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.

Here in northcentral Pennsylvania late June is the peak of breeding season for black bears. In this case the camera may have been an annoying distraction from the bear’s amorous interest in the other animal.

Two days later, on a morning when it was raining fairly hard, the same camera again took a photo of two bears. Unfortunately, there was rain on the lens – how much better the photo would have been if the lens had been dry. This time the following animal was a large male, the other was obviously smaller and almost certainly a female.

That evening, while it was still raining, a second camera about one-quarter mile away took a photo of a large male bear. 

Although at first I thought the two cameras photographed the same large male, but when the photos are side by side it appears they were two different bears.

What do you think?


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 –

Nine days after the female and the cubs visited there was a day of heavy rain with 5 ¼ inches in the rain gauge at our house, then lighter rains on several subsequent days.  As much rain as fell that day, it apparently didn’t affect the attraction of the castoreum. The rain didn’t keep a white-tailed deer from stopping on the day of heavy rain –

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.