AusBirders,
This email was picked up off FloridaBirds. It would be interesting to
know if late winter conditions have also been experienced in Siberia
and if so what implications they could have on juvenile shorebird
numbers coming to Australia or adult birds returning early.
Dean Cutten
Victor Harbor, SA
Currently living in Huntsville , AL, USA
==================================================================
Big chill in Churchill
Winter grips 90 per cent of north, migratory birds can't breed
By: Robert Alison
13/06/2009 1:00 AM |
It is the winter that refuses to go away in northern Manitoba and most
of the eastern Arctic.
Prolonged cold snowy conditions in the Hudson Bay area are expected to
obliterate the breeding season for migratory birds and most other
species of wildlife this year.
According to Environment Canada, the spring of 2009 is record-late in
the eastern Arctic with virtually 100 per cent snow cover from James
Bay north as of June 11.
May temperatures in northern Manitoba were almost four degrees C below
the long-term average of -0.7, and in early June, temperatures
averaged three degrees below normal.
National Oceanic and Atmospheric Administration images confirm snow
and ice blanket all of northern Manitoba, part of northern Ontario and
almost all of the eastern Arctic as of June 12. U.S. arieal flight
surveys confirm the eastern Arctic has no sign of spring so far.
"I have lived in Churchill since the 1950s, and this the latest spring
I have ever seen here," said local resident Pat Penwarden. "The spring
of 1962 was almost this bad."
Six-foot snowdrifts blocked Churchill-area roads. A thick blanket of
snow, in places three- and four-feet deep, coated 90 per cent of the
local taiga in northern Manitoba. Ecotourists, who normally flock to
northern Manitoba every June to see birds and other wildlife,
cancelled their plans this June "in droves," according to local
ecotourist specialists. Snowy conditions are largely to blame.
"It is like a winter landscape," said Ruth Baker, a Michigan tourist
who spent June 9 to 12 at Churchill. "I couldn't believe the
snowdrifts, like mountains of snow".
Researchers confirm that the lateness of the spring of 2009 dooms
local birds to a virtually complete reproductive failure.
According to Robert Jefferies, professor emeritus of botany at the
University of Toronto, the last time there was a late spring in
northern Manitoba, in 1983, there was a total reproductive "bust" in
lesser snow geese. Most species of birds did not nest at all.
Aerial inventories of fall migrant geese from the eastern Arctic that
year confirmed 0.005 per cent of the fall population comprised
juvenile birds, compared to the normal figure of over 50 per cent.
According to Cornell University researchers, currently at Churchill,
shorebird nesting is already three-weeks late, and has yet to start.
The first Canada goose nests were initiated on June 7, more than one
month later than normal, and probably not early enough to allow
goslings to mature before the fall migration flight. Canada geese are
the first birds to nest in northern Manitoba. Many northern birds
require more than 100 days to nest, incubate young and rear offspring
to a condition suitable for fall migration.
According to Robert Rockwell of The City University of New York, who
studies geese in northern Manitoba, if the geese have not begun
incubating clutches of eggs before June 11, there is almost no chance
that their offspring will be strong enough to endure the long
southbound fall flight.
In 1983, that was the case, and 1983 was not nearly as late as 2009.
Research by Hugh Boyd, scientist emeritus at the Canadian Wildlife
Service, states late Arctic springs reduce northern waterfowl
production by up to 90 per cent, with very late springs having a
devastating impact.
According to Vern Thomas, a University of Guelph researcher,
record-late springs produce "reproductive failures" in northern geese.
"These late springs generate reproductive busts," confirmed Joe Jehl,
who has studied birds in northern Manitoba since the late 1960s and
recently retired from the Smithsonian Institution.
Studies at Churchill show that in late springs, female birds delay
nesting, and rather than starve for lack of food, they re-absorb
already-formed eggs to benefit from their nutritional content.
Nesting often does not occur under those conditions. In 2004, a late
spring caused many northern Manitoba migratory birds to abandon
nesting efforts and head back south in late June, more than two months
early.
Recent late springs in the Hudson Bay area have been more frequent
than normal: 2004, 2002, 2000 and 1997.
According to NOAA scientists, although the Arctic is warming, more
frequent annual oscillations in temperature are likely to occur, often
resulting in late springs.
"Such major oscillations are part of a bumpy ride toward global
warming," said Thomas Karl of the National Climate Center. "For awhile
at least this will be the shape of things to come."
Vegetation is also impacted upon by late Arctic springs, with green-up
about three weeks late this year. Consequently, herbivorous animals
have delayed breeding
"People often confuse climate with weather, and this spring is a
weather phenomenon," said an Environment Canada spokesperson.
Robert Alison is a Victoria-based wildlife biologist and writer with a
PhD in zoology.
==============================www.birding-aus.org
birding-aus.blogspot.com
To unsubscribe from this mailing list,
send the message:
unsubscribe
(in the body of the message, with no Subject line)
to:
=============================
|
