Thursday, April 4, 2013

Snow Goose "Overpopulation"

Snow Goose
White and blue forms of the Snow Goose
During my second spring of birdwatching, in 1976, I searched wetlands all around East Lansing, Michigan, trying to see as many kinds of waterfowl as possible. I was thrilled to add Snow Geese and Blue Geese to my lifelist. Then in 1983, the American Ornithologists’ Union snatched one of those species right off my list, deciding that the white and blue forms of these birds were subspecies of a single species. Because the white form was named first, they kept that name for the whole species, even though some Snow Geese were blue.

Geese are clannish birds, and young usually choose their mates within the large circle of distant relatives and acquaintances that their family hangs out with during fall and winter. This leads to limited breeding isolation, causing the many subspecies found in some goose species. But because different circles of geese do descend on the same wetlands in fall and winter, some young geese do choose their mates from other groups and breed successfully, so the groups aren’t genetically isolated enough to be considered separate species.

 For being so abundant, Snow Geese keep a lot of secrets from ornithologists. The blue-type birds have a much more restricted breeding range than the white-type, and nesting colonies of the blue-morphs were not discovered until less than 90 years ago, in 1929, after a direct and intentional search that lasted 6 years and covered over 30,000 miles.

Right now, numbers of Snow Geese are surging, and a lot of wildlife managers are in panic mode, crying “overpopulation,” and that they’re destroying the tundra. I’ve read a lot about this, and keep hearing that these high numbers are “unprecedented,” but there is plenty of evidence to the contrary. One of my friends on the national Bird Chat listserv, Barry Kent MacKay, this year’s featured artist for the Smithsonian’s International Migratory Bird Day and the Canadian representative of Born Free USA, a wildlife organization, notes that there were records of huge numbers of Snow Geese in the late nineteenth and early twentieth century. Obviously, this was before aerial surveys, so all the accounts by researchers earlier than the past few decades are dismissed as anecdotal, but that discounts a lot of professional eyewitness data to the contrary, and also discounts the huge toll on game birds made by unregulated hunting, for market and for sport, in the 19th and early 20th century. Birds of many species were barely recovering from that when I started birding, and no wildlife managers living today have any memory of how many birds there were before the slaughter.

 Wildlife managers are right that tundra habitat is in jeopardy, right when goose numbers are peaking, but that hardly implies a cause-and-effect relationship. Barry Kent MacKay notes that the critical problems facing the tundra stem from global climate change leading to the loss of permafrost, and from the oil and mining industries, and points out that the human, not goose, population explosion is the root of the real problems facing the tundra. 

Canada Goose numbers have increased due to adaptations individuals have made to urban and suburban habitats, opening up a whole new set of habitats that they can exploit successfully. There is no evidence that Snow Geese are exploiting new habitats, and frankly, very little evidence that their high numbers right now are greater than their numbers before they were overhunted. I’m thrilled that they’re rebounding, and hope that in a world where so many birds are declining, Snow Geese can stay abundant.

Snow Goose
Snow Geese during migration at Montezuma National Wildlife Refuge
  Here is Barry Kent MacKay's post on BirdChat (reprinted with his permission.)
Here in southern Ontario birders tend to report their Ross's Goose sightings. But if the federal government has its way, that will stop. Canada wants to kill off as many as 9 out of every 10 Ross's Geese. At best I hold wildlife managers in low esteem but this is a new level of absurdity even for them. In 1999 the federal governments of both the U.S.and Canada amended regulations to let them kill huge numbers of migratory waterfowl species deemed "overabundant" as defined by the North American Waterfowl Management Plan (NAWMP). The U.S. was able to include the Ross's Goose, but we successfully challenged Canada, and here the courts ruled that "overabundance", as defined under NAWMP, had not been demonstrated by the Canadian Wildlife Service (CWS) for Ross's Goose. 
It still hasn't, but no matter; the idea is now to PREVENT those pesky Ross's Geese from becoming overabundant. And while we don't know how many there are (they have an annoying habit of looking like Snow Geese when being counted from the air) the estimate is up to a million, and growing. The objective is to reduce the number to 100,000. That's up to a 90 percent reduction in a native bird species, in the name of, get this, "conservation". NAWMP's goal is "Abundant and resilient waterfowl populations to support hunting and other uses without imperiling habitat." The kicker is in those last three words, although I think the first part fuels motive. Waterfowl hunting is in decline, and therefore so is licensing revenue that pays wildlife managers salaries and keeps them employed. But the "imperiling" comes, as it does from Snow Geese, from the fact that these birds "grub", meaning they dig with blunt beaks for the roots and rhizomes of arctic plants, creating mudflats. They've been doing this since the glaciers freed the land, and long ere that in other regions - tens of thousands of years - but now it's wrong. 
I confess that when NAWMP first set population goals I assumed that they were for minimum populations, not that they didn't want populations to increase beyond the goals they set; that there had to be the number they decided on, not less, but not more, either. Their argument is the increase is of concern by "imperiling habitat". And so they decided how many of each population of Snow Goose there should be, and "managed" to achieve that goal. For example, for the "greater" Snow Goose, which nests in the eastern arctic and winters along the Atlantic coast, the goal was 500,000 birds. Oops. Didn't work. They figure there are about 923,800. For the mid-continent population of "lesser" Snows the goal was 1,500.000. Oops.the real number is estimated to be 2,628,400. For the western central flyaway the goal was 110,000, but the estimate is for 170,300. For the Wrangle Island Snows they are only about 20,000 birds over their objective, but for the Snows nesting in the western Arctic the goal was 200,00, instead of the current 608,000. In business that would all be considered a spectacular failure and abandoned, but for government the plan is to take something that doesn't work and apply it to the Ross's Goose. Kill nine for every ten. 
The concern might well be valid if three conditions existed: 
One: wildlife populations are static 
Two: current and projected numbers are unprecedented 
Three: the arctic is unchanging. 
None is true, a fact that is, well, ignored. Of particular value to the pro-cull argument is the idea that these birds are out of control. This is easily proved by ignoring all evidence to the contrary. When I pointed this out regarding Snow Geese years ago I was told that yeah, okay, there were records of huge numbers of Snow Geese in the late nineteenth and even early twentieth century, but they were anecdotal, thus don't count. Of course they were anecdotal; the means to make more objective counts using aircraft flying in grids and analyzing photographs didn't exist. That should not negate them, but in the small minds of wildlife managers, it doesn't count. 
I believe their panic derives from remembering arctic habitat as they first saw it as students, when the "white geese" were at their lowest numbers. 
The fact is the arctic was largely unknown up to and even after 1938, when the nest of the Ross's Goose was finally discovered (it's amazing to realize that I shook the hand of the man who discovered the nest of the subarctic-breeding Harris's Sparrow, in Churchill!). About all that Arthur Cleveland Bent could say about the population of Ross's Goose in his "Life Histories of North American Wild Fowl", published 1923, was that it was "quite common". He added, "many are shot for market". 
Exactly. 
The enormity of the killing of birds in the 19th and early 20th century has largely been forgotten, as has the paucity of ornithological documentation of much of the continent, especially the far north. Bent also points out that Ross's were a lot "tamer" and less cautious than Snows, so would have been preferentially selected by market gunners. 
Ethical hunters really don't want to kill the numbers of Snows expected of them, since they can't eat that many birds and many have told me they won't kill what they don't need to eat. Our governments have done all they can to demonize these birds in the interest of "conservation" while, ironically, global climate change and loss of permafrost; the subsequent opening of the Northwest Passage and shipping of oil; the discovery of gold and diamonds and subsequent mining and the human population growth are real problems of our creation. 
Canada's response? According to The Toronto Star, January 2, 2013, one bill, C-38, "included more than $160 M in cuts to environmental spending, significantly impairing our ability to measure or mitigate our impact on Canada's wilderness and wildlife." We are the first country to withdraw from the Kyoto Accord and our greenhouse gas emissions are increasing. So what do we propose doing? Let's blame the Ross's Goose for "imperiling" the arctic, and kill 9 out of every ten.

4 comments:

  1. I think the facts say otherwise Laura. There is plenty of evidence that shows the obvious effects Snow Geese have on the tundra (i.e. plots that exclude Snow Goose foraging are lush and healthy compared to the barren, denuded ground Snow Geese can leave behind). A colony of geese can ruin tundra a lot quicker than climate change can.

    The new habitat they are exploiting? Agriculture. Such a good and widely-distributed source of forage surely has bolstered their winter survival rates tremendously (which would also affect breeding success, of course). These habitats largely did not exist a few hundred years ago, at least not on the scale they do now.

    I totally dig Snow Geese but I think there isn't any evidence out there that disputes the harmful effects they can have on sensitive tundra habitats.

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  2. But where is your evidence that denuded tundra is a new phenomenon, rather than a long-standing pattern in the way that, say, Passenger Pigeons impacted forests?

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  3. I'm no expert, but I understood that at one time (not so long ago, pehaps), an equal concern was the destruction of the wintering habitat by Snow Geese. Not so?

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  4. As more and more natural habitat is plowed for agriculture, especially corn, geese and cranes have indeed adapted to feeding on farm fields in winter, and yes, this comes at a cost to farmers, though Snow Geese are among the last to arrive in fall and the first to leave in spring, so are mainly in these fields after harvest and before the spring planting. They do consume winter wheat, too, which is a larger problem.

    But it's deceptive of wildlife managers to claim their numbers are "unprecedented" and focus on the tundra when there is plenty of evidence that they were extremely abundant before market hunting, if their real concerns are about agricultural and economic interests in the U.S. When people debate issues of wildlife management, I expect the scientists above all to base their arguments on reality.

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