Magpies may not be a pesky Australian import—new research finds their ancestors thrived in NZ a long time ago

For many New Zealanders, the Australian Magpie is a familiar, but sometimes annoying view. Introduced from Australia in the 1860s, the Magpies were known for their territorial diving bombing during the nesting season, which cemented their reputation for unwanted importation.

But our new research reveals a fascinating turn in this story.

For more than two decades, we have found fossils from sites near St Bathans in the center of Otago. These sites, once at the bottom of a large prehistoric lake, offer the only significant overview of the land vertebrates of the New Zealand Aotearoa of around 16 to 19 million years ago.

This unique window on the past has recently revealed fossils belonging to an ancient Australian Magpie. This discovery suggests that Magpies has a much deeper link with Aotearoa than we thought previously, which questions common perceptions about their “Australian immigrant” status.

With the fossils of other singing birds of St Bathans, these discoveries reshape our understanding of what it means for a species of being “native”. They brush a painting from a dynamic and constantly evolving country, rather than a static pre-human ecosystem.

An old parent

We have named the species that we describe in our research the St Bathans Currawong (Miostrepera Canara). He lived in New Zealand about 19 to 16 million years ago at the start of Miocene.

This bird, roughly the same size as the Australian Pie today, was a Cracticine – a group of singing birds which includes modern currawongs, pies and butcher birds. His discovery questions the very notion of what is “native” or “introduced” on a geological time scale.

We often consider Magpies as an unwanted Australian species which has no room in the New Zealand ecosystem. However, his close relatives have lived here in the past, and probably do so until a cooling climate limits their habitat towards the end of the Miocene, about five million years ago.

The presence of this former ancestor Magpie strongly suggests a dispersion event on Australia water at Zelodia at the start of the evolution of the Magpie-Currawong group.

We propose that this colonization has probably been helped by a subtropical flora or at a diversified hot temperature then present in New Zealand. This vegetation has created a hospital environment for species from Tasman.

Currawongs eat a wide variety of fruit, insects and small animals. New Zealand’s flora of Miocene of Miocene included many fruit trees, of which Poliri and Taraire are two survivors and offered abundant food.

Constantly evolving ecosystems of New Zealand

Our research on the fossil sites of St Bathans reveal a past far from a static and immutable paradise before human arrival.

We know by numerous pollen studies that New Zealand forests have evolved continuously for millions of years. This continuous reshuffle of the composition and distribution of forests questions the objective of common conservation to return New Zealand to a pre-human ecological state.

Indeed, during the Miocene, the forests of New Zealand would have been unrecognizable for modern eyes. They boasted of many eucalpts, laurels and casuarinas – plants more typical of Australian forests in Queensland today. This rich floral diversity supported a wider range of fauna, including the newly described Currawong, illustrating how different Aotearoa has been.

A symphony of ancient singers birds

Additional research of our team on other fossil singers birds (of the Order of Bird Passeriforms) of St Bathans painted an even richer image of old avian life.

Our analysis of the diversity of tiny legs of the legs indicates that the Bush of New Zealand of early Miocene had many more types of singers than just before human arrival.

Our studies demonstrate the presence of potentially up to 17 different singers birds in the primitive fauna of Miocene. This old choir included species varying in size with large honey (from the Meliphagidae bird family), which was larger than today’s Tūī, to a small Wren from New Zealand. Several different families are also represented.

These results suggest that zealania had a much greater diversity of singers at the start of Miocene than in Holocene (last 11,000 years).

Inheritance of the cooling of the miocene climate

Why these various old singers birds, including the St Bathans Currawong, disappeared?

Research indicates spectacular global climate change. From around 13 million years ago, during the last part of the Middle Miocene, New Zealand experienced a rapid cooling period. This deep climate change has sparked a drastic loss of floral diversity throughout the medium and late Miocene.

Many plants that prospered in warmer climates have turned off. This loss of life of plants has had devastating cascade effects on birds. The disappearance of many fruit trees meant the decline and the possible local extinction of birds such as Currawongs and certain pigeons that counted on these food sources.

A lower complexity of the habitat and less types of food have led to a significant decrease in the number of species of singing birds.

The story of St Bathans Currawong and the rich diversity of singer birds of New Zealand ancient serves as a powerful recall that ecosystems are not static. They are constantly evolving, shaped by climate change, geological events and dispersion through the ocean.

Understanding this deep story allows us to see concepts such as “native” and “introduced” with more nuances. We then appreciate that the biodiversity that we have today is only an instant in a long, dynamic and always non -folding story.

Changes are to be expected and underway, as the most recent of the native birds in New Zealand show – the barn owl and the Australian wooden duck – which is self -produced in the last decade.

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