In 1965, a mountaineer climbed 6,000 feet and found a seabird's last two colonies; he spent the next 50 years keeping it from extinction

Most bird lovers probably feel happy watching from a backyard feeder. Geoff Harrow was not one of them. In February 1965, this Christchurch pharmaceutical salesman climbed into the Seaward Kaikōura Range of New Zealand, up towards country almost 6,000 ft above sea level, following a tip about “muttonbirds” nesting in the mountains. In a Forest & Bird profile of Harrow, David Brooks describes discovering a decomposing seabird, which turned out to be a Hutton's shearwater, a species whose breeding grounds had never been confirmed by science. He would spend the next 50 years protecting it.

A hunting tip led to a mountain search

Harrow first heard about the birds from Ivan Hislop, a motel owner near Kaikōura, who said that he and his brother had seen the burrows at an elevated site in the Kōwhai Valley more than ten years ago. Interested, Harrow decided to find out for himself and started searching in early 1965. This first try proved fruitless, as all he could hear were wild goats on the mountain. On the second day, while climbing down a deer track, he saw the carcass of a shearwater. Looking across, he noticed the other side of the valley was dotted with burrows. Harrow returned with three birds, and the Dominion Museum of Wellington identified them as Hutton's shearwaters, which had been scientifically described in 1912 but whose nests had never been found.

How the colonies disappeared

In the years that followed, Harrow returned to the mountains as many as eight times a year, taking off weekends and holidays from his day job. He discovered eight different nesting colonies in all. Over the course of two decades, six of these colonies were gone. Two were left, Kōwhai Valley and Shearwater Stream.

It turned out the predator was pigs, not stoats

For decades, it was suspected that the reason for the disappearing colonies of shearwaters was a group of stoats, small carnivorous mammals introduced to New Zealand from overseas, and Harrow frequently saw them around the burrows. However, a 2002 study titled ‘The role of introduced mammals and inverse density-dependent predation in the conservation of Hutton's shearwater’ published in the journal Biological Conservation, written by a British scientist, Richard Cuthbert, pointed to a different culprit: wild pigs. The research showed all six colonies that had disappeared had pigs present, while the two surviving colonies were in terrain pigs couldn't reach, suggesting pig access was the key factor in which colonies survived. They travel in family groups and dig through burrow complexes, and the study found they could eliminate a large colony in two years and a small one in a few weeks. At the same time, stoats were not capable of taking more than a certain number of birds each year, as the number of birds living together in one place was too great.

Counting the losses

Harrow estimated that when he began his surveys in 1965, the shearwater population in the areas he knew was about two million birds. However, as per his estimate, within 25 years, their number dropped to 500,000. These were rough field estimates, and more recent, more precise surveys, the 100,000 breeding pairs and roughly 400,000 total birds cited later, reflect improved counting methods rather than a further decline from that 1990 figure.

Presently, the IUCN Red List classifies Hutton's Shearwater as an endangered species since it is found at only two breeding sites in the world. It is also the only seabird known to nest in alpine terrain, making the protection of those two remaining sites especially urgent.

Building a backup colony by the sea

To reduce the risk of losing the birds in a single event, New Zealand's Department of Conservation began moving chicks from the mountains to a new habitat on the Kaikōura Peninsula in 2005. Even here, however, the birds were at risk from feral cats, which is why Harrow founded the Hutton's Shearwater Charitable Trust in 2008 to help fund an exclusion fence specifically targeting the predators found on the peninsula, distinct from the pigs that had devastated the original mountain colonies. Within one year, the trust says it collected $300,000, and the project was completed in the early part of 2010. Birds moved to the peninsula are raised in wooden nest boxes and fed sardine smoothies until they are ready to migrate to the coast of Australia.

The climber behind the conservationist

Harrow was a serious mountaineer well before the shearwaters. He joined Forest & Bird as a boy in 1936 and, by his early teens, was biking to Arthur’s Pass and joining a high school mountaineering club. Harrow was a member of Sir Edmund Hillary's New Zealand expedition to the Himalayas in 1954, the year after Hillary's ascent of Everest. The team had to abandon their Makalu bid when Hillary collapsed with malaria and broken ribs at 21,982 feet. Weeks later, Harrow and his climbing partner Colin Todd made the first ascent of the neighboring 23,389-foot peak Baruntse.

A legacy that outlived him

Harrow was awarded the Old Blue award from Forest & Bird in 2007 for his decades of work in conservation. He died in Christchurch on 16 January 2023, at age 96. Thanks in large part to his early discoveries and the protections that followed, the Hutton's Shearwater Charitable Trust estimates more than 100,000 breeding pairs and over 400,000 Hutton's shearwaters are now believed to use the two colonies he first found as a young man with a hunch and a pair of hiking boots.