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Amazing eggs

Credits: Steve Waterhouse

Think of eggs and the types of animals that lay them, and the first one that comes to mind is probably a bird. The breeding season is a busy time of year for them, and for a short while all their attention will be focussed on these delicate, precious objects. But they're not the only animals in the UK to lay eggs, as we discover here...  

Brilliant birds

Birds lay a few, hard-shelled eggs, often in finely constructed nests hidden carefully from sight. Bird eggs come in many sizes and colours - from bright blue, to speckled white to spotted browns. Birds such as the oystercatcher which nest on open beaches camouflage the shells of their eggs with black flecks, helping them to blend in. Birds like gulls which nest on high sea cliffs have pointed eggs that are less likely to roll off!

 

The blue tit lays the most eggs of any small UK bird - sometimes up to 14! The mother doesn't start to incubate them until she has completed her clutch, which means that some eggs may wait for two whole weeks before being sat on and warmed up. They very often still hatch!

 

Amazing amphibians

Most amphibians lay many more eggs at once than birds and need water or damp places to do so. The soft eggs are often clustered together which protects some of them from hungry predators.

 

Jelly-like frogspawn sits in large clumps, toadspawn is strung out in a long line, and newts stick their eggs to the undersides of water plants.

 

 

 

 

Remarkable reptiles 

Reptile eggs are not quite as hard as bird eggshells, but are not as soft as frogspawn. They have leathery cases which are easy for the young to break out of. Reptiles do not incubate their eggs by sitting on them like birds do, but some - like the grass snake - seek out warm places to bury them to help them develop faster.

 

Grass snake eggs are sometimes found in garden compost heaps, using the warmth of all that rotting fruit and veg to help them grow!

 

Incredible insects

Some of the tiniest but most numerous eggs are those of the insects. The cases of eggs laid by minibeasts such as butterflies are often packed full of useful nutrition.

 

Young insects - like these glow worms - sometimes eat the cases once they've hatched, giving them their first easy meal.

 

 

 

Fantastic fish

Many fish lay thousands of eggs at once, often leaving them to take their chances in a world full of enemies. Others, like the stickleback, take their parenting duties much more seriously.

 

When trying to attract a mate, the male stickleback builds a tube shaped nest on the river bed, advertising it to passing females with poses and dancing. If a female takes a fancy to it, she will lay her eggs inside for the male to guard all by himself!

 

Have you seen birds near you gathering nesting material to build their nests? Why not become a Nest Investigator by downloading our special recording sheet and write down all your observations!