Why so many Snow Geese? (1 Viewer)

Greetings,
I was recently thinking about endangered birds and the types that are nearing the brink of extinction here in North America. Particularly here in the midwest. (The Ivory-Billed Woodpecker is the poster child for this.) Then I got to thinking about the other extreme, where you have far, far too many in abunance... such as the video I just got done watching with well over a million Snow Geese at the Squaw Creek National Wildlife Refuge on YouTube. This got me to thinking about other species that we have far too many of such as Canadian Geese, American Robins, House Sparrows, European Starlings... etc. I was not aware of the overwhelming abundance of Snow Geese however. Does anyone know the reason behind the huge numbers we have of them? Are they being allowed to multiply like rabbits just so hunters have something to shoot at or what?

Thanks

Wasn't there a ban on shooting them a few years back?

Jon Turner said:

Wasn't there a ban on shooting them a few years back?

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Yes, but most were lifted in the mid-1990s. They are now legal to hunt in most states. About 400,000 are shot annually in the US and Canada (according to Cornell).

I agree we have too many House Sparrows and European Starlings, since they are introduced species, but American Robins??? I was unaware that we are having a Robin problem. Snow Geese have adapted well to agricultural fields, so they have lots of habitat while the birds that used to live in the grass fields and forests that were cleared have much less habitat. They are also benefitting from a general warming in their arctic breeding grounds.

I think what you are perceiving as "far too many" are just species that have managed to co-exist with humans, and most other lesser seen species are "far too few" in numbers. We have had major environmental impacts to most North American species, mostly through habitat degradation, and some hunting. Remember, we used to have billions of Passenger Pigeons, and I for one would have loved to have seen a Carolina Parakeet.

What constitutes "far too many"? Generalists, such as House Sparrow and Common Starling ( in Nth America ) are found in many habitats, while species with more specialised needs may only occur in very limited areas. Snow Geese tend to winter in large flocks, in quite defined, traditional areas, and so build up numbers that appear to be (over) abundant. To put it into context. The sight of 1, 000, 000+ Snow Geese on one single preserve is probably a fraction of the flock sizes that occurred in many more places before European intervention in the environment. Would you consider the tens of millions of Great Auk that occurred in the North Atlantic until 3 June 1844 "far too many"? In 1870 a flock of birds containing a single species passed over Cincinnati that measured a mile wide and 320 miles long and estimated to contain 200 million birds. Were Passenger Pigeons "far too many"? Flocks of Eskimo Curlew were recorded covering 40 - 50 acres in Nebraska on multiple occasions. "Far too many"? While introduced birds / animals / plants can become over abundant, native species are, nowadays, a remnant of what was present previously ( no matter how 'abundant' they may appear ).

p.s. It is estimated that Passenger Pigeons constituted nearly 40% of the entire bird population of North America. 1September 1914 is a date that those who claim there are "too many" of a species should be forced to repeat once a day - for the rest of their lives. R.I.P Martha.

I think we may take it that the OP believes there are far too many human beings in North America. I shall keep an eye on international breaking news....

John

Punchy71 said:

[/URL]. This got me to thinking about other species that we have far too many of such as Canadian Geese, American Robins, House Sparrows, European Starlings... etc. I was not aware of the overwhelming abundance of Snow Geese however. Does anyone know the reason behind the huge numbers we have of them? Are they being allowed to multiply like rabbits just so hunters have something to shoot at or what? Thanks

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On Wrangel Island, it traditionally was the case that Snow Geese had one successful brood every four years or so, because on average, conditions were against successful breeding 3 years out of 4 - long-lying snow, late vegetation growth, severe gales and low overnight temperatures. Over the last few decades, the trend to warming in the Arctic has led to successful breeding on average 3 years out of every four, with the consequent result of a steep increase in Snow Goose population. I would hazard that the increase in the North American wintering Snow Goose populations may be due to the same, or related causes. I understand that North American Arctic Swan populations have also increased.
MJB

Snow Geese winter on big refuges near where I live. On a few occasions Bald Eagles have gotten 10's of thousands into the air. Quite a sight! Like a cloud under the sun. Darker for brief periods. I'm still waiting for enough salmon to walk across our river. Probably a long wait.

Snow Geese were once declining enough that they did ban hunting them. They recovered enough that hunting was allowed again, but they didn't stop increasing. Now they are so prolific that they are destroying habitat for other species in the Arctic.

I'm not sure how much is certain about the reasons for their numbers. I'm sure there have always been a lot of them (except for the brief period when they declined), but they certainly seem to be responding well to current conditions. Arctic warming may be a big part of it, but their migration route is also now full of grain fields that they make heavy use of. This would favor them over species that don't eat corn but would have eaten food found in the former grasslands. Many of the wetlands have been drained, to the detriment of numerous species, but Snow Geese can roost on man-made lakes with little vegetation.

To your larger point about some species being common and others rare, each species has a particular habitat, and some habitats are more common than others. Some species occupy a range of different habitats. Snow Goose habitat in both winter and summer is vast, so they can be numerous. Robins are generalists who do very well in human-altered habitats, so they are also numerous. Ivory-billed Woodpecker habitat was never common comparatively, so neither were the birds.

The Labrador Duck had the misfortune of favoring shallow, non-rocky waters near the shore of what is now New England to New York... We never even had a chance to discover its breeding habitat preferences.

In some of the wintering range of Snow Geese of the southern midwest to northern reaches of the south, areas that were devoted to commercial rice growing has undergone a change. Areas that were flooded periodically, have been drained again, with artificially aided water inflow, stopped. Those areas now devoted to corn for ethanol. Once harvested in fall, ripe for influx of overwintering Snow Geese.

Periodic spring flooding in Mississippi valley has floods described as 500 year events, occurring in spans of 3 or 4 years. Due to channelization, straightening, and elimination of alluvial riverbottom. Once a dike is over topped or breached, there's an latency in returning those areas to commercial agricultural operations. That phenomena presents more habitat to overwintering geese. Albeit, of a more temporary nature. The periodic aerial surveys US Fish & Game makes, indicates populations are in dynamic state of flux

LabradorDuck said:

Snow Geese were once declining enough that they did ban hunting them. They recovered enough that hunting was allowed again, but they didn't stop increasing. Now they are so prolific that they are destroying habitat for other species in the Arctic.

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Even if Snow Geese are up to pre-19th century levels ( the levels before the invention of modern fire arms ) they cannot, by any stretch of the imagination, be the cause of the destruction of Arctic habitat. They, and their congeners in the Arctic, cohabited in balance for millennia without destroying the habitat. To push the 'blame' for the changes occurring in the Arctic onto Snow Geese is to deny the effects of climate change ( anthropogenically driven, or not ) and the increasing disturbance to habitats by the 'industrialisation' of the Arctic with oil, gas, coal, gold, diamond extraction / prospecting along with the attendant infrastructure. And what about the Eurasian Arctic? The same degradation of habitat is going on there - and no Snow Geese, apart from the aforementioned birds on Wrangel I.