Plumages, Molts, and Structure

Ethiopian Boubou 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 outermost r6 on each side of the tail). Little or no geographic variation in plumages has been reported (see Systematics). The following plumage descriptions are based on those of Fry et al. (1 Fry, C.H., Keith, S. and Urban, E.K. (2000). The Birds of Africa. Vol. 6. Academic Press, London. Close ), Harris and Franklin (2 Harris, T., and K. Franklin (2000). Shrikes & Bush-shrikes Including Wood-shrikes, Helmet-shrikes, Flycatcher-shrikes, Philentomas, Batises and Wattle-eyes. A. & C. Black, London, UK. Close ), Nguembock et al. (3 Nguembock, B., J. Fjeldså, A. Couloux, and É. Pasquet (2008). Phylogeny of Laniarius: molecular data reveal L. liberatus synonymous with L. erlangeri and “plumage coloration” as unreliable morphological characters for defining species and species groups. Molecular Phylogenetics and Evolution 48(2):396–407. Close ), Fry (4 Fry, H. (2009). Family Malaconotidae (Bush-shrikes). In Handbook of the Birds of the World, Volume 14 (J. del Hoyo, A. Elliott, J. Sargatal, D. A. Christie, and E. de Juana, Editors). Lynx Edicions, Barcelona, Spain. pp. 50-122. Close ), and Finch et al. (5 Finch, B. W., N. D. Hunter, I. Winkelmann, K. Manzano-Vargas, P. Njoroge, J. Fjeldså, and M. T. P. Gilbert (2016). Redefining the taxonomy of the all-black and pied boubous (Laniarius spp.) in coastal Kenya and Somalia. Bulletin of the British Ornithologists’ Club 136(2):74–85. Close ); see Lefranc (6 Lefranc, N. (2022). Shrikes of the World. Bloomsbury Publishing, London, U.K. Close ) and Pyle (7 Pyle, P. (2022). Identification Guide to North American Birds. Part I, Second Edition. Slate Creek Press, Forest Knolls, CA, USA. Close ) for molt and age criteria in shrikes (Lannidae) which appear to be similar to those of bush-shrikes. See Molts for molt and plumage terminology. Sexes appear similar in plumage; definitive appearance is attained following the Second Prebasic Molt. Timing of plumages generally may revolve around a peak breeding season of April-June, but fresh and worn examples of all plumages possibly may be found at other times of the year (see Breeding: Phenology).

Natal Down

Nestlings are likely to hatch naked, blind with pinkish-brown skin and mouth spots. Otherwise, no published information on natal down in Ethiopian Boubou.

Juvenile (First Basic) Plumage

Present for up to 1-2 mo following fledging, perhaps primarily in June-September in most populations. Not specifically described, but appears to be similar to that of the formerly conspecific Tropical Boubou (Laniarius major)(see, e.g., ML209817491) in being browner than later plumages; most upperpart feathers tipped tawny-buff; underparts dull whitish with breast and flanks pale brown with some dusky barring (see right-hand image under Formative Plumage, below). Juvenile body feathering is more filamentous due to lower barb densities and juvenile remiges and rectrices are relatively narrow and tapered at the tips, the outer 1-2 pairs (among r5-r6) with wider white tips. Juvenile upperwing coverts are weak and can be marked dusky (white median and greater coverts) or fringed pale (dark secondary and primary coverts). See also Bare Parts for iris-color changes by age.

Formative Plumage

Likely present from 2-10 months following fledging, perhaps primarily in August (when fresh) to May (when worn) in most populations. Similar to Definitive Basic Plumage but upperpart body feathering averages duller, browner, and less glossy. Formative Plumage best distinguished by molt limits among the upperwing coverts (and probably often 1-3 tertials) along with condition of retained juvenile flight feathers. Scapulars and a few to all inner secondary coverts replaced and blackish, contrasting distinctly with worn and brownish or fringed pale, retained juvenile outer secondary coverts (when present), primary coverts, alula, and remiges; the white juvenile coverts can be marked dusky and the dark coverts can be fringed pale. Beware birds in worn Definitive Basic Plumage can also show contrasts between blacker scapulars and browner wing coverts and remiges. One to 3 tertials (s8, s8-s9, or s7-s9) may also be replacedin those birds that replace most or all secondary coverts, contrasting with worn brown outer secondaries. Retained juvenile outer primaries and rectrices are relatively narrow, tapered or rounded at the tips, and abraded when worn, the outer 1-2 rectrices (r5-r6) with wider white tips (than basic feathers) when not worn off. See also Bare Parts for iris-color changes useful for aging.

Definitive Basic Plumage

Likely present from 1-10 months following breeding, perhaps primarily in July (when fresh) to May (when worn) in most populations. Upperparts including crown and sides of head extending below eye primarily glossy bluish black; the feathers of the lower back and rump are filamentous grayish or whitish with white subapical mark and black ends, overlying glossy bluish-black uppertail coverts. Filamentous back feathers are characteristic of family Malaconotidae but in Ethiopian Boubou this feature is usually obscured in the field. The tail is black, slightly glossy, and the outer feathers are sometimes tipped thinly with white; upperwing coverts and remiges mostly black (but becoming brownish when worn), slightly glossy when fresh but less so than the upperparts, the median coverts white distally and the innermost greater coverts with white outer webs. The sides of the head and neck (below the black) and entire underparts white, the breast and flanks tinged salmon-pink when fresh; underwing coverts white, axillaries white with pink tinge.

Definitive Basic Plumage is best separated form Formative Plumage by averaging glossier and blacker (bluish black, less brownish) upperparts. The upperwing secondary coverts, primary coverts, alula, and remiges are uniform in coloration and wear, without molt limits (but beware they become tinged brownish with wear and contrast with the glossier back feathers). The outer primaries and rectrices are broader, relatively fresher, and more truncate at the tips. See also Bare Parts for iris-color changes useful for aging.

Molt and plumage terminology follows Humphrey and Parkes (8 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. (9 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 current breeding seasons, locations, or time of the year, the latter generally referred to as “life-cycle” molt terminology (10 Jenni, L., and R. Winkler (2020). Moult and Ageing of European Passerines. Second edition. Bloomsbury, London, United Kingdom. Close ; see also 11 Pyle, P. (2022). Defining moults in migratory birds: a sequence-based approach. Journal of Avian Biology 2022(5):e02958. Close , 12 Kiat, Y. (2022). Moult terminology: Let’s make it simpler! Ibis 165(2):697-703 Close ). Prebasic molts often correspond to “post-breeding“ or “post-nuptial“ molts and preformative molts often correspond to “post-juvenile“ molts; however, there is often a lack of correspondence due to different bases of definition, especially among birds that reside at tropical latitudes. 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 little published information on the molts of Ethiopian Boubou but based on examination of Macaulay Library images, it shows a Complex Basic Molt Strategy, similar to that shown by many shrikes (6 Lefranc, N. (2022). Shrikes of the World. Bloomsbury Publishing, London, U.K. Close , 7 Pyle, P. (2022). Identification Guide to North American Birds. Part I, Second Edition. Slate Creek Press, Forest Knolls, CA, USA. Close ), with a partial preformative molt and complete prebasic molts but no prealternate molts. Based on patterns of wear, molt appears to occur primarily 1–3 months following fledging and immediately following breeding, as is typical of passerines. Timing of molts may generally follow the peak breeding season of April-June (see Breeding: Phenology) but it may also be found throughout much of the year at the population level.

Prejuvenile (First Prebasic) Molt

The Prejuvenile Molt occurs in the nest, perhaps primarily in April-July. There is little to no information on this molt in Ethiopian Boubou.

Preformative Molt

Partial, likely within 1–3 months of fledging at the individual level, perhaps primarily in May-September. Based on Macaulay Library images (see for example those under Formative Plumage), the Preformative Molt is partial, including body feathering, some inner to all upperwing coverts (juvenile outer median coverts sometimes and greater coverts more often can be retained), and likely often 1–3 tertials (as found in the formerly conspecific Tropical Boubou (Laniarius major); cf ML205988761). and perhaps occasionally also 1–2 central rectrices, but no primary coverts, primaries, or outer secondaries or rectrices. This is a typical extent for the Preformative Molt among passerines (10 Jenni, L., and R. Winkler (2020). Moult and Ageing of European Passerines. Second edition. Bloomsbury, London, United Kingdom. Close , 7 Pyle, P. (2022). Identification Guide to North American Birds. Part I, Second Edition. Slate Creek Press, Forest Knolls, CA, USA. Close ).

Definitive Prebasic Molt

Complete, likely within 1–4 months of completion of breeding at the individual level (as in Tropical Boubou; 2 Harris, T., and K. Franklin (2000). Shrikes & Bush-shrikes Including Wood-shrikes, Helmet-shrikes, Flycatcher-shrikes, Philentomas, Batises and Wattle-eyes. A. & C. Black, London, UK. Close ) perhaps primarily in May-October. As in most passerines and shrikes (10 Jenni, L., and R. Winkler (2020). Moult and Ageing of European Passerines. Second edition. Bloomsbury, London, United Kingdom. Close , 7 Pyle, P. (2022). Identification Guide to North American Birds. Part I, Second Edition. Slate Creek Press, Forest Knolls, CA, USA. Close ), primaries appear to be replaced distally (from innermost p1 to outermost p10), secondaries bilaterally from the second tertial (s8) and proximally from the innermost secondary (s1), and rectrices from the central feather (r1) distally on each side of the tail, with some variation in sequence to be expected. Molt may be protracted or suspended in some individuals (e.g., see middle image below); suspension for breeding can occur regularly in tropical passerines (13 Pyle, P., K. Tranquillo, K. Kayano, and N. Arcilla (2016). Molt patterns, age criteria, and molt-breeding dynamics in American Samoan landbirds. Wilson Journal of Ornithology 128:56–69. Close ).

Descriptions of bare part coloration comes from Harris and Franklin (2 Harris, T., and K. Franklin (2000). Shrikes & Bush-shrikes Including Wood-shrikes, Helmet-shrikes, Flycatcher-shrikes, Philentomas, Batises and Wattle-eyes. A. & C. Black, London, UK. Close ) and examination of Macaulay Library images for age-related differences in iris color.

Bill and Gape

The bill in is stout and strong, with a slight hook at the tip, as is typical of family Malaconotidae (as well as the closely related Laniidae). In adults it is jet black; in nestlings and juveniles, it can be horn-colored or changing to blackish. The inside of the mouth and gape of nestlings is likely orange-yellow, and the gape swollen, as in the formerly conspecific Tropical Boubou (Laniarius major) (e.g., see ML209817341).

Iris and Facial Skin

In adults, the iris is deep red-brown to reddish. In juveniles, it is duller and brown to sepia brown (or washed grayish), becoming reddish-brown during the first year. The orbital skin is black.

Tarsi and Toes

In adults, the legs and feet are pale grayish, bluish slate, or slaty and the claws are black. It may be paler and washed pinkish in nestlings.

Linear Measurement

Unknown in Ethiopian Boubou; the information below is bases on measurements of Tropical Boubou for all taxa (including Ethiopian Boubou) from Harris and Franklin (2 Harris, T., and K. Franklin (2000). Shrikes & Bush-shrikes Including Wood-shrikes, Helmet-shrikes, Flycatcher-shrikes, Philentomas, Batises and Wattle-eyes. A. & C. Black, London, UK. Close ) with both sexes combined.

Overall Length

19.5–25 cm.

Wing Length

89–102 mm (mean 97.6 mm, n = 14).

Tail Length

90–102.6 mm (mean 96.3 mm, n = 14).

Bill Length

20.5–23.5 mm (mean 22 mm, n = 14).

Tarsus Length

29.5–34 mm (mean 32 mm, n = 14).