More than 30,000 years ago
The fossil record for birds for the past 30,000 years is exceptional, but before this date the record is patchy at best and non-existent at worst. Penguins aside, the oldest fossil bird found in New Zealand was an albatross, whose fossils have been found in Oligocene rocks, formed 33.7–23.8 million years ago (Ma). This extinct albatross, Manu antiquus, lived around our ancient coasts.
Birds such as false-toothed pelicans (pelicans with serrated beaks) appear rarely in Miocene siltstones (23.8–5.3 Ma) in North Canterbury, and bird footprints of Miocene age are also known from the northern South Island at Murchison and Manaroa, Pelorus Sound.
In Central Otago there are fossil records of waterfowl, including ducks, geese and a host of other aquatic birds, preserved in Miocene lake sediments. Other fossils there include masses of freshwater fish bones.
Shearwaters and false-toothed pelicans have also been unearthed from Pliocene rocks (5.3–1.81 Ma). The Pleistocene epoch, the past 1.8 million years, has a better bird fossil record than earlier periods but is still poor. Only a few moa fossils up to 2 million years old have been found.
The last 30,000 years
Peat, swamp, dune and cave deposits mostly less than 30,000 years old have produced a wealth of bones from birds, many of which are now extinct. Included in this fossil record are moa, kiwi, various water birds, huge eagles, rails, shorebirds, parrots, passerines and oceanic birds that nested ashore. This record was unearthed from about 1850, when the scientific world was astounded by huge moa leg bones pulled out of swamps, dunes, caves and river gravels in New Zealand.
In England in 1839, naturalist Richard Owen identified a bone fragment brought to him from the North Island’s East Coast as belonging to a huge bird, the moa. Other Europeans such as Walter Mantell, who arrived in New Zealand in 1840, were also fascinated by the fossilised bones of this extinct bird and collected them wherever they travelled. Mantell bemoaned the Māori custom of smashing bones unearthed by erosion.
The founder of Canterbury Museum, Julius Haast, collected many moa bones and published papers on his discoveries. Most of these early finds came from dunes, swamps, Māori middens (rubbish heaps) and caves. In Central Otago, caves containing mummified moa with preserved soft tissue were found. Throughout the country, caves revealed the fossil bones of many other extinct birds.
New Zealand’s exceptional recent fossil record has allowed modern researchers such as Richard Holdaway and Trevor Worthy to show that a number of birds became extinct about the same time as humans arrived. Radiocarbon dates obtained from fossils from archaeological sites suggest that Polynesians arrived in New Zealand around 1250–1300 CE.
The fossil record has allowed many bird species to be studied in detail. In many cases this has allowed evolutionary links to be made between living and extinct species.