Tweets - Apparently the Swainson's Hawk situation has not been
ignored. Here is an article from the Feb. 15th Globe and Mail in
Toronto which appeared recently. Peter Whelan is their "bird"
columnist and writes a weekly Sunday column. This was a Thursday
special.
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ARGENTINE SPRAY KILLS HAWKS FROM CANADA
- Race on for answer before next winter -

By PETER WHELAN
Special to the Globe and Mail

Pesticides sprayed on fields in Argentina are killing tens of
thousands of wintering Swainson's hawks that nest on the Canadian Prairies and
the adjacent U.S. Great Plains.
A researcher from the U.S. Forest Service counted 3,909 dead hawks
in a 50-kilometer square last week and estimated they represented between
20,000 and 40,000 dead. The count was incomplete, partly because scavenging
vultures and caracaras were eating the bodies quickly.
The insecticide monocrotophos and other pesticides are being
sprayed from aircraft and tractors to control grasshoppers in fields of
alfalfa and other new crops. Hawks flying behind the tractors to seize
flushed grasshoppers get sprayed directly, then eat more pesticide in the
grasshoppers. Scientists from Canadian and U.S. governments and
universities are working with the Argentine environmental agency, INTA, to
propose a change to less severe pesticides.
Research scientist Geoff Holroyd of the Canadian Wildlife Service
in Edmonton said the situation needs urgent action, especially since the
Swainson's hawks have been in decline for a decade in their main
Canadian breeding grounds in Saskatchewan and Alberta. Nesting failures have
explained part of the problem, but researchers have been puzzled and alarmed
by a further downward drift.
"I think this is comparable to what happened to the peregrine
falcon in the 1950s and 1960s. Hopefully, we have caught it in time," Mr.
Holroyd said. "This went to the Environment Minister's desk, and he approved
action within 24 hours."
The anatum race of peregrines was all but wiped out by pesticides
in eastern North America three decades ago and is just coming back now
with the help of planting programs. Mr. Holroyd is chairman of the Canadian
committee working to rebuild the peregrine population.
Environment Canada is funding field work by INTA, and Canadian
farm experts are to offer advice about pesticides. "It is too late to do
anything this year, but we hope for a solution by next winter," Mr. Holroyd
said.
The Swainson's hawks will leave Argentina at the end of February
and spend two months migrating north.
The big, dark-chested hawk is a familiar sight soaring over the
Canadian Prairies on uptilted wings, like a vulture. It raises its young
largely on Richardson's ground squirrels but eats many insects after migrating
in large flocks to the wintering grounds on the South American pampas.
The Canadian population is estimated at 40,000 to 100,000 in a
world population of 350,000 to 400,000. Canadian birds were inordinately
represented in the Argentine deaths. Of 12 leg bands recovered, nine
were from Alberta and Saskatchewan hawks. Two Alberta hawks tagged with
satellite transmitters are both in the danger area.
The study area is at the junction of the states of Cordoba, Buenos
Aires and La Pampa. Cattle ranching used to dominate, but irrigation
recently opened the area to a variety of crops. This is only a small part of
the winter range of the hawks and a small part of the cultivated farmland.
"We don't know how far this problem extends," Mr. Holroyd said. Ninety
per cent of the killed hawks were adults. The separate winter range of
immature birds is not known.
Monocrotophos is an organic phosphate insecticide that is
fast-acting and highly toxic to birds and animals. It kills insects either on
contact or when taken in with crops. It is no longer sold in the United
States and was never registered in Canada.
At worst, the Argentine toll would represent 5 per cent of the
world population and half the Canadian population, Mr Holroyd said.
"This appears to explain the decline in this hawk. We also
speculate that secondary effects of the pesticides could be reducing nesting
success of the birds when they return to Canada."
Concern that Argentine pesticides were hurting migrant North
American hawks appeared in birding literature as long ago as 1968, but there
were no specifics. The first solid evidence came last year when 700
Swainson's hawks were found dead in the same area, apparently from pesticide
poisoning.

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- Jack



Jack Bowling
Prince George, BC
CANADA
jcbowling at mindlink.bc.ca