Saturday, June 28, 2014
Big Guys
Yesterday
I checked several of my camera traps in the Big Woods. Two of the cameras had
photos of bears. The first camera I checked had a photo of two bears, both
adults. The animal closest to the camera seemed to be interested in or annoyed
by the camera – a reaction that camera traps elicit from many bears.
Friday, June 20, 2014
Butterfly Aggregation
Most folks who have spent much time in
forest and field have seen aggregations of butterflies. The aggregations are
found in damp places, on decaying plant and animal material, on piles of
droppings and occasionally in areas that don’t seem to offer anything special
and, to human eyes, are no different than many nearby spots. Butterflies appear
to aggregate to obtain moisture and/or nutrients from the spot where they’ve
gathered.
In this area the most commonly seen
aggregations are of the butterfly with the common name of red-spotted purple
(also known as the white admiral); but tiger swallowtails also frequently
aggregate.
Riding along a gravel path we came upon
an aggregation of what initially appeared to be the drabbest brown butterflies
we’d ever seen.
After looking at them more closely, that description didn’t
seem too far off – although they weren’t quite as drab as they first appeared,
having some small whitish spots on the wings and a tan margin on the wings’
trailing edges.
At
the time we had no idea of the species and it took some searching to confirm
that they were either wild indigo duskywings (Erynnis baptisiae) or columbine duskywings (E. lucilius). According to the
literature, both of these duskywings have two broods a year and the mature larvae
of the second brood overwinter to pupate in early spring. Indigo duskywings
feed on wild indigo and crownvetch while the columbine duskywings feed on wild
columbine. Neither wild indigo nor crownvetch are found near the spot we found
the butterflies. However, wild columbine is common in the area, as is the
deciduous forest habitat with rock outcrops that both the plant, and
reportedly, the butterfly prefer.
Columbine
duskywing is considered critically imperiled in Pennsylvania, having been found
in only two counties – these aggregating butterflies were not in either of
those counties. Were these the rare species and did we find a new location for
the species? We’ll never know because, not knowing what they might be, I didn’t
collect a specimen to be identified by an expert.
Friday, June 13, 2014
Down by the Riverside
Took a walk
down by the riverside where, for about three miles, there’s a narrow strip of
woodland no more than 200 feet wide and a comparably narrow strip of
occasionally mowed vegetation between the river and railroad tracks. On the
other side of the tracks is an industrial area with some houses mixed in.
Although the strip has a good population of gray squirrels, chipmunks and
cottontail rabbits – and an occasional woodchuck, it’s not a place where anyone
would expect to see larger critters other than wandering dogs and housecats.
So, on this
day I was surprised to see a white-tailed deer standing at the edge of the
wooded strip.
Took a few
photos as a second deer joined the first. Both deer were bucks with antlers
clearly visible.
As I walked closer, the deer gradually walked into the dense woodland and stood watching me go past. The woodland is comprised of silver maple and a host of other species including invasive exotic species like Norway maple and Ailanthus. But the densest cover for the deer is the thick understory of invasive Japanese knotweed, which deer won’t eat.
White-tailed
deer are very adaptable animals evidenced by the high population densities they can
reach in suburban areas. These two bucks bring a host of questions to mind: How
long have the bucks been here? How far do they travel beyond this narrow strip,
or do they spend all their time here? Are there does there too? Will the bucks
leave; and if they do, where will they go? How many people have seen them?
If I was a
bow hunter – which I’m not – these two bucks might tempt me to spend more time in
this narrow strip of woodland and perhaps to hunt there.
Friday, June 6, 2014
Mom and the Kids
There’s a small section of the Big Woods where, over the last
ten years, I’ve seen and/or gotten photos of a fairly small female black bear
that has on multiple occasions given birth to three or more cubs.
The last time I checked one of my camera traps in the Big
Woods it had a sequence of photos of a female black bear (possibly the one
that’s produced so many offspring) and three cubs reacting to beaver castoreum* that
had been painted on a fallen limb. In all, there were well over 80 pictures
showing them rolling and laying on the branch.
In the sequence of photos one cub seems fairly indifferent to
the odor while the other two spend quite some time at the branch.
The castoreum has attracted a good variety of wildlife: Two
days before Mom and the Kids appeared, it was a male bear –
Very early in the morning of the sixth day after the heavy
rain, when it was again raining, another bear stopped to smell the branch and
was photographed through a rain-smeared lens –
That night two raccoons visited –
Four days later a porcupine ambled up –
The odor of beaver castoreum is obviously irresistible to a
wide variety of mammals.
* Beaver castoreum is produced by beavers’ anal glands and is
used by beavers to mark their territories.
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