Cinnyris whytei skye, Bowie, Rauri C. K., Fjeldså, Jon, Kiure, Jacob & Kristensen, Jan Bolding, 2016

Bowie, Rauri C. K., Fjeldså, Jon, Kiure, Jacob & Kristensen, Jan Bolding, 2016, A new member of the greater double-collared sunbird complex (Passeriformes: Nectariniidae) from the Eastern Arc Mountains of Africa, Zootaxa 4175 (1), pp. 23-42 : 38-40

Cinnyris whytei skye , subspecies nov.

Holotype: ZMUC 103.506 , Ad. male, 30 Nov. 2002, Mafwemiro Forest , Rubeho Highlands, Mpwapwa District, Tanzania; collected by J. Bolding Kristensen.

Description of holotype: Entire head and upper parts of body, including lesser and median wing coverts, iridescent Peacock Green (varying from Dark Viridian Green to Yellow Green depending on angle of view) with Dark Mouse Grey basal parts of feathers, upper tail coverts Marine to Azurite Blue; greater wing coverts and remiges Dark Neutral Grey, worn edges appearing lighter; rectrices Bluish Slate Black, outer rectrix with pale grey outer edge and medium grey distal quarter, next rectrix medium grey distal quarter. Upper breast same colour as head, with narrow violet transition to Paris Blue pectoral band (combined 4.4 mm wide), lower breast Scarlet with narrow blue terminus on most feathers (see Figs. 3 & 4 ) (15 mm wide), lateral feathers Lemon Chrome; underparts of body behind the red band between Mouse Grey and Light Mouse Grey, washed Citron Yellow on central belly; underwing-coverts Neutral Grey. Eyes dark brown, bill black, legs and feet black. Bill (tip to nostril) 18.0, wing 60.5, tarsus 15.5, tail 51.3 mm, 9.5 g, testes small, ossification complete.

Paratype: ZMUC 103.507 , Ad. female; 29 Nov. 2002, Mafwemiro Forest , Rubeho Highlands, Mpwapwa District, Tanzania; collected by J. Bolding Kristensen.

Description of paratype: Upper parts from forehead to base of tail Mouse Grey, wing coverts Deep Mouse Grey, remiges Dark Mouse Grey, worn edges paler; rectrices Dull Violet Black, outer Deep Mouse Grey with narrow pallid grey outer and terminal edges. Side of head like upperparts, with Pale Mouse Grey anterior supercilium and blackish lore; lower head-sides, chin, throat and breast Light Mouse Grey with deep grey centers of feathers, sides Light Mouse Grey and belly to vent similar but appearing more olive-buff due to Citron Yellow wash towards the tips of the feathers. Axillaries Barium yellow, under wing-coverts to carpal edge Sea-foam Yellow; breast with darker feather centers. Eyes dark brown, bill black, legs and feet black. Bill 16.3, wing 57.5, tarsus 16.4, tail 44.4 mm, 9.5 g, ovary with no large follicles, skull 90% ossified.

Diagnosis. Resembles other members of the C. afer species complex ( Table 1 ) by its large size and relatively long tail, but differs from C. afer and C. stuhlmanni by having a relatively short and broad bill, and hence is most similar to C. whytei . Males differ from those of C. whytei from Nyika Plateau by having longer tarsi, a broader blue pectoral band ( Table 4 ), and narrow blue feather-tips producing a scaly effect on much of the scarlet pectoral band ( Figs. 3 & 4 ). Within its range, it is readily distinguishable from sympatric C. fuelleborni and C. moreaui , even in the field, by its larger size, more elongated body and tail, lack of olive wing-panel, very broad and dark red breastband (males) and deep grey underparts of the body. Similarly, it differs from C. manoensis of adjacent woodland habitats by size, shape, dark grey belly and, in males, broader breast-band.

Other specimens examined and individual variation. Rubeho Highlands at Chugu Hill: ZMUC 93.056 ad. ³; southwestern edge of Mafwemiro Forest : ZMUC 93.057 ad. ³, ZMUC 94.021 ad. ♀ (skin and partial skeleton), ZMUC 101.719 ad. ³, ZMUC 101.720 ad. ³, ZMUC 101.721 ad. ♀, ZMUC 101.722 ad. ♀, ZMUC 101.723 ad. ♀, ZMUC 101.724 juv. ♀; Ukwiva Forest : ZMUC 93.129 ad. ³.

Individual variation in measurements are reported in Table 4 . The colours vary very little: underparts of males may vary from Mouse Grey over Quaker Drab to Drab, or Benzo Brown; thus, generally very dull greyish. Juvenile resembles adult females, but has a softer plumage and more uniform Mouse Grey to Quaker Drab underparts with little yellow wash on the belly.

Etymology. The scientific name is used as a noun in apposition and acknowledges the contributions of the Skye Foundation to the education of African students. The Skye Foundation was established in 1997 in South Africa by the Zylstra Family Trust to fund postgraduate scholarships, tenable worldwide, and awarded on the basis of academic achievement in any subject.

Distribution. This new sunbird inhabits a narrow ecological zone along the border between humid montane forests and drier woodlands in the rain shadow to the north and west, around 2000 m elevation in the Rubeho and Udzungwa Highlands of western Tanzania ( Fig. 1 ). Localities are: (1) western edge of Kisinga-Rugaro Forest ( Fig. 1 ), which covers a large granitic dome in the highland 20 km east of the town of Iringa (observations 16 February 2008 in forest/grassland mosaics along the western edge of the highland, at 7 ° 48'S, 35 ° 54'E, 2200 m, near the village Kidodi; JF and Michael K. Poulsen; photo documentation). (2) Image Forest Reserve ( Fig. 1 ), south of Ibumu Village at 7 ° 22'–33'S, 36 ° 08'–12'E and around 2000 m (observations by JF, January 2000). (3) Mangalisa Forest ( Fig. 1 ), at 7 ° 07'S – 36 ° 25'E, at c. 2200 m (forest edge and small groups of evergreen trees in adjacent farmland; observations by JF in Dec. 2001; this is a mesa-like highland in the northeastern part of the Great Ruaha Basin, close to the Rubeho Highlands but separated from them by arid lowland habitat. (4) Western edge of Ukwiva Forest ( Fig. 1 ), approximately 7 ° 06'S – 36 ° 40'E at 2100 m, May 2000, and seen August–September 2002 (JK). (5) Mafwemiro Forest ( Fig. 1 ), Mpwapwa District, the top ridge of the northern Rubeho Highlands (collecting on Chugu Hill 6°50'S 36°34'E, 2050 m by JK May 2000; observations and collecting by JF, JBK and JK at the southwestern forest edge at 7 ° 55–58'S, 36 ° 33–34'E, 1700–1900 m, Nov–Dec 2002). Additional populations could be expected to inhabit wooded mountain ridges west of Mafwemiro Forest and isolated mountain tops north of the Ruaha Basin, such as the Wota Mountains; however, skye was not detected during recent collecting trips to the Ukaguru and Kiboriani Mountains near Mpwapwa. Since most ornithological research in the Nyumbanitu and Ndundulu Mountains of the Udzungwa Highland ( Fig. 1 ) has been conducted inside the forest, we do not exclude the possibility that the new sunbird could occur at the western edge of these forests. However, since it has never been seen near Iringa or anywhere further west in Tanzania, such as in well-collected sites in the southern highlands (Kipengere, Poroto and Livingstone Mountains), it seems reasonable to believe that Kisingo-Rugaro represents the range limit towards the southwest.

Ecology. Cinnyris whytei skye of the Iringa Region of Tanzania has been recorded at 1700–2250 m along the eastern and northern parts of large undulating highlands, right on the transition between humid montane forest and the adjacent farm and fallow land extending towards the western sides of forest penetrating the rainshadow. These areas are rather nutrient-poor, with light brown sandy soils. Rainfall is mostly orographic on the eastern scarps, and considerable mist precipitation probably occurs, as the forests in question are often enshrouded at night by carpets of mist. Further, the trees are often covered with "old man’s beard" ( Usnea ), suggesting a strong mist effect.

The sunbird is locally common and easily found, but restricted to the narrow ecological zone on the rainshadow (western) side of the highland forests ( Fig. 7 ; with Bersema abyssinica , Maesa lanceolata , Myrica salicifolia, Nuxia congensta, Parinari excelsa, Podocarpus spp. and Syzygium spp.), in places where groups of small trees ( Myrica salicifolia and Erica [ex- Philippia ]) form a mosaic with montane grassland or in shrubby areas with bracken ( Pteridium ) and brambles ( Rubus ). The vine Tecomaria capensis is generally abundant, and its orange-red flowers seem to be an important food plant. Much of the forest edge habitat is strongly disturbed by human activity (cutting of poles, fires); there are clearings (after past cultivation) inside the forest, and much of the area outside the forest is cultivated. Some observations of the sunbird were thus in small clumps of evergreen trees in farmland within a few hundred meters of the forest edge. In (generally rocky) areas without strong human influence, the typical vegetation is open woodland ( Brachystegia boehmii , B. microphylla , B. spiciformis and Uapaca kirkiana , some Acacia abyssinica ) with tall grasses ( Themeda triandra ).

The ecological zone in which this sunbird has been seen is only a few hundred meters wide, and most observations are right at the forest edge. Because intensive fieldwork has been conducted inside the forest, and considerable time spent in the more open habitats, we believe that the species does not normally occur in dense forest or open habitats, but primarily in the narrow transition between these habitats.

Several other sunbird species occur locally; this large-bodied member of the C. afer complex ( Table 1 ) seems to be narrowly squeezed between C. moreaui / C. fuelleborni in montane forest and C. kilimensis (Shelley) , C. manoensis and C. venusta (Shaw & Nodder) in the more open grass-shrubland mosaic.

Conservation. Cinnyris whytei whytei and C. whytei skye of Malawi and Tanzania, respectively, appear to be fairly common where they occur. However, their restricted and disjunct range seems to suggest a relict distribution.

The generally high human density in rainshadow areas immediately adjacent to humid montane forests ( Fjeldså & Burgess 2008) has resulted in a significant loss of habitat in this zone. Therefore, the mosaic vegetation that characterizes this transition zone under natural conditions has, in most places, been cleared for agriculture or now appears largely as bracken-covered fallow areas, with a sharp boundary towards the remaining (disturbed) forest in Tanzania. Some birds can be found in tiny thickets in the cleared land, but in general there are only a few places left with sufficient areas of habitat to accommodate a significant population. The situation is better for the nominate subspecies in Malawi, where most of the species’ range is restricted to the Nyika Plateau, a large protected area.

Figures

FIGURE 1. Satellite image with forest shaded dark reddish-brown depicting the Rubeho and Udzungwa Highlands of the Eastern Arc Mountains of Tanzania.

FIGURE 3. Drawing of the exact scaling pattern on the breast of three male specimens of the new taxon. The violet-blue colouration is indicated in black, and the scarlet portion of the central breast-band is stippled. Drawing by J. Fjeldså.

FIGURE 4. Depiction of male Cinnyris whytei whytei on the left, and male and female of the new taxon on the right. Males of the new taxon have longer tarsi than male whytei, a broader blue pectoral band, and narrow blue feather-tips produce a scaly effect on much of the scarlet pectoral band. The underparts of males of the new taxon appear more uniform dark greyish, with less buffish tinge on the belly than in whytei. The feather tips of the belly, vent and under wing-coverts are washed pale yellow in adult females of the new taxon, and overall the females are less olivaceous-tinged than those of whytei. Painting by J. Fjeldså.

FIGURE 7. Typical habitat of Cinnyris whytei skye as seen on the western edge of Kisinga-Rugaro Forest in the Udzungwa Highlands. Photo by Michael Køre Poulsen.