Toe be or not toe be?

What can bird toe pads and their genetic footprint reveal about Pacific parrots of the past?

Blog by Patricia Pillay, AMI Postgraduate Scholar.

Patricia Pillay working with parrot specimen

When you think of a bird, you might think of their vibrant feathers, distinctive calls, or their flight patterns. But have you ever wondered what we might learn from bird toe pads? In the world of ancient DNA research, something as small as a bird's toe pad can unlock vital information about species that lived long ago, helping scientists better understand the past.

At Auckland Museum, a collection of historical bird study skins (a type of taxidermy for research purposes) are playing a key role in shedding light on Polynesian avifauna, particularly Pacific parrots. Among these specimens, the Museum’s collection of Vini parrot toe pads has become invaluable in helping refine genetic identification.

The Power of Toe Pads: A Genetic Time Capsule

Toe pads might seem unremarkable, but they carry a wealth of genetic information. These small patches of skin are often the only source of DNA left from bird specimens collected decades —or even centuries— ago. In our dedicated Anthropology Palaeomolecular Lab at the University of Auckland, I’ve been able to extract genetic material from these preserved Vini australis parrot toe pads to reconstruct their genetic makeup. This historical DNA provides a vital reference point for comparison with the much older, often degraded, ancient DNA (aDNA) samples from archaeological sites.

*Vini australis*, LB6805, Collection of Tāmaki Paenga Hira Auckland War Memorial Museum
© Auckland Museum CC BY NC

Confirming Genus and Enhancing Taxonomic Confidence

One of the most perplexing challenges in studying ancient DNA is ensuring that the genetic sequences you recover can be accurately compared to known species. This is where the Vini parrot toe pad samples have proven incredibly valuable. By extracting and sequencing the DNA from these historical specimens, I have been able to compare them as a reference to ancient parrot DNA found from tropical Pacific archaeological bird bone samples. These comparisons increase taxonomic confidence, especially when ancient DNA is fragmented or incomplete.

To do this, we use DNA primers (short, specific single-stranded fragments of DNA) to amplify a targeted region of the mitochondrial CO1 (cytochrome oxidase subunit 1) gene. This gene is widely used in DNA barcoding, acting like a genetic fingerprint to help distinguish between species. Even with degraded samples, primers can selectively bind to matching sequences, making it possible to retrieve DNA needed for taxonomic identification.

Filling the Gaps: Adding to a Global Genetic Database

One of the fascinating aspects of working with ancient DNA is how often reference sequences for comparison are missing from global sequence databases like GenBank, which is produced and maintained by the National Centre for Biotechnology Information (NCBI). Many Pacific bird species, including some within the Vini genus, are underrepresented or absent from these databases. This makes it difficult to classify ancient samples with high confidence.

Thanks to Auckland Museum’s historical study skins, including well preserved bird toepads, new genetic sequences are now being added that were not previously available. These sequences not only improve the identification of ancient samples but also contribute to a more comprehensive global genetic database, supporting researchers across multiple fields.

*Vini australis*, LB8399, Collection of Tāmaki Paenga Hira Auckland War Memorial Museum
© Auckland Museum CC BY NC

A New Lens on Pacific Parrots

The genetic insights gained from historical bird specimens like the Vini parrots offer a new perspective on the diversity of Pacific species and their cultural significance. These toe pads act as a bridge between past and present, helping us uncover the genetic footprints of birds that have played an important role in Pacific ecosystems and human life.

As we continue investigating the genetic legacy left behind by birds in the Pacific, these small but powerful toe pads will remain essential to understanding how species evolved and interacted with people over time.

Conclusion

Birds, especially parrots, are culturally important in many cultures across Oceania and through the careful study of even the most unassuming parts —like toe pads— we can add to new information to birds of the past. Thanks to Auckland Museum’s parrot samples, we are gaining a richer understanding of the genetic history of East Polynesian endemic parrots, and further contributing to documenting Pacific biodiversity.

Acknowledgements

Patricia Pillay is a Doctoral student in Anthropology, School of Social Sciences, investigating human-bird ecodynamics in the Marquesas Islands supervised by Professor Melinda Allen, Associate Professor Anna Santure, and Dr Natalie dos Remedios. She is the 2024 recipient of the AMI Postgraduate Scholarship currently working with the Natural Sciences land bird collections supported by Dr Josie Galbraith and Ricky-Lee Erickson.

Archaeological materials in Patricia's PhD research are part of Professor Melinda Allen's ongoing project on Human Ecodynamics in the Marquesas Islands at the University of Auckland.