Eggs must be fertilised to hatch into chicks. Parent birds incubate eggs to keep them warm so that the embryo can develop. The yolk and albumen in an egg provide all the nutrients needed for development into a chick. The albumen also protects the embryo from bacterial and other microbial attacks. The porous eggshell allows the chick to get its supply of oxygen.
In the wild, if eggs are taken by predators, birds will often lay another clutch. In Bird Paradise, we carefully collect the eggs of very rare species when they breed. The parents will then produce another clutch of eggs, and we can double our chances of raising chicks! The eggs collected are artificially incubated.
The eggs of rare species are artificially incubated and hatched in the Avian Health, Nutrition, Breeding and Research Centre. The chicks are then cared for by our `bird nannies’ who hand-feed them with specially prepared formula every two to three hours. The formula must be around 38°C – if the food is too hot, it will burn the chicks’ crop. Too cold, the chicks will get indigestion.
Egg candling is the process of holding a light near an egg to check for fertility and to monitor the development of the embryos. Bad eggs (infertile or with dead embryos) can be identified and removed to avoid the risk of rotten eggs exploding and contaminating the other eggs. Egg candling is regularly conducted at the Avian Health, Nutrition, Breeding and Research Centre.
The extinct elephant bird laid the largest egg ever. Each egg weighed about 10Kg! Amongst all the living birds today, the ostrich ranks the top in producing the largest egg. One ostrich egg holds a volume that is equivalent to 25 to 30 chicken eggs!
Ostrich eggshell measures 3.5mm thick, the thickest amongst bird eggs, to withstand the weight of an ostrich during incubation.
All bird eggs start with a white base. Different amounts of bluish-green and reddish-brown pigments are added to create an amazing variety of colours on eggshells. Pigments are sprayed in a particular manner to create different streaks and spots. The colours and patterns are added just hours before eggs are laid.
Eggs vary amazingly in colours and patterns. Cassowaries lay large green eggs in well-camouflaged nests that blend in well with forest vegetation. Other birds lay eggs with streaks and spots that are great for camouflage to reduce predation. Macaws lay white eggs in dark tree hollows and scientists believe the stark colour allows the parents to locate their eggs
easily.
