Coexistence and Competition between Overwintering Willow Warblers Phylloscopus trochilus and Local Warblers at Lake Naivasha, Kenya

Rabøl, Jørgen

doi:10.2307/3676845

Cited by 47 publications

(50 citation statements)

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“…At Lake Naivasha, Kenya, Rabøl (1987) noted how the resident species black-breasted apalis (Apalis flavida) and grey-backed camaroptera (Camaroptera brevicaudata) foraged lower in less-preferred heights of the vegetation and that the black-breasted apalis clearly diverged in foraging behaviour from the migrant willow warbler (Phylloscopus trochilus) upon its arrival. Upon the arrival of willow warblers, Rabøl also reported decreased arthropod abundance, a diet switch by the black-breasted apalis, increased aggression among guild members, and a change in migrant foraging manoeuvres.…”

Section: Seasonal Shifts In Foraging Niche and Resource Competition Imentioning

confidence: 99%

“…In a follow-up study, however, Rabøl (1993) reconsidered resource competition as the primary explanation, because changes in brood rearing corresponded with the arrival of migrants and potentially explained the foraging shift (see below). His later study did not show as great a niche shift as his earlier research and arthropod abundances did not appear limiting.…”

Section: Seasonal Shifts In Foraging Niche and Resource Competition Imentioning

confidence: 99%

“…The four studies that examine how tropical residents forage before and after migrant arrival found that while a majority of resident species did not appear to change their foraging behaviour upon migrant arrival, a few generalist resident species exhibited seasonal shifts in foraging niche (Chipley 1976, Rabøl 1987, 1993Waide 1981). In these cases, certain resident bird species were found to forage higher in the vegetative strata (in more favourable or preferred locations) when migrants were absent than when they were present.…”

Section: Introductionmentioning

confidence: 99%

“…The resource competition hypothesis is commonly offered as a possible explanation for this behavioural shift (Chipley 1976, for review see Leisler 1990Leisler , 1992Rabøl 1987, Waide 1981. When migrants arrive they consume large numbers of arthropods in the canopy, and the resource competition hypothesis holds that this consumption results in such low densities of arthropods that it is no longer profitable for certain residents to forage in the canopy.…”

Section: Introductionmentioning

confidence: 99%

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Seasonal shift in the foraging niche of a tropical avian resident: resource competition at work?

et al. 2006

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This study examined the foraging behaviour of a resident bird species, the rufous-capped warbler (RCWA, Basileuterus rufifrons), in a shaded-coffee farm in Chiapas, Mexico. Unlike many resident species that use shaded-coffee agroecosystems seasonally, RCWAs do not move to other habitats when migrants are present. RCWA foraging was compared when migrant birds were present (dry season) and absent (wet season). It was hypothesized that RCWAs would exhibit a seasonal foraging niche shift because of resource competition with migrants. Observations from both the canopy and coffee understorey show that RCWAs foraged almost equally in both vegetative layers during the wet season although they were more successful foraging in the canopy. In the dry season, migrants foraged primarily in the canopy and RCWAs shifted so that 80% of RCWA foraging manoeuvres were in the understorey. At that time RCWAs foraged less successfully in both vegetative layers. Avian predation in the dry season was found to reduce densities of arthropods by 47-79% in the canopy, as opposed to 4-5% in the understorey. In the canopy, availability of large (>5 mm in length) arthropods decreased by 58% from the wet to dry season. Such resource reductions could have caused the RCWA foraging niche shift yet other alternative or additional hypotheses are discussed. Shifts in foraging niche may be a widespread mechanism for some small insectivorous residents to avoid seasonal competition with abundant migrant species.Resumen: Este estudio examinó el comportamiento de forrajeo de un ave residente, Basileuterus rufifrons (RCWA), en una finca de café con sombra en Chiapas, México. A diferencia de muchas aves residentes que usan los agroecosistemas de café con sombra solamante durante una estación, RCWAs no se van a otros hábitats cuando los aves migrantes están presente. El forrajeo de RCWA fue comparado cuando las aves migrantes eran presente (laépoca seca) y ausente (lá epoca de lluvia). La hipótesis fue que los RCWA exhibirían un cambio de forrajeo con los cambios de estaciones a causa de la competencia de recursos con los migrantes. Observaciones en el docel y el sotobosque en un cafetal muestran que durante laépoca de lluvia, los RCWAs forrajean igualmente en los dos niveles de vegetación, pero tienen máś exito forrajeando en el docel. Durante laépoca seca, los migrantes forrajean principalmente en el docel y los RCWAs se mueven al sotobosque donde efectúan 80% de las maniobras de forrajeo. Durante ese tiempo, los RCWAs tuvieron menoséxito forrajeando tanto en el docel como en el sotobosque. Durante laépoca seca el número de artrópodos bajó entre 47-79% en el docel y entre 4-5% en el sotobosque a causa de la depredación de las aves. En el docel, la disponibilidad de artrópodos grandes (>5 mm en longitud) bajó en un 58% de laépoca de lluvia a laépoca seca. Tales reducciones de recursos podrían causar el cambio de lugar a forrajeo observado en RCWA, pero otras explicaciones e hipótesis son discutidas. Pueden ser que este cambio de forrajeo sea comú...

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Section: Seasonal Shifts In Foraging Niche and Resource Competition Imentioning

confidence: 99%

Section: Seasonal Shifts In Foraging Niche and Resource Competition Imentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Seasonal shift in the foraging niche of a tropical avian resident: resource competition at work?

et al. 2006

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“…None of these predictions are supported by the data, favouring the alternative view that birds visiting the study site for very short periods are not passing migrants, but rather nomads or floaters that have much larger individual wintering ranges (see also : Finlayson 1998;Catry et al 2003). Nomadic behaviour at the winter quarters has been described for at least one other species of the same genus as the chiffchaff, namely the willow warbler P. trochilus (Rabøl 1987;Salewski et al 2002). Despite this evidence for nomadic behaviour, some individual chiffchaffs settled down and remained at the study site for part of the winter.…”

Section: Discussionmentioning

confidence: 99%

Sex differences in settlement behaviour and condition of chiffchaffs Phylloscopus collybita at a wintering site in Portugal. Are females doing better?

2007

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In passerine birds, males are generally larger and dominant over females. In line with the dominance theory, in all known differential migrant passerines, females migrate further than males. However, there are alternative explanations to the dominance hypothesis, including the specialisation hypothesis, predicting that females should do better than males in habitats and/or regions to which they are specially adapted, and where they predominate in numbers. Few studies have aimed at comparing the behaviour and condition of males and females wintering in locations largely dominated by female birds. We studied a partly nomadic species, the common chiffchaff Phylloscopus collybita, at a wintering site in Portugal. Most individuals caught at this site were transients. The only consistent and relatively powerful predictor of settlement behaviour was sex. Almost all the birds that settled in the study area were female, while there was an almost even sex ratio in the transient sample. Females had higher muscle and postjuvenile moult scores when first captured. In addition, there was a significant sex-based difference in mass trajectories, with females maintaining body mass and males losing body mass when settled at the study site.Results from this study suggest that the poor performance of males was either due to inferior male competitive ability in a region/habitat where females predominate and/or it resulted from the fact that males that reach these wintering grounds are of inferior individual quality.

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Current Ornithology

1989

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A Continuation Order Plan is available for this series. A continuation order will bring delivery of each new volume immediately upon publication. Volumes are billed only upon actual shipment. For further information please contact the publisber. = Current ornithology. 1. Ornithology-Periodicals. I. Johnston, Richard F. QL671.C87 598'.05-dcl9 84-640616 [8509] AACR 2 MARC-S ISBN 978-1-4757-9920-0 ISBN 978-1-4757-9918-7 (eBook) v PREFACEThis edited series has three principal goals. The first is to provide information in a relatively concise way for researchers needing an overview of specific disciplines. The second is to provide an update on specific schools of thought, bringing together ideas from colleagues whose works often appear in a variety of journals. And the third is to stimulate and suggest directions for new research. Volume 6 continues the tradition established by the previous editor and editorial board in providing new information, updating our understanding of specific disciplines, and stimulating new research. In the first chapter, Randall Breitwisch examines mortality patterns and sex ratios in monogamous birds. He argues that there are many more components to measuring parental investment than are often realized; our knowledge is weak in several areas. Understanding the evolution of mating systems depends on better distinguishing the different intensities of natural selection that operate on males and females. Gregory Butcher and Sievert Rohwer develop a framework for assessing the role of colorfulness in birds. They propose several hypotheses to test and advocate evaluating more than one hypothesis at a time. Future work on the evolution of distinctive coloration and of sexual and age dimorphism must take these ideas into account.Paul Kerlinger and Frank Moore examine the structure of the atmosphere (e.g., thermals, winds, temperature) as it may be relevant to avian migration. They develop the hypothesis that atmospheric structure is an important force in natural selection for timing and altitude of migration. A comparison is made with other presumed selective vii viii PREFACE influences, such as predation and competition. Gabor Lovei of Hungary shares his review of passerine migration between the Palaearctic and Africa, allowing comparisons to be made with the Nearctic-Neotropical system. Geographic barriers for birds migrating from Europe and Asia to Africa are greater than those existing between North and South America; these barriers influence the patterns of passerine migration.Noel and Helen Snyder summarize their knowledge of the biology of the California Condor and the history and issues that led to conservation efforts and capture of the last remaining birds. They reveal the fascinating undercurrent of politics and interactions driving the development of decisions affecting endangered species. The prospects ahead for captive breeding and release of condors in the wild, and the ultimate goals for condor conservation, are addressed. Jerry Waldvogel concludes the volume with an excellent syno...

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Coexistence and Competition between Overwintering Willow Warblers Phylloscopus trochilus and Local Warblers at Lake Naivasha, Kenya

Cited by 47 publications

References 12 publications

Seasonal shift in the foraging niche of a tropical avian resident: resource competition at work?

Seasonal shift in the foraging niche of a tropical avian resident: resource competition at work?

Sex differences in settlement behaviour and condition of chiffchaffs Phylloscopus collybita at a wintering site in Portugal. Are females doing better?

Current Ornithology

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