Moving Birds: Translocation in an Unraveling World

THE ISLAND OF NIHOA is, by all accounts, a difficult place to dock a boat. An isolated and uninhabited island in the Northwestern Hawaiian Islands, its sheer cliffs rise steeply out of the surrounding ocean. Arriving at the island involves the tricky job of skirting the boat along a narrow rock ledge and holding it steady in the heaving waves while people clamber out and unload gear. This is how a small team of scientists arrived on Nihoa in September 2011. Over the rocks they scrambled, carrying an assortment of cages, nets, and other equipment required to catch and transport 24 Nihoa millerbirds. Over the next several days, the team did just this, spreading out across the rocky island to catch, weigh, and band the birds. Once collected, the birds were carefully loaded onto the ship for the three-day sail to Laysan Island, 1,000 kilometers northwest of Nihoa.

The Nihoa millerbird (Acrocephalus familiaris kingi), also known by the Hawaiian name ulūlu, is just one of the many endangered species of animals, which, along with plants, have been shuffled around the world in recent years in an effort to stave off their extinction. Current and projected climatic changes mean that ever more species are at risk. If they are unable to move themselves or adapt, then translocation — sometimes called managed relocation or assisted colonization — becomes a viable and perhaps necessary option for the continuation of the species. Translocation is a complex topic with uncertainty at its core. But the millerbird offers us a way of understanding the stakes.

To borrow the words of Sheila Conant, a biologist who has studied the millerbird for much of her life, this is the story of a “tiny population, of a tiny bird, on a tiny island, where almost no one is going to go.” In appearance, the bird is pretty unremarkable, even drab: small, gray-brown, insectivorous, weighing in at a mere 15 grams. As Sheila puts it to me: “You might be able to post two of them with one forever stamp.” But all of the people who have spent time with these birds seem to have become captivated by them. Like many island endemics, unfamiliar with humans and other potential predators, millerbirds are bold and inquisitive, keen to explore new items or opportunities in the landscape. As they move through the scrubby vegetation in a manner that is as reminiscent of a mouse as it is of a bird, they expertly catch and consume insects of all kinds, from the smallest fruit flies to the island’s large trapdoor spiders. It is these kinds of behaviors that have allowed these birds to persist on a windy, harsh, salty, island with no real fresh water.

As a single island endemic with a small population, the ulūlu has always been at risk of extinction. Its dogged persistence thus far is in itself impressive. But in the coming years, climate change is expected to increase the frequency and intensity of large storms and hurricanes moving through the region, and may worsen current drought and fire patterns, any one of which might wipe the species out entirely. Meanwhile, increased shipping and movement in this isolated island chain might lead to the accidental introduction of damaging new species. The arrival of rats, for example, might rapidly decimate the millerbird population through their predation of eggs and chicks. As a result of these factors, in the mid-2000s the US Fish and Wildlife Service (USFWS) determined that a second “security” population of the species should be established.

Laysan Island was selected. On the surface, the key reason for this choice was that until the 1910s, when rabbits and other livestock were introduced, this island was itself home to a closely related, now extinct, subspecies: the Laysan millerbird (Acrocephalus familiaris familiaris). After decades of habitat improvement on Laysan, conservationists hoped that the relocation might simultaneously restore a missing piece of the ecology of the island and help to secure an endangered species. But they did not make this decision on their own. This translocation was part of the broader management of the Papahānaumokuākea Marine National Monument (PMNM), which in a range of ways includes Native Hawaiian, or Kānaka Maoli, representation. Taking up the work of assisted colonization in a colonized land is a particularly complex process that requires ongoing dialogue and collaboration with Kānaka Maoli communities about how these decisions are made and who gets to make them.


Over two years, in 2011 and 2012, a team of conservationists collected and relocated a total of 50 ulūlu to Laysan, a long, relatively flat island. At the center of Laysan, running most of the length of the island, is a huge, hyper-saline lake. The area selected to release the millerbirds was at the northern end of this lake, in a large expanse of vegetation dominated by naupaka, a low growing shrub with a distinctive half-flower. Although these birds had presumably never encountered this particular plant before, they settled in right away, quickly beginning to establish and defend territories.

And yet Laysan is far from being an ideal home for the millerbird.

On the positive side: Conservationists have now removed the rabbits and other introduced livestock, and revegetated large areas of the island. Laysan is also home to very large rookeries of several species of breeding sea birds, including Laysan and black-footed albatrosses, great frigatebirds, and sooty terns. In short, the island is in a much healthier state than it has been for almost 100 years, when its last millerbird inhabitants were extirpated and their subspecies extinguished from the world. The question, however, is how long it will remain this way.

And the negative part: Unlike Nihoa, Laysan is a relatively low-lying island, with an average height of about 10 meters. Dynamic inundation modeling indicates that with sea level rise of just one to two meters, the majority of the island’s millerbird habitat will likely be lost. Of course, the USFWS know this. They have explicitly noted that “[c]reating a second population of Millerbirds on Laysan is a short-term solution.” They are buying time. Laysan was selected, despite these very significant limitations, because all of the high islands in the Hawaiian chain that might have become a new home to millerbirds are already home to introduced rats and mosquitoes. While rats are being eradicated on some of these islands, the avian malaria that is spread by mosquitoes is a much more intractable problem. Indeed, these threats are so pervasive that the high islands can no longer really offer suitable habitat for any of Hawai‘i’s endemic forest birds. Of the 113 avian species known to have lived exclusively on these islands just prior to human arrival, almost two-thirds are now extinct. Of the 42 species that remain, 31 are federally listed under the US Endangered Species Act. [1] As Sheldon Plentovich, the USFWS team leader for the Nihoa Millerbird project put it to me, Hawai‘i’s ecosystems are not unraveling, they’re already largely unraveled. And so Laysan, despite its limitations, emerged as the best available option for ulūlu.

Seven years after their introduction, the millerbirds of Laysan are doing very well. From the original founding population of 50 birds, there are now thought to be several hundred. Millerbirds only live around seven years, so almost all of these birds hatched on Laysan. They are the rare, but much hoped for, result of a species translocation: a breeding, self-sustaining, population.

Part of me celebrates the fact that the resourceful little millerbird is, at least for now, a bit more secure in the world. But another part of me can’t let go of the fact that this is such an uncertain and ultimately short-term success. We just don’t know how long Laysan will remain a livable island for this new population. It is hard to believe that it will be more than 100 years. Laysan is not an ideal new home; it’s not even an improvement on Nihoa. In all likelihood, the new population will be lost before the old one.

None of this is to say that these birds ought not to have been moved. The point of a second population is to avoid having the whole species in one small, vulnerable, spot. My point is not to reject translocation. Rather, my concern is that all of these minor victories not distract us from the larger patterns of loss. Buying time for species like the millerbird is important. But buying time for what? Without the larger systemic changes that will actually make a difference for the species — foremost among them, effective action on climate change — “buying time” becomes nothing more than a process of delaying the inevitable: drawing out the death of yet one more species.

Sadly, it seems clear that the world is losing its capacity to sustain the ulūlu, despite the bird’s many adaptations to life in harsh conditions. There is simply nowhere left to move these birds that can offer them anything like a long-term future. Between the rats, the mosquitoes, the rising sea levels and the escalating extreme weather events, they are being squeezed out. Of course, this is true of so many species today. Many of Hawai‘i’s birds are in a similar, if not worse, situation as a result of these interacting conditions.

But there is something about the millerbird story that makes this “unraveling of a world” particularly palpable. Perhaps it is only when we actively take up the work of moving birds, when we free ourselves to ask, “Where else might they go?,” that we can see the full scale and significance of our situation. When we do this, we cannot help but find that the millerbird’s problem is not only that their particular island environment is likely to become increasingly unlivable, but that all of those places they might reasonably inhabit have already been made similarly, or indeed more, inhospitable. In short, by raising the possibility of movement we see that there is nowhere left to go.

To the extent that this is the case for a single species like the millerbird, imagine how infinitely more complex the situation becomes when we consider the vast numbers of species likely to become candidates for translocation in the coming years as our climate continues to change. The millerbirds of Laysan ought not to, indeed cannot, be understood as an exemplar of a new conservation paradigm. They do not signify a bold new future, but rather the desperate nature of our current situation. The simple fact of having to take on this work should disturb us. We are literally shuffling species around the Earth — with all of the risks, impacts, and costs that this entails — in order to buy them a handful of years.

We need to get better at telling stories of ambivalent success. Tales of what the anthropologist Anna Tsing has called “gardening in the ruins” [2] — of dedicated care and achievement that are nevertheless tinged with the unavoidable uncertainty of our Anthropocene epoch. The millerbird project was an ambivalent success not because the plan didn’t work out, but rather because we now live in a world in which the best plans, the best options, are so far from ideal, and far even from what might have been possible a few decades ago.

While the millerbird story is undoubtedly one of success, it is simultaneously a profound tragedy acted out across an ocean, a tragedy that must summon us into new modes of responsibility. In the coming years, we will likely need to ask, again and again, whether translocation is the right course of action, and if so when and where to, and who should decide? These are vitally important questions. But they are not enough. Moving birds will never be enough. We must also be moved by them, moved by the tragedy of so many unraveled and unraveling worlds, by the growing need to relocate so many of Earth’s species. If we are to responsibly take on the work of fledging new populations of animals and plants in distant places, then we must own up to the seriousness of this role. While I sincerely hope that the movement of the ulūlu has bought the species a little more time, my more solemn hope is that the story of this species, tangled up as it is with so many threatened others, might help to set in motion all those more substantial changes that are vitally needed to sustain all of our futures.


Thom van Dooren is an associate professor and Australian Research Council Future Fellow in the School of Philosophical and Historical Inquiry at the University of Sydney. He is the author of Flight Ways: Life and Loss at the Edge of Extinction (Columbia University Press, 2014).


Featured image: “millerbird on its new home turf” by USFWS Headquarters is licensed under CC BY 2.0.

Banner image: “Millerbird in release box” by USFWS – Pacific Region is licensed under CC BY 2.0.


[1] David L. Leonard Jr., “Recovery Expenditures for Birds Listed Under the US Endangered Species Act: The Disparity Between Mainland and Hawaiian Taxa,” Biological Conservation, 141 (2008): 2054-2061.

[2] Anna Lowenhaupt Tsing, “Blasted Landscapes (And the Gentle Art of Mushroom Picking),” in Eben Kirksey (ed.), The Multispecies Salon: Gleanings from a Para-Site (Durham: Duke University Press, 2016)