Enter Teachers' Guide

Many animals consider eggs an ideal food. They're nutritious, and relatively easy to hunt – they can't run away or fight. All a predator has to do is find them. So, to keep their eggs safe, a bird has to keep them out of reach or out of sight.

Most birds build nests for their eggs, but a nest is not a bird's "house." A nest is a safe place to hatch eggs and raise chicks, but some birds have found very different ways to protect or hide their eggs.

Lay an egg on a cliff ledge
The murre lays it's eggs right on narrow cliff ledges. Look at the shape of the egg and you can see why they don't roll off the edge: the eggs are very pointy, so they roll in a tight circle.

Hide an egg in plain sight, then trick predators
The killdeer lays its egg out in the open on rocky beaches. Its eggs are well camouflaged, so they're hard to find. The parent has a second defense: If a predator comes near, the bird will pretend to be hurt, moving as if it had a broken wing. It distracts the predator into following it, and leads it away from the eggs.
Roll over the image at left to see the egg more clearly.

Hold an egg on your feet
The emperor penguin has no predators that might eat its egg, and no materials to build a nest from. It's greatest need is to keep the egg warm. So, the male penguins take an egg and rest it on top of their feet, and underneath a flap of downy skin, and stand still. For two months! While the females are feeding at sea, the fathers stand still, without a single meal. They can lose close to half of their body weight as they live off fat reserves.

Some incredible nests
The hammerkop, an African bird, builds a nest that can weigh over 100 lbs. It's a huge, messy pile of sticks, and it takes weeks to build.

The weaver bird's name tells you what kind of nest it makes. It takes twigs and grasses and builds a hanging basket in which to lay it's eggs. Weavers and other birds will often use a hammerkop's nest as a starting point on which to build their own nests, turning the platform into a giant apartment building for different birds.

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