First of all, let’s get the big science words and what they mean out of the way, and then we can move on and get down to the fun facts.
Ornithology: The zoological study of birds. The word comes from the Greek ‘ornis’ meaning bird.
Oology: A branch of ornithology focused on the studying of birds’ eggs, nests and their breeding behaviours. Oology also refers to the “hobby” of collecting eggs of wild birds, this hobby is also commonly called egg collecting, birdnesting and egging – it is very much illegal in the UK (except for those specially licensed).
Oviparous: Animals that reproduce by depositing fertilised eggs, that are cared for by either or both parents outside of the mother’s body.
Nidification: The act of building nests. From the Latin ‘nidificatio’ and comes from nidus – a nest.
The history of egg collecting
Eggs have always been collected, and historically this was mostly for food. It wasn’t until the Victorian era that collecting eggs for more than just food became increasingly popular.
What began as a hobby of elite gentlemen working with local collectors scouring the land for rare and exciting eggs, trickled down to more serious naturalists and even lay people.
Some wealthier gentlemen also paid collectors on overseas expeditions to collect eggs to enhance their collections. The desire to collect eggs became so popular that every year thousands of eggs were being removed from nests. This began to impact populations of more desirable species, particularly birds of prey.
Three peregrine falcon eggs from the Horniman’s egg collection
The largest collection around this time was assembled by Lord Rothschild (creator of his own museum in Tring– later Natural History Museum at Tring) whose collections reached around 200,000 eggs.
The Natural History Museum holds the largest comprehensive collection of blown bird eggs – where the insides of the eggs have been removed through a hole in the shell – numbering around one million.
The collecting and possession of eggs became illegal in the UK through the introduction of the Protection of Birds Act 1954 and Wildlife and the Countryside Act 1981, though unfortunately there are still some that illegally poach the eggs of wild birds today.
Cadbury’s Assorted Chocolates box full of different British bird eggs resting on cotton wool
Eggs at the Horniman
The egg collection at the Horniman Museum and Gardens is not as large as the Natural History Museum collection but it is still significant. It is made up of many very different collections – mostly small-scale amateur ‘chocolate box’ collections, and a few more comprehensive cabinets containing examples of clutches of eggs taken mainly from British species. It also contains a small number of specimens from around the world.
Four eggs of an Adelie penguin and two Arctic Skua, (now South polar skua) obtained by Captain Colbeck on the National Antarctic Relief Expedition 1902
But it’s not just birds’ eggs that the Horniman has. We also hold:
- reptile eggs
- shark and fish eggs
- amphibian eggs
- mollusc eggs
- and even a replica dinosaur egg.
As well as dried and blown eggs we also have eggs that are kept in preserving fluids, to keep the insides of the egg as well as its outsides for scientific research.
So now to some fun facts!
What is the smallest bird egg?
The world’s smallest bird egg is laid by the world’s smallest bird. This is the bee hummingbird, whose eggs are the size of a coffee bean.
What is the largest bird egg?
The largest egg is that of the ostrich. Their eggs are 15cm long and 13cm wide, and they can weigh 20 times more than a chicken egg. Oddly the ostrich lays the smallest eggs in relation to its body size – whereas the Kiwi lays the largest egg in relation to its body size.
The kiwi egg takes up 20% of the mother’s body weight. To give you an idea, human babies usually only take up 5% at full term.
So why such a huge egg?
The egg of the kiwi is mostly made up of yolk (the yellow bit that feeds the developing young). This substantial yolk enables the chick to hatch far more advanced than other birds, being fully feathered and independent. Adult kiwis don’t even have to feed their young after they hatch as they are able to use the energy from the yolk until they can feed and look after themselves.
Which bird lays the most eggs?
The Mallee fowl (an Australian bird distantly related to the domestic chicken) can lay between 3-33 eggs producing some of the largest clutches seen in birds.
It takes the domestic chicken around 24-26 hours to produce an egg, and they can lay around 25 eggs per month totalling roughly 300 per year. Their eggshells can have as many as 17,000 pores, and a female hen will rotate her eggs 50 times a day to ensure that the yolk doesn’t stick to the inside of the shell.
In 1971 in New York Diane Hainsworth cracked open an egg that one of her chickens had laid to discover that it contained nine yolks inside it.
What are the oldest eggs?
The oldest decorated eggs were from South Africa dating to as far back as 65,000 years ago. These ostrich eggs were possibly used to carry water through the Kalahari Desert. Their decorations were made by scratching into the shell enabling the whiter undersides to stand out more from the creamy colours of the eggs surface. It is thought that these decorations were used as a means of identifying whose egg was whose.
So enough about bird eggs! There are numerous other animals that lay eggs including a group of mammals.
Mammal eggs
The only mammals that lay eggs are the monotremes which include the platypus and the two genera of the echidna. These eggs are not the same as bird eggs, looking slightly more like reptile eggs due to having a more ‘leathery’ shell.
These animals retain their eggs within their bodies for a few weeks before laying them – the mother provides the eggs with nutrition during this time.
Taxidermy mount of a platypus
Birds are also not the only animals that build nests for their eggs.
The three-spined stickleback is a small fish that can be found in the waters of the UK. The males build a nest by digging a small pit which they then fill with vegetation such as algae. The male then sticks this all together using a substance from its kidneys called spiggin.
The male then swims through the nest to make it a tunnel, which the female then enters to lay around 400 eggs. The male then fertilises these. The eggs are ferociously defended by the male of other fish until the eggs hatch a few weeks later.
Eggs at the Horniman
Although the Natural History Gallery is closed for its transformation as part of our Nature + Love project you can still see some decorated Easter eggs from Poland in the European section of the World Gallery. This tradition has been active for around 1,000 years with many designs and techniques coming from the different areas of Poland and beyond.
You can also see a taxidermy mount of the North Island brown kiwi in our Natural History Pop-up. Try to imagine what it must be like to have an egg of such a size inside that small body!
Members’ can hear more from Chris about some of the wonderful eggs and nests in our collection at Members’ Meet the Curators on 17 April.