Plumages, Molts, and Structure

The African Tailorbird has 10 primaries (numbered distally, from innermost p1 to outermost p10, the p10 reduced in length), 9 secondaries (numbered proximally, from outermost s1 to innermost s9, and including 3 tertials, s7‒s9 in passerines), and 12 rectrices (numbered distally, from innermost r1 to to outermost r6 on each side of the tail). The following plumage descriptions are based on those of Slater and Moreau (1 Sclater, W. L., and R. E. Moreau (1933). Taxonomic and field notes on some birds of North-Eastern Tanganyika Territory. Parts 3–5. Ibis 75(1):1–33, 75(2):187–219, 75(3):399–440. Close ) and Irwin (1 Sclater, W. L., and R. E. Moreau (1933). Taxonomic and field notes on some birds of North-Eastern Tanganyika Territory. Parts 3–5. Ibis 75(1):1–33, 75(2):187–219, 75(3):399–440. Close ), along with examination of images in Macaulay Library. See Systematics for slight geographic variation in plumage and see Molts for molt and plumage terminology. Definitive appearance may be attained following the preformative molt (if complete) or following the second prebasic molt (see below); study is needed. Sexes similar in all plumages.

Natal Down

Information needed.

Juvenile (First Basic) Plumage

Upperparts gray, head and neck a warmer color, upperparts reportedly can be olive yellow and belly is slightly washed with yellow. Some rust coloration may be present on the head. Juvenile feathering appears to be filamentous due to lower barb densities in body feathers (see image below).

Formative Plumage

Examination of images in Macaulay Library suggests that the preformative molt may be partial in at least some birds, including some but not all wing coverts and the central but not other rectrices, allowing formative plumage to be identified by molt limits in these tracts (see images, below). Plumage coloration may also average slightly duller than definitive basic plumage, and iris color appears to be browner (see Bare Parts). Confirmation of these criteria is needed.

Definitive Basic Plumage

Crown, auriculars, and sides of neck are rufous-chestnut, brightest on forehead and around the eyes. Elongated occipital feathers can be present in the crown, perhaps forming slight crest for display purposes. Mantle and back are drab olive-brown becoming greener on the upper wings. The tail is dark gray with a reddish wash. The throat is paler, off-white in the center. The breast is gray, shading into warm buff on flanks and undertail coverts, and with the belly whitish; thighs are dark chestnut and underwing coverts white.

Upperwing coverts and wing feathers uniformly basic following complete molt. Basic primaries, secondaries and rectrices appear to be broader and more squared than juvenile feathers, and lack of molt limits appears to allow separation of definitive basic from formative plumage (see images), but confirmation is needed.

Molt and plumage terminology follows Humphrey and Parkes (2 Humphrey, P. S., and K. C. Parkes (1959). An approach to the study of molts and plumages. Auk 76(1):1–31. Close ), as modified by Howell et al. (3 Howell, S. N. G., C. Corben, P. Pyle, and D. I. Rogers (2003). The first basic problem: a review of molt and plumage homologies. Condor 105:635–653. Close ). Under this nomenclature, terminology is based on evolution of molts along ancestral lineages of birds from ecdysis (molts) of reptiles, rather than on molts relative to breeding season, location, or time of the year, the latter generally referred to as “life-cycle” molt terminology (4 Jenni, L., and R. Winkler (2020). Moult and Ageing of European Passerines. Second edition. Bloomsbury, London, United Kingdom. Close ; see also 5 Pyle, P. (2022). Defining moults in migratory birds: A sequence-based approach. Journal of Avian Biology e02958. Close , 6 Kiat, Y. 2022. Moult terminology: Let’s make it simpler! Ibis. Close ). In north-temperate latitudes and among resident passerines, the Humphrey-Parkes and life-cycle nomenclatures correspond to some extent, but terms are not synonyms due to the differing bases of definition. Prebasic molts often correspond to “post-breeding“ or “post-nuptial“ molts, and preformative molts often correspond to “post-juvenile“ molts. The terms prejuvenile molt and juvenile plumage are preserved under Humphrey-Parkes terminology (considered synonyms of first prebasic molt and first basic plumage, respectively) and the former terms do correspond with those in life-cycle terminology.

There is very little information on molt strategies and timing of the African Tailorbird. It likely shows a Complex Basic Molt Strategy (see 3 Howell, S. N. G., C. Corben, P. Pyle, and D. I. Rogers (2003). The first basic problem: a review of molt and plumage homologies. Condor 105:635–653. Close ), with preformative and prebasic molts but no prealternate molts, as in other species of Cisticolidae. Study is needed on the extent of the preformative molt, which is reported as usually complete but sometimes of variable extent in Cisticolidae (7 Gauci, C., and J. Sultana (1981). The moult of the Fan-tailed Warbler. Bird Study 28(2):77‒86. Close , 8 Higgins, P. J., J. M. Peter, and S. J. Cowling, Editors (2006). Handbook of Australian, New Zealand and Antarctic Birds. Volume 7, Part B: Dunnock to Starlings. Oxford University Press, Melbourne, Australia. Close , 9 Blasco-Zumeta, J., and G.-M. Heinze (2022). Zitting Cisticola. Identification Guide of Birds of Aragón and Continental Spain. Aranzadi Sciences Society, Donostia-San Sebastián, Spain. Close ). Examination of Macaulay Library images (see those under Plumages) suggests that the preformative molt may be partial and include some or up to all upperwing coverts, up to 2‒3 tertials, and sometimes the central rectrices, an extent which is common in this molt in passerrines (4 Jenni, L., and R. Winkler (2020). Moult and Ageing of European Passerines. Second edition. Bloomsbury, London, United Kingdom. Close , 10 Pyle, P. (2022). Identification Guide to North American Birds. Part I, Second Edition. Slate Creek Press, Forest Knolls, CA, USA. Close ). As in other species of Cisticolidae, primaries are likely replaced distally (from p1 to p10), secondaries are replaced bidirectionally from the middle tertial (s8) and proximally from s1 such that the last feather replaced is s5 or s6, and rectrices are generally replaced distally from the central r1 to the outer r6 on each side of the tail, with some variation occurring.

Bill and Gape

In juveniles, the culmen is gray, with edges of upper mandible and entire lower mandible yellow to yellowish horn, and the gape is yellow (1 Sclater, W. L., and R. E. Moreau (1933). Taxonomic and field notes on some birds of North-Eastern Tanganyika Territory. Parts 3–5. Ibis 75(1):1–33, 75(2):187–219, 75(3):399–440. Close , 11 Irwin, M. P. S. (1997). African Tailorbird (Artisornis metopias). In The Birds of Africa. Volume V (E. K. Urban, C. H. Fry, and S. Keith, Editors), Academic Press, London, United Kingdom. pp. 291–292. Close ). In adults, the bill is blackish.

Iris and Facial Skin

Iris darkish brown in juveniles but appears to become reddish brown during the first year and tinged orange in adults.

Tarsi and Toes

Legs and feet reddish-brown.

Linear Measurements

West Usambara Mountains, Tanzania

Mean wing length, unsexed 49.1 mm (47.2, 51.0, n = 2) (12 van der Willigen, T. A., and J. C. Lovett (Editors) (1981). Report of the Oxford Expedition to Tanzania 1979. Unpublished report. Close ).

Mean wing length, male 48.0 mm (range 47–50, n = 5) (13 Ripley, S. D., and G. Heinrich (1966). Comments on the avifauna of Tanzania I. Postilla 96:1–45. Close ).

Wing length, female 44.0 mm (n = 1) (13 Ripley, S. D., and G. Heinrich (1966). Comments on the avifauna of Tanzania I. Postilla 96:1–45. Close ).

Mean wing length, juvenile female 45.0 mm (45, 45, n = 2) (13 Ripley, S. D., and G. Heinrich (1966). Comments on the avifauna of Tanzania I. Postilla 96:1–45. Close ).

Uluguru Mountains, Tanzania

Mean wing length, male 47.5 mm (46, 49, n = 2) (13 Ripley, S. D., and G. Heinrich (1966). Comments on the avifauna of Tanzania I. Postilla 96:1–45. Close ).

Mean wing length, female 44.3 mm (range 43–46, n = 3) (13 Ripley, S. D., and G. Heinrich (1966). Comments on the avifauna of Tanzania I. Postilla 96:1–45. Close ).

Udzungwa Mountains, Tanzania

Mean wing length, unsexed 46.5 mm (range 44–49, n = 6) (FPJ, unpublished data).

Wing length, female 46 mm (n = 1) (13 Ripley, S. D., and G. Heinrich (1966). Comments on the avifauna of Tanzania I. Postilla 96:1–45. Close ).

Mdando Forest, Tanzania

Wing length, male 47 mm (n = 1) (13 Ripley, S. D., and G. Heinrich (1966). Comments on the avifauna of Tanzania I. Postilla 96:1–45. Close ).

Mount Chitagal, Mozambique

Mean wing length, unsexed 49 mm (47, 51, n = 2) (14 Jones, S. E. I., J. K. Clause, L. Geeraert, G. A. Jamie, E. Sumbane, T. van Berkel, and M. Jocque (2017). The Njesi Plateau Expedition: A biological assessment of Mt Chitagal, Mt Sanga and the Njesi Plateau in Niassa Province, Mozambique. BES Report 6.3. Biodiversity Inventory for Conservation, Glabbeek, Belgium. Close ).

Njesi Plateau, Mozambique

Mean wing length, unsexed 49.3 mm (range 47–52, n = 3) (14 Jones, S. E. I., J. K. Clause, L. Geeraert, G. A. Jamie, E. Sumbane, T. van Berkel, and M. Jocque (2017). The Njesi Plateau Expedition: A biological assessment of Mt Chitagal, Mt Sanga and the Njesi Plateau in Niassa Province, Mozambique. BES Report 6.3. Biodiversity Inventory for Conservation, Glabbeek, Belgium. Close ).

Mass

West Usambara Mountains, Tanzania

Mass, unsexed 8.8 g (n = 1) (12 van der Willigen, T. A., and J. C. Lovett (Editors) (1981). Report of the Oxford Expedition to Tanzania 1979. Unpublished report. Close ).

Mean mass, male 9.0 g (8.5–9.5, n = 5) (13 Ripley, S. D., and G. Heinrich (1966). Comments on the avifauna of Tanzania I. Postilla 96:1–45. Close ).

Mass, female 9.0 g (n = 1) (13 Ripley, S. D., and G. Heinrich (1966). Comments on the avifauna of Tanzania I. Postilla 96:1–45. Close ).

Uluguru Mountains, Tanzania

Mass, male 9.5 g (n = 1) (13 Ripley, S. D., and G. Heinrich (1966). Comments on the avifauna of Tanzania I. Postilla 96:1–45. Close ).

Mass, female 9.5 g (n = 1) (13 Ripley, S. D., and G. Heinrich (1966). Comments on the avifauna of Tanzania I. Postilla 96:1–45. Close ).

Udzungwa Mountains, Tanzania

Mean mass, unsexed 8.8 g (range 8.0–10.0, n = 6) (FPJ, unpublished data).

Mass, female 9.0 g (n = 1) (13 Ripley, S. D., and G. Heinrich (1966). Comments on the avifauna of Tanzania I. Postilla 96:1–45. Close ).

Mount Chitagal, Mozambique

Mean mass, unsexed 8.7 g (range 8.3, 9.1, n = 2) (14 Jones, S. E. I., J. K. Clause, L. Geeraert, G. A. Jamie, E. Sumbane, T. van Berkel, and M. Jocque (2017). The Njesi Plateau Expedition: A biological assessment of Mt Chitagal, Mt Sanga and the Njesi Plateau in Niassa Province, Mozambique. BES Report 6.3. Biodiversity Inventory for Conservation, Glabbeek, Belgium. Close ).

Njesi Plateau, Mozambique

Mean mass, unsexed 8.7 g (range 8.0–9.2, n = 3) (14 Jones, S. E. I., J. K. Clause, L. Geeraert, G. A. Jamie, E. Sumbane, T. van Berkel, and M. Jocque (2017). The Njesi Plateau Expedition: A biological assessment of Mt Chitagal, Mt Sanga and the Njesi Plateau in Niassa Province, Mozambique. BES Report 6.3. Biodiversity Inventory for Conservation, Glabbeek, Belgium. Close ).