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1. Identifying the processes that determine avian migratory strategies in different environmental contexts is imperative to understanding the constraints to survival and reproduction faced by migratory birds across the planet. 2. We compared the spring migration strategies of Fork‐tailed Flycatchers (Tyrannus s. savana) that breed at south‐temperate latitudes (i.e., austral migrants) vs. tropi‐ cal latitudes (i.e., intratropical migrants) in South America. We hypothesized that austral migrant flycatchers are more time‐selected than intratropical migrants during spring migration. As such, we predicted that austral migrants, which mi‐ grate further than intratropical migrants, will migrate at a faster rate and that the rate of migration for austral migrants will be positively correlated with the onset of spring migration. 3. We attached light‐level geolocators to Fork‐tailed Flycatchers at two tropical breeding sites in Brazil and at two south‐temperate breeding sites in Argentina and tracked their movements until the following breeding season. 4. Of 286 geolocators that were deployed, 37 were recovered ~1 year later, of which 28 provided useable data. Rate of spring migration did not differ significantly between the two groups, and only at one site was there a significantly positive relationship between date of initiation of spring migration and arrival date. 5. This represents the first comparison of individual migratory strategies among con‐ specific passerines breeding at tropical vs. temperate latitudes and suggests that austral migrant Fork‐tailed Flycatchers in South America are not more time‐se‐ lected on spring migration than intratropical migrant conspecifics. Low sample sizes could have diminished our power to detect differences (e.g., between sexes), such that further research into the mechanisms underpinning migratory strategies in this poorly understood system is necessary., Facultad de Ciencias Naturales y Museo

Made available in DSpace on 2018-11-26T16:16:25Z (GMT). No. of bitstreams: 0 Previous issue date: 2015-09-01 PEDECIBA CSIC-UdelaR. from Uruguay Smithsonian Conservation Biology Institute's Center for Conservation and Evolutionary Genetics National Zoo Cleveland Metroparks Zoo's Scott Neotropical Fund American Zoo Association's Maned Wolf Species Survival Plan The maned wolf (Chrysocyon brachyurus) is one of the largest South American canids, and conservation across this charismatic carnivore's large range is presently hampered by a lack of knowledge about possible natural subdivisions which could influence the population's viability. To elucidate the phylogeographic patterns and demographic history of the species, we used 2 mtDNA markers (D-loop and cytochrome b) from 87 individuals collected throughout their range, in Argentina, Bolivia, Brazil, and Uruguay. We found moderate levels of haplotype and nucleotide diversity, and the 14 D-loop haplotypes were closely related. Genetic structure results revealed 4 groups, and when coupled with model inferences from a coalescent analysis, suggested that maned wolves have undergone demographic fluctuations due to changes in climate and habitat during the Pleistocene glaciation period approximately 24 000 years before present (YBP). This genetic signature points to an event that occurred within the timing estimated for the start of the contraction of the Cerrado around 50 000 YBP. Our results reveal a genetic signature of population size expansion followed by contraction during Pleistocene interglaciations, which had similar impacts on other South American mammals. The 4 groups should for now be considered management units, within which future monitoring efforts should be conducted independently. MEC, IIBCE, Dept Biodiversidad & Genet, Genet Conservac, Montevideo 11600, Uruguay Fac Ciencias UdelaR, Secc Genet Evolut, Montevideo 11600, Uruguay Smithsonian Inst, Natl Museum Nat Hist, Dept Vertebrate Zool, Washington, DC 20013 USA Natl Fish & Wildlife Fdn, Sci & Evaluat, Washington, DC 20005 USA Univ Estadual Paulista, Dept Zootecnia, Nucleo Pesquisa & Conservacao Cervideos, BR-14884900 Jaboticabal, SP, Brazil Secretaria Ambiente & Desarrollo Sustentable Naci, Buenos Aires, DF, Argentina Smithsonian Conservat Biol Inst, Ctr Conservat & Evolutionary Genet, Washington, DC 20008 USA Univ Estadual Paulista, Dept Zootecnia, Nucleo Pesquisa & Conservacao Cervideos, BR-14884900 Jaboticabal, SP, Brazil