The Rat Island Saga

Guest Essay by Kip Hansen – 29 March 2021

RAT ISLAND, as it used to be known when it was overrun by rats, is a tiny speck way out in the west end of the Alaskan Aleutian Islands – which extend from the southwestern point of mainland Alaska and head out south and west towards the coast of Siberian Russia.

It is a little bit of rock sticking up out the Pacific Ocean to the south of the Bering Strait.  [ This Rat Island is not to be confused with the Rat Island in the Easter Group of the Houtman Abrolhos archipelago 78 km west of Geraldton, Western Australia.]

[ Note: This essay is a long ramble through the history of Rat Island and the efforts of well-intentioned environmentalist intervention there.  Read it when you’ve settled in for the evening with a cup of hot cocoa. ]

Recent science news outlets carried stories like this:  Island Overrun With Rats Completely Recovers in Only 11 Years After Ecosystem Had Been Decimated, based on this recently published study:  Indirect effects of invasive rat removal result in recovery of island rocky intertidal community structure.  In Australia, 9News covered the story here.

“An Alaskan archipelago once dubbed the “Rat Islands” have provided a stunning example of ecological recovery, a new study has said.  The group of islands are on the western edge of the Aleutian archipelago and had been overrun with rats since shipwrecks dating back to the 18th century . . .

The rats, not native to the local system, quickly drove it to the edge of destruction, preying on shore birds and their nests.

However, in 2008, a group of researchers led a conservation effort which removed the rats from one isle [Rat Island] – now renamed Hawadax – in 2008.

Merely 11 years later, the researchers said, the island ecosystem had made a great recovery.

“You don’t often get the opportunity to return to a remote location and collect data after the fact,” study lead author Associate Professor Carolyn Kurle said.  “Sometimes it’s hard to say that a conservation action had any sort of impact, but in this particular case we took a conservation action that was expensive and difficult, and we actually demonstrated that it worked. But we didn’t expect it to be so fast.”

All the reports based on the University of California San Diego Press Release are a Fairy Tale version of actuality.  I hope no one is surprised by that – University Press releases are designed primarily to boost the prestige of the University and thus help to attract further research grants.  In my experience, these press releases do more to distort actual study results than do stories that appear in the mass media. Almost everything in the University Press Release is – ermmm – not exactly true as presented and leaves out a great deal of important information.

The U.S. Fish and Wildlife Service tells this story:

“…Rat Island is a remote island in the Aleutian chain about 1,300 miles west of Anchorage, invasive Norway rats arrived via a 1780’s shipwreck preying on native birds and altering the native vegetation during the ensuing 220 years. The Rat Island restoration is the most recent project in a long campaign to restore otherwise healthy seabird habitat in the Aleutians.”  and  “With the rats gone, restoration partners and the Aleutian Pribilof Island Association agree that an Aleut (Unangan), name was a fitting tribute to the restored island. The U.S. Board on Geographic Names, at its May 10, 2012 meeting, approved the proposal to change the name of Rat Island to Hawadax Island in the Aleutians. Hawadax (pronounced “how AH thaa”) is a return to the original Aleut name, in acknowledgement of the absence of rats—a return the island’s previous ecological state prior to European/Japanese contact. The word ‘Hawadax’ roughly translates to “those two over there” as in “the island over there with two knolls”, referring to two modest hills on the island.” [ source ]

Isn’t it a lovely story?  Our good and brave United States Fish and Wildlife Service, along with a couple of partner NGOs wades into battle against those nasty rats, killing them by the thousands by bombing the island with poisoned bait  [nobody likes those rats anyway] and saving the day for Endangered Birds®. 

Everyone claims credit for getting rid of the filthy rats and “saving the island”…9News says “a group of researchers”,  UCSD says “a coordinated conservation effort”,  each of the  NGO partners claim to have led the effort “Together with Island Conservation and the U.S. Fish and Wildlife Service, The Nature Conservancy led a campaign to restore seabird populations.” says The Nature Conservancy.  “The restoration of the 10-square-mile island was led by Island Conservation,” says Island Conservation.

A better description of what took place is this:

“In 2008, the U.S. Fish and Wildlife Service, in partnership with Island Conservation and The Nature Conservancy, saturated Rat Island with brodifacoum-laced bait.” [ source

Basically, they bombed the island with poisoned grain from an airplane.

“Brodifacoum is a highly lethal … anticoagulant poison. … It is typically used as a rodenticide, but is also used to control larger pests such as possum.  It has one of the highest risks of secondary poisoning to both mammals and birds.”   [ source ]

More on the consequences of indiscriminately saturation-bombing an island with poison later.  In the meantime….all these stories leave out a whole century-long episode of the Rat Island Saga.

The Century of the Fox

You see, in 1984, also in order to “save” the Aleutian Canada Goose,  “Foxes were eradicated from Hawadax Island in 1984” and then, 24 years later,  “rats were eradicated in 2008 using aerially broad-cast rodenticide (25-ppm brodifacoum32).”  [ source ]

“Arctic fox were introduced to most of the Aleutian Islands for the purpose of fur farming by the Russians at the turn of the century. [the turn from  1700s -> 1800s — kh]…. Fox introductions significantly disrupted a relatively simple ecosystem. The food derived from occasional dead marine mammals and a wealth of bird life allowed introduced arctic fox populations to soar, thereby suppressing many bird species and endangering the Aleutian Canada goose. According to Murrie  (1959) the importance of birds in the diet of arctic fox is  evident when one considers 57.8 percent of Aleutian fox prey  throughout the Aleutian Islands is provided by native bird life.  This includes islands with large concentrations of storm-petrels  and auklets such as Kasatochi, Kiska or Amukta islands and islands having smaller bird population such as Rat Island where the  foxes’ diet is 28.8 percent rat and about 40 percent amphipods or beach fleas. [ and 30 % birds and sea mammal carcasses– kh ] On many Aleutian islands including Rat Island, ground nesting species such as the endangered Aleutian Canada goose and several seabird species have been extirpated by the introduction of arctic fox.“  and  “To assure recovery of the endangered Aleutian Canada goose,  islands at various locations in the Aleutian Islands are being cleared of introduced foxes to allow natural pioneering by or transplanting of Aleutian geese.” [ source ]

In many parts of the world, Canada Geese are considered an Invasive Species – yet this smaller (and cuter) Aleutian Canada goose, a sub-species of the Canada Goose,  was one of the first of the birds identified under the Endangered Species Act in 1967.  What endangered the Aleutian Canada Goose?  Rats?  No, the foxes. 

“The principal cause of the decline of the Aleutian Canada goose was predation by arctic fox (Alopex  lagopus). Foxes were introduced to many North Pacific islands for fur farming, principally between 1915 and  1939, but dating back as early as the  1750’s. This introduced predator decimated populations of many species of native birds on the islands. Geese were particularly susceptible to predation not only during egg and chick stages, but also as molting adults became flightless. In addition, suitable wintering habitat is disappearing due to urbanization and changing agricultural practices, particularly in the Central Valley of  California. [ source = USFWS Aleutian Canada Goose Fact Sheet ]

Forbidding the building of cities in the rapidly changing Central Valley of California was an unlikely approach to the problem of the Aleutian Canada Goose in the late 1960s.  Just as unlikely was attempting to force agricultural-practice changes there – “It is California’s most productive agricultural region and one of the most productive in the world, providing more than half of the fruits, vegetables, and nuts grown in the United States.” [ source ]  So, the Fish and Wildlife Service decided to go after the Aleutian Island’s foxes with an eye to their total elimination.  But not all of them, most of the islands were just too big and the terrain too rough to make such an attempt likely to succeed – but Rat Island, at just over 10 square miles (~27 km²), looked doable.

There was a usable abandoned shack leftover from previous human visits and the smaller, semi-detached island (lower right of this aerial photograph) could be reached at low-tide.  The island had no permanent human population and might make a good location to attempt to introduce the Aleutian Canada goose, in hopes that they would form a breeding colony there.  Note that there was no evidence that the Aleutian Canada Goose had ever bred on the island.

The story of the Great Rat Island Fox Hunt (I admit, I am the only one that calls it that –kh) is contained in a document labeled by the Fish and Wildlife Service “Internal Document – Not for Publication”.  “INTRODUCED ARCTIC FOX ERADICATION AT RAT ISLAND, ALEUTIAN ISLANDS, ALASKA,  SUMMER — 1984” by Kim Hanson, Mike Goos, and Fredric G. Deines. 

Here’s the description of the project from this official document:

”OBJECTIVE:  Remove the introduced arctic fox from the fauna of Rat Island to benefit the endangered Aleutian Canada goose.

METHOD OF STUDY:   Two biologists from the FWS ADC [Animal Damage Control] staff in Region 6 came to the Aleutian Islands for 65 days to remove all foxes from Rat Island. They used leg hold traps, M-44 coyote getters, predator calls, rifles and 12 gauge shotguns during their efforts.”

“For the first time, the Alaska Maritime National Wildlife Refuge recruited Animal Damage Control (ADC) personnel stationed in the “Lower 48″ to independently conduct a fox removal effort. Kim Hanson of Colorado and Mike Goos of North Dakota – were selected to perform the task. The effort detailed in this report spanned the period 25 May to 29 July 1984.”

“During the 65 day eradication effort on Rat Island, a total of 175 fox were killed. Of this number, 163 were adults and 12 were pups. The number of pups killed was small because the lactating females were taken before the pups were weaned, therefore, most of the pups starved before they could emerge from the den. According to estimates from placental scars, approximately 450 pups were eliminated in this manner. A special effort was made to accomplish this and it was a key factor in the success of the Rat Island fox removal effort!” [ source ]

In short, Kim  and Mike, both very experienced professional  hunters and trappers specializing in predator control, were armed up, supplied, and dropped off on the island as soon as weather permitted in the spring, with scheduled re-supply by boat,  intending to eliminate all the foxes before the season’s pups emerged from their breeding dens.   And they did.

The whole saga of the hunt, which is well worth reading for those interested in outdoor hunting and adventure stories, is included as an appendix to the report I’ve been quoting above.  It is Kim Hanson’s hunt diary – very readable and absolutely free of today’s apologetic nonsense about the necessary killing of invasive predators.    Here’s a sample:

June 16 (Saturday) -Well, it started out to be a pretty normal day. We loaded the packs and headed for the north end of Sandy Beach to hunt and set traps to Krysi Point. We called [used sound-making devices that approximate various wildlife sounds] the first beach and nothing came so we started to set traps and three fox came around the corner. Mike got two but he only had 10 rounds of ammo left to start with, so I snuck up to where he was and shot the third one. The day went on like that. We called two on one beach and were going to set traps in the middle. I laid my pack and rifle down and Mike said “come here, there’s a sea lion carcass and a fox”. He said, “get your rifle and two bullets”! I stepped up to where he was looking and about 10 yards away, two fox had their heads stuck inside this sea lion carcass. One looked up so I shot and the other one was right behind him, so I got them both with one shot. A few minutes later another one was coming down the hill to the carcass and one was peeking over the top. So I shot the one on top and as he rolled down the hill, the other one ran back up and I shot him and he rolled down right by the first one. On another beach, Mike called three up to about 10 yards, one right after the other. One had been carrying a pup and she put him down and came in to the hurt pup call. We ended up with 25 fox today. Could have had two more but we both ran out of bullets. Got back to cabin about 11 PM. Real tired, knees sore, missed radio check too (I shot 18 fox today and Mike got 7 because I had more bullets).”

A note on ”calling”:  “Fox responded to any reasonable imitation of their bark. A pheasant call might make a good fox call. The most effective call was a Burnham Brothers close range fox call that imitated the yelp of an injured pup.”

At the end of Kim and Mike’s stay, it was assumed (and later confirmed) that Rat Island was now officially Fox Free.

Did the Aleutian Canada Goose return?  No.  Did lots of those bird species return?  Not so much, you see, because with the foxes gone. . . the rats took over (again?) as the apex predator on the island. 

The top half of this illustration is from the paper that prompted our interest in Rat Island and shows how the rats reduced the number of birds thus the birds ate fewer intertidal grazers (snails and such) thus there was less algal cover (seaweed).  The huge recovery being celebrated by Carolyn Kurle et al. is on the right-hand side:  Rats gone, more birds, fewer intertidal grazers, more seaweed.  It is uncertain what the situation of the intertidal zone was during the reign of the foxes – or if it matters in any way at all. 

What is not being celebrated is the return of the Aleutian Canada Goose – which did not return because it was probably never there as far as anyone knows.  For 200 years, either the foxes or the rats (or both) have made Rat Island (now Hawadax Island) unsuitable for the goose and a bit dicey for many other shore birds.  In 1984, when the Great Fox Hunt was staged, there were not any large bird rookeries on Rat Island.  In fact, on a larger, nearby island, ”Amchitka Island was cleared of foxes by 1963, but attempts to reintroduce Aleutian Canada geese there at that time were unsuccessful, at least in part due to predation by a large bald eagle population…”  The focus of our attention today, Rat Island, also had Bald Eagles, which would have eaten the geese had they been there. 

Oh, did I mention the Bald Eagle disaster yet?   No, well then, here goes . . . .

“In 2008, the U.S. Fish and Wildlife Service, in partnership with Island Conservation and The Nature Conservancy, saturated Rat Island with brodifacoum-laced bait. A lot went wrong. Early snow covered and preserved the bait. Bald eagles, off their routine of feasting on distant salmon, ate the poisoned rats. Monitors recovered 422 bird carcasses, including 46 bald eagles and 320 glaucous-winged gulls. Opponents of rodent eradication call the project a “disaster.”

Advocates acknowledge the horrendous by-kill but cite ecological success. Today, the island, again called Hawadax, is rat free. Eagles are essentially recovered; gulls are more than recovered; and an entire ecosystem, including native plants and birds rarely (if ever) seen for 230 years, has been reborn. Surging back have been species including giant song sparrows (found only in the Aleutians), tufted puffins, black oystercatchers, rock sandpipers, Leach’s storm petrels, snow buntings, Pacific reed grass, longawn sedge, and crowberry.” [ source ]

Imagine the general public response if they had been told at the time that the US Fish and Wildlife Service had inadvertently killed 46 Bald Eagles (at least – this number is an after-the-fact body count, many others may have flown away to die at sea or on other nearby islands) in a single project at a single location.  Glaucous-winged gulls however are a very common, very abundant “sea gull” found over a very wide range; still, a pity to have killed 320 of them.

So, a great success – depending on your viewpoint.   This little 10 square mile (27 km2 ) island now has what is assumed to be a pre-rat/pre-fox ecosystem – apparently more desirable to environmentalists than the 200-year-old ecosystem that had developed there since the late 1700s.  The rat-and-fox version of Rat Island had been a haven and breeding area for Bald Eagles and Peregrine Falcons and, of course, foxes and rats.

There is no mention in Kurle et al. of Bald Eagles breeding now on the “New Improved Rat Island”  but there are more gulls and oystercatchers, both of which are plentiful on all the other nearby islands and are classified as Least Concern by the ICUN.  

However, Carolyn Kurle and her associates are thrilled that there is now more kelp in the intertidal zone:  

“…  we found a dramatic shift in invertebrate and algal cover dominating the rocky intertidal community on Hawadax Island after rat eradication. Specifically, 11 years post rat eradication, we found: 1) a significant increase in percent cover of fleshy algae, 2) significant decreases in grazers of fleshy algae (isopods, limpets, and snails), as well as four other invertebrate groups (anemones, mussels, seastars, and sponges), and 3) significant increases in the shorebird predators (Glaucous-winged Gulls and Black Oystercatchers) of these intertidal invertebrates both five and 11 years post-rat eradication. Isopods [link to drawings of isopods] were the only invertebrate that showed a statistically significant decrease in abundance five years post-rat eradication.”

This whole story is typical of the many instances of humans interfering with nature – even if it is to remove invasive rats (a good idea) and introduced foxes (it is a simply a choice – more birds?  more foxes?).

The decades-long justification for the fox and rat eradication was the restoration of the Aleutian Canada Goose.  That did not happen and is unlikely to happen, at least on Rat Island/Hawadax Island.  To successfully to do that, they’d have to eradicate the remaining Bald Eagles….

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Author’s Comment:

Humans have transported a lot of life forms from one place to another on the planet over the millennia.  Some of them intentionally and some unintentionally.  Once that takes place, what we call Nature takes over and what happens, happens.  Some of what happens we view as “good” and some we view as “bad” and a lot of it we don’t even notice.

Invasive species have the greatest effects on islands, as you probably already know.  Particularly rats, cats, dogs, pigs, goats, wild sheep and weirdly, the brown tree snake.   Add to those a lot of destructive insects and diseases….   A .pdf booklet of the 100 Worst Invasive species is available here (English)  and here (español).

Human attempts to rectify these intentional and unintentional transplantations almost never succeed in the way they were intended. 

Personally, I think that the two experiments on Rat Island, elimination of the foxes and then the rats are interesting and maybe scientifically important.  I am not surprised that the experiments did not achieve the stated goal: restoration of the Aleutian Canada Goose. 

Address your comments to “Kip…” if speaking to me.

Thanks for reading.

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via Watts Up With That?

March 29, 2021 at 08:20AM

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