FOAM LAKE
BIRDING
No. 172
Although it
seems that this winter will never end, it will.
Soon, I hope. Before that happens
I want to cover one of our very long distance migratory birds, the Swainson's
Hawk. This hawk nests as far north as
our area and travels south all the way to central Argentina for the winter where it
spends about three weeks before starting the long journey back.
As
mentioned last week the Swainson's Hawk is one of a trio of large hawks that
can be found in our area. Unlike the Red
Tailed and Northern Harrier the Swainson's is more a hawk of the plains but not
exclusively as is the Ferruginous Hawk .
It is quite similar to the Red Tailed and is often confused with it but
there are differences that can be quite easily utilized in the field. First, if seen from above or from behind the
Red Tailed has a rusty tail the Swainson's does not. Second, The Red Tailed has a black chin while
the Swainson's has a white one. Third, the
Red Tailed has a broad dark breast band while the Swainson's has a dark
chocolate upper breast but no band. Fourth,
when in flight and viewed from below the Red Tailed has dark leading wing
feathers while the Swainson's has dark trailing wing feathers. (see a good bird book for a better idea of
the differences). When perched or in
flight to me the Red Tailed has a light breast with black chin while the
Swainson's looks as if it were dipped in chocolate head first up to its belly
leaving the front half of the bird dark except for the white chin.
The
Swainson's is a relatively weak hawk feeding on small mammals and large insects
like grasshoppers. This food preference
for insects almost wiped the species out several decades ago. What happened is that one of the agricultural
insecticides was banned in North America
because it did not break down after use but stayed intact on the insects that
it had killed. The manufacturers
disposed of their stock by selling it at a deep discount to farmers in South America where it was used extensively. As the Swainson's Hawks migrated south they
fed on the dead and dying poisoned insects thereby poisoning themselves. The result was a massive kill-off of hawks
numbering in the tens of thousands. A
number of wildlife organizations saved the hawks by having the poisons banned
world wide. The good news is that the
Swainson's Hawk population , though severely decimated, is slowly making a
comeback.
This week's
picture was taken alongside a dirt road near Coronach, SK. in the Big Muddy
Valley. I was not able to get a frontal view of the
hawk but the white chin is visible as is the dark breast - although
barely.
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