Breeding biology, extra-pair birds, productivity, siblicide and conservation of the Madagascar Fish Eagle

Watson, Richard T.; Razafindramanana, Suzanne; Thorstrom, Russell; Rafanomezantsoa, Simon

doi:10.1080/00306525.1999.9634522

Cited by 12 publications

(7 citation statements)

References 19 publications

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“…Thus, factors such as habitat availability, direct/indirect human persecution, or the introduction of pathogens are likely to be of more immediate concern for this species’ long‐term persistence (e.g. Watson et al . 1999; Watson & Rabarisoa 2000; Tingay 2005).…”

Section: Discussionmentioning

confidence: 99%

“…Direct persecution by humans includes destruction of nests and young (Thiollay & Meyburg 1981; Rabarisoa et al . 1997), theft of nestlings for pets and food (Watson et al . 1999), shooting and trapping of adults, and the use of eagle body parts in traditional medicine (Rabarisoa et al .…”

Section: Discussionmentioning

confidence: 99%

“…1997; Watson & Rabarisoa 2000). After having been exposed to negative environmental perturbations, the Madagascar fish‐eagle population would also be less likely to recover quickly due to low reproductive rates by producing only a single chick per reproductive cycle (Watson et al . 1999).…”

Section: Discussionmentioning

confidence: 99%

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Long‐term survival despite low genetic diversity in the critically endangered Madagascar fish‐eagle

et al. 2008

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The critically endangered Madagascar fish-eagle (Haliaeetus vociferoides) is considered to be one of the rarest birds of prey globally and at significant risk of extinction. In the most recent census, only 222 adult individuals were recorded with an estimated total breeding population of no more than 100-120 pairs. Here, levels of Madagascar fish-eagle population genetic diversity based on 47 microsatellite loci were compared with its sister species, the African fish-eagle (Haliaeetus vocifer), and 16 of these loci were also characterized in the white-tailed eagle (Haliaeetus albicilla) and the bald eagle (Haliaeetus leucocephalus). Overall, extremely low genetic diversity was observed in the Madagascar fish-eagle compared to other surveyed Haliaeetus species. Determining whether this low diversity is the result of a recent bottleneck or a more historic event has important implications for their conservation. Using a Bayesian coalescent-based method, we show that Madagascar fish-eagles have maintained a small effective population size for hundreds to thousands of years and that its low level of neutral genetic diversity is not the result of a recent bottleneck. Therefore, efforts made to prevent Madagascar fish-eagle extinction should place high priority on maintenance of habitat requirements and reducing direct and indirect human persecution. Given the current rate of deforestation in Madagascar, we further recommend that the population be expanded to occupy a larger geographical distribution. This will help the population persist when exposed to stochastic factors (e.g. climate and disease) that may threaten a species consisting of only 200 adult individuals while inhabiting a rapidly changing landscape.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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Long‐term survival despite low genetic diversity in the critically endangered Madagascar fish‐eagle

et al. 2008

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“…The Madagascar Fish Eagle breeding season coincides with the southern hemisphere winter, beginning in late April to early May and ending in October, a period when rainfall and daytime temperatures are the lowest for the year (Watson et al 1999). During this period, the species is fairly easy to detect at the nesting site due to its large size, appearance, habit of perching near the tops of trees and vocalisation.…”

Section: Methodsmentioning

confidence: 99%

Population status of the Madagascar Fish EagleHaliaeetus vociferoidesin 2005–2006

Razafimanjato¹,

Rakotondratsima²,

Roland³

et al. 2013

Bird Conservation International

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SummaryCoastal and inland surveys for the endemic and “Critically Endangered” Madagascar Fish Eagle Haliaeetus vociferoides were conducted in western Madagascar from Antsiranana in the north to Manja in the south during the 2005 and 2006 breeding seasons (May–October). Surveys covered typical Madagascar Fish Eagle habitat: lakes, rivers, mangroves, estuaries, and marine islands within their known distribution. In total, 287 individuals were encountered, including 98 breeding pairs (196 individuals), 23 breeding trios (69 individuals), 15 single adults and seven immature birds. Of these 287 birds, 128 individuals (44.6%) were observed on lakes; 116 (40.4%) in coastal areas, consisting of 103 (35.9%) in mangroves and 13 (4.5%) in estuaries; 32 (11.2%) on marine islands and 11 (3.8%) on rivers. There was an increase between surveys in 1995 and this study in the number of Madagascar Fish Eagles counted, from 222 to 287, and in the number of pairs from 99 to 121. This study confirms that the Madagascar Fish Eagle population is still low due to human persecution (hunting, collection of eggs and nestlings), overfishing and habitat destruction. We recommend monitoring fish eagles annually at the higher concentration sites to evaluate human activities and conducting a population survey every five years throughout western and northern Madagascar.

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“…An alternative explanation to cost-effectiveness at the nestling stage for the occurrence of covariation between the intensity of broodmate aggression and certain life history traits was advanced by Simmons (1988Simmons ( , 1991, who suggested that intense aggression was an adaptation to maximize juvenile survival and competitive ability in long-lived species with an intense competition for breeding sites due to habitat saturation. Despite Simmons' (1988) idea is highly cited, and sometimes invoked as an explanation for observed patterns of fertility or broodmate aggression (Bosch, 2003;De Lucca & Saggese, 1995;Watson, Razafindramanana, Thorstrom, & Rafanomezantsoa, 1999), few studies have tested it critically (Simmons, 1993(Simmons, , 2002Viñuela, 1999), with mixed results. Certainly, it was unfortunate that…”

Section: Broodmate Aggression As a Trait Linked To A Slow Life-histmentioning

confidence: 99%

Broodmate aggression and life history variation in accipitrid birds of prey

Redondo

Romero

Dı́az-Delgado

et al. 2019

Ecology and Evolution

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Aggressive sibling competition for parental food resources is relatively infrequent in animals but highly prevalent and extreme among certain bird families, particularly accipitrid raptors (Accipitriformes). Intense broodmate aggression within this group is associated with a suite of traits including a large adult size, small broods, low provisioning rates, and slow development. In this study, we apply phylogenetic comparative analyses to assess the relative importance of several behavioral, morphological, life history, and ecological variables as predictors of the intensity of broodmate aggression in 65 species of accipitrid raptors. We show that intensity of aggression increases in species with lower parental effort (small clutch size and low provisioning rates), while size effects (adult body mass and length of nestling period) are unimportant. Intense aggression is more closely related to a slow life history pace (high adult survival coupled with a restrained parental effort), rather than a by‐product of allometry or food limitation. Consideration of several ecological variables affecting prey abundance and availability reveals that certain lifestyles (e.g., breeding in aseasonal habitats or hunting for more agile prey) may slow a species’ life history pace and favor the evolution of intense broodmate aggression.

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Breeding biology, extra-pair birds, productivity, siblicide and conservation of the Madagascar Fish Eagle

Cited by 12 publications

References 19 publications

Long‐term survival despite low genetic diversity in the critically endangered Madagascar fish‐eagle

Long‐term survival despite low genetic diversity in the critically endangered Madagascar fish‐eagle

Population status of the Madagascar Fish EagleHaliaeetus vociferoidesin 2005–2006

Broodmate aggression and life history variation in accipitrid birds of prey

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