Black Sparrowhawk brooding behaviour in relation to chick age and weather variation in the recently colonised Cape Peninsula, South Africa

Katzenberger, Jakob; Tate, Gareth J.; Koeslag, Ann; Amar, Arjun

doi:10.1007/s10336-015-1199-0

Cited by 27 publications

(32 citation statements)

References 44 publications

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“…The total rainfall up to 28 days after hatching was significant in predicting the outcome of a breeding attempt, whereas rainfall during shorter periods after hatching was less important, demonstrating the susceptibility to nest failure beyond just the first few weeks of chick rearing. From a recent review of brooding behavior in raptors, the allometric relationship predicts that for a bird of this size, intensive brooding requirements should occur until the young are~27 days old (Katzenberger et al 2015), which links well with our findings. Our finding that timing of breeding influences success is in agreement with multiple studies of raptorial species (Newton and Marquiss 1984, Margalida et al 2003, McDonald et al 2004, Martin et al 2014.…”

Section: Other Variables Affecting Breeding Performancesupporting

confidence: 86%

Fluctuations in bush and rock Hyrax (Hyracoidea: Procaviidae) Abundances Over a 13-Year Period in the Matopos, Zimbabwe

Barry¹,

Chiweshe²,

Mundy

2015

African Journal of Wildlife Research

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Section: Other Variables Affecting Breeding Performancesupporting

confidence: 86%

Fluctuations in bush and rock Hyrax (Hyracoidea: Procaviidae) Abundances Over a 13-Year Period in the Matopos, Zimbabwe

Barry¹,

Chiweshe²,

Mundy

2015

African Journal of Wildlife Research

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“…For our population, this situation may be further exacerbated, since the female may spend more time brooding the chicks due to the wet winters experienced in the region (Katzenberger et al . ). The hunting success of the male is therefore crucial for productivity, but may also contribute to longer‐term effects such as recruitment.…”

Section: Discussionmentioning

confidence: 97%

Family morph matters: factors determining survival and recruitment in a long‐lived polymorphic raptor

Sumasgutner

Tate

Koeslag

et al. 2016

Journal of Animal Ecology

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From an evolutionary perspective, recruitment into the breeding population represents one of the most important life-history stages and ultimately determines the effective population size. In order to contribute to the next generation, offspring must survive to sexual maturity, secure a territory and find a mate. In this study, we explore factors influencing both offspring survival and their subsequent recruitment into the local breeding population in a long-lived urban raptor, the black sparrowhawk (Accipiter melanoleucus). Adult black sparrowhawks show discrete colour polymorphism (dark and light morphs), and in South Africa, morphs are distributed clinally with the highest proportion of dark morphs (c.75%) present in our study population on the Cape Peninsula. Parental morph was associated with both survival and recruitment. For survival, parental morph combination was important - with young produced by pairs of contrasting morphs having higher survival rates than young fledged from like-pairs. The association between recruitment and morph was more complex; with an interaction between male morph and breeding time, whereby recruitment of offspring from dark morph fathers was more likely when fledging earlier in the season. The opposite relationship was found for light morph fathers, with their offspring more likely to be recruited if fledged later in the season. This interaction may be due to differential morph-specific hunting success of fathers (males contribute most food provisioning), linked to background matching and crypsis in different weather conditions. Dark morph males may hunt more successfully in rainier and cloudier conditions, which occur more frequently earlier in the breeding season, and light morph males may be more successful later on, when weather conditions become increasingly brighter and drier. Our results reveal a complex situation whereby the family morph combination influences survival, and the father morphs specifically recruitment, revealing morph-specific benefits dependent on the timing of breeding. These empirical data are among the first to support the idea that differential fitness consequence of morph combination may explain balanced polymorphism in a vertebrate population.

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“…Previous research has shown these two approaches produced near identical results in nest behaviour measurements (Katzenberger et al . ).…”

Section: Methodsmentioning

confidence: 97%

“…Chick age was determined either from the date of hatching recorded from the camera footage or for older chicks where hatch date was unknown, by comparing the relative plumage development and chick size to a reference collection of photographs of known age nestlings (Katzenberger et al . ).…”

Section: Methodsmentioning

confidence: 97%

Differential foraging success across a light level spectrum explains the maintenance and spatial structure of colour morphs in a polymorphic bird

2016

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Detectability of different colour morphs under varying light conditions has been proposed as an important driver in the maintenance of colour polymorphism via disruptive selection. To date, no studies have tested whether different morphs have selective advantages under differing light conditions. We tested this hypothesis in the black sparrowhawk, a polymorphic raptor exhibiting a discrete white and dark morph, and found that prey provisioning rates differ between the morphs depending on light condition. Dark morphs delivered more prey in lower light conditions, while white morphs provided more prey in brighter conditions. We found support for the role of breeding season light level in explaining the clinal pattern of variation in morph ratio across the species range throughout South Africa. Our results provide the first empirical evidence supporting the hypothesis that polymorphism in a species, and the spatial structuring of morphs across its distribution, may be driven by differential selective advantage via improved crypsis, under varying light conditions.

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Black Sparrowhawk brooding behaviour in relation to chick age and weather variation in the recently colonised Cape Peninsula, South Africa

Cited by 27 publications

References 44 publications

Fluctuations in bush and rock Hyrax (Hyracoidea: Procaviidae) Abundances Over a 13-Year Period in the Matopos, Zimbabwe

Fluctuations in bush and rock Hyrax (Hyracoidea: Procaviidae) Abundances Over a 13-Year Period in the Matopos, Zimbabwe

Family morph matters: factors determining survival and recruitment in a long‐lived polymorphic raptor

Differential foraging success across a light level spectrum explains the maintenance and spatial structure of colour morphs in a polymorphic bird

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