Drivers of clutch-size in Fork-tailed Flycatchers (Tyrannus savana) at temperate and tropical latitudes in South America

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Many species of birds exhibit a latitudinal gradient in annual reproductive investment, laying more eggs and producing more nestlings at higher latitudes. However, few studies have evaluated the mechanisms that underlie such patterns and such differences in grassland birds specifically. We monitored...

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Autores principales: Jahn, A.E., Tuero, D.T., Mamani, A.M., Bejarano, V., Masson, D.A., Aguilar, E.
Formato: JOUR
Materias:
arthropod
breeding season
brood size
clutch size
food availability
geographical variation
latitudinal gradient
life history trait
Neotropical Region
passerine
temperate environment
tropical environment
Argentina
Bolivia
Tyrannus savana
Acceso en línea:http://hdl.handle.net/20.500.12110/paper_01584197_v114_n4_p337_Jahn
Aporte de:
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
id todo:paper_01584197_v114_n4_p337_Jahn
record_format dspace
spelling todo:paper_01584197_v114_n4_p337_Jahn2023-10-03T15:01:13Z Drivers of clutch-size in Fork-tailed Flycatchers (Tyrannus savana) at temperate and tropical latitudes in South America Jahn, A.E. Tuero, D.T. Mamani, A.M. Bejarano, V. Masson, D.A. Aguilar, E. arthropod breeding season brood size clutch size food availability geographical variation latitudinal gradient life history trait Neotropical Region passerine temperate environment tropical environment Argentina Bolivia Tyrannus savana Many species of birds exhibit a latitudinal gradient in annual reproductive investment, laying more eggs and producing more nestlings at higher latitudes. However, few studies have evaluated the mechanisms that underlie such patterns and such differences in grassland birds specifically. We monitored nests of Fork-tailed Flycatchers (Tyrannus savana) over two breeding seasons at a tropical site in Bolivia (in 2010-11 and 2011-12) and three breeding seasons at a southern temperate site in Argentina (2010-11, 2011-12 and 2012-13), testing two hypotheses explaining variation in clutch-size among populations: the food-limitation hypothesis and the nest-predation hypothesis. Mean clutch-size and mean brood-size were significantly larger at the temperate study site than at the tropical site. Availability of arthropod food per individual bird was significantly higher at the temperate site. There was no relationship, positive or negative, between rates of nest predation and either clutch- or brood-size, and thus no support for the nest-predation hypothesis. We conclude that food availability explains much of the latitudinal variation in clutch-size in this species. We discuss avenues for future research on the mechanisms underlying geographical variation in the life histories of Neotropical birds. © 2014 BirdLife Australia. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_01584197_v114_n4_p337_Jahn
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic arthropod
breeding season
brood size
clutch size
food availability
geographical variation
latitudinal gradient
life history trait
Neotropical Region
passerine
temperate environment
tropical environment
Argentina
Bolivia
Tyrannus savana
spellingShingle arthropod
breeding season
brood size
clutch size
food availability
geographical variation
latitudinal gradient
life history trait
Neotropical Region
passerine
temperate environment
tropical environment
Argentina
Bolivia
Tyrannus savana
Jahn, A.E.
Tuero, D.T.
Mamani, A.M.
Bejarano, V.
Masson, D.A.
Aguilar, E.
Drivers of clutch-size in Fork-tailed Flycatchers (Tyrannus savana) at temperate and tropical latitudes in South America
topic_facet arthropod
breeding season
brood size
clutch size
food availability
geographical variation
latitudinal gradient
life history trait
Neotropical Region
passerine
temperate environment
tropical environment
Argentina
Bolivia
Tyrannus savana
description Many species of birds exhibit a latitudinal gradient in annual reproductive investment, laying more eggs and producing more nestlings at higher latitudes. However, few studies have evaluated the mechanisms that underlie such patterns and such differences in grassland birds specifically. We monitored nests of Fork-tailed Flycatchers (Tyrannus savana) over two breeding seasons at a tropical site in Bolivia (in 2010-11 and 2011-12) and three breeding seasons at a southern temperate site in Argentina (2010-11, 2011-12 and 2012-13), testing two hypotheses explaining variation in clutch-size among populations: the food-limitation hypothesis and the nest-predation hypothesis. Mean clutch-size and mean brood-size were significantly larger at the temperate study site than at the tropical site. Availability of arthropod food per individual bird was significantly higher at the temperate site. There was no relationship, positive or negative, between rates of nest predation and either clutch- or brood-size, and thus no support for the nest-predation hypothesis. We conclude that food availability explains much of the latitudinal variation in clutch-size in this species. We discuss avenues for future research on the mechanisms underlying geographical variation in the life histories of Neotropical birds. © 2014 BirdLife Australia.
format JOUR
author Jahn, A.E.
Tuero, D.T.
Mamani, A.M.
Bejarano, V.
Masson, D.A.
Aguilar, E.
author_facet Jahn, A.E.
Tuero, D.T.
Mamani, A.M.
Bejarano, V.
Masson, D.A.
Aguilar, E.
author_sort Jahn, A.E.
title Drivers of clutch-size in Fork-tailed Flycatchers (Tyrannus savana) at temperate and tropical latitudes in South America
title_short Drivers of clutch-size in Fork-tailed Flycatchers (Tyrannus savana) at temperate and tropical latitudes in South America
title_full Drivers of clutch-size in Fork-tailed Flycatchers (Tyrannus savana) at temperate and tropical latitudes in South America
title_fullStr Drivers of clutch-size in Fork-tailed Flycatchers (Tyrannus savana) at temperate and tropical latitudes in South America
title_full_unstemmed Drivers of clutch-size in Fork-tailed Flycatchers (Tyrannus savana) at temperate and tropical latitudes in South America
title_sort drivers of clutch-size in fork-tailed flycatchers (tyrannus savana) at temperate and tropical latitudes in south america
url http://hdl.handle.net/20.500.12110/paper_01584197_v114_n4_p337_Jahn
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AT mamaniam driversofclutchsizeinforktailedflycatcherstyrannussavanaattemperateandtropicallatitudesinsouthamerica
AT bejaranov driversofclutchsizeinforktailedflycatcherstyrannussavanaattemperateandtropicallatitudesinsouthamerica
AT massonda driversofclutchsizeinforktailedflycatcherstyrannussavanaattemperateandtropicallatitudesinsouthamerica
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