From Winter to Summer at the Log Bridge

Several years ago a medium-sized hemlock tree fell across a small stream in the Big Woods. The stream isn’t very large and at the shallower riffles the water’s only three or four inches deep for most of the year. Nonetheless there are animals that use such log bridges to cross streams wherever one is available.

One of my camera traps was placed so it could capture videos of the animals and birds using this log bridge. There were high hopes of getting a video of a bobcat crossing the log and perhaps an eastern coyote or black bear doing the same.

Here are six months of videos from the log bridge – minus hundreds of videos of gray squirrels running back and forth.

Well, no bobcat crossed the log bridge – nor did a black bear or eastern coyote although the camera trap caught the last two after they crossed the stream just beyond the log. Never before has one of my camera traps caught a video of a belted kingfisher. The camera trap will stay there watching the log bridge – here’s hoping that a bobcat will pass its way.

Gypsy Moth

The last couple of times I’ve walked in the Big Woods the forest has looked like this –

That wasn’t November it was early June and a view of the hillsides revealed that extensive areas were bare of leaves –

The cause was these caterpillars –

Not just one caterpillar but many thousands, perhaps millions, to each and every acre – here climbing the trunk of a white oak in search of additional leaves to eat –

They’re the caterpillars of the gypsy moth (Lymantria dispar) an insect native to Europe and accidentally released in Massachusetts in 1869, from there it has spread extensively wherever its favored food species (oak, aspen, apple and others) are abundant.

In 2021 the Entomological Society of America (ESA) decided to change the insect’s name from gypsy moth to spongy moth since the name, gypsy, could be considered offensive to the Roma people (often called Gypsies). Gypsy moth has been the insect’s name for over 150 years and so it will remain here until the ESA changes any other moth names that could be offensive to someone (e.g. The German Cousin, The Hebrew, Finnish Dart, the Setaceous Hebrew Character, a large group called Quakers and others).

Back to the Big Woods: There are gypsy moth caterpillars of many sizes, some almost ready to pupate and others needing more time to feed and grow. The younger caterpillars may well starve as most of the trees’ leaves have already been eaten or fallen to the ground as scraps –

Larger, older caterpillars will soon enter their pupal stage where they will transform into adults –

Adult females are white moths, flightless due to the heavy masses of eggs they carry and will soon lay as tan spongy masses –

Male gypsy moths are tan and fly about searching for females with which to mate. They find females by the scent (pheromone) the females emit and is detected by the males’ feathery antennae –

The tan egg masses contain the eggs that will produce next year’s caterpillars. A number of tiny wasps parasitize the gypsy moth eggs, helping to control the population. The few species of birds that eat hairy caterpillars feed on those of the gypsy moth as do white-footed mice. The larvae of several introduced species of parasitic flies feed on gypsy moth caterpillars as does an introduced fungus; caterpillars killed by the fungus hang in a characteristic “J” shape –

But the parasites, predators and diseases don’t always keep gypsy moth populations in check, every 10-20 years there’s an explosive population increase such as we’ve seen this year. What of the trees that have been stripped of their leaves? Almost all will survive and grow new leaves in the next several months; if the trees are defoliated next year, roughly 30% will die; a third year of defoliation will probably kill 60% of the trees. But perhaps the predators, parasites and diseases will succeed in killing enough gypsy moths that the trees will not be defoliated for a second or third year – time will tell.

Note – Introduction of several species of flies to control the gypsy moth has had an unintended consequence,

they also parasitize our most beautiful large moths (including the luna, polyphemus and promethia) with devastating consequences to their populations.

 

National Bald Eagle Day

June 20 is National Bald Eagle Day, known to many as National American Eagle Day. The actual name for the bird is “bald eagle”, the name used by the U. S. Fish and Wildlife Service, and so that’s the name for the day used on In Forest and Field. The bald eagle was adopted as the symbol of the United States in 1782, an image of the bald eagle has adorned the Great Seal of the U. S., flags, statues, buildings, currency, and military patches, as well as an abundance of un-official objects.

Ironically, the bald eagle was on the verge of extinction in the 1950s and 60s, primarily due to the widespread use of DDT which caused such eggshell thinning that the eggs broke and never hatched.

In the 1980s there were only three active nests in Pennsylvania, now there are over 300 with more being found each year. The use of DDT has been curtailed and over time the species has recovered.

In celebration of the bald eagle’s recovery from the brink of extinction here are a few photographs I've taken of the majestic bird –

How fortunate we are to be able to see eagles in the sky.

Diggin' for Dinner

Pileated woodpeckers are usually considered birds of extensive woodlands although they can also be found in forested parks and wooded suburbs.

Here I was, in town, driving through a section with few large trees, indeed with few trees at all. In a tree lawn, that narrow strip between sidewalk and street where shade trees are often planted, there was something red moving. Curiosity aroused, I slowed down and then came to a quick stop. That moving red thing was the crest of a pileated woodpecker chiseling, chopping away next to the rotten stump of a tree that had been removed 10-15 years ago.

I’d stopped against the curb directly across the street from the stump and the woodpecker. Down went the window, out came the camera – it quickly became apparent that what I’d seen was a female pileated woodpecker –

She seemed to ignore the car and the human within as she continued working, not on the stump but in the soil next to the stump –

In the soil she certainly was – frequently her entire head and neck disappeared into the hole –

The woodpecker would chop in the depths of the hole a few times, raise her head to look around and then resume work –

Suddenly she extracted a large beetle larva, and quickly swallowed it as a starling looked on –

Occasionally cars and pick-up trucks passed and still she worked. I’d watched her working for well over five minutes and switched from taking photographs to recording a short video –

The passing of a city bus caused her startled reaction; but, as you saw, she rapidly resumed her excavation. She gave no indication of finishing her work any time soon, so after about ten more minutes I went on my way.

The larvae she extracted, presumably from a large root below ground, appeared to be the larvae of stag beetles or some other large beetle whose immature stage feeds on decaying wood.

The presence of this pileated woodpecker in such atypical habitat raises a number of questions:

• What caused this woodpecker to leave her usual habitat and visit this isolated stump in the midst of pavement and closely-spaced houses?

• Does she regularly visit such a built-up area?

• Do pileated woodpeckers examine every decayed stump they see?

• The stump, in which the homeowner had planted pansies, was quite rotten but showed no sign of recent woodpecker activity, had she visited this stump in the past and come back again?

• Woodpeckers usually seem to locate beetle larvae and carpenter ants by sound, can pileated woodpeckers detect beetle larvae beneath almost a foot of soil?

• Did she locate the larvae in some other way?

Ruby

Ruby is a male ruby-throated hummingbird – giving individual human names to wild creatures is not something of which I normally approve, but ... Yeah I know Ruby is usually considered a feminine name, but he doesn’t seem to mind and it’s an appropriate name for a bird of this species.

He was the first hummingbird that visited the feeder hanging outside our kitchen window this spring. From the feeder he’d go to a nearby dead twig to survey his domain. I realize we hold the deed to this property, but several other species also claim the same piece of the world. We don’t mind in the least; they, actually their predecessors, were here first. We hope they don’t mind us too much – although I know some of them would be more comfortable if we, and all other humans, disappeared.

Ruby visited the feeder one evening and then headed to the dead twig to rest and preen before heading back to the feeder. Fortunately the camera was on the tripod awaiting some interesting development, these photos may give you a brief glimpse into the life of a ruby-throated hummingbird. The throat feathers depend on reflected light for their brilliant red color, hence his throat appears black unless the light is just right – 

 

 

The next day a female ruby-throated hummingbird showed up at the feeder, a mate for Ruby perhaps. Ruby-throats depend on often scarce and widely scattered flowers and so they usually don't graciously share feeders, nor are they faithful to their mates. Ruby may soon begin chasing the female away from his food. 

A Three Nest Day

In the 1980s there were but three bald eagle nests in Pennsylvania, all far to the west near the border with Ohio. It wasn’t just in Pennsylvania that eagle nests were few and far between, they were in trouble throughout their range with the exception of Alaska and Canada’s Pacific coast. While shooting and habitat loss contributed to the eagle’s decline, the primary cause was the widespread use of DDT which caused their eggshells to be so thin they broke beneath the incubating bird.

The use of DDT has been curtailed and there were major efforts to reintroduce bald eagles. In the intervening years the number of bald eagle nests in Pennsylvania has gone from three to over 300. One of those nests is on a steep hillside above the north branch of the Susquehanna River and adjacent to a heavily-traveled highway. The nest has been there since at least 2016, at eye level when standing along the roadway.

This year there had been two eggs and then two young birds in this nest, but one either died or was pushed out of the nest by its sibling. I first photographed the eagles at the nest in mid-April when the remaining chick was about three weeks old –

In mid-May I returned to photograph the birds. It was a hot and sunny day, the eaglet was sheltering in the shade of a large limb and panting to keep cool –

With eaglets of this age the parents spend much of their time elsewhere, returning only to feed the young. I’d been squeezed between the road’s guide-rail and the steep drop-off for about 45 minutes when the adult female swept in with food for the young one –

She stayed for less than five minutes before departing. The young eagle then spent some time moving around the nest and at one point balanced precariously on the edge before settling down and surveying its world –

While adult bald eagles can be said to look regal, that’s not a good description of the young one – especially when it expels a pellet of indigestible material (as do all raptors) –

Shortly afterwards it began to exercise its wings with much flapping, a necessity to build the muscles used in flight –

That done the eaglet proceeded to preen it’s new feathers –

Next came a hike around the nest during which it rearranged some of the nest’s structure and furnishings –

And more wing exercises and flapping –

All that activity on a hot day must have been pretty tiring, so the eaglet settled down, panting and spreading its wings to dissipate heat –

Suddenly the eaglet lay down flat in the nest, looking skyward –

The alarm was apparently caused by two turkey vultures riding the breeze along the steep sidehill. The vultures soon rode the breeze downstream and out of sight. But still the young eagle lay flat, looking up. So I too looked up and saw nothing for quite some time – until my merely human eyes picked up a dot high in the sky. The camera’s telephoto lens revealed the dot to be a third-year bald eagle soaring on a thermal (a rising column of warm air) –

By now the nest was in deep shadow while the far side of the valley was in bright sunlight so the opportunities for photography were very poor. I’d been there for about two hours and it was time to pack up; I put the good camera in its pack and had the pack on my back before glancing at the nest once again – just as the adult female swept in again, bringing more food for her eaglet –

Time to leave and head south. About fourteen miles away as the eagle flies, but much further by road I stopped to photograph another eagle nest – this one on a smaller creek and much further from the road, and not on the official inventory of eagle nests in the state. One adult was in the nest, as was at least one eaglet, while the other adult perched above them –

The eaglet in this nest appears to be somewhat younger than the first one pictured in this post –

In February 2020 I photographed a common raven taking an egg from this eagle nest while both adults were occupied with driving an immature from their territory –

Onward says I, and so back on the road and past yet another bald eagle nest, this one in a huge sycamore and almost obscured by the new spring foliage on adjacent trees –

That foliage is a portent of things to come and the rapidly diminishing chance of getting good photos of these nests’ new generation of bald eagles.