Ask a Naturalist: Birds are disappearing at an alarming rate while porcupines and fishers are making a comeback

In Ask a Naturalist, we direct the attention of our esteemed experts to the local animal environment. Some take on topics of seasonal interest. Others address issues of wildlife population and ecosystem crisis. The goal of these columns is to satisfy and to inspire curiosity, but also to attune the larger community to the uncommonly rich  biodiversity for which the mid-Hudson Valley is famous.
– John Burdick

The rusty blackbird has seen a decline of 89 percent in the past few decades. The rusty blackbird is not the only bird in decline. A recent article in Science magazine reports that three billion birds have vanished since 1970. (Andy Reago & Chrissy McClarren)

According to a recent article in the journal Science, if you were alive in the year 1970, more than one in four birds in the US and Canada has disappeared within your lifetime. What’s happening, and which birds are most in danger?

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The first time I saw a rusty blackbird – a black bird with a rusty mantle and a haunting white eye – my friend Peter said, “Look closely: This is a bird that will be extinct in your lifetime.” I took in my surroundings in the Tivoli Bays – a lush habitat filled with birds – and didn’t want to believe him. The bird and its flock were so full of vibrant life. Yet Peter might be right: The rusty blackbird has seen a decline of 89 percent in the past few decades.

The rusty blackbird is not the only bird in decline. A recent article in Science magazine reports that three billion birds have vanished since 1970. And it’s not just the rare birds, but common ones as well, from sparrows and finches to the starling. Another way to think of this is that when I was nine years old, there were 25 percent more birds out there singing and winging about.

Often the reasons for a species’ decline is a bit mysterious, but we do know some of the reasons, and top of the list is habitat loss, particularly where birds breed. Those habitats that are hardest hit are grasslands, which hold many of our sparrows as well as birds like the meadowlark, and boreal forests, where many birds, including warblers, breed. Bird species have gone down in all habitats except wetlands (which could be due in part to the interest in duck hunting and the effort as a result to protect these habitats).

There are other causes for bird population decline: outdoor cats (which kill between 1.4 and 3.7 billion birds a year), collisions with windows (365 to 988 million a year) and pesticides. It was the pesticide DDT that brought the bald eagle and other raptors to the brink of extinction. Thanks to the research and writings of Rachel Carson, we eliminated DDT from our ecosystem and the eagles are back; the one family of birds that is thriving, according to the study in Science, is our raptors. Other families that are not in decline are vireos, gnatcatchers, ducks and geese and turkey. This shows that if we change our ways – let our grasslands grow and keep our cats indoors – we can turn around these declines. And maybe the rusty blackbird won’t go extinct.

– Susan Fox Rogers
Board member, John Burroughs Natural History Society
http://jbnhs.org

As porcupines maneuver to mate, the male covers the female with his urine. Presumably the pheromones present help boost her fertility and increase the chance of conception. (Photo by John Mizel)

Are porcupines making a comeback here?

I have a special fondness for porcupines, and I will forever associate them with the Shawangunk Ridge.  When I first moved to this area in October 2015, I was eager to get out into the woods and start learning about the local flora and fauna. On my second day in my new town, I took a walk on Mohonk Preserve’s Overcliff/Undercliff loop.  I passed a couple going in the other direction who warned me to be careful, because they had just seen a porcupine up ahead.  Delighted, I quietly continued along the carriage road and came to a spot next to a jumble of boulders where a porcupine stood, minding its own business. It didn’t seem at all concerned by my presence, and why should it? Its heavy coating of sharp quills provides a great defense against most predators. I stood and watched the animal for several minutes, enthralled, until it eventually waddled off into the boulder pile. This wasn’t my first porcupine encounter, and it wouldn’t be my last, but it’s one of my favorites. Now whenever I see porcupines it brings back a little bit of the joy from my first days here in the Shawangunks.

Since then, I’ve learned that porcupines have made a remarkable comeback in our forests. Today, the Shawangunk Ridge looks very different than it did a century ago. Early European settlers cleared much of the land for farming, eliminating the thick forests that animals like porcupines need for food and shelter. Animals that we now take for granted, like white-tailed deer, were rare or absent altogether. As agriculture on the Ridge subsided, the forests returned, and so did many of the original animal inhabitants. Indeed, one of the most interesting records on file in the Daniel Smiley Research Center’s natural history records database sheds light on this. An observation recorded by Daniel Smiley, Jr. reads: “A. K. Smiley, Jr. saw one on Woodland Drive at Lake Shore Path 9-11-1930 Mohonk Lake, NY… He was not apparently foraging but headed somewhere. He passed within about two feet of [Keith] paying no attention to him.As far as I know this is the first record here.”

It isn’t surprising that Keith Smiley’s encounter with this porcupine happened in autumn, as this is when the normally solitary animals begin to look for mates. Females are only fertile for a very short time – sometimes only a few hours – each year. To improve her chances of finding a mate, she spreads a trail of urine as she wanders widely through her territory. Males are attracted by the pheromones in her urine and use the scent to track her. Porcupines have a complex mating ritual involving noise and teeth clacking, and things get stranger from there – at least by human standards! As the two animals maneuver to mate, the male covers the female with his urine. Presumably the pheromones present help boost her fertility and increase the chance of conception.

Porcupines have other unusual traits, including their reddish-orange teeth. Like all rodents, a porcupine’s teeth grow continuously throughout its life and get sharpened and worn down by gnawing on tree bark or even bones. Their teeth have to be very strong to withstand all this gnawing, and that’s where the color comes in. That color is actually iron oxide in the enamel of their teeth, which helps keep them strong. You may be lucky enough to see the handiwork of these orange teeth if you have these animals living near you. Look at tree trunks and branches in wintertime when the leaves are off the trees. Porcupines often strip the bark off trees as they gnaw on wood and eat leaves and stems. 

– Elizabeth Long
Director of Conservation Science
Mohonk Preserve
www.mohonkpreserve.org

Nature has endowed these ruminants with a very useful adaptation: In the wintertime, they switch their digestive system, based on leaves and seeds, to twigs and buds, which are above instead of below the snow. (Tuchodi)

Snow: Bane or boon to local wildlife?

While conducting an informal survey with neighbors and friends about the recent heavy snow, I found, not surprisingly, that some hated snow, others loved it and many were mixed. The latter explained that, although they disliked driving and shoveling on snowy days, they felt that snow wasn’t all that bad – and often beautiful.

Within the animal world, it’s also a mixed bag. Russian scientist A. N. Formozov actually created three categories of animals’ relationships with snow: those that love snow, those that hate it and those that tolerate it. Some of the snow-haters, mainly birds, have developed the ultimate solution: They leave! They migrate to warmer climes. Lovers of snow, like the lynx and snowshoe hare, hang out to the north of us, where snow is abundant.  But let’s consider our local tolerators of snow, and how they adapt.

Many of those able to succeed in winter depend on the insulating characteristics of snow. Recently, I went out on a chilly, 25-degree day, put a thermometer under the snow and found that the temperature was in the mid-30s! The ground was not only not frozen, but was actually muddy. Local excavators inform us that no matter how cold it gets, if there is adequate snow, the ground below rarely freezes. This is also a boon for the small four-leggeds, such as mice, voles and shrews, who can still excavate their tunnels during chilly winters. While digging, they’re also able to munch on seeds, bits of foliage, plus any stray insects. And when the snow melts, we notice their surface tunnels crisscrossing our lawns.

Most of this activity transpires while these small mammals are safely hidden from their aerial predators. Certainly, these little ones are much more secure when there is good snow cover for most of the season. Birds of prey, on the other hand, often “dance with starvation” when their food sources are obscured by snow. Despite the mammals’ protection from raptors, snow is no protection from the voracious weasel, who adapts by turning snow-white in the wintertime. But nature cursed it with a black tail tip that can attract its own predators.

Our white-tailed deer have a complex relationship with snow. Most of the food sources they utilize during milder weather are low to the ground, and less available under even a few inches of snow. Nature, however, has endowed these ruminants with a very useful adaptation: In the wintertime, they switch their digestive system, based on leaves and seeds, to twigs and buds, which are above instead of below the snow.

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Deep snow, while difficult to navigate, can also offer them protection from wind and cold, especially when they yard up, packing down the snow and hunkering together. Deer, however, can experience starvation if the snow gets too deep or develops an icy crust. Most people don’t appreciate the fact that harsh winters are far more effective in culling the herd than hunting.

So instead of grousing about having to shovel all this “white stuff,” let’s think about the amazing adaptations that our animal neighbors must utilize to survive the extreme cold and snow of winter.

– Ann Guenther
Regular contributor, Bluestone Press
Former educator/naturalist, Mohonk Preserve

Photo of fisher at Mohonk Preserve’s Coxing Kill by David Johnson

What is a fisher? Should I call it a fisher cat?

I was recently in front of a class of first-graders, excited to soon be walking in the forest behind their school. We were running through a list of animals that we might find signs of in the forest. Bear elicited squeals of excitement. Coyote too. When I got to fisher, there were blank stares.

I wasn’t surprised. They are missing from most picture books featuring “classic” woodland animals – most likely because they are only recently making a comeback in the lower 48 states after having been overhunted for their pelts. Thanks to many state agencies’ reintroduction programs, they are back and doing very well. They are expert hunters and very adaptable, which is allowing them to carve a niche once again in our ecosystems. In our area – in fact, behind the kids’ school – I have seen evidence that they will actively vie for territory with much larger predators. A coyote marked the middle of a hiking trail with a pile of scat, and a fisher very carefully deposited scat on top, covering it in a circular pattern like a swirl of frosting on a cupcake.

“Fisher cat” is what many people call them, but they don’t fish and they’re not cats. They’re in the family Mustelidae (weasels), which includes mink, badgers and otters. I’ve heard some say the cat part came from their catlike screech, which is terrifying. But “cat” comes from early American immigrants noticing their similarity to the European polecat, which also went by “fitch.” So, it’s not wrong to call them fisher cats, just possibly misleading. I prefer to leave the “cat” off.

So, what do they look like? They have dark fur, long, sleek bodies and a long tail. Full-grown males can be four feet long, although almost half of this is tail. Females are smaller. They make homes for raising young in trees. Old forests are important to them. In fact, to help fishers out where there aren’t many old trees with hollow cavities, some biologists are installing fisher boxes. (These do quite well.) To help them descend trees quickly, headfirst, their hind feet swivel 180 degrees. This is handy when attacking a porcupine, which hides its vulnerable head against a tree. The fisher’s swivel feet and sharp claws let it hold onto the trunk while it attacks the head, eventually incapacitating it, flipping it over and fileting it. They have a preference for fresh meat; their scat is very dark from blood and doesn’t tend to have much fur. Besides porcupines, they enjoy rabbits and other small mammals. These ferocious predators will even attack a grey fox that is easily their size. So, keep an eye out for signs of this resourceful, fierce underdog (undercat?).

– Julie Seyfert-Lillis
Director, Mill Brook Preserve
www.millbrookpreserve.org

There is one comment

  1. Felix Unger

    Bird-watchers are dedicated, but not to getting domestic cats licensed and kept indoors? As to places like Saugerties Village, they put bird killing feline species out on the street to do more habitat damage.
    What’s the deal?

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