Earth & Sky

Interview with Tim Coonan

Right now, Channel Islands National Park is involved in a very aggressive recovery program for Island foxes. And island foxes are a species of canid that only occur on the Channel Islands. There’s six sub-species, they occur on the six largest of the Channel Islands, and they’re geographically isolated from all other canids. They’re one of the smallest canid species – they’re only as small as a housecat. So they’re a pretty special species, the only canid species, or even carnivore species that’s unique to the state of California. And prior to the mid 1990s, they were thought to be doing quite well, in spite of the fact that many of the sub-species lived at very small population sizes. That’s because islands themselves are very small. For example, in San Miguel, the most Island foxes that we’ve ever had there is about 400 — and that’s not many when you’re talking about a vertebrate species or subspecies. So, we started monitoring their populations in the early 1990s, and that’s because we were very interested in how they were doing, really for two reasons. First of all, they are fairly rare, so if we’re going to worry about any species, we’re going to worry about the rare ones first. Secondly, they were thought to be somewhat of an indicator species for the Channel Islands. They’re the largest native terrestrial vertebrates on the islands, and so our thinking was, if we’re monitoring these guys, they may indicate how the ecosystem is doing. And so we started doing that in the early 1990s, we started trapping them every summer on San Miguel Island, and basically counting them – estimating how many foxes we had on San Miguel Island. And the news at first was fine. We thought we had 300 foxes there in 1994, and it went up to 450 in 1995, and then it appeared to drop back down to 300 in 1996, but beyond that, the drop kept getting deeper, ^^^ and we knew that we had a serious population decline on our hands, but for no apparent reason, because we were also monitoring the populations of some of their prey species, such as deer mice – and deer mice populations are doing fine as a matter of fact. There was no lack of food on the islands. We started investigating he possibility that a canine disease had gone through their population, because it appeared to act that way. We saw the decline on the west end of San Miguel first, and then on the east end. So we pulled blood samples from foxes on all six islands where they occured, and we looked for evidence of exposure to canine diseases such as distemper or parvo virus, and we found nothing that could explain the kind of decline that we were seeing. So in 1998 we put radio collars on island foxes in San Miguel, and that really did the trick for us – that told us what we were looking at. Within four months of putting radio collars on, six of our eight study animals had died, and four of those six had died from golden eagle predation, which was very unusual in that had never seen golden eagles out there at other times of the year, and also golden eagles are not known from the Channel Islands at all. They never bred there naturally. Bald eagles bred there, but bald eagles had disappeared from the Channel Islands by 1960 due to the effects of DDT in the ecosystem out there. So we were really taken aback by this evidence of predation, and that evidence is pretty obvious – when we found the caracsses of the radio collared animals. They had been eaten in such a manner as to suggest that a large raptor such as a golden eagle had eaten them. And those deaths came at the same time as observations of golden eagles in the environment, and at a couple of carcasses – feathers were left behind. ^^^ We had those feathers analyzed at the Fish and Wildlife Services Forensics Lab, in Ashland, OR, and they identified them as not only being from Golden Eagle, but they’re very specific up there. They identified them such as being the the rump feather of an immature golden eagle, etc… So that was really a smoking gun. And at the same time, a companion study was going on at Sant Cruz Island, two islands to the east of us, on San Miguel, and they were coming up with the same conclusions. So here we had, really a massive population decline of island foxes that had taken place from about 1995 to 1999, and the population plummet was so deep that that it was 95 to 99% of the animals that were out there. For example, in San Miguel, we think we had 450 foxes in 1994. By the time we brought some into captivity in 1999, there were only 15 left. There were only 14 left on Santa Rosa Island, and that’s from an estimated population of about 1500 or 1600. So, we were dealling with very large declines due to an unusual situation. A predator that apparantly recently arrived on the scene, and for which the foxes were little equipped to deal with. And that’s because the island fox is more diurnal, its behavior occurs more in the daytime than other carnivoirs on the mainland, which are more nocturnal. So consequently, they’re exposed to diurnal – or daytime – predators, such as raptors. And so there’s little defense from the sudden appearance of a large raptor in the skies above the Channel Islands. Secondly, they are more vulnerable on the islands today than they might have been 100 years ago. ^^^ Because all the islands have been grazed extensibly, and what that did was cause some of the vegetation to change from woodland, or chapperal communities, shrub communities, to alien, annual grasslands, which offer no cover from predators whatsoever. So that made the foxes vulnerable as well. And, when you think about it, golden eagles are a species that require quite a bit of prey, every year, to succesfully breed. Typically, on the mainland, what they do is, they go after small, vertebrate species such as rabbits or ground squirrels, and we don’t have anything like that on the islands. We have the island fox, which is more in prey size range, but there really weren’t enough of them to make a living on. But, we’ve come to the conclusion that other alien species on the Channel Islands offer a prey base that’s accepted to golden eagles. There are pigs on the islands, ferral pigs that have been there since the 1850s, and They’re on Sant Cruz Island, and they form a prey base that’s real prolific at certain times of the year. When the piglets come out in the spring, and later in the season, they are perfect prey size for golden eagles, and they are just little packages of fat and protein. And we think that eagles take those pigs until they grow up, and then they actually become too big for the eagles to kill, and then they switch over to other species like island foxes or the skunk species that’s on the Northern Channel Islands, or even birds such as ravens or seabirds. And so it’s this prey switching by this newly arrived predator that’s probably responsible for this massive decline of island foxes. So what we’ve done, is that we’ve started implementing two very aggressive actions. We’ve started captive breeding these foxes for two reasons. One, the populations are so small that they’re going to go extinct if we don’t step in. When you’re down to 14 animals, 4 of them male, there’s no chance of survival or persistance in the wild for that population. So we brought island foxes into captivity on all three Northern Channel Islands. At the same time we knew that we had to get rid of the golden eagles that are out there right now. And we thought we could do this in a couple of years. We thought that maybe a handful of golden eagles had made it out to the islands and were responsible for this decline. So in 1999 we started working with raptor biologists who trap and remove golden eagles from the islands. They had never been known to breed before 1999, but they were discovered breeding on Santa Cruz Island in that year. And since that time, raptor biologists have live-trapped and removed 31 golden eagles – which is great. ^^^ And satellite radio transmitters on some of those birds indicate that none of them have attempted have come back to the Channel Islands. They were released in Northeastern California, and most of their movement has been north and east of their release sites, which is great news. That aspect of it has worked really well. But there are a lot more golden eagles on the islands than we ever thought. So there are still about eight eagles left right now. And, hopefully we can remove those animals within the next two years. ^^^ But in the meantime, we’ve been breeding foxes in captivity, and that’s an act born of desperation. Whenever you remove from the wild the last members of a species or a subspecies and bring them into captivity. But that’s what we found ourselves doing in 1999-2000. ^^^ We brought 14 foxes into captivity in San Miguel, and there’s still one left in the wild out there. That’s a female that we captured once in 1998, and she hasn’t gotten into our trap since, and God love her for that – she’s a survivor. She’s the only one left in the wild out there. Those 14 foxes have grown to 38 in captivity, and we’re ready to release foxes perhaps in 2004 in San Miguel. In Santa Rosa, we brought in 14 foxes in 2000, and there are none left in the wild out there. But those 14 foxes have grown to 56 in captivity. So we’re pretty much ready to start releases back into the wild on Santa Rosa, but we’re still pretty uncomfortable with the number of golden eagles left. So right now we haven’t yet completed golden eagle removal, the way we want to. But certainly we’re poised to begin releases as soon we can get to a level of eagle removal that’s comfortable for us.

ES:

TC: They are breeding on the islands, and golden eagles had never been observed out there before the mid 1990s, that’s when they first started showing up. And it’s thought that eagle populations had rebounded so well that, on the mainland, they were finally sending out colonizers. And when you’re on the mainland, say in the wilderness areas just across the Channel Islands, basically the channel islands are just one big ridge to the west. And so golden eagles essentially found the islands in the 1990s. A few birds may have come through before that time, over the centuries, but there was never a prey base to support them, until the arrival of feral pigs, and other animals, such as the colonization of the islands. But it was almost a culmination of pure chance, and also these burgeoning populations of golden eagles on the mainland that probably accounted for their being there in the 1990s and not before.

ES:

TC: ^^^ Well, the pigs have been there for a long time, and that’s the curious thing. Pigs were brought over in the 1850s, and were released shortly to the wild after that, and have been there some time. I think it’s more a fact that golden eagles never found on the islands prior to that, prior to the 1990s that account for their lack of being out there.

ES:

TC: Yeah that’s the thought. When you look at the habitat on the Channel Islands for golden eagles, it’s really rather marginal. There is no great prey source out there on any one of the islands, except for feral pigs, and that’s even seasonal. And what we see in the eagle breeding out there, is it’s really hit or miss. Some of the nests are successful, but some eagle pairs abandon their nests because there’s not enough prey to support them. So, it’s kind of marginal habitat for them. ^^^ Another reason we think that is, that when these eagles are transported to the mainland, they don’t attempt to return to the channel islands, even if they attempted to breed there before – they don’t come back. It’s much better habitat where they’re relocated to, in Northeastern California. Another reason we think that the habitat is not that good is that the eagles seem to be a bit desperate for prey items out there – they’re acting very much unlike golden eagles in other areas. They’re taking skunks, which are fairly nocturnal animals, and they are clearly the size of island foxes. They’re hunting hard for those skunks. They’re taking birds as small as meadowlarks. And so they’re really seeking out an existence out of whatever prey species is out there, and it’s not nearly as varied as it could be on the mainland, where you could have many more vertebrate species in their prey size range. ^^^ So it’s almost as if a few eagles found the islands in the late 1990s, and that population expanded, and now we’re dealing with that expanded population. But we think that when we get these breeders off, these breeding eagles that will take care of most of the problem. Sure, some other animals might come out there. But, right now we have a hardcore group of breeding golden eagles that have been attempting to breed out there maybe since 1998 or 1999, if not before.

ES:

TC: Yes, the National Park Service, we really attempt to maintain the integrity of our native ecosystems, and that means that when non-native plants or animals take hold, we take management actions to the extant that we can – because those non-native species really can wreak havoc on an ecosystem, especially on islands, where island ecosystems are simpler. There’s not as many species out there, so each one of them is relatively more important. ^^^ You throw a feral pig, or a group of feral pigs onto an island, suddenly they’re impacting plants that have never had that kind of herbervoricity before. And so, there are currently 3000 feral pigs on Santa Cruz Island, and we’re going to start a joint removal program – with the Nature Conservancy, who also co-owns that island us – in the coming year. And we figure it’ll take three or four years to rid that island of feral pigs. But that’s one of the biggest restoration actions that we can take from the Northern Channel Islands. Those pigs are rooting up native vegetation, are impacting about 10 endangered species of plants on Santa Cruz Island. They’re rooting through archaeological sites, and they’re forming a prey base that supports golden eagles that wouldn’t be there if they weren’t there.

ES:

TC: No, not so far at least. We haven’t been sued yet because of our plans to remove feral pigs from Santa Cruz Island. And in fact, the Park Service removed feral pigs from Santa Rosa Islands back in the early 1990s. So we’ve already removed influence of that non-native animal on Santa Rosa, and we want to complete the job and remove that devastating impact to the Santa Cruz Islands.

ES:

TC: What we’re going to do is split the island into zones, and basically trap and hunt those zones out. And probably, over half the pigs can be gotten out just by trapping. But we anticipate probably having teams of dogs and hunters go in after the remaining animals.

ES:

TC: ^^^ it’s an important part of the island ecosystem out there. Biologically, we’re looking at the results of its absence. On San Miguel Island, where they’ve been out for a while, we’ve had an increase in the deer mouse population. The deer mouse population, in turn, is probably eating more seeds. And that has an impact on the regeneration of native plants out there. We’re also seeing birds nesting on San Miguel Island that never nested there before, ground nesting birds like, Northern Harriers – which is a type of hawk. They’re now nesting on San Miguel Island, and they’d probably not be nesting there if foxes were out in the wild, because foxes would eat their eggs. So when you take an important species out of an ecosystem that’s simple to begin with, you see these cascading effects throughout the trophic structure. But, the fox is such and unusual and unique species, that I think that the ante is raised just by that fact alone. They are truly one of the most unique carnivore species in the world. They are the most geographically restricted, and they’re one of the smallest canid species. And for many people, they represent the Channel Islands. Because that’s the only place where they occur. They were certainly important to the native Chumash Indians that lived out there. We find evidence that the Chumash ate many type of species of marine species in their environment. They were great fishermen, they probably ate at a bunch of their protein, from the wild. But there’s no evidence that they ever ate island foxes. They probably domesticated them, or they were important, ceremonially, to the Chumash Indians. They would domesticate very easily into pets. So in that regard, they are a very unusual species as well. It’s very easy to develop an affinity for such a species.

ES:

TC: Yes, the bald eagle is the missing link in this story as well. Had bald eagles been out there still, when golden eagles showed up, we may not be in the dire straits that we are right now. And that’s because bald eagles are known to be vigorously territorial when they are breeding. At one time, there were as many as 20 breeding pairs on the Channel Islands. And they may have been able to deter golden eagles from using the islands. But, of course, with those eagles gone from the ecosystem, the goldens are not challenged at all. So currently, there is a reintroduction effort going on for bald eagles. Bald eagles, whose numbers declined because of DDT, are now being restored to the islands, and being supported by settlement monies from a contamination case involving the makers of DDT. And so, for the next three to five years, every summer, up to twelve young eagles will be released on Santa Cruz Island. And hopefully, within four to five years, they will mature, and elect to stick around and defend territories of their own. And we’ll have functioning bald eagles in the ecosystem once again.

ES:

TC: There were. There were probably several eagle nests per island. And we found those historic eagle nests out there. We have anecdotes of people coming across their nests and their eggs, they actually did quite well. Bald eagles specialize in marine species. They eat fish, they eat sea birds, they eat pinnaped or seal and sea lion carcasses – and there’s plenty of that on the Channel Islands. And so, they were the apex predators in the ecosystem until DDT, which was manufactured in the LA area. The effluent, our outfall from that production plant, went into the waters of Santa Monica Bay during the whole time that DDT was being produced down there, from the 1940s to the 1970s. And that stood still, in a big sediment pile down at the bottom of the bay, slowly leaching out, and the currents have carried it all throughout the Southern Californian byte. And so, that DDT moved up through the marine ecosystem here and ended up in the tissues of the bald eagles. And it resulted in very thin eggs being laid by bald eagles – so thin that when the females went to incubate, they crushed the eggs. And that pretty much caused the demise of the bald eagle populations on the Channel Islands. So we’re hoping to start to reverse that by this reintroduction effort for bald eagles.

ES:

TC: The bald eagle restoration is being conducted by the Institute for Wildlife Studies, which is a non-profit wildlife outfit out of Arcadia. And they’re the ones who have been doing the reintroduction of bald eagles into Catalina Islands as well. But that effort is funded by the contaminant case that I mentioned before. That effort is going to take three to five years of releases, and then monitoring of the released bald eagles beyond that, and that started in 2002, so we’ll probably have three more years of releases, so there could be as many as 50 bald eagles will be released on the Northern Channel Islands. The removal of feral pigs from Santa Cruz Island is a project that’s run jointly by the National Park Service, and the Nature Conservancy. And that will start early in 2004 and run for maybe three or four years, depending on how quickly they can make progress on that. Captive breeding of island foxes is a project that we started in 1999, and we thing that once we get to production levels, which is a captive population where maybe we can turn out 12 to 20 foxes per year, it’ll probably take us a decade to reintroduce enough foxes into the Northern Channel Islands where those populations are strong and robust enough to persist over time. And what we’re looking for is a wild population of about 200 foxes. So it’s probably going to take at least a decade to get there, at least on San Miguel. And the golden eagle removal program will probably go on as long as we need it to go on. We’d like to get this first flood of golden eagles off the island within two years. Because right now we’re faced with the prospect of releasing foxes into an environment where there’s still some predators out there, and we’re still not entirely sure what’s going to happen, so we’d like to clear the skies of golden eagles prior to that.

ES:

TC: ^^^ What you think of as a simple species management program, suddenly has implications for management of the entire ecosystem, and requires ecosystem management in the long-run to be successful.

ES:

TC: ^^^ there were several very surprising things. One was the depth of the decline, right before our eyes, and not for a very apparent reason. But that was very frightening, when we became perilously close to extinction on two islands before figuring it out. Also, just personally, and we had these radio-collared foxes on San Miguel, and in many cases, we knew who these animals are, because they had shown up in our monitoring group for years. We had this one veteran, I would call her 84601. She had bred every year, we had seen her every year in our traps. And, for a while, I thought, maybe it’s the young ones that are getting picked off, or maybe for some reason, the young ones are having trouble surviving from year to year. So we had a radio collar on her, and when she died from eagle predation, it really hit home just how bad a problem this was. Because it’s one thing for stupid, naive, juveniles to be killed – and juvenile mortalities are always higher than adults, for almost every species. So when you start losing your veterans, that’s what tells you that you have this decline going on which cuts across all age classes. And that’s a serious problem. ^^^

ES:

TC: It’s just a question of time. We’ve shown that they can be bred in captivity, which is a big question mark. No one had ever bred this animal in captivity. But it’s been done. If they hadn’t bred in captivity, there’d be no hope whatsoever. And as far getting the eagles off, it’s just a question of time. We’re making progress on that, it just hasn’t been as quick as we wanted. And we’re getting to the larger ecosystem issues as well. We’re taking feral pigs off the island. We’re reintroducing bald eagles. Some of the ecosystem problems, such as the lack of shrubby vegetation, they’ll take decades to solve. But we are making real progress toward a lot of these short and long term objectives. So it’s just a question of time at this point. ^^^ And it’s something that, obviously is going to test our resolve – both as an agency and as a natural resources community. Because this came up all of a sudden. Island foxes weren’t, and aren’t on anybody’s radar screen. Hardly anyone really knows what an island fox is, much less that they’re functionally endangered right now. So, it’s taken a while just to generate enough interest in this problem just to keep the funding going, because it’s not yet an endangered species. Yet it certainly is endangered. So it certainly is something that we’ll need to stay on top of for at least a decade, I think, before we can breath easy again.

ES:

TC: Well there are six populations, or subspecies, and four of them actually are in trouble. There are two fairly dense populations of island foxes, one on San Nicholas Island – about 500 foxes. And another of about 600 foxes on San Clemente Island. Both of those islands are owned by the U.S. Navy. And those are part of the southern Channel Islands which are not visited by golden eagles much at all, because they’re right across the coast from southern California, and all the development there. So they don’t have the golden eagle visits, they don’t have the golden eagle predation.

ES:

TC: I think one of the biggest difficulties was generating the captive breeding program from scratch. We really had no idea how to go about this – how to do house the animals, what to feed them, how to breed them – that type of thing. And so we worked closely with other institutions like zoos, the National Zoo of the Smithsonian Institute, as well as canid experts from other endangered species programs such as red wolf, and kit fox and swift fox, to put together a husbandry program. The proof of the pudding is whether you produce pups or not. And we haven’t had as much success as we wanted on San Miguel, but certainly on Santa Rosa, they have produced pretty much the way we wanted them to. So that was the toughest thing, to come up with breeding program, and to look at the number of pups you have, and to adjust your strategy somewhat.

ES:

TC: Well, right now we’re in a little bit of a gray zone, because we’d like to release these animals out into the wild. But there are still some eagles out there. So there are a lot of folks out there that don’t want us to release until, absolutely, all of the eagles are gone. That may not happen for three or four more years. I don’t think we can delay releases until that time, because the populations keep growing on the islands, and we’d have to have twice the program out there, which is not fully funded even as it is. That brings up a whole host of decisions that have to be made. Because if we were to delay the program, we would have to house these foxes, either on the island, or move them on the mainland. But many of the pathologists and disease experts that we’re working with don’t want to even consider having these foxes on the mainland, because they’re naive, in that they haven’t been exposed to a lot of the diseases or parasites the live on the mainland. They would be exposed to them, on the mainland, and then they would bring them back to the islands – and then who knows what kind of consequences that might have. So right now, we’re working on an island based system that really has constraints, because we can’t make it too big. We really can’t afford to do everything that we would like to do in captivity on the islands, and at the same time we can’t move it to the mainland because of the disease considerations. So that’s another area where some people take issue with the approach that we have. One thing that we’ve done is – this species is not listed, there’s no recovery program, there’s no recovery team, but we’re acting as if it’s endangered. And every year, we convene a group of about 60 to 70 people who are either managing island foxes, or have them on their islands, or are researching them, or are in other endangered canid programs, and we talk about these issues for three days and come up with recommendations. It’s called the Island Fox Conservation Working Group. And it’s a very unofficial way to get at some of these problems, or at least bring them up and try to come to a consensus on as many of them as possible. Other issues that come up – some folks want us to have a much larger on-island-breeding program, but we run into the constraints of doing it on an island. Other folks think that we should attempt to kill the other remaining golden eagles, but we want to do this without going to that extreme step, at least in this point in the game.

ES:

TC: Well one thing that’s been very frustrating, even though the island fox is one of the cutest species around, it’s had very little luck with outside fundraising – because there’s no Island Fox Foundation right now, or Save the Foxes Foundation. It’d be nice if there was outside interest in the species that result in funding, but that certainly hasn’t been the case.

ES:

TC: Yes, they’re our partner in island fox recovery, as well as feral pig removal, so we actually have a joint island fox captive breeding program on Santa Cruz Island with them.