Friday, December 9, 2011

Fall is Falling

Snow Geese with 2 blue morphs-Wikimedia
With the falling temperatures and overcast weather of late, it is hard to remember that it is still officially fall until December 21.  The bare trees and a light snow add to the winter illusion.  Leave it to the birds to keep the seasons straight.

This past week there were faint sounds* over Bull Creek.  Looking up into the cold grey skies there were tiny spots almost too small to see initially,  large V and U formations of geese headed in a east-southeast direction.

Greg Swick from Audubon (GOAS)*** tells me that these were snow geese and there have been flights of 7,000 to 40,000 per day for nearly the whole week.  "They have intensely overpopulated and have taken over and destroyed nesting habitat for many species of concern in the tundra.  Still there is something strikingly beautiful about seeing them."

The snow goose, also known as blue goose**, declined in numbers until hunting was stopped in 1916.  Hunting was allowed again in 1975 and the populations have increased dramatically in spite of it.  They now have created habitat destruction at both ends of their range.  According to the US Fish and Wildlife Service:
"In the northern breeding grounds, snow geese are 'grubbing' the soil to dig up high-energy roots and tubers.  Plant regrowth is extremely slow in the tundra climate.  Without plants to cover the soil, salts in the subsoil begin to accumulate on the surface, creating a saline environment hostile to desirable plants.
Within the Rainwater Basin, snow geese are aggressively competing for limited water available and waste grain in crop fields. Snow geese are known carriers of avian cholera.  This fatal disease occurs annually in the Rainwater Basin when birds become concentrated on areas with poor water quality and quantity."
This damage not only affects the tundra but harms the snow geese and other bird species that live there in season.  After returning south, snow geese feeding on natural vegetation create more damage.  Like human excesses, nature can suffer from too much of a good thing.

*  This sound can be heard by turning your speakers way down and clicking on this sound.
**  There is a snow goose genetic variant called the blue goose.  It occurs from the mating of a goose with a single dominant gene and one with a homozygous recessive gene.  Offspring may be either color.  See Wikipedia
***Greater Ozarks Audubon Society (GOAS) has an informative website above and meets at 6:30 PM the third Thursday each month at the Springfield Conservation Nature Center

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