Vaccinating wild birds?

5 01 2015

For most of its history, the field of wildlife management largely ignored or dismissed the role of disease in wildlife populations. Not to say they denied the existence of disease, certainly they did not, but for many years, its role was seen as one of natural correction: when populations grew too large or dense, a disease outbreak would prune down those numbers, bringing the population back to a sustainable level. Indeed, for millennia, this was the case. Now, the study of wildlife disease and disease ecology is booming. What happened? We did.

When wild populations evolve alongside their diseases, be they viral, bacterial, parasitic, or otherwise, the two are engaged in a constant arms race. Pathogens evolve new ways to infect and spread, and hosts evolve new defenses. This dynamic breaks down, however, when a pathogen infects a host population with no previous exposure or defenses. In human history, there were the infamous smallpox outbreaks among Native Americans upon first contact with Europeans. The Pilgrims arrived in a land largely emptied of its native human inhabitants after they were nearly annihilated by infections brought by previous European traders and their rats. Without natural immunity, what we call a naive population can be very nearly exterminated by a disease that coexists in ancient balance in another population.

Things are not much different in wildlife. Wild populations exposed to new diseases carried across oceans by human travelers can face extinction when those diseases run unchecked through their ranks. We have seen this happen with the spread of avian malaria in Hawaiian songbirds, and with the Geomyces destructans fungus that causes White Nose Syndrome in North American bats but seems to cause no harm to its normal European host species.

As awareness has spread of the threat posed by disease in wildlife, people often ask why we can’t develop vaccines to combat them. The typical response is that it would not be practical. For many reasons, this is true. First, developing a vaccine is expensive and without a large scale market for the product, it’s not likely to get done. Wildlife medicine doesn’t pay well, I can tell you from personal experience, so the economics alone are daunting. Second, not every disease is well suited to vaccination. We mainly vaccinate against viruses, though some vaccines (Tetanus, Diphtheria, e.g.) target the toxins released by bacteria. Even within viruses, some are stable and relatively unchanging, while others are constantly mutating. This is why we have a standard vaccine for rabies (stable), an annually shifting one for flu (not so stable or consistent), and no vaccine for HIV (constantly mutating). But let us assume we had a vaccine on hand that could combat a particular disease threatening a population, and that we knew we could capture enough individual animals to administer it to a high percentage of the population. Even then, there are challenges.

When I was a first year vet student, I had to get a series of rabies vaccinations. We all did, given our line of work and our higher than average risk of exposure. After that initial three shot series, we were told we should have a titer checked every two years to make sure we are still protected. A titer tests the blood to see what level of antibodies are still patrolling for a particular virus. So far, every two or three years, my titer has shown that my body is still alert to the threat of rabies, and if the virus did find its way into my body, the level of antibodies in my system would be sufficient to neutralize those viral particles and destroy them.

Cory's Shearwaters in their nest burrow. (Photo: JardimBotanico)

Cory’s Shearwaters in their nest burrow. (Photo: JardimBotanico)

The reason I have to be checked so often is that this response is variable. Some people never need a booster shot after receiving the series. Others do. The level of antibodies can decline over time. Knowing how long a protective level persists is critical to any vaccination plan, so when contemplating vaccinating a wild population, we must have a sense of how long the protection will last. If an animal would require annual boosters, that vaccine is not likely to be of much use long term in wildlife where capturing individuals repeatedly ranges from difficult to impossible.

The question of vaccinating wild animals must also encompass the life history strategy of the particular species. Many seabirds, for instance, are extremely long-lived, and their population structure is based on an extended juvenile or subadult phase, low annual reproduction, but a tradeoff in many, many years of reproduction (for a particularly amazing example, read about Wisdom). In such birds, if a vaccine were found to lead to multi-year protection from a serious disease, the balance could tip toward attempting it.

Thinking along just these lines, a team of researchers set out to study vaccine responses in Cory’s Shearwaters, another long-lived seabird species. Some seabirds are susceptible to Newcastle Disease Virus, a potentially deadly disease that also affects domestic chickens. Given that last point, there is a vaccine currently available for use in poultry, and these researchers administered it to shearwaters instead and then tracked not only their own bodies’ responses over a period of years, but also how the antibodies passed into the birds’ eggs and persisted in hatchlings. What they found was that the adult birds did mount an immune response to the injection and that the antibody levels in their blood rose quickly, and then gradually declined over a period of years. Some of the birds received a booster shot a couple years after the initial one, and the antibody levels rose again in response to that. Levels of antibodies passed to the chicks as the egg was forming persisted after hatching, and the higher the levels of antibodies in the mother at the time of reproduction, the higher the levels in the chicks.

Antibody levels in adults (upper graph) and chicks (lower). Green bands are from unvaccinated birds. Orange band on upper graph are adults vaccinated once. Blue band are birds that received a booster shot two years into the study.

Antibody levels in adults (upper graph) and chicks (lower). Green bands are from unvaccinated birds. Orange band on upper graph are adults vaccinated once. Blue band are birds that received a booster shot two years into the study.

Just as every virus is different, every vaccine is different, and the results from this study do not mean that all vaccines would result in persistent antibody levels for several years. Additionally, what made this multi-year study possible is the site fidelity of shearwaters and other seabirds, many of which return year after year to the same exact burrow or nest site, and can be captured and resampled reliably. For many wild animals, this type of resampling is simply impossible, as would be booster shots. Finally, this was a study aimed at determining persistence of antibody levels, not at actually protecting the population from Newcastle Disease. Generally, something around 80% or so of the population need to be vaccinated to keep a disease from spreading. To attain those kinds of levels would be incredibly labor intensive, and in many cases, not feasible. But this study is an indication of the rising profile of disease ecology in wildlife management, and an awareness that we must shift finally away from a view of disease as a natural corrector and toward viewing it as another of the anthropogenic threats we created, and that we must strive to address.

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Is wind power bad for birds?

20 09 2014

As promised, I spent some time reviewing the scientific literature on wind farms and their impacts on bird populations. While the details are complex (and I will get to some of them), the short answer to the question, “Does wind power kill birds?” is, “Yes.” The longer answer is, “Yes, and so do all other forms of power generation currently in use. Generating power kills birds.” The still longer, and better, answer is as follows:

First off, the topic of birds and wind power is far too broad for my poor capacity here on this blog. The issues involved in land based wind farms are different from ocean based ones, and wind turbines affect different species of birds differently. This is not to mention the additional suite of circumstances around wind turbines and their effects on bats. I can’t cover it all. So, since this is the SEANET blog, I elected to restrict myself mainly to an investigation of the impact of ocean-based wind power on seabirds. That’s in itself a broad topic, but here goes.

A wind farm off the shore of Denmark. (Photo by Koppelius).

A wind farm off the shore of Denmark. (Photo by Koppelius).

Wind farms can kill or harm birds in more ways than one might expect. There is the obvious and violent spectacle of birds killed due to direct flight into the turbine blades or the support structure. But there are subtler impacts as well. While the wind farm is being constructed, birds will be displaced substantially from that location by all the activity. Once construction is complete, the human presence is much reduced, but the turbines themselves alter the seascape from ocean floor to the tip of the tallest blade. The footings and pylons holding up the turbine disrupt and reduce the area of ocean floor and water column available for foraging, and birds may well steer clear of an extended area around the farms. If that area was a rich hunting ground, then the birds will suffer for its loss. How much? Depends on the wind farm, depends on the bird, depends on the prey. Up above the water’s surface, in addition to birds that are killed outright by the turbine blades, there are the birds that instead fly around them and pass by safely. But how far around do they fly? If, for instance, on a migration, a flock of birds gives a wind farm a very wide berth, they will have to increase their energy use for the extra flight time. That demands extra foraging to make up the lost calories. For some species where survival is on the slimmest of margins energetically, might this tip the balance?

While there are currently no offshore wind farms in the United States, Europe, led by Germany and its much touted Energiewende, have been investing heavily in such farms, and this gives us an ever increasing body of scientific literature on the observed impacts at real-life sites. Here in the U.S. many scientists have been using mathematical models to game out what impacts wind farms of various sizes, heights, and locations might have. Taken together, we gain ever more insight into how to sensibly and responsibly navigate the way toward cleaner energy sources.

Pulling out just a few papers, it becomes clear how unclear the answers become when we try to group even all seabirds together and assess risk. Collisions with turbines are fairly rare in seabirds overall, and especially in comparison to some nocturnally migrating songbirds, for instance. Many water birds actively avoid the turbines, flying above or below the blades, or around the entire farm. A 2012 study using radar detection of migrating pink-footed geese found that 94.25% of all flocks identified flew safely around the farm. Other species, however, are less successful in avoidance; a 2013 study in Scotland identified gulls, gannets and skuas as being at higher risk for collisions, and white-tailed eagles appeared to show little to no avoidance behavior.

As to the issue of loss of foraging grounds, the impacts will vary from species to species. By way of example, however, I can offer up the Black Scoter, and a study out in January from researchers in Rhode Island. This paper points out that while many species of seabirds will avoid a newly built wind farm, they will often begin to return to forage in the area after three years or so. It seems that many birds are able to acclimate to the presence of the turbines. A similar phenomenon has been observed at land based farms, where mortality from collisions declines over time as the birds learn that the turbines are there and adjust their flight patterns accordingly. In a species group that tends to be very long-lived, like seabirds, we could certainly anticipate that the knowledge a bird gains about where the farms are and how to work around them, once acquired, would continue to serve that bird over its potential decades of life.

An aggregation of scoters. (Photo: Kevin T. Karlson).

An aggregation of scoters. (Photo: Kevin T. Karlson).

But let’s assume that the birds leave the area of a new wind farm and never return. What does that mean for the species? Again, it depends on the species. Black scoters are only loosely tied to particular foraging waters. Even in the absence of any offshore development, individual birds may spend the winter off Rhode Island one year, but the next year be somewhere closer to Delaware, or Cape Cod. In a species with this kind of flexibility, the impact of losing the foraging territory may be minimal since the birds are quite accustomed to moving around and trying new spots. But in a species with greater site fidelity, a poorly placed wind farm could have profound effects. That, in turn, leads us to the question of how we define well versus poorly placed wind farms. Rhode Island, Massachusetts and North Carolina are all examples of governments who have chosen to take on the process of marine spatial planning. They have realized that random and haphazard development of the marine environment could mean catastrophe for wildlife. By taking a rational, evidence-based approach, these plans lay out the best and worst places to site a wind farm or other offshore development project. Black scoters forage for invertebrates like mussels relatively nearshore, over hard bottom or coarse sand, and in relatively shallow waters. A wind farm placed in an area that matches those characteristics would be highly likely to impact Black scoters. The same farm shifted out of Black scoter prime range? Rather unlikely to have a major impact. Take a look at this figure from a 2013 paper by Winiarski, et al:

Figure from the Loring, et al paper on marine spatial planning.

Figure from the Winiarski, et al paper on marine spatial planning.

On the left side are maps of the Block Island area showing the relative importance of the habitat to scoters. The darker the area, the more critical the habitat to bird survival. Darker areas are classed therefore as “priority habitat.” On the right side are graphs showing various species or species groups and how they are projected to decline based on how much of their habitat has been made inaccessible to them. Eventually, if you left zero habitat at all, there would be no birds left because they have no place to be. But up to that point, removing habitat will affect different species differently. The longer the colored line remains level, the more resilient that species is to loss of habitat, possibly because that species is flexible in its habitat use and can shift somewhere else. Other species with a more even distribution decline steadily as soon as habitat begins to become unavailable.

Moving down the figure, and looking at b) and c), we can see areas on the map that have been whited out completely. This is a simulated wind farm, and the model treats it as a total loss in terms of habitat. If a wind farm were sited there, we can look at the line graph and see some subtle shifts. Most notable in b): the reddish line representing Common Loons drops off quickly before leveling off somewhat. This indicates that the habitat chunk removed just west of Block Island is a particularly important one for loons. The change is c) is even more striking. There, the removal of a different piece of habitat to the southwest of Block Island causes a precipitous drop in the distribution of scoters, indicating that that area is of significant importance to their population. By manipulating these models, the scientists can come up with sites that we can expect will do the least harm. When habitat farther offshore, with fewer of the characteristics sought by seabirds, is removed in a simulated development project, the impacts on the birds are reduced. Such areas, shown in light gray in d) and e), would be better places for a wind farm, for the birds at least. For Rhode Island, the planning map thus recommends that wind farms not be sited within five kilometers of shore, or in waters less than 20 meters deep.

The key point of marine spatial planning is the planning. The creators of these maps and documents and guidelines realize that we need cleaner energy, and ocean-based wind is a huge potential source. By choosing the right location, we can also mitigate the risks to wild birds. Just like a LEED-certified, net zero office building is far superior to a conventional building in terms of sustainability, it would be irresponsible folly to construct it in the middle of a wetland housing the last population of a critically endangered species. We need clean energy, and we need to find the right places to get it.

To the question of whether or not we should be building wind farms at all, knowing they kill individual birds and pose some level of threat to the population, we must look at the alternatives. The fact is, we need power. The question is, where are we going to get it in the future. A 2009 analysis by Benjamin Sovacool sought to quantify how many birds are killed per kilowatt-hour of energy produced by various types of power, from fossil fuels, to nuclear, to wind. Some critics of wind power have pointed out that the reason so few birds are killed by wind turbines each year in the United States is solely because we have so few wind turbines. Scale up the technology, they argue, and the numbers of birds killed will skyrocket. Sovacool attempted to neutralize this factor by calculating not total mortality, but mortality per kWh, extrapolating out to an energy future where wind power is supplying far more of the grid.

Figure from Sovakool (2009). Blue shows annual avian mortality from each power source, and red shows mortality per gigawatt-hour of electricity generated.

Figure from Sovakool (2009). Blue shows annual avian mortality from each power source, and red shows mortality per gigawatt-hour of electricity generated.

Though his exact numbers have been challenged, and I agree with some of the critiques of his techniques and summation, his fundamental idea is sound. When we look at the entire fuel cycle of, say, coal versus wind power, we will come down on the side of wind being substantially more bird friendly. Sovacool points out that mining coal or drilling for oil destroys habitat for birds. Of course, building wind turbines does also. The most egregious methods of extraction, like mountaintop removal for coal, are the opposite of the kind of reasoned, strategic approach seen in a marine spatial plan. But turbines do disrupt habitat as well. Then comes the generation of power. Fossil fuel plants themselves kill large numbers of birds through collisions with their cooling towers and other structures, just as birds collide with cell phone towers and skyscrapers. Build something up into the air, and birds will hit it. An estimated 175 million birds are killed annually in collisions with transmission lines feeding the plants themselves. This issue of power lines remains for wind power too, of course; we have to move the power around and distribute it after all.  So by some measures, it seems that the different power sources have similar liabilities in terms of avian mortality. Add in, however, the mercury and the acid-rain producing compounds that enter the atmosphere through the burning of fossil fuels, and the balance shifts to favor wind power. But even if we judged them equal up to that point, we’ve left out the greatest existential threat of them all: climate change. Whereas some species are more affected by wind turbines than others, it’s almost impossible to find a bird species that will be unaffected by climate change, and for some, it will spell extinction.

Sovacool also points to all the other anthropogenic causes of bird mortality: an estimated 100 million to domestic cats, 100-900 million dead by collisions with windows. “However,” he writes, “since house cats and office windows do not yet produce electricity, the comparisons are less relevant than those that assess avian deaths from other sources of electricity generation.” Less relevant to questions of our power supply, true, but the comparison is still useful. House cats are not inherently evil (though I know people who will argue that point), nor are office windows. House cats safely indoors are lovely pets to have. House cats hunting outside are a menace. Office windows are nice to gaze out of. Office windows illuminated at night when throngs of nocturnally migrating songbirds are passing through that exact geographic corridor are a killing field. Yet we see scant efforts at legislation to block new construction of office buildings, or even legislation to make windows in new construction less hazardous to birds. I don’t see legislation aimed at keeping house cats indoors either, and it’s not as if having a cat outside does us some essential service, as if it were a public utility. The fact is that knee jerk opposition to wind power on the basis that some birds will be killed by wind farms is not credible scientifically. Birds die by our actions in droves. We are always making the cost-benefit analysis of using cars, living in buildings, having cell phones and many other things that kill a lot of birds. We have the science on how to intelligently site these projects. We can put them where they will do the least harm to birds, knowing that the shift from fossil fuels to wind is, in itself, a benefit to birds. Not to an individual bird killed by a turbine, I’ll grant you that. But we are in the business of the population level threats. And those don’t get any bigger than our continued reluctance to shift to renewable energy.

 





We’re not the only species trying to fish around here.

28 06 2013

The U.S. Fish and Wildlife Service’sMaine Coastal Islands National Wildlife Refuge encompasses over 8,200 acres on more than 55 islands and coastal parcels. On eight of these islands, seabird restoration projects have been established to encourage and maintain nesting of Atlantic Puffins, Razorbills, and Common, Arctic and Roseate Terns. Working on a seabird island is, I can attest, challenging, and the summer researchers (many college students) stationed on the islands must put up with heat, harsh weather, primitive living conditions and not much contact with the outside world as the islands are closed to visitors from April through August. (They do apparently have enough access to modern conveniences to blog about the experience, so do check that out.)These researchers document numbers of pairs, numbers of chicks produced, what the parents feed those chicks, and how many survive to fledge.
The programs have been highly successful, with increases documented in nesting pairs of all five species over the 30 years the projects have been underway. Now, however, some troubling signs.

Arctic Tern on Petit Manan Island. (photo: USFWS)

Arctic Tern on Petit Manan Island. (photo: USFWS)

After 25 years of upward trends, numbers of breeding pairs of Arctic Terns in Maine have dropped by 42 percent, from 4,224 pairs in 2008 to 2,467 pairs in 2012. Linda Welch, Refuge biologist, reports that not only are the numbers of pairs declining, but among those pairs that do nest, fewer young are successfully fledged. Arctic Terns make the longest migrations of any birds in the world, traveling more than 36,000 miles round trip skipping out on the northern hemisphere’s winter to spend those months off Antarctica. They then fly north again to breed from New England up to the high Arctic. Scientists speculating about the decline in breeding success in these birds posit that they may be failing to find sufficient food while overwintering, and are returning to the breeding grounds with insufficient body reserves to reproduce (if they return at all).

Seabirds live a long time, and one lost breeding year would not be catastrophic, but this assumes that one bad year doesn’t turn into five, or ten. Additionally, the not-enough-food-in-the-Antarctic hypothesis does not necessarily explain why the birds that do breed seem to be less able to successfully raise their young. A likely reason: the same problem they may be facing over the winter. Not enough fish.

In 2007, 3,500 pairs of terns abandoned their nests on Machias Seal Island, up to that point the largest tern colony in the Gulf of Maine. The birds have never returned. Arctic Terns that do attempt to raise chicks seem unable to find enough of their accustomed food sources such as herring, and are, Welch says, “desperate. They try to bring in other kinds of fish or invertebrates for the chicks to eat. Sometimes the fish are too big for the chicks to swallow whole. So the chicks starve to death with all those fish carcasses lying around them. It’s really sad.”

Adult Atlantic Puffins on the breeding colony. (photo: USFWS)

Adult Atlantic Puffins on the breeding colony. (photo: USFWS)

The same saga is playing out among Atlantic Puffins, which also rely heavily on herring. Unable to find sufficient numbers of that prey, Puffin parents have been returning to the nest with butterfish, a warm water species gradually expanding its range northward while the herring, intolerant of warmer waters, are apparently moving deeper or farther north, out of reach of the beaks of terns and puffins in Maine. The broad, oval-bodied butterfish are mostly too wide for the young Puffins to swallow, and, like the terns, the birds gradually starve, surrounded by piles of food.

There is, of course, no way to link climate change to the death of a particular chick, or to a particular freak storm, or a single drought year. But we have overwhelming evidence of all these trends all pointing only one way, and as I watch this video of a puffin chick trying, for hours, to choke down a butterfish, I can think of no sterner indictment of what we have done than that fuzzy head and flat black eye gazing into a camera it doesn’t even know is there.





Online atlas of marine Important Bird Areas

18 10 2012

BirdLife International has just released a marine conservation e-atlas outlining areas of the world’s oceans that are of particular import to seabird conservation. Such a project is overwhelming in scope, as individual seabirds can range over thousands of miles in a single season, and entire species or species groups are even more far flung. So pinpointing which areas of the oceans and which phases of the birds’ long travels are most critical to their survival is daunting to say the least. BirdLife has been at work on this project for 6 years and has brought together countless collaborators. The result is a publicly available atlas of over 3,000 Important Bird Areas (IBAs). The criteria for designating an IBA emphasized its use by threatened or endangered species, and large concentrations of individual birds during at least one phase of their lives. Breeding colonies and the foraging waters around them rank high on the list, as do dense congregations of wintering birds, or migration “bottlenecks” concentrating large numbers of birds into a narrow geographic area.

As you SEANET readers explore the atlas, you may be surprised to find that no IBAs are confirmed or proposed along the U.S. east coast from Maine to Florida (though Bermuda is one). While our initial reaction to that may be to ask why no one is protecting “our” birds, the atlas really serves to drive home just how truly global “our” seabirds are. The gannets our Cape Cod walkers see spent the summer on the islands off the Canadian maritimes. The Greater Shearwaters that range up along the Carolinas and into the New England coast in June and July came up from tiny islands midway between the tip of South America and the tip of Africa. This is the very reason why we need international groups like BirdLife. More than any other animals, seabirds cross and recross international borders easily from day to day and sometimes hour to hour. In order to truly protect these species, we have to take an international approach and collaborate in defending these birds during all the phases of their remarkable lives. SEANET applauds BirdLife for the immense and ambitious project, and we think you will enjoy the virtual tour of seabird hotspots that this e-atlas affords.





Where the sea meets the sky: government agencies formalize collaboration

20 09 2012

Unaware of the oversight of two different agencies, these seabirds forage perilously close to a fishing vessel.

We have a tendency to think of our federal government as a monolithic force with a consistent, and very general, federal perspective on things. As one delves into the day to day activities of particular government agencies, it becomes rapidly clear how distinct, separate, and sometimes even isolated they are from each other. In our experience with SEANET, we have worked most closely with the U.S. Fish and Wildlife Service (FWS), followed rather closely by the National Oceanic and Atmospheric Administration (NOAA), specifically their National Marine Fisheries Service (NMFS). The list of acronyms grows ever more dizzying, as we have had occasion to interact with The USDA and their Animal and Plant Health Inspection Service (APHIS) and within that, their Wildlife Services (WS) division. When we work on a disease outbreak with the federal government, it’s (strangely) through the U.S. Geological Survey (USGS). A project like ours tends to cross the boundaries between these agencies on a daily, sometimes hourly basis, so it can be a challenge to remember that they do not, necessarily, keep in close contact with each other. This is not a criticism: these so-called “siloed” agencies each have their own mandates and areas of focus. With so much information and so many resources to manage, we require specialized agencies to keep on top of it all. In fact, we revere specialized knowledge and expertise in our daily lives; smart as a rocket scientist may be, I’d prefer she not deliver my baby or represent me in a court of law.

So given the need for specialization and a somewhat narrow focus, the question is, how can these agencies ensure communication and collaboration when their mandates and purviews do overlap? Two such parties, the Fish and Wildlife Service and the National Marine Fisheries Service have now issued a formal Memorandum of Understanding (MOU), outlining their shared and divergent interests, the need for increased information sharing, and greater cooperation. The MOU, at its most basic level, says formally, “We will speak to each other.” But by putting this into writing, the relationship between the two agencies is publicly and officially declared. The MOU also gets into a great deal of specifics, and is focused particularly on seabird/fisheries interactions. With one agency (FWS) overseeing the well-being of aerial seabirds, and another (NMFS) the stewardship of marine resources below the waves, it has been difficult to effectively address the threats to either that occur at the interface between the two. Policies that end at the water’s surface will never be sufficient for either side.

Seabirds forage near fishing vessels and get fatally entangled in fishing gear. Endangered fish stocks may face additional pressures from growing populations of Great Black-backed or Herring Gulls. The interconnectedness and complexity of even a relatively simple food web defies the siloed nature of our agencies. FWS and NMFS have recognized the need to bridge the gap in order to maintain sustainable fisheries and protect seabird populations.

We at SEANET applaud this MOU, and as an independent, University-based program, welcome the formalization of a relationship between two of our most important government partners. From use of our Beached Bird Field Guides by NMFS Fisheries Observers, to SEANET volunteers documenting seabird entanglements in gillnets, our program fully inhabits the spaces between the groups and we fully appreciate the need for close collaboration.

We hope to both contribute to, and reinforce this newly stated bond between two agencies working hard to defend and understand the wide range of organisms inhabiting our marine environment.





Good fences make good neighbors, if your neighbor is a rat.

17 07 2012

“Something there is that doesn’t love a wall,” opens the Robert Frost poem “Mending Wall.” And I suspect that, aside from the poetic longing for human connection, the “something” may actually be introduced rodents on seabird breeding islands. Ever since the sea-going Polynesians unwittingly scattered rats all over the tiny islands of the remote Pacific, ground-nesting seabirds have hit by wave after wave of human-induced damage. After the Polynesians came Europeans with cats and dogs, and more rats. Then the Americans fortified many Pacific islands in response to the looming Japanese threat in the 1940s, and along came, yes, more rats. The population of Bonin Petrels, for instance, dropped from 500,000 down to only 5,000 after 1940 when the Americans arrived on Midway Atoll with their rats. The rodents make easy meals of the helpless, blobby seabird chicks, and BirdLife International reports that 75% of threatened, ocean-dwelling seabirds are affected by invasive nest-predators.

Ka-ena Point, Oahu: A nice place to be a Laysan albatross. Bad place to be a rat.

On small islands, it’s sometimes possible to exterminate the entire rodent population and restore the ecosystem to its prehistoric, seabird friendly state. But on a big island, say Oahu, for instance, total eradication just isn’t feasible. Enter a relatively simple and apparently very successful solution: a big, sturdy fence. On Ka’ena Point at the western end of Oahu, scientists exterminated all the rodents within the fenced area, and so far, it seems to be working, keeping even little baby mice from passing through.

A husband and wife team of biologists continue to monitor the population, and are hopeful for its continued success. The location of Ka’ena Point, only 30 miles from Honolulu, also provides unparalleled opportunities for people to observe the albatross colony and its comical denizens.

With the bewildering daily increase in scientific technical complexity, molecular pathways and sterile bench top cell cultures, ecology remains perhaps my favorite discipline, where sometimes, the solution is as simple as a really good fence across the rocks.





Endangered status considered for Black-capped Petrel

26 06 2012

Gliding toward endangered status?

In response to a petition filed by WildEarth Guardians in September of last year, the U.S. Fish and Wildlife Service (USFWS) has begun a 12 month process examining the conservation status of the Black-capped Petrel. The decision, known as a 90-day finding, triggers a thorough review of existing data on the Caribbean-nesting birds, and the public is encouraged to submit documentation about the bird, its habitat, and potential threats to its survival by August 20.

In a previous post, I gave a bit of background on the life history of this secretive seabird, but there remains much that is unknown about them. Regarding threats to the species, the USFWS  writes:

“The black-capped petrel faces many potential threats to its continued existence, including human encroachment, deforestation, agricultural modification, offshore oil exploration and development, overuse from subsistence hunting, predation by introduced species, pollution, mercury bioaccumulation and inadequate regulatory mechanisms. […]  Pollution, bioaccumulation of heavy metals, and oil spills potentially threaten the existence of the petrel as researchers have noted that the species has a mercury concentration seven to nine times higher than other similar seabirds.

Additionally, impacts specific to the black-capped petrels could include changes in habitat suitability, loss of nesting burrows washed out by rain or flooding, increased petrel strandings inland during storm events, and increased risk from animal-borne disease (emphasis mine).”

These last are most certainly the domain of the Seanetter, and of our wildlife disease investigating cousins over at the Northeast Wildlife Disease Cooperative. It isn’t surprising that Seanetters have never found a beached Black-capped Petrel since they are, obviously, rare enough to be considered for endangered species status. But we do pride ourselves on being a clearinghouse for all dead seabird news, and we will contribute any information we gather on the species during this 90 day period. All members of the public can submit comments via the Federal Goverment’s ePortal, but be aware that at this point in the process, the government is looking for scientific reports, journal articles, unpublished data, photo documentation and the like. Evidence, in other words, rather than personal reflection or simple pleas for the species. These will be noted if submitted, but will not sway the decision making at this point.

We will, of course, be following this story for you, Seanetters, and welcome any input or questions you may have along the way. It should be a good civics lesson on how the Endangered Species listing process works.