Physiological ecology of incubation of ptarmigan eggs at high and low altitudes

Abstract

The broad altitudinal distribution of ptarmigan Lagopus spp. makes this group an excellent model with which to ask how morphological and physiological specializations foster successful reproduction of birds at their distributional limits. Eggshell conductance and permeability to gases, shell surface area, shell thickness, daily water loss, and egg volume were measured in willow ptarmigan Lagopus lagopus breeding at 720 m a.s.l. and whitetailed ptarmigan Lagopus leucurus breeding between 3,600 and 4,100 m a.s.l. Of these characteristics, only egg volume and shell surface area differed significantly between the two species. Since the rate of daily water loss is similar at the two breeding locations, embryos develop in similar hydric environments inside the shell. High altitude embryos facilitate oxygen delivery with acclimatory adjustments in certain cardiovascular and cellular characteristics.

The comparison of blood characteristics in low- and high-altitude chickens

“…When lowland animals enter the plateau, hypoxia causes the number of RBC and HGB content to increase (Wideman et al 2002). A previous study showed that native whitetailed ptarmigan reared at high altitude had higher HCT than white-tailed ptarmigan reared at low altitude (Carey and Martin 1997).…”

“…TCs living in the low-pressure hypoxia environment of the plateau are part of a complex process. Previous studies have shown that there is a significant difference in chicken blood characteristics at low and high altitudes (Carey and Martin 1997;Gou et al 2005;Zhang et al 2007). TCs inhabiting high-attitudes have an increased number of RBC, oxygen affinity in blood and HGB concentrations and a decreased MCV to overcome an environment of harsh extremes (Zhang et al 2007).…”