Latitude does not influence cavity entrance orientation of South American avian excavators
Ojeda, Valeria
Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET)
Schaaf, Alejandro
INECOA UNJujuy CONICET
Altamirano, Tomas A.
University of British Columbia
Bonaparte, Bianca
IBS UNMisiones CONICET
Bragagnolo, Laura
UNLa Pampa FCEyN
Chazarreta, Laura
Adm Parques Nacl DRPN
Cockle, Kristina
University of British Columbia
Dias, Raphael
Centro Universitario de Brasilia (UniCEUB)
Di Sallo, Facundo
IBS UNMisiones CONICET
Ibarra, J. Tomas
Pontificia Universidad Catolica de Chile
Ippi, Silvina
Universidad Nacional del Comahue
Jauregui, Adrian
National University of La Plata
Lammertink, Martjan
IBS UNMisiones CONICET
Lopez, Fernando
INCITAP UNLPam CONICET
Montellano, Maria Gabriela Nunez
Residencia Univ Horco Molle
de la Pena, Martin
Tres Febrero 1870, RA-3080 Esperanza, Santa Fe, Argentina
Rivera, Luis
INECOA UNJujuy CONICET
Vivanco, Constanza
INECOA UNJujuy CONICET
Santillan, Miguel
Museo Hist Nat La Pampa
Vergara, Pablo M.
Universidad de Santiago de Chile
Wynia, Amy
University of North Texas System
Politi, Natalia
INECOA UNJujuy CONICET
Journal
Ornithology
ISSN
0004-8038
2732-4613
Open Access
green
Volume
138
In the Northern Hemisphere, several avian cavity excavators (e.g., woodpeckers) orient their cavities increasingly toward the equator as latitude increases (i.e. farther north), and it is proposed that they do so to take advantage of incident solar radiation at their nests. If latitude is a key driver of cavity orientations globally, this pattern should extend to the Southern Hemisphere. Here, we test the prediction that cavities are oriented increasingly northward at higher (i.e. colder) latitudes in the Southern Hemisphere and describe the preferred entrance direction(s) of 1,501 cavities excavated by 25 avian species (n = 22 Picidae, 2 Trogonidae, 1 Furnariidae) across 12 terrestrial ecoregions (15 degrees S to 55 degrees S) in South America. We used Bayesian projected normal mixed-effects models for circular data to examine the influence of latitude, and potential confounding factors, on cavity orientation. Also, a probability model-selection procedure was used to simultaneously examine multiple orientation hypotheses in each ecoregion to explore underlying cavity-orientation patterns. Contrary to predictions, and patterns from the Northern Hemisphere, birds did not orient their cavities more toward the equator with increasing latitude, suggesting that latitude may not be an important underlying selective force shaping excavation behavior in South America. Moreover, unimodal cavity-entrance orientations were not frequent among the ecoregions analyzed (only in 4 ecoregions), whereas bimodal (in 5 ecoregions) or uniform (in 3 ecoregions) orientations were also present, although many of these patterns were not very clear. Our results highlight the need to include data from under-studied biotas and regions to improve inferences at macroecological scales. Furthermore, we suggest a re-analysis of Northern Hemisphere cavity orientation patterns using a multi-model approach, and a more comprehensive assessment of the role of environmental factors as drivers of cavity orientation at different spatial scales in both hemispheres.
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