Abstract
Abstract Populations that breed along steep elevation gradients show diverse physiological and morphological changes in response to the different environmental conditions. The latter has been discussed by Bergmann’s and Allen’s ecogeographic rules about body and appendage sizes and environmental temperature. We compared morphometric measures (mass, bill width, tarsus, wing, and tail length) of a Zonotrichia capensis population in two localities at different elevations with similar latitudes and photoperiods on the western slope of the Colombian Central Andes. We compared a Low Elevation locality (LE) at 1800 m a.s.l. and a High Elevation locality (HE) at 3853 m a.s.l. that have approximate wind speeds of 1.3 m/s and 8.4 m/s, respectively. During 12 months of sampling, we captured 46 adults using mist-nets; 26 in the LE and 20 in the HE. Each individual was sexed using molecular techniques at the Laboratory of Genetics of the Department of Biological Sciences of Universidad de Caldas. Individuals (males + females) from the HE had longer wings and tails than those from the LE (F1,44 = 5.93; P = 0.019). Also, wings of males in the HE were longer than those of females in both localities and tails of males in the HE were longer than those of LE males. Our results did not agree with what was expected according to Allen’s and Bergmann’s ecogeographic rules. Longer wings and tails increase sustainment, maneuverability, and balance in low atmospheric pressures and strong air currents and these conditions are found at high elevation habitats. Most likely, the longer wings found for HE males allow greater movement during territorial behavior. Further, these differences in morphological traits along elevational gradients could result from micro-evolutionary changes between localities or phenotypic plasticity of individuals exposed to different environmental conditions.
Highlights
Ecogeographic variations in the morphometry of bird populations have been associated with climatic, latitudinal, and elevational factors (Alderich & James 1991, Blackburn & Ruggiero 2001)
This study identified the morphological changes in a Z. capensis costaricensis non-migratory population at different elevations in the Colombian Central Andes
These studies suggest that the longer length in flight structures at high elevations is associated with low atmospheric pressure and strong wind speed
Summary
Ecogeographic variations in the morphometry of bird populations have been associated with climatic, latitudinal, and elevational factors (Alderich & James 1991, Blackburn & Ruggiero 2001). Large animals with smaller extremities expend less energy in thermoregulation because of their smaller surface to volume ratio This has been a reference framework to explain the morphological differences between bird populations exposed to different environmental conditions (Gutierrez-Pinto et al 2014, Sun et al 2016, Blackburn et al 1999). Environmental changes resulting from elevational gradients have been associated with variations in morphological traits between bird populations, as well as between sexes These such traits include body mass, plumage color, wing length, tail, peak, among others (Landmann & Winding 1995, Bears et al 2008, Blackburn & Ruggiero 2001, Graves 1985, Price 1991). It is suggested that each sex can respond differently regarding behavior and morphology with altitude (Bears et al 2009, Zammuto & Millar 1985)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
