Homeotherms, such as mammals and birds, have adaptations that protect developing offspring and young from the ill effects of cold.
The masnawi Lisān ul-tayr (1498; "The Language of the Birds"), an adaptation of Manṭeq al-ṭeyr (The Conference of the Birds) by the Persian poet Farīd al-Dīn ʿAṭṭār, is a similarly important work.
He went on to delineate some of the bird's adaptations, such as the bony ridges above each eye that make hawks look as if they have permanent frowns but are actually built-in sunshades.
These birds have special adaptations enabling them to extract and utilize efficiently the reduced oxygen levels at high altitudes.
They include Andean peaks, tropical rainforests and - 1,000km (600 miles) off the coast - the volcanic Galapagos Islands, home to the animals and birds whose evolutionary adaptations shaped Charles Darwin's theories.
Birds have various adaptations for flight, including a lightweight skeleton, two large flight muscles, the pectoralis (which accounts for 15% of the total mass of the bird) and the supracoracoideus, as well as a modified forelimb (wing) that serves as an aerofoil.
During the course of evolution, birds have acquired adaptations to manage their high mass-specific metabolic rate, including an increased of reactive oxygen species (ROS) protection and lower ROS production [ 55, 56].
There is also the possibility that birds show local adaptations in their orientation system affecting the functional characteristics of their compass systems, and how they perform these compass calibrations (Åkesson, 1994; Åkesson et al., 2002).
Apparently, birds lack some adaptation that would permit them to become viviparous.
It has been proposed that reduced genome size in birds represents an adaptation to the high rate of oxidative metabolism in birds, which results primarily from the demands of flight [ 1- 4].
