The Development of Senegal Coucal Nestlings

Steyn, Peter

doi:10.1080/00306525.1972.9632576

Cited by 8 publications

(6 citation statements)

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“…So far, there has been only little information on the breeding biology of coucals in general [14,51,52] and the African black coucal in particular [57]. In this paper we gave a description of the nests, eggs and nestlings and reported provisioning and growth rates as well as nesting success of black coucals.…”

Section: Discussionmentioning

confidence: 96%

“…With the black nestlings huddled together the nest looks as if it was empty with just some dry ''grasses'' (the trichoptiles) covering the ground (W. Goymann, personal observations). (3) If disturbed the nestlings defecate a black and very unpleasant smelling liquid that is not covered by a faecal sac (see also [57] tarsus growth (mm/day) and [51] for another coucal species). Normally, coucal nestlings deposit their excrements at the nest entrance in a faecal sac which is picked up and carried away by the male (W. Goymann, personal observations).…”

Section: Discussionmentioning

confidence: 99%

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Breeding biology, sexually dimorphic development and nestling testosterone concentrations of the classically polyandrous African black coucal, Centropus grillii

2005

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Many internal and environmental factors influence the growth of birds. Here we ask whether the reversed sexual dimorphism in the classically polyandrous black coucal is reflected in differential growth and fledging parameters of females and males. We also investigate whether androgen concentrations were higher in females than males during the nestling development, thus, providing a potential mechanism for the 'behavioural masculinization' of female black coucals. Furthermore, we give a detailed description of the breeding biology of this little studied and unusual bird species. Black coucal eggs were smaller, and the incubation and nestling periods were shorter than expected for a bird of that size. In absolute terms female black coucals grew faster than males and left the nest with a larger body mass, suggesting that females are the more expensive sex to rear in this species. However, in relation to adult body size, females grew slower and reached a smaller proportion of their adult body size than males upon fledging. 'Testosterone' concentrations were significantly higher in male than in female nestlings, hence not supporting a role of circulating androgens in the ontogeny of sex-role reversal. To our knowledge, the early sex differences in 'testosterone' levels of black coucals represent the first evidence that such differences exist in nestlings of altricial birds. We present anecdotal evidence that the differences may be related to an early maturation of male reproductive organs in black coucals. In females but not in males, 'testosterone' concentrations were related to structural growth rates.

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Section: Discussionmentioning

confidence: 96%

Section: Discussionmentioning

confidence: 99%

Breeding biology, sexually dimorphic development and nestling testosterone concentrations of the classically polyandrous African black coucal, Centropus grillii

2005

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“…In addition, they make a snakelike hissing sound and defecate a foul-smelling liquid if handled or threatened. These are probably anti-predator devices (Van Someren, 1956;Frauca, 1967;Vernon, 1971;Steyn, 1972;Frith, 1975;Taplin & Beurteaux, 1992).…”

Section: I8 I Inrroductionmentioning

confidence: 98%

“…The eggs are usually laid in intervals of several days, incubation starting with the first egg, making the chicks differ markedly in age and size (e.g. Van Someren, 1956;Steyn, 1972;Frith, 1975;Rowan, 1983;Taplin & Beurteaux, 1992).…”

Section: I8 I Inrroductionmentioning

confidence: 99%

Evolution of reversed sex roles, sexual size dimorphism, and mating system in coucals (Centropodidae, Aves)

Andersson

1995

Biological Journal of the Linnean Society

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The evolution of greater male than female parental care remains poorly understood. In birds it is thought to be related to precocial chicks and small clutch size. This review shows, however, that such role reversal has also evolved in a family with altricial young and relatively large clutch size: coucals (Centropodidae, Cuculifonnes). Malcs perform most nest building, incubation, and feeding of young. As predicted by sexual selection theory, coucals have also reversed sexual size dimorphism, females being larger than males in all 12 spc-cies for which size data are available. Most coucals that have been studied are monogamous, but the black coucal Ohlropus g d i i appears to be polyandrous, and males perform almost all parental care, whereas females show more active advertisement behaciour. In this speries, females are about 50% heavier than males. Polyandry in the black coucal seems to be associated with a shift to a habitat with seasonally rich food resources. Difficulties for female coucals of gathering enough resources for producing several clutches of relatively large eggs may favour mainly male parental care. Female sexual competition and resonrce storage, and male foraging economy, may explain why females are larger. Additional field studies are needed to test these hypotheses; the coucals are of great interest to sexual selection and mating systems theory.

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“…This nauseous brown fluid is similar to that of coucals. and further discussion may be found in Steyn (1972).…”

Section: At 9 Dayamentioning

confidence: 98%

Some Notes on the Breeding Biology of the Striped Cuckoo

Steyn¹

1973

Ostrich

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The Development of Senegal Coucal Nestlings

Cited by 8 publications

References 1 publication

Breeding biology, sexually dimorphic development and nestling testosterone concentrations of the classically polyandrous African black coucal, Centropus grillii

Breeding biology, sexually dimorphic development and nestling testosterone concentrations of the classically polyandrous African black coucal, Centropus grillii

Evolution of reversed sex roles, sexual size dimorphism, and mating system in coucals (Centropodidae, Aves)

Some Notes on the Breeding Biology of the Striped Cuckoo

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