Because of the hummingbird’s small size, these eggs are some of the tiniest in the world and are laid in a nest the size of a walnut.
Where the female lays her eggs all depends on colour. If their pattern is vivid, she will lay them at a site that matches their darker colour, but if it is weak, she will hide them away somewhere more beige. Mysteriously, each female knows the colour of her eggs before they are laid.
The pale blue colour of these eggs may help to camouflage them by imitating the dappled rays of sunlight hitting the surrounding green leaves.
Temperature is critical for house wren eggs. If a burst of sunlight breaks through the trees and warms the eggs to 40 degrees Celsius (104 degrees Fahrenheit) for just an hour, the chicks won’t survive.
An osprey nest is constantly changing. When eggs are first laid, the nest is specially built to prevent them rolling out. After the eggs have hatched, the nest becomes wider and more material is added to the sides.
One emu egg is the equivalent in size to 12 chicken eggs. Emus lay some of the largest eggs in the world, second only to the ostrich.
These eggs are buried and left to fend for themselves. Hidden away beneath a mound of earth and soil, once they are ready to hatch the chicks must lie on their backs and use their feet to dig their way out.
The cunning little cuckoo creeps into other nests to lay its eggs and then sneaks away. To make sure they go unnoticed, their shells mimic the colour of the host’s eggs to trick other birds into accepting the eggs as their own.
Kestrels are busy birds and don’t have time for basic chores like nest building. These mottled eggs can mostly be found squatting in the disused nests of crows or balancing on the ledges of cliffs and buildings.
These eggs are specially designed for the high life. The unusual conical shape prevents them from rolling off the cliffs where they are laid. Not only do they defy gravity, but they are also self-cleaning, removing salt spray from the sea and waste from the many other birds around.
These flimsy nests are built floating on lakes, which the males stand on while caring for the eggs. Unlike most eggs, they’re waterproof, so if they do happen to fall in, there’s no harm done.
The perfect disguise for a large egg is camouflage. The dark brown colour blends perfectly with the nests made from twigs and matted grass, built by diving to the bottom of lakes to collect mud and vegetation.
Scientists aren’t really sure why these eye-catching eggs are so blue, but it’s thought that male robins make better parents and are more likely to care for their young the brighter the eggs are.
Image from www.flickr.com/photos/stuutje