17.04.2025, Treasure of the month: Eggs and nests at Museum Koenig Bonn

We are in the starting blocks for the egg hunt: it's only a matter of hours until the Easter bunny fills his hiding places. The search for real eggs - which are not made of delicious chocolate - is also a real passion for researchers. Museum Koenig Bonn is home to many specimens, some of which were collected over 100 years ago by museum founder Alexander Koenig. This month, we are taking a closer look and introducing you to our egg and nest collection.

Bird eggs have their very own science dedicated to them: oology describes their shape, size, weight, colour, pattern, structure and degree of hatching. Eggs were collected as early as the late 16th century and exhibited in the cabinets of curiosities of the time - a forerunner of today's scientific collections in natural history museums. However, with the first scientific expeditions at the turn of the 18th and 19th centuries, the collections and the first natural history museums were systematised. Eggs were now prepared in such a way that they are still preserved for us today. Basically, this works in a very similar way to how we prepare our chicken eggs for colouring today: The inside is blown out and the outside is properly cleaned before they are very carefully stowed away in the drawers of the collection.

Museum Koenig Bonn has a total of around 85,000 bird eggs in around 22,000 clutches, which bird researcher Dr Till Töpfer keeps in his collection. The collection began in the late 19th century, when Alexander Koenig began systematically collecting and curating during his school days. Probably the most historically significant eggs in the collection come from the giant auk, which Koenig purchased in the early 1900s when the bird was already extinct. Three of the eggs can still be found today in the bird collection at the Museum Koenig Bonn. From the small hummingbird egg weighing around one gram to the ostrich egg weighing around 1.5 kilograms, Alexander Koenig collected or purchased around 40,000 eggs himself - which makes up almost half of today's collection.

Curator and Head of Ornithology at the Museum Koenig Bonn, Dr Till Töpfer, in the bird collection.

There are also specimens of the crowned lapwing in the drawers of the collection.

The information card was handwritten by museum founder Alexander Koenig, who had integrated these lapwing eggs into the collection himself.

Kiwis lay very large eggs compared to their body size...

...while the hummingbirds are among the smallest specimens in the collection.

Ostrich eggs are available in the collection in many different variations and colours.

The eggs of the nightjar show very different spots on the shell.

They look as if they have been specially painted for Easter: Tinamou eggs. But so beautifully shiny and colourful, they are laid directly in the nests by the birds.

Till Töpfer has also shown the egg collection to WDR

There is always a suitable nursery for the eggs so that they are protected from the weather, temperatures and enemies. The diversity of the bird world is matched by the diversity of their clutches, as the nests ultimately have to match the living environment of their inhabitants. The blackbird, for example, builds its nest with the material it finds in its environment. As a true city bird, this can also be plastic film, paper or textile scraps. The Southeast Asian red-fronted tailor bird opts for a little more exclusivity when building its nest and lives up to its name by tailoring: Leaves on a shrub are carefully punctured and sewn together with plant fibres to form a sturdy funnel that can carry eggs and birds.

Even tiny birds lay eggs: here we see a hummingbird egg in its nest. They are among the smallest items in the egg collection.

A highlight from the egg collection: three specimens of giant auk eggs.

Clutch of goshawks (Accipter gentilis) with historical scientific name ("F. palumbarius") from the Alexander Koenig Collection.

Great pictures of our nests are also in the Leibniz magazine!

If you still want to look for eggs at Easter, you can also do so in our museums: Here at the Museum der Natur Hamburg, you will also find two large specimens in the zoological exhibition. Perhaps real egg hunters will find out which species they come from. At Museum Koenig Bonn, there is also an Easter quiz at the entrance that turns your visit to the museum into a little Easter challenge.

Easter opening hours

Museum Koenig Bonn:

Open on all Easter days from 10 am to 6 pm.

Museum der Natur Hamburg - Zoology:

Open on Saturday and Sunday from 10 am to 5 pm. Closed on Friday and Monday.

Museum der Natur Hamburg - Mineralogy:

Closed.