Contrasting latitudinal patterns of life-history divergence in two genera of new world thrushes (Turdinae)

Journal of Avian Biology
By:  and 

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Abstract

Several long-standing hypotheses have been proposed to explain latitudinal patterns of life-history strategies. Here, we test predictions of four such hypotheses (seasonality, food limitation, nest predation and adult survival probability) by examining life-history traits and age-specific mortality rates of several species of thrushes (Turdinae) based on field studies at temperate and tropical sites and data gathered from the literature. Thrushes in the genus Catharus showed the typical pattern of slower life-history strategies in the tropics while co-occuring Turdus thrushes differed much less across latitudes. Seasonality is a broadly accepted hypothesis for latitudinal patterns, but the lack of concordance in latitudinal patterns between co-existing genera that experience the same seasonal patterns suggests seasonality cannot fully explain latitudinal trait variation in thrushes. Nest-predation also could not explain patterns based on our field data and literature data for these two genera. Total feeding rates were similar, and per-nestling feeding rates were higher at tropical latitudes in both genera, suggesting food limitation does not explain trait differences in thrushes. Latitudinal patterns of life histories in these two genera were closely associated with adult survival probability. Thus, our data suggest that environmental influences on adult survival probability may play a particularly strong role in shaping latitudinal patterns of life-history traits.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Contrasting latitudinal patterns of life-history divergence in two genera of new world thrushes (Turdinae)
Series title Journal of Avian Biology
DOI 10.1111/jav.01113
Volume 48
Issue 4
Year Published 2017
Language English
Publisher Wiley
Contributing office(s) Coop Res Unit Seattle
Description 10 p.
First page 581
Last page 590
Country United States, Venezuela
State Arizona
Other Geospatial Coconino National Forest, Parque Nacional Yacambu