Porter, R.N., Howells, W.W., Weiersbye, I.B., Hoffman, B. and Porter, S.N., 2025. Yellow-billed Kite Milvus aegyptius nesting dynamics and breeding success across a human-modified landscape. Ostrich, 96(1), pp.42-53.
  10. ^ Sergio F, Penteriani V. 2005. Public information and territorial establishment in a loosely colonial raptor. Ecology 86: 340–346. https://doi.org/10.1890/04-0137
  11. ^ Hiraldo F, Veiga JP, Manez M. 1990. Growth of nestling black kites Milvus migrans: effects of hatching order, weather and season. Journal of Zoology (London, England) 222: 197–214
  12. ^ a b Mendelsohn, J.M., 1997. Yellowbilled Kite. The atlas of southern African birds, 1, pp.166-167.
  13. ^ Del Hoyo J, Elliott A, Sargatal J. 1994. Handbook of the birds of the world, vol. 2: New World vultures to guineafowl. Barcelona: Lynx Edicions.
  14. ^ Ferguson-Lees J, Christie DA. 2001. Raptors of the world. London: Christopher Helm.
  15. ^ Dean, W. R. J. (2005). Black kite and yellow-billed kite Milvus migrans. In P. A. R. Hockey, W. R. J. Dean, & P. G. Ryan (eds.), roberts birds of Southern Africa. VIIth ed. (pp. 479–481). Pretoria.
  16. ^ a b c d Porter, R.N., Gula, J., Howells, W.W., Weiersbye, I.B., Hoffman, B., Singh, P. and Downs, C.T., 2025. Interannual Synchrony in the Post‐Breeding Migration Departure of Yellow‐Billed Kites (Milvus aegyptius) From a Roost Site in South Africa. African Journal of Ecology, 63(5), p.e70081.
This article is issued from Wikipedia. The text is available under Creative Commons Attribution-Share Alike 4.0 unless otherwise noted. Additional terms may apply for the media files.