Question

a) Briefly explain 2 factors (with specific examples) that might have affected the evolution of exaggerated ornaments or intense colors in males of several species of birds?

Answer 1

a.

i. The exaggerated ornaments in male birds helps in sexual selection of males by females. Females usually select males who have more ornamentation in their body. It has been proved that bright coloured males have healthier sperms and their sperm counts are more. They are often more resistant to parasitic infections.

Example: The male quetzal has elaborate ornamentation which help them to be selected by the females. male quetzals have brightly coloured green wing which covers their back, chest and head. They have also bright  red belly. In mating season thay also develop twin tail feathers with dazzling colour. Females which do not possess such structure choose those males which have more bright colouration and more elaborate ornamentation.

ii. Bright colouration also help some birds to end messages to other members of the same species and also help them to protect their territory.

Example: Many parrots by their bright colour warn other parrots when they want to invade their territory. Thus they show their dominance to other male parrots. Brighter birds are more stronger and dull males want to avoid them. Colors may also be flashed as a warning signal to other parrots in the colony which make them aware about approaching danger.