1 Module # 6 Component # 5 Kites and Buzzards Kites The species that are included in this group are pretty much a mixed bag, put together for convenience, and do not reflect any taxonomic affinity. Of these, the Black Kite and Yellow-billed Kites are true kites. The Yellow-billed Kite (fork-tailed) is sometimes regarded as a subspecies of the Black Kite, both in the Genus Milvus. The Kites are dived up into three subfamilies, namely, Elaninae - the white-tailed kites Perninae - the fork-tailed kites and Milvinae - the true kites This genus is characterised by birds that are bold, and mainly scavenging. They have a dextrous graceful flight, and are capable of swooping quickly to the ground to snatch an item of food. The Black-winged Kite which is far more common and is the most likely species of the group to be encountered. For this reason, it has been chosen to be examined in detail. Until March of 2009, this section of this Component dealt with the Black Shouldered Kite, not the Blackwinged Kite. This is due to yet another taxonomic review of the group. The name Black Shouldered Kite has now been bestowed exclusively on Elanus axillaris, an Australian kite of remarkably similar description, while Elanus caeruleus has been renamed the Blackwinged Kite.
2 Black-winged Kite - Elanus caeruleus Vital Statistics Wingspan Weight Preferred prey Incubation period Clutch size Status Nesting site Nestling period Hunting success Habitat 84 cm [34 in] 250 g [ 10 ounces.] Rodent specialist 31 days 3-6 eggs Very common resident Tree tops, usually Acacia Spp. or other thorn trees 35 days 20 % (of each attempt) Open Grassland and Savanna Woodland
3 Description This diminutive little raptor is one of the best-known birds of prey in Southern Africa, and is very commonly seen. It has pure white underparts, grey upperparts, and a very distinctive black shoulder patch, hence its name. Its eyes are red, bill black, feet and legs yellow and it has a short white tail. The sexes are indistinguishable. The juveniles of the species have basically the same plumage pattern, but their upperparts are washed with brown, as is the top of its head and neck. Its eyes are also grey - brown. Change to the adult plumage takes about a year.
4 Reproduction This species of bird displays quite an involved courtship ritual. This consists of the male doing several circling passes around the female while both are in flight. During this movement, the male might dive down at the female who side slips out of his way or who turns and presents her talons at his. This all occurs to the accompaniment of much calling by the male. He may also fly around her with his legs dangling together with exaggerated stiff wing beats. He also brings prey to her. Their nesting sites are very variable, but the top of thorn trees is favoured when available. One consistent feature of all the sites, irrespective of their height, diameter, protection and construction, is the fact that they are all easily accessible from the air. Although both birds play an equal part in the nest construction, the female does not hunt during this period, but relies on the male to bring prey to her. Breeding occurs throughout the year in Southern Africa, but has different peaks depending on the locality. In the Lowveld area, breeding peaks from August to November and from February to May. Male Black-winged Kites defend a territory to which they attract females, and continue to occupy them after the females have left. These areas may be up to one kilometre [± ½ mile] around his nest, and are defended from conspecifics, as well as other smaller birds of prey. The females tend to wander around and select the best available territories. Eggs are laid approximately 24 days after copulation. Between three and six eggs are laid at one to two day intervals. Breeding is also very variable, and may be correlated with prey abundance. They may breed twice or three times in a season, and not at all the following season. During one rodent plague, several successive broods were recorded. Incubation seems to be the sole responsibility of the female, while the male continues to feed her. Incubation averages at around 31 days. There does not seem to be any sibling aggression, although they all compete for food from their parents. The nestling stage averages around 35 days, and at around 10 days on the wing, the female deserts them, and the male cares for them, feeding them in flight. They may remain with him for up to three months.
5 Diet and Feeding These raptors feed mostly on rodents and have two different hunting strategies: Striking prey from a perch Striking from a hovering position While using the perching tactic, the bird changes its vantage point every 10 to 20 minutes. When it takes to the wing, it soars to 30 or 40 m [100 130 ft] and begins hovering. It will hover for only 10 to 20 seconds over one point while carefully scrutinizing the ground, and then breaks off to repeat the process in another position. When it spots a rodent while hovering, it begins its strike in a gentle fashion, only speeding up a few metres from the ground, plunging head first at 90º, and only at the last moment extending its talons for the kill. When striking from a perch, it merely drops onto its prey at the desired angle. Roughly 70 % of its time is spent hunting from a perch, and 30 % hovering. Its success rate is in the order of one successful kill from five attempts. The Black-winged Kite is a small rodent specialist, concentrating on three species. These are the Angoni Vlei Rat (Otomys angoniensis), the Striped Mouse (Rhabdomys pumilio) and the Multimammate Mouse (Mastomys coucha). This is also the order of their preference. When these are not available, this kite will also kill lizards, insects, and very occasional doves or tortoises. However, these alternative prey species only consist of less than 2 % of their diet. The birds are often nomadic, and opportunists, moving from prey scarce areas to prey abundant areas. Some ringed birds have been recovered over 900 km's [340 miles] from their initial ringing area. However, this is probably an exception. It is important to remember that this bird is only some 250 grams [10 ounces]. The species will always remain a favourite with bird watchers and enthusiasts alike.
6 Buzzards There are seven Southern African species that have been allocated to the group of birds known as buzzards. These include the Steppe (Common), Forest, Longlegged, Honey, Jackal, Auger and Lizard buzzards. Attempting to select which one of these species to describe in detail provided a few problems. Firstly, the Lizard Buzzard is in fact not a buzzard at all taxonomically, and many modern authors prefer to place it with the goshawks, and it was even earlier placed with the eagles. Secondly the Forest Buzzard is a rare bird to see, and most visitors are unlikely to meet them. And lastly the Steppe (common), honey, auger and long-legged buzzards are not resident species, but rather summer migrants. However, for those people, just starting their acquaintance with birds of prey, the Steppe (common) Buzzard is the species most likely to provide the first encounter, during the summer months. Another reason for selecting the Steppe (common) Buzzard is that a description of this species is also basically a description of the Forest Buzzard as well. The bird is also interesting, as three basic plumage forms can characterise the adults. The most common is a brown form, but individuals may be very much darker in the second form, and thirdly a russet form can be seen.
7 Steppe (Common) Buzzard - Buteo buteo Vital Statistics Wingspan Weight Preferred prey Status Habitat Home range 115 cm [46 in] ± 900 g [ 32 ounces] Rodent specialist Very common non-breeding migrant Savanna Woodland and forest when in Southern Africa. Also, agricultural lands Summer migrant
8 Description For the most part the birds are medium brown with an indistinct whitish band across their chests. Above this band, the plumage is streaked or smudged, and below it is banded. Irrespective of which variation the main plumage is, their eyes are brown, while their cere, legs and feet are yellow. The beak is black. Their tails are also always pale rufous above and have a fine dark-brown barring with a broader band near the tip. This is one of the key characteristics that distinguish adults from juveniles. Although the plumage of the immatures is also very variable, their full breast is vertically streaked, and not barred. Their eyes are also a pale yellow.
9 Flight and Migration As already mentioned, these birds are summer migrants to Southern Africa, coming from the Northern Hemisphere. The Steppe (common) Buzzards breed in Finland and eastwards to Mongolia. Being the very successful species that they are, witnessing their migration in their large numbers is truly spectacular. Like all other raptors, these buzzards utilise warm thermals in flight. However, these air currents don't form over water bodies, and the birds make large detours so as not to fly over water. Thus, instead of crossing the Mediterranean Sea, they fly over Israel, to get to and from Africa. One count had over 315 800 buzzards coming through in one Spring. These birds are resident here from around late September to early April. Their round-trip journey is approximately 26 000 kilometres [16 100 mi].
10 Hunting The Steppe (common) Buzzards hunt from a perch, simply dropping down gently onto its prey. Their preferred quarry is small rodents, although it will take small birds, lizards, snakes, frogs and even insects. Its insectivorous prey mainly includes the larger beetles, locusts, breeding termites and caterpillars. The birds are also mostly silent and solitary, and individuals seen together calling or performing flight displays are likely to be our resident Forest Buzzards. Since these birds are non-breeding migrants, details of their reproduction are not relevant as it is never seen in Southern Africa.