No full-text available
To read the full-text of this research,
you can request a copy directly from the author.
Owls of the World, 2nd ed. — Claus König and Friedhelm Weick . 2009. Yale University Press, New Haven, Connecticut. 528 pp., 72 color plates, distribution maps, line drawings. ISBN 9780300142273. Cloth, $75.00.
p>La progresiva expansión de las urbes no solo implica modificación de los ecosistemas, está también asociada a la introducción de especies plaga. En este sentido, es importante evaluar cómo especies nativas actúan como controladores de plagas. Para asegurar esto, se presenta un análisis de la dieta, basada en egagrópilas, de Tyto alba (Lechuza Campanaria) en la ciudad de Cuenca, Ecuador. En base a 32 egagrópilas, colectadas entre Abril y Junio de 2017, se registró un total de 154 presas asociadas a nueve identidades taxonómicas. Los roedores fueron las presas más abundantes con 129 registros (84%) como así también fueron los de mayor biomasa, 49 g (93%). Más importante, tanto la abundancia como biomasa del género Rattus (ratas) fueron significativamente mayores al comparar con el resto de presas. Es evidente, que T. alba cumple un rol como controlador de plagas en la ciudad de Cuenca. Estos hallazgos son similares a los reportados para T. alba en varias localidades a través del continente; en consecuencia, es una especie clave en el control de roedores con un efecto positivo sobre la salud de los ecosistemas urbanos.</p
Knowledge of avian phylogeny is prerequisite to understanding the circumstances and timing of the diversification of birds and the evolution of morphological, behavioral, and life-history traits. Recent molecular datasets have helped to elucidate the three most basal clades in the tree of living birds, but relationships among neoavian orders (the vast majority of birds) remain frustratingly vexing. Here, we examine intron 7 of the beta-fibrinogen gene in the most taxonomically inclusive survey of DNA sequences of nonpasserine bird families and orders to date. These data suggest that Neoaves consist of two sister clades with ecological parallelisms comparable to those found between marsupial and placental mammals. Some members of the putative respective clades have long been recognized as examples of convergent evolution, but it was not appreciated that they might be parts of diverse parallel radiations. In contrast, some traditional orders of birds are suggested by these data to be polyphyletic, with representative families in both radiations.
Patterns of diversification and timing of evolution within Neoaves, which includes almost 95% of all bird species, are virtually unknown. On the other hand, molecular data consistently indicate a Cretaceous origin of many neoavian lineages and the fossil record seems to support an Early Tertiary diversification. Here, we present the first well-resolved molecular phylogeny for Neoaves, together with divergence time estimates calibrated with a large number of stratigraphically and phylogenetically well-documented fossils. Our study defines several well-supported clades within Neoaves. The calibration results suggest that Neoaves, after an initial split from Galloanseres in Mid-Cretaceous, diversified around or soon after the K/T boundary. Our results thus do not contradict palaeontological data and show that there is no solid molecular evidence for an extensive pre-Tertiary radiation of Neoaves.
Sequences of the mitochondrial cytochrome b gene (930 base pairs) were used to examine patterns of variation within and between Eastern (Megascops asio) and Western (M. kennicottii) Screech-Owls, and to assess taxonomic affinity of Flammulated Owls (Otus flammeolus) and Whiskered Screech-Owls (M. trichopsis). Analyses support monophyly of the New World Megascops, a sister-group relationship between O. flammeolus and New World forms of Megascops, rather than with Old World Otus, and a closer relationship between the mostly North American M. trichopsis and South American Megascops than between M. trichopsis and North American Megascops. Megascops asio and M. kennicottii formed two distinct monophyletic clades, supporting species-level designations as suggested by morphology and song. Evidence for distinctive subspecies of eastern and western forms of screech-owls was less compelling. In the M. asio group, M. a. mccallii was the only subspecies with a unique haplotype; other subspecies within M. asio were phylogenetically indistinguishable. Subspecies within M. kennicottii were partitioned into three geographic groups, and differences are probably the result of barriers to gene flow (e.g., mountains above 2300 m), which are more pronounced throughout the distribution of M. kennicottii than in the distribution of M. asio.
Owls: A Guide to the Owls of the World
- C König
- F Weick
- J.-H Becking
-
König, C., F. Weick, and J.-H. Becking. . Owls: A Guide to the Owls of the World. Yale University Press, New Haven, Con-necticut.
Phylogeny and Classifica-tion of Birds
- C G Sibley
- J E Ahlquist
-
Sibley, C. G., and J. E. Ahlquist. . Phylogeny and Classifica-tion of Birds. Yale University Press, New Haven, Connecticut.