The kakapo is a strange little bird. Native to New Zealand, this flightless parrot feels its way through the forest night with a set of modified, whisker-like feathers. And, as Last Chance to See made clear, the avian formally known as Strigops habroptilus isn’t above embarrassing a nature documentary host in its own awkwardly choreographed way.
There are only 126 kakapo left. These closely-managed birds are the vestiges of populations that spread over most of New Zealand until about 800 years ago. The arrival of humans, along with rats and our other commensal hangers-on, quickly eliminated almost all the kakapo in existence.
What remains of the kakapo that thrived prior to human arrival are bones and feces, often preserved in caves that birds inhabited. The traces of these avians record a New Zealand full of wonderful birds, the fantastic moa and Haast’s eagle among them. In particular, excrement – Kakapo coprolites – outline what individual birds were eating.
Studies of kakapo poop reinforced what naturalists had observed among the few remaining avians. Pollen and spores preserved inside the coprolites showed that the ancient birds foraged for a wide variety of vegetation just as their living relatives still do. But when a team led by Jamie Wood of New Zealand’s Landcare Research analyzed an approximately 900 year old kakapo turd from South Island’s Honeycomb Hill Cave System, they found something that has never been witnessed among the living birds. About 8.9 percent of the pollen in the coprolite came from Dactylanthus taylorii – a root parasite that produces a great deal of highly-scented nectar during the two weeks each year the plant flowers. No one had seen a kakapo feed on the “Hades flower” because the two didn’t exist in the same place.
Like the kakapo, the root parasite is quite rare. The Hades flower can only be found over four percent of its historic range, and is rare enough that botanists hand pollinate the plant when possible. Naturally, the flower is pollinated by the New Zealand lesser short-tailed bat – another island oddity who spends a great deal of time clambering over the ground in search of food – and rats, although the rodents often eat the flower rather than volunteering themselves as pollinators.
The remaining Hades flower populations are scattered across the North Island, far from the tiny patches of kakapo preserves. Yet the coprolite Wood’s team studied hints at an ancient connection between the two organisms. Perhaps, before humans fundamentally disrupted New Zealand ecosystems, kakapo were important Hades flower pollinators.
In the parlance of deep ecology, the Hades flower might be an anachronism. The plant persists, even though its chief pollinators have either gone extinct or been extirpated from the same habitat. A different cast of pollinators cropped up to maintain the essential reproductive exchange in the plant’s life cycle, representing a case of co-option rather than the normal state of affairs prior to human arrival.
Researchers have been searching for such traces of extinct interactions for decades. While unconfirmed, the idea that pronghorn owe their speed to now-missing cheetah mimics relies on the same logic, as well as Daniel Janzen and Paul Martin’s 1982 proposal that the palm Scheelea rostrata produces an apparent overabundance of fruit because, until recently, the plant relied on mastodons to consume, transport, and fertilize the nuts encased inside. Janzen and Martin urged their colleagues to stop thinking of the world as if everything had just popped into existence, perfectly balanced, not so long ago. Startling speed, an excessive profusion of fruit, and other natural history conundrums could be hints of prehistoric interactions that were severed in the not-too-distant past.
The trick, however, is testing these stories. To place both predator and prey, or herbivore and forage, in the same place at the same time is not enough. As far as dietary puzzles go, coprolites are one way to investigate these problems – each specimen is a time capsule from a brief period in an animal’s life. These clues have shown that Hawaii’s extinct Maui Nui Moa-nalo bird consumed a great deal of ferns, and that New Zealand’s own moa included small annual herbs in their diet.
Yet even records locked in coprolites must be interpreted with care. Pollen, especially, can be transported far distant from the plant it issued from. But Wood and coauthors propose that the kakapo in question really did feed on the Hades flower because of the plant’s natural history. The root parasite is only found close to the ground, and its extremely sticky pollen doesn’t travel far unless assisted by a pollinator. And since the bats that sometimes visit these flowers have only trace amounts of the plant’s pollen in their guano, Wood and colleagues point out, the 8.9 percent proportion of Hades flower pollen in the kakapo coprolite hints that the bird frequently drank the nectar of the flower, or possibly ate it. Even if the bird destroyed the flower, though, “pollen would potentially have adhered to the long whiskery feathers surrounding the kakapo’s face” and allowed the bird to pollinate whatever flowers it didn’t destroy.
So far, Hades flower pollen has only been recognized in the single kakapo coprolite. This might be attributable to the rarity of kakapo coprolites and the short season during which the Hades flower blooms. Given these facts of lifecycle and preservation, it’s not surprising that the connection has not been found before. We may soon find out whether the coprolite underscores a true connection, though. Last year, eight kakapo were transported to an island where the Hades flower still hangs on. Researchers set up camera traps to see whether or not the birds take any interest in the flowers.
Will kakapo again pollinate the Hades flower? We will have to wait and see. As Wood and colleagues argue, though, “The discovery that Dactylanthus may not be specifically adapted for bat pollination suggests that other ecological interactions currently thought of as specialized or mutualistic may simply be a legacy of extinctions and range contractions.” The root parasite isn’t so closely tied to a single, essential pollinator as previously thought. The plant might be able to thrive in other habitats where rich communities of nectar-feeding pollinators exist. Perhaps, the researchers propose, the Hades flower could be translocated to islands that lack predators but are rife with proxy pollinators. This is not restoration ecology, or an attempt to set back the clock to a time before human interference. This is a type of “rewilding” that is just emerging – an attempt to kickstart essential interactions in new combinations, creating patches of wild nature that have never been seen before.
Janzen, D., Martin, P. Neotropical anachronisms: the fruits the gomphotheres ate. Science. 215, 4528: 19-27
Wood, J., Wilmshurst, J., Worthy, T., Holzapfel, A., Cooper, A. 2012. A lost link between a flightless parrot and a parasitic plant and the potential role of coprolites in conservation paleobiology. Conservation Biology. 26, 6: 1091-1099