Phoeniculus Purpureus Research Articles

Obligate cavity-roosting as a constraint on dispersal of green (red-billed) woodhoopoes: consequences for philopatry and the likelihood of inbreeding.

I studied and compared life histories and dispersal patterns of two populations of green (red-billed) woodhoopoes Phoeniculus purpureus, occupying different habitats (with widely different vegetation, topography and climate), over a period of eight years (258 "flock years") in the eastern Cape Province, South Africa. The birds are obligate cavity-roosters, and I performed an experiment in which several woodhoopoe territories were established after the introduction of artificial roost sites in an area which previously supported no woodhoopoes. The evidence supports the hypothesis that roost cavities are critical in determining the limits to woodhoopoe distribution. Group size, dispersal frequency and dispersal distance differed significantly between the two study sites. I suggest that where cavities are in short supply and unevenly distributed, long-distance scouting forays are undertaken at a high probability of not finding a safe roost site to sleep in. This may result in an increased probability of predation, or physiological conditions with which an individual in poor body condition cannot cope. I propose that among woodhoopoes a stay-and-foray dispersal strategy is preferred to a depart-and-search strategy for a number of reasons. First, there is no within-group competition for limiting resources, since roost cavities do not provide a situation in which within-group conflict could arise. Second, I show that competition for breeding vacancies is more severe at the inland than at the coastal site, further borne out by the fact that, compared to coastal birds, inland ones are proportionally more likely to attain breeding status in the natal group than elsewhere. Finally, I propose that such environmentally-induced differential dispersal patterns between the two study sites have indirectly affected the frequency with which apparent inbreeding occurs, and I suggest that since incestuous pairings are relatively common, the either have no deleterious consequences for breeder fitness, or the potential costs of inbreeding are counterbalanced by the risks associated with dispersal.

The role of helpers in feeding chicks in cooperatively breeding green (red-billed) woodhoopoes

Observations were made of ten green (red-billed) woodhoopoe Phoeniculus purpureus flocks during the breeding season in order to quantify the relationship between flock size and the amount of food delivered to chicks. The study period was kept short specifically to minimize the effects of environmental stochasticity. Neither woodhoopoe feeding visit rates nor the total amount of food brought to chicks increased with flock size. Although nonbreeders did not increase the net rate of food provisioning to chicks, they reduced parental input in chick rearing, and hence energy expenditure by the breeding pair. However, over an 8-year study period, which includes data for 144 flock years, this did not result in increased breeding frequency or enhanced survival of breeders. There is thus no evidence that helpers' feeding contributions to young per se influence the indirect fitness of helpers.

Female-Biased Sex Ratio at Hatching in the Green Woodhoopoe

Female-Biased Sex Ratio at Hatching in the Green Woodhoopoe

THE INFLUENCE OF ROOST-CAVITY AVAILABILITY ON FLOCK SIZE IN THE REDBILLED WOODHOOPOEPHOENICULUS PURPUREUS

Summary Du Plessis, M.A. 1989. The influence of roost-cavity availability on flock size in the Redbilled Woodhoopoe Phoeniculus purpureus. Ostrich suppl. 14: 97–104. The availability of roost-cavities to Redbilled Woodhoopoes Phoeniculus purpureus was compared between two different populations in the eastern Cape Province of South Africa in order to identify the influence that this resource may have in promoting group-living. Food availability and predatory pressure appeared to be similar at the two sites, but roost-cavity availability differed significantly. The latter was attributable to differences in the vegetation composition of territories at the different sites. Inland birds formed significantly larger flocks than coastal birds. The presence of marginal habitat (in terms of cavity availability) at the coastal site may have ensured an outlet for young birds from their natal territories, resulting in smaller flock sizes, whereas lack of such habitat at the inland site may have resulted in forced rete...

Cavity Roosting, Philopatry, and Cooperative Breeding in the Green Woodhoopoe May Reflect a Physiological Trait

Abstract Cooperative breeding in birds generally is related to a critical resource. A critical limiting factor for the Green Woodhoopoe (Phoeniculus purpureus) is the availability of roost cavities. Although predation at roost holes is the major source of mortality, woodhoopoes invariably roost in cavities or under loose bark. This dependence on cavities appears to be related to the birds' inability to cope physiologically with low nighttime temperatures. This is the first evidence to suggest that a physiological limitation has played a major role in the evolution of philopatry and possibly cooperative breeding in an avian species.

Reciprocity in the green woodhoopoe ( Phoeniculus purpureus)

Green woodhoopoes ( Phoeniculus purpureus) exhibit behaviours that appear to meet all the criteria of reciprocity. In this species social units typically are composed of one breeding pair plus a variable number of helpers. A helper (X) that feeds nestling Y often is repaid by Y via Y's critical assistance in the acquisition of territorial ownership and breeding status by X; Y later also feeds the offspring of X. This pattern follows whether or not X and Y are related. Unrelated adult woodhoopoes of the same sex also may merge to form new social units, with the younger, lower ranking bird helping the older to acquire and retain territorial space. Later, it also provides care for the older bird's offspring. It is here suggested that a population structure based on a combination of cooperatively-breeding groups and high rates of mortality have favoured the evolution of reciprocal exchanges between unrelated individuals.

Cooperation and Reciprocity in Avian Social Systems

Here I describe a variety of mutually beneficial interactions between birds that typically are not genetically related. As viewed here, avian cooperation and reciprocity can take several forms. In addition to monogamy and reciprocal exploitation I recognize two major categories of reciprocity, and opportunistic. Obligate reciprocity occurs in populations in which an individual must have one or more allies to have much chance of obtaining breeding status and reproductive success. For example, in the cooperatively breeding green woodhoopoe only five pairs without any helpers have been recorded, out of about 120 flock-yr of observations; i.e., allies are normally a requisite for obtaining and retaining breeding status. A second kind of obligate reciprocity may occur in certain lekking species in which two or more males are required to hold a display site and to attract females. Opportunistic reciprocity occurs in three kinds of situations: certain cooperative breeding systems, mate procurement v...

The Cooperative Breeding Behavior of the Green Woodhoopoe

The Cooperative Breeding Behavior of the Green Woodhoopoe

Another interpretation of communal breeding in green woodhoopoes

Another interpretation of communal breeding in green woodhoopoes

Another interpretation of communal breeding in green woodhoopoes (reply)

Another interpretation of communal breeding in green woodhoopoes (reply)

Communal breeding in green woodhoopoes as a case for reciprocity

RECIPROCITY1, or reciprocal altruism2, and kin selection3 are concepts basic to sociobiology. Although both theories have been widely accepted4, little critical evidence exists for either5,6. Communal, or cooperatively breeding, birds are important organisms for testing these theories because nonbreeding helpers regularly provide aid to nestlings, such as food and protection. Helpers are often related to the nestlings they aid, frequently being older siblings7,8, leading some authors to conclude that kin selection is the evolutionary basis for the apparent altruism seen in cooperative breeders8,9. However, the possible influence of other, individual strategies has not been completely separated from kin selection for any communal bird; this would require elimination of kinship ties as a variable5. Aid by a helper to an unrelated young bird must either be considered an ‘accident’ or it suggests that factors other than, or in addition to, kin selection might be the evolutionary bases for helping behaviour, at least in that particular species. Here we report information on a tropical, communal bird, the green wood-hoopoe (Phoeniculus purpureus), that suggests helping is a strategy for personal gain10.

An «ad hoc» association of hornbills, starlings, coucals, and other birds

An association of several different species of birds was observed at M Bour in western Sénégal in early 1977. The two species of greatest social weight were the Longtailed Glossy Starling (Lamprotornis caudatus) and the Redbilled Hornbill (Tockus erythrorhynchus) . Individuals of both species were gregarious among themselves. The Redbilled Hornbills also were attractive to coucals (Centropus senegalensis), Hoopoes (Upupa epops), and Longtailed Shrikes (Corvinella corvina). They were themselves attracted to the starlings. The net result of the interactions among these species was the daily formation of large mixed flocks. The flocks were sometimes visited by birds such as Phoeniculus purpureus and Tockus nasutus, but they were ignored by many other species in the neighborhood. The benefits derived from the habit of associating in mixed flocks were obviously varied. Mutual help in finding or flushing food seemed to be less important, in the local circumstances, than protection against predators or the regulation of competition by monitoring of rivals. Some aspects of the behavior involved in the formation and maintenance of the mixed flocks were distinctive. They may be adaptations to facilitate social flexibility in the short term and over small distances. Opportunism would be expected in the rigorous and fluctuating environment of most of Sénégal. The species that associated with one another at M Bour are known to show other kinds of interspecific behavior in other areas and/or at other seasons, not far away in either space or time. Some of the variation may be due to individual choice. Among the apparent consequences or correlates of this opportunism are the absence of certain kinds of visual signals, the partial suppression of acoustic signals, and a reliance upon many and probably complex clues for recognition of potential companions. The mechanisms of such interactions probably are highly specialized.

Ecological Determinants of Group Sizes of Foraging Lions

Ecological Determinants of Group Sizes of Foraging Lions

The Edibility of Birds: Illustrated by Five Years' Experiments and Observations (1941–1946) on the Food Preferences of the Hornet, Cat and Man;and considered with Special Reference to the Theories of Adaptive Coloration

The Edibility of Birds: Illustrated by Five Years' Experiments and Observations (1941–1946) on the Food Preferences of the Hornet, Cat and Man;and considered with Special Reference to the Theories of Adaptive Coloration