Woodpeckers in a small burn on Base Petawawa in Renfrew Co.,
by Chris Michener
As a result of the article "What was found in
the burn" by Margaret Carney in Seasons, Winter 1999, the magazine
of the Federation of Ontario Naturalists, a group of five curious
naturalists went exploring on January 28, 2000. The burn was
illustrated on page 30 of the article in a map showing recent burns
and accompanied by a call for all birders to check them out!
The above picture was taken at the south end of a 100m by 700m
burned area of Jack Pine with some small White Pine mixed in. The
forest is residual, the remnants of a beautiful Jack Pine forest
which was clear cut 2-3 years ago. You can see the cut behind the
burned area. The burn is heavily blackened at the north end, but the
south end has more Jack Pine survivors. Other burned areas on the
west side of Base Petawawa were off limits to us. We were told live
rounds may still exist in other burned areas.
We saw five female Black-backed Woodpeckers (BBWO) and two
males. This concentration gives a ratio of 1 BBWO/ hectare,
similar to the estimate in the article. This burn is postage stamp
size, however. There was considerable evidence of insect
infestation... tiny pin prick holes drilled through the Jack Pine
bark. Woodpecker feeding holes showed the frenetic activity of the
winter's woodpeckers. Also seen were two Hairy and one Downy
Woodpecker in the burn. Some Black-capped Chickadees were present,
- This picture is an example of how the BBWO feeds. We watched a
male extract two bark beetle grubs from holes it made through the
bark. First it chose a spot. We weren't sure how it decided on the
location of the grub search. Perhaps by tapping the bark it can
sense the difference in density of the area under the bark or
perhaps it tests a spot to see if any sawdust (larval feeding
leftovers) is present. In any case, it starts a hole or continues
a hole that a larva has made and tests to see if the hole is wide
enough to pull the grub through. It has to be able to open its
beak wide enough to grasp the grub. It 'spits' the wood bits out
as it works the hole deeper and wider. Once it grasps the larva,
it pulls it out through the hole and in one gulp, it swallows it.
It then moves to another area on the tree or flies to a different
tree to continue its feeding.
- picture 3
- This Jack Pine from the burn shows large areas of bark removed
by the woodpecker in its feeding activity. This feeding is
different than that used on Tamarack. In Tamarack stands, the BBWO
chips the bark with a sideways motion removing large pieces and it
strips extensive areas of bark searching for its insect meal. More
of the Jack Pines showed holes like the tree above (picture 3) without much bark chipping.
Perhaps this means that there is a greater population of bark
beetles present in the burn than in our typical Tamarack stands.??
Not only upright trees were searched. Downed branches in brush
piles, were tested as in picture 2.
Epilogue: A follow up
trip to the burn site was taken on January 10, 2001 to determine if
Black backed Woodpeckers would again be concentrated on the dead
trees. Merv Fediuk, Leo Boland, Manson Fleguel and Ted and Kathy
Krug (from Parry Sound) hiked into the burn area and found there was
no evidence of any woodpeckers in the site. No woodpeckers of any
species were present. Many of the trees now had chunks of peeled
bark hanging from them as a result
of the weathering effects of rain and snow, but there was no freshly
chipped bark on the snow around the base of the trees, nor freshly
chipped surfaces on the dead trees. It is assumed that the
woodpeckers gather to feast on the larvae of the White-spotted
Sawyer Beetle, and that this is a one year phenomenon, occurring
during only the first winter after the fire.
- Also in the burn were many vole tracks,
which looked like zippering with two footprints and a tail line
between. When I asked Bruce Winterbon what small mammal he thought
they belonged to, he said there were two options...either a type
of vole, or, if you find the slider on the zippering, you could
open it and see what was underneath! On one vole trail was
superimposed an imprint of a large bird, probably a Barred Owl.
The story from the evidence in the snow indicated that the owl had
tried to pick up the vole with its claws but the vole veered
sideways and the owl missed. The owl settled briefly on the snow
with wings outstretched before taking to the air again. The vole
tracks continued past the impression the owl left in the shallow
- Other participants on the outing were Merv
Fediuk, Manson Fleguel and Lynn Hardy.