Tern and oyster catcher eggs donated by Nick Boyce-Bacon in the Whangārei Museum archives at Kiwi North (2014.75 (1). Photo / Supplied
The beginning of spring is not always determined by fixed calendar dates, but is often defined by the phenological occurrences relating to plant and animal life cycle events influenced by the seasons.
Spring is possibly more noticeable in the country with the birth of lambs, flowering of daffodils and nesting of birds.
In fact, there is a science for the study of bird nests called Caliology, but it was the study and collecting of bird eggs that was of greater interest in the 19th century.
Oology, sometimes called egg collecting, birdnesting or egging, refers to the hobby of collecting wild birds' eggs, and during the 1800s it became increasingly popular.
The Victorians were obsessed with oology and caliology.
Naturalists and bird hobbyists enthusiastically collected bird eggs and nests for display in private collections and museums, the more experienced collectors being employed by such institutions for the sole purpose of broadening their natural history collections.
Although Whangārei Museum holds various bird egg collections and individual egg specimens, it is on a much smaller scale compared with larger museums, such as the Natural History Museum in London which holds an astounding 610,000 eggs in its collection.
Oology was seen as an entirely worthy and indeed wholesome hobby, especially for children who were out in the fresh air and learning their natural history at the same time.
Dedicated Victorian egg collectors would swap, sell or trade their eggs - creating fevered competition among wealthy or intrepid collectors.
Some enthusiasts would go to extreme lengths to collect eggs and although considered a hobby, it was not for the faint hearted.
One famous 19th century ornithologist was willing to have his tooth pulled out to remove an egg that had become stuck in his mouth after he had placed it there for safekeeping before climbing down the tree.
Another egg fanatic was strangled to death by his climbing rope while trying to reach a nest on his honeymoon.
Unfortunately, the history behind the museum's egg collections is patchy but they still provide a wealth of information in their own right for students and researchers alike.
Comprising native and exotic eggs with natural subtle and varied hues, these examples demonstrate how evolution has dictated the diversity of colour patterns in the bird eggshells for various purposes such as mimicry, recognition and camouflage.
Victorian oologists never dreamed of how their eggs would be used in the future and in some cases, these historical eggs have played a role in recent major scientific discoveries.
While the collection of wild bird's eggs by amateurs was considered a respectable scientific pursuit in the 19th and early 20th centuries, from the mid 1900s onwards it was increasingly regarded as being a hobby rather than a scientific discipline.
Thankfully, many of the vintage egg collections have found their way into museums or other types of research institutions where they can be used by scientists to help better understand bird taxonomy as well as recognise the effects of environmental pollution and climate change on current bird populations.
Although 19th century oology-mania has declined and the collection of bird nests and eggs is more regulated, there are still countless opportunities for today's amateur bird fandoms to study these perfectly formed wonders of nature.