Latitudinal variation in clutch size-lay date regressions in Tachycineta swallows: Effects of food supply or demography?

• Autores: Winkler, David W.; Ringelman, Kevin M.; Dunn, Peter O.; Whittingham, Linda; Hussell, David J. T.; Clark, Robert G.; Dawson, Russell D.; Johnson, L. Scott; Rose, Alexandra; Austin, Suzanne H.; Robinson, W. Douglas; Lombardo, Michael P.; Thorpe, Patrick A.; Shutler, Dave; Robertson, Raleigh J.; Stager, Maria; Leonard, Marty; Horn, Andrew G.; Dickinson, Janis; Ferretti, Valentina; Massoni, Viviana; Bulit, Florencia; Reboreda, Juan Carlos; Liljesthrom, Marcela; Quiroga, Martin Anibal; Rakhimberdiev, Eldar; Ardia, Daniel R.
• Año de publicación: 2014
• Idioma: inglés
• Tipo de recurso: artículo
• Materia: lay date; life history traits; geographic variation; Swallows
• Institución: Consejo Nacional de Investigaciones Científicas y Técnicas

In a study of almost 16 000 nest records from seven swallow species across the entire Western Hemisphere, clutch sizes decline with relative laying date in each population, but the slope of this decline grows steeper with increasing distance from the equator. Late-laying birds at all latitudes lay clutches of similar sizes, suggesting that latitudinal differences may be driven primarily by earlier-laying birds. Focused comparisons of site-years in North America with qualitatively different food availability indicate that food supply significantly affects mean clutch size but not the clutch size-lay date regression. Other studies on the seasonality of swallow food also indicate that steeper clutch size-lay date declines in the North are not caused by steeper earlier food peaks there. The distribution of lay dates grows increasingly right-skewed with increasing latitude. This variation in lay-date distributions could be due to the predominance of higher quality, early-laying (and large-clutched) individuals among populations at higher latitudes, resulting from latitudinal variation in mortality rates and the intensity of sexual selection. Our results underscore the importance of studying clutch size and lay date in tandem and suggest new research into the causes of their joint geographic variation.
Fil: Winkler, David W.. Cornell University; Estados Unidos
Fil: Ringelman, Kevin M.. University Of Delaware; . Cornell University; Estados Unidos
Fil: Dunn, Peter O.. University Of Wisconsin-milwaukee;
Fil: Whittingham, Linda. University Of Wisconsin-milwaukee;
Fil: Hussell, David J. T.. Ontario Ministry Of Natural Resources; Canadá
Fil: Clark, Robert G.. Environment Canada; Canadá
Fil: Dawson, Russell D.. University Of Northern British Columbia; Canadá
Fil: Johnson, L. Scott. Towson University;
Fil: Rose, Alexandra. University Colorado Museum;
Fil: Austin, Suzanne H.. State University of Oregon; Estados Unidos
Fil: Robinson, W. Douglas. State University of Oregon; Estados Unidos
Fil: Lombardo, Michael P.. Grand Valley State University;
Fil: Thorpe, Patrick A.. Grand Valley State University;
Fil: Shutler, Dave. Acadia University; Canadá
Fil: Robertson, Raleigh J.. Queen's University, Kingston; Canadá
Fil: Stager, Maria. Cornell University; Estados Unidos. University of Illinois. Urbana - Champaign; Estados Unidos
Fil: Leonard, Marty. Dalhousie University Halifax; Canadá
Fil: Horn, Andrew G.. Dalhousie University Halifax; Canadá
Fil: Dickinson, Janis. Cornell Lab Of Ornithology;
Fil: Ferretti, Valentina. Cornell University; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”; Argentina. Cornell Lab Of Ornithology;
Fil: Massoni, Viviana. Universidad de Buenos Aires; Argentina
Fil: Bulit, Florencia. Universidad de Buenos Aires; Argentina
Fil: Reboreda, Juan Carlos. Universidad de Buenos Aires; Argentina
Fil: Liljesthrom, Marcela. Universidad de Buenos Aires; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; Argentina
Fil: Quiroga, Martin Anibal. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Ciencias Veterinarias del Litoral. Universidad Nacional del Litoral. Facultad de Ciencias Veterinarias. Instituto de Ciencias Veterinarias del Litoral; Argentina
Fil: Rakhimberdiev, Eldar. Cornell University; Estados Unidos. Lomonosov Moscow State University; . Royal Netherlands Institute For Sea Research - Nioz;
Fil: Ardia, Daniel R.. Franklin And Marshall College, Lancaster;