Mountain Buzzard Buteo oreophilus Scientific name definitions

The Mountain Buzzard is a rather small Buteo of montane forests (mainly 2,000–3,800 meters) in East Africa that is patchily distributed from Ethiopia south to eastern Democratic Republic of Congo, Burundi, Tanzania, and Malawi. This species hunts for small mammals, reptiles, birds, and insects while perched within forest (often Hagenia and Hypericum woodland) or forest edge, but may also hunt in grassland or moorland habitats near forest cover. At the onset of the breeding period, pairs perform undulating flight displays, calling while engaged in plunging dives and upward swoops above forest. This species was formerly considered conspecific with the Common Buzzard (Buteo buteo), and more recently with the Forest Buzzard (B. trizonatus) of southern Africa. Classified as Near Threatened, the Mountain Buzzard is considered vulnerable because of the limited and patchy distribution of montane forest habitat, which is subjected to cutting and other human-caused degradation. The global population, estimated to range from 670–6,700 individuals, is suspected to be experiencing a moderately rapid decline (1 BirdLife International (2021). Species factsheet: Buteo oreophilus. Close ).

Length 41–48 cm; wingspan 102–117 cm; mass ~700 g (2 Ferguson-Lees, J., and D. A. Christie (2001). Raptors of the World. Christopher Helm, London, UK. Close ). Rather small buteo; adults with dark brown upperparts and large brownish blotches on white underparts (though variable); thighs barred with brown and rufous; tail with narrow dark bars and broader subterminal band. In flight , shows dark carpal patches, dense spotting on wing linings, white bases to primaries. Separated from similar migratory Common (Steppe) Buzzard (<em>B</em>. <em>buteo</em> <em>vulpinus</em> ), with which it overlaps in winter, by more uniform covering of blotches on breast and belly and spotting on wing linings. Juvenile has narrow bars across tail and is finely streaked below on white underparts. In adult, irides dark brown , cere and feet yellow; soft parts paler in juvenile.

Buteo oreophilus Hartert and Neumann, 1914 [type locality = Koritscha, Ethiopia].

Monotypic.

Closely related to Common Buzzard (Buteo buteo), along with Eastern Buzzard (B. japonicus) and Himalayan Buzzard (B. refectus), and perhaps Madagascar Buzzard (B. brachypterus), and possibly also to Red-tailed Hawk (B. jamaicensis) and Rufous-tailed Hawk (B. ventralis); in one major genetic study, however, association with B. brachypterus was not supported (3 Kruckenhauser, L., E. Haring, W. Pinsker, M. J. Riesing, H. Winkler, M. Wink, and A. Gamauf (2004). Genetic vs. morphological differentiation of Old World buzzards (genus Buteo, Accipitridae). Zoologica Scripta 33(3):197–211. Close ). Has been considered conspecific with B. buteo, genetic differentiation from which difficult to establish (3 Kruckenhauser, L., E. Haring, W. Pinsker, M. J. Riesing, H. Winkler, M. Wink, and A. Gamauf (2004). Genetic vs. morphological differentiation of Old World buzzards (genus Buteo, Accipitridae). Zoologica Scripta 33(3):197–211. Close ). Until recently, considered conspecific with Forest Buzzard (Buteo trizonatus) of southern Africa, which differs from present species in having unstreaked vs. streaked chin and throat (2); plain white band across breast vs. all-streaked breast (2); weaker (nonexistent) terminal tailband (2); plain white vs. dark-spotted undertail coverts (ns[1]); rufous tones in various parts of plumage including back and tail, tarsal feathering and wing-coverts (ns[1]); slightly smaller size (effect size for bill −1.94, score 1) (see further published details [3 Kruckenhauser, L., E. Haring, W. Pinsker, M. J. Riesing, H. Winkler, M. Wink, and A. Gamauf (2004). Genetic vs. morphological differentiation of Old World buzzards (genus Buteo, Accipitridae). Zoologica Scripta 33(3):197–211. Close , 4 Clark, W. S. (2007). Taxonomic status of the Forest Buzzard Buteo oreophilus trizonatus. Ostrich 78(1):101–104. Close ]).

Highlands of Ethiopia and south, patchily, to eastern Democratic Republic of Congo, Burundi, Tanzania, and Malawi.

Frequents extensive montane forest , mainly from 2,000–3,800 m, though occasionally up to at least 4,500 m (2 Ferguson-Lees, J., and D. A. Christie (2001). Raptors of the World. Christopher Helm, London, UK. Close ) and down to ~900–1,200 m (5 Romdal, T. S. (2001). Altitudinal distribution and abundance patterns of bird species in the Eastern Arc Mountains, Tanzania. Scopus 21:35–54. Close ). In montane zones in Ethiopia and Democratic Republic of the Congo, occurs especially in Hagenia and Hypericum woodlands (6 Brown, L. H., E. K. Urban, and K. Newman (1982). The Birds of Africa. Volume 1. Academic Press, London, UK and New York, USA. Close ). Sometimes hunts or soars over grassland or moorland habitats near forest cover (2 Ferguson-Lees, J., and D. A. Christie (2001). Raptors of the World. Christopher Helm, London, UK. Close ).

Considered sedentary, with no evidence for elevational movements among seasons (7 Burgess, N. D., and C. O. F. Mlingwa (2000). Evidence for altitudinal migration of forest birds between montane Eastern Arc and lowland forests in East Africa. Ostrich 71(1–2):184–190. Close ).

Little information. Reported to take small mammals (including bats [8 Carswell, M., D. Pomeroy, J. Reynolds, and H. Tushabe (2005). The Bird Atlas of Uganda. British Ornithologists’ Club and British Ornithologists' Union, Oxford, UK. Close ]), reptiles, birds, and insects. On Mt. Kilimanjaro, Tanzania, observed eating eggs from nest of Rameron Pigeon (Columba arquatrix) (9 Grimshaw, J. M. (1995). Birds of prey and owls of the western and northern slopes of Mt Kilimanjaro, Tanzania. Scopus 19(1): 27–37. Close ). Hunts from perch within forest, often on the edge overlooking open habitat; drops onto prey on the ground below or snatches it from low foliage.

Vocal Development

No information.

Vocal Array

The vocalizations of this species have not been studied in detail. Many raptors are particularly or exclusively vocal around the nest, but no information has been published of such nest observations. We suspect that vocal array is more extensive than the following, but nevertheless these are the main calls which can be hard throughout the year:

Peeeeow. Main call is a loud plaintive mewing scream, similar to Common Buzzard (Buteo buteo). Typical duration of call note ⁓0.7‒0.8 s. Pitch initially shows a steep increase after which gradually decreases. Fundamental frequency reaches a maximum of ⁓1.4 kHz, but first harmonic is loudest in amplitude. Occasionally call notes have a wavering frequency modulation. Repeated with irregular long intervals, occasionally in faster series (e.g., when taking off).

Kyew. A much shorter version of previous vocalization is often given in a fast series. Lacks the plaintive sound quality of longer calls, more like short yelps.

Geographic Variation

Has not been studied in detail, but no indication of any geographic variation. Differentiation even within the genus Buteo seems quite limited, with Peeeeow call main vocalization for many Buteo species. Sometimes described as more piercing and higher-pitched than migrant Common (Steppe) Buzzard (B. b. vulpinus) (6 Brown, L. H., E. K. Urban, and K. Newman (1982). The Birds of Africa. Volume 1. Academic Press, London, UK and New York, USA. Close , 2 Ferguson-Lees, J., and D. A. Christie (2001). Raptors of the World. Christopher Helm, London, UK. Close ), but available sound recordings do not seem to support such statement.

Phenology

Quite vocal all year, but especially during the breeding season.

Daily Pattern of Vocalizing

Mostly calls when soaring, requiring thermal lift, and thus typically heard from mid to late morning, and in late afternoon.

Places of Vocalizing

Peeeeow call is typically heard in flight, while soaring above its territory of highland forest, but individuals also utter this call while perched in a tree.

Sex Differences

Little information. Pairs do soar together while calling both.

Social Content and Presumed Functions of Vocalizations

While vocal array seems limited at first sight, subtle differences of Peeeeow call may be linked to different functions, analogous to Common Buzzard. However, no such study has been performed for this species. The Peeeeow advertisement call is typically uttered while soaring above its territory. At the onset of the breeding period, pairs indulge in breeding displays (10 Redman, N., T. Stevenson, and J. Fanshawe (2011). Birds of the Horn of Africa: Ethiopia, Eritrea, Djibouti, Somalia and Socotra. 2nd edition. Christopher Helm, London, United Kingdom. Close ) that involve calling while performing undulating flights (6 Brown, L. H., E. K. Urban, and K. Newman (1982). The Birds of Africa. Volume 1. Academic Press, London, UK and New York, USA. Close ); see Breeding. Outside the breeding period, Peeeeow call presumably has a more communicative function between members of a pair. Kyew call is typically associated with distress or alarm.

None documented.

Little published information. Nesting reported from March–September in Uganda (2 Ferguson-Lees, J., and D. A. Christie (2001). Raptors of the World. Christopher Helm, London, UK. Close , 8 Carswell, M., D. Pomeroy, J. Reynolds, and H. Tushabe (2005). The Bird Atlas of Uganda. British Ornithologists’ Club and British Ornithologists' Union, Oxford, UK. Close ), and March–June and September–December in Kenya (2 Ferguson-Lees, J., and D. A. Christie (2001). Raptors of the World. Christopher Helm, London, UK. Close ). At the onset of the breeding period, pairs perform display flights (10 Redman, N., T. Stevenson, and J. Fanshawe (2011). Birds of the Horn of Africa: Ethiopia, Eritrea, Djibouti, Somalia and Socotra. 2nd edition. Christopher Helm, London, United Kingdom. Close ), calling while engaged in undulating flights of plunging dives and upward swoops above forest (6 Brown, L. H., E. K. Urban, and K. Newman (1982). The Birds of Africa. Volume 1. Academic Press, London, UK and New York, USA. Close ). Builds a large stick platform 6–30 m up in forest tree, lined with green foliage. Clutch is usually 2 eggs (occasionally 3); incubation reportedly by female only (6 Brown, L. H., E. K. Urban, and K. Newman (1982). The Birds of Africa. Volume 1. Academic Press, London, UK and New York, USA. Close ). Chicks have grayish white down; fledging at ~50 days; post-fledging period up to 130 days.

Currently considered Near Threatened. CITES II. Vulnerable because of limited and patchy distribution of forest habitat, which is subjected to cutting and other human-caused degradation. Not known to be affected by pesticides.

The global population of Mountain Buzzard is estimated to range from 670–6,700 individuals, and is believed to be decreasing (1 BirdLife International (2021). Species factsheet: Buteo oreophilus. Close ). This species ranges from uncommon to moderately common within montane forest zones (11 Zimmerman, D. A., D. A. Turner, and D. J. Pearson (1996). Birds of Kenya and Northern Tanzania. Christopher Helm, London, United Kingdom. Close , 12 Stevenson, T., and J. Fanshawe (2002). Field Guide to the Birds of East Africa: Kenya, Tanzania, Uganda, Rwanda, Burundi. T. & A. D. Poyser, London, UK. Close , 10 Redman, N., T. Stevenson, and J. Fanshawe (2011). Birds of the Horn of Africa: Ethiopia, Eritrea, Djibouti, Somalia and Socotra. 2nd edition. Christopher Helm, London, United Kingdom. Close ).