Black Crake Zapornia flavirostra Scientific name definitions

19–23 cm; male 78–118 (96·5) g, female 70–110 (81) g; 159 both sexes 69–118 (89·5) g; weight varies greatly during year. Sexes alike. Non-breeding birds have duller red legs and feet. Very similar to <em>Z. olivieri</em> , but upperparts washed olive-chestnut (in the field appearing slaty black, like rest of plumage) as opposed to rich dark brown; bright red orbital ring , legs and feet . Immature paler than adult; upperparts olivaceous brown; throat whitish; head, neck and underparts grey; bare parts duller than in adult. Juvenile entirely brown; bill blackish, changing to darkish green; iris grey to brown, changing to dark red; legs and feet blackish, changing to dull red.

Sub-Saharan Africa from N edge of Sahel zone S (except in desert regions of NE & SW) to Cape. Extralimital breeding record in N Niger (L Arrigui) (1 Taylor, P.B. and van Perlo, B. (1998). Rails. A Guide to the Rails, Crakes, Gallinules and Coots of the World. Pica Press, Robertsbridge, UK. Close ).

Occupies many types of freshwater wetland, normal requirements including moderate vegetation cover and some permanent flooding. Inhabits rank grass, sedges, reedbeds, papyrus , swampy thickets, bushes and other vegetation beside flowing and still waters; occurs in dense undergrowth of boggy clearings in forest; in open areas may occupy grassy marshes. Often found on ponds covered with Nymphaea and other floating vegetation; likes tangled vegetation, in which climbs, roosts and sometimes nests. Very adaptable, and in dry regions will occupy tiny streams with thin cover. Occurs close to human habitation and is quite bold and tolerant of disturbance, emerging to feed some distance from cover. Occurs from sea-level to 3000 m; in Natal, South Africa, most widespread and numerous below 1200 m, rarely recorded above 1800 m.

Worms, molluscs, crustaceans, adult and larval insects, small fish, frog tadpoles and small frogs; also seeds and other parts of water plants. Takes eggs and nestlings, including those of herons; kills small birds caught in mist-nets. Scavenges carcasses of crabs, crayfish and small birds. Often feeds in the open along shorelines, on floating vegetation, in short grass or cultivation, and on dry or burned ground; may venture some distance from cover. Takes food from surface of ground , water and vegetation, and from shallow water; probes into mud and dead vegetation; shifts fallen vegetation to search beneath. Readily perches and feeds on backs of hippopotami (Hippopotamus amphibius); perches on warthogs (Phacochoerus aethiopicus), apparently gleaning ectoparasites. Diurnal; markedly active after rain.

Black Crake is not only the most conspicuous rallid in Africa by being highly visible and having bright-coloured bare parts, it has also a very characteristic and funny-sounding Advertisement call which combines nervous jabbering with low-pitched growls.

Vocal Development

Chicks begging for food make quiet squeaks and tsip calls, and (shared with juveniles) also quiet chee and cheea calls are given (2 Taylor, B., and B. van Perlo (1998). Rails: A Guide to the Rails, Crakes, Gallinules and Coots of the World. Pica Press, Robertsbridge, United Kingdom. Close ). Elsewhere, vocalisations of hatchlings are described as soft mews, gradually becoming louder as the bird grows, to keep contact with tending adult (3 Parker, I.S.C. & Parker, A.C. (2019). Notes on Black Crakes Amaurornis flavirostra 2: Vocalizations, feeding and interactions with other species. Scopus 39:38-43. Close ). Juveniles and immatures join duetting parents, participating in the chorus. On one occasion, a duet was performed by one adult and an immature bird (3 Parker, I.S.C. & Parker, A.C. (2019). Notes on Black Crakes Amaurornis flavirostra 2: Vocalizations, feeding and interactions with other species. Scopus 39:38-43. Close ).

Vocal Array

Advertisement call. This very characteristic 'song' typically is a duet: one bird gives a repeated harsh repeated krraaa or korrrhaaaah (sometimes preceded by mellow low-pitched ventriloquial accelerating note series poo-poo-po-po), the other utters a continuous higher-pitched chatter of nasal notes, with a loose rhythmic pattern including a returning motif kikikiki-ke-reee. Either sex may give either call (2 Taylor, B., and B. van Perlo (1998). Rails: A Guide to the Rails, Crakes, Gallinules and Coots of the World. Pica Press, Robertsbridge, United Kingdom. Close ). The duet often is asynchronous, but may also reach a well-timed synchronous antiphonal cadence. Sometimes other family members join in, and calling birds may crouch in a circle, heads facing inwards. The number of birds effectively vocalising in such a chorus is however unclear. A typical duet has a duration of about 5s and is repeated a few times, but when excited duration and rate of repetition may increase.

Kyew. A series of sharp emphatic downslurred kyew! or pew! notes is given in alarm (note duration ⁓0.12s, dropping from ⁓1700Hz to ⁓800Hz).

Cluck. A variety of different short calls are given, usually as a series of identical notes repeated at stable pace. Such notes may vary from a soft mellow overslurred pu or bup and a gentle kwep to subdued growling grrr notes or sharp tsik notes (2 Taylor, B., and B. van Perlo (1998). Rails: A Guide to the Rails, Crakes, Gallinules and Coots of the World. Pica Press, Robertsbridge, United Kingdom. Close ,3 Parker, I.S.C. & Parker, A.C. (2019). Notes on Black Crakes Amaurornis flavirostra 2: Vocalizations, feeding and interactions with other species. Scopus 39:38-43. Close ). Too little sound recordings are available for a further classification of these calls, and available descriptions don't allow for an unequivocal match with these .

Geographic Variation

Has not been studied in detail, but Advertisement call is very similar over its entire range.

Phenology

Mainly vocal during the breeding period(s), much less so the remainder of the year when they are not territorial (4 Taylor, P. B. (1994). The biology, ecology and conservation of four flufftail species, Sarothrura (Aves: Rallidae). Ph.D. thesis, University of Natal, Pietermaritzburg, South Africa. Close ,2 Taylor, B., and B. van Perlo (1998). Rails: A Guide to the Rails, Crakes, Gallinules and Coots of the World. Pica Press, Robertsbridge, United Kingdom. Close ). However, in Kenya Advertisement call was heard throughout the year with only some increase in vocal activity prior to egg-laying and up to incubation (3 Parker, I.S.C. & Parker, A.C. (2019). Notes on Black Crakes Amaurornis flavirostra 2: Vocalizations, feeding and interactions with other species. Scopus 39:38-43. Close ).

Daily Pattern of Vocalizing

Advertisement call is mainly heard during the morning and in late afternoon.

Places of Vocalizing

Typically vocalises from within the reeds or other aquatic growth in marshy habitat, but much more so than other rails may also venture into the open while vocalising.

Sex Differences

Advertisement call is a duet given by both sexes, and either sex may give either call (2 Taylor, B., and B. van Perlo (1998). Rails: A Guide to the Rails, Crakes, Gallinules and Coots of the World. Pica Press, Robertsbridge, United Kingdom. Close ); possible vocal differences between male and female version have not been documented.

Social Content and Presumed Functions of Vocalizations

Advertisement call is given for territorial defence, and also for reinforcing the bond between the pair and members of a family group (2 Taylor, B., and B. van Perlo (1998). Rails: A Guide to the Rails, Crakes, Gallinules and Coots of the World. Pica Press, Robertsbridge, United Kingdom. Close ). Kyew call is given in alarm, other Cluck calls typically associated with keeping contact.

None documented.

In suitable conditions breeding may occur throughout year, with seasonal peaks in most regions, during or following rains: Senegal and Gambia, Dec–Mar, May–Jun, Aug–Sept; Sierra Leone, Jan, Mar, Oct, Dec; Liberia, Nov; Ghana, Jun, chicks Mar; Nigeria, Jan, Jun, Aug–Nov; Gabon, Mar, Jul; Zaire, almost all months; Sudan (Darfur) Oct; Ethiopia, Apr–Oct; Burundi, Mar; Uganda and W Kenya, all months (peaks Apr, Nov); rest of Kenya and NE Tanzania, all months (peaks Apr–Jun, Oct); rest of Tanzania, Apr, Oct–Nov; Zambia, Nov–Aug (peak Dec–Mar); Malawi, Mar–May, Jul–Sept, Dec; Mozambique, May–Jun; Zimbabwe, all months except May and Jul (peak Jan–Feb); Botswana, Aug–Oct; South Africa, Aug–May (peaks Nov, Jan–Mar). Monogamous; territorial when breeding. Nest a deep, bulky bowl of reeds, rushes, sedges, creepers, grasses or other water plants; placed in vegetation over water with rim 20–50 cm above water, but sometimes floating; also on ground or in grass tussock near water; sometimes up to 3m high in bushes, possibly as protection against sudden flooding. External diameter 10–30cm, depth 8–18cm; cup depth 5–9 cm. Both sexes build, sometimes helped by young of previous broods; male may build extra nests or platforms for roosting. Usually 3 eggs (2–6), laid at daily intervals; 2 females once laid 6 and 4 eggs in same nest; incubation 13–19 days, by both parents, sometimes assisted by immatures; hatching asynchronous; black downy chicks have grey iris, pink bill with black band around centre, and slate legs and feet; chicks leave nest 1–3 days after hatching; fed and cared for by parents, helped by young of previous broods, for at least 3–6 weeks; juvenile plumage attained by 4–6 weeks; young fly at 5–6 weeks; may still beg for food when 2–3 months old; post-juvenile moult occurs between 2 and 4 months of age. Able to breed within 1 year of hatching. Up to 4 broods recorded per season; clutches may be laid when young of previous brood are as little as 3 weeks old. Co-operative breeding normal, young remaining within family group until end of breeding season, sometimes (Natal) until 16 months old.

Not globally threatened (Least Concern). Commonest and most widespread crake in Africa; less secretive than other terrestrial wetland rallids of region, and has well known advertising call, so occurrences are relatively well documented. Common to abundant over most of range, but very localized and rare in drier W & C regions of S Africa. In favourable conditions, population density may be very high in some areas. Must have been affected by loss of wetland habitats, but is under no immediate threat anywhere. Readily occupies artificially created wetlands and temporary habitats.