A bountiful year for seeing Castor canadensis

It has been my privilege to go on safaris in Africa and my outings in nature there resulted in sightings of multiple mammalian species each time. Where I live now, there are also a variety of mammals but I don’t see them often, other than squirrels, chipmunks, deer, opossums and raccoons. I was lucky to see chewed trees as evidence of American beavers’ (past) presence, but I was not seeing members of the Castor canadensis species. Some of the chewing patterns on the trees were interesting though.

I saw my first beaver lodge at Brumley Nature Preserve South in early 2016 and had the good fortune to get a quick glimpse of a beaver there. (Before that, I had seen them in zoos.) Then I began noticing beaver dams more often on walks, like the one below near the Haw River. So for my first long blog of 2019, I’d like to share with you how 2018 became my bountiful beaver year.

In the spring, a friend told me about a creek where beavers’ dams had resulted in marvelous wetlands along some nature trails. Their handiwork at Pokeberry Creek was appreciated by a considerable number of nearby residents, who were pleased with an increasing number of waterfowl and other birds at the wetlands, as well as otters.

 

They spoke about the benefits of beavers’ presence, such as the increased biodiversity, improved water quality and more opportunities for wildlife viewing, and celebrated their arrival. Some birding groups began leading walks there to view the numerous songbird and other avian species.

For me, the chance to see the beavers in action was wonderful. One day, I saw an adult chewing branches as part of its meal; it was quiet and didn’t seem disturbed to have me nearby watching.

On other occasions, I saw individuals bringing reeds back to a lodge, presumably to feed young ones left at home. (The offspring may stay with their parents up to two years.)

As beavers are mostly crepuscular, visiting at dusk offered a good chance to see them at work felling trees for their dams and lodges. It struck me that when I had observed them eating, they were very quiet. When they were working to cut trees down, however, I could hear them chewing very loudly.

Some people living near Pokeberry Creek brought chairs and drinks to watch the animals at work in the evenings and everyone present seemed to be learning a lot about them. Apparently, many people are interested in beavers – the ranger station at the Jordan Lake Dam has a taxidermied beaver and information about their lodges on display.

Nature’s aquatic engineers are certainly interesting mammals. North America’s largest rodents can swim underwater without coming up for a breath for some 15 minutes; this is because they slow their heart rate. Their transparent eyelids function as goggles so that they can see underwater.

They build dams to ensure that the ponds in which they construct lodges are deep enough so that the entrance remains under water. When the water is at least 2-3 feet, they will be safe from predators and the entrance to their home will stay ice-free in the winter. If they are in a spot where the water remains high enough all the time, they may forego building dams. At Pokeberry, the animals felt a need to build dams in two places. Research has shown that the noise made by water flowing away contributes to their decisions to shore up dams; they apparently cannot tolerate the sound of running water above a certain number of decibels.

The beavers’ environmental engineering irritated some members of the Home Owners Association (HOA) of a nearby community which is still under development. Some people complained that the water was encroaching onto properties (other property owners were ok with it). The rising waters also sometimes flooded a long walking bridge and a cul de sac. Numerous repairs were needed for the bridge and “opposing” parties emerged.

After the HOA announced a plan to have 35 beavers killed, a petition to save the mammals was begun. Within a few days, more than 3700 signatures had been gathered and the HOA undertook a consultation process with different agencies to explore other options. The Friends of Pokeberry Creek Beavers and Wetlands, in the meantime, put up small barriers so that the waters would not encroach so easily onto the cul-de-sac. They also installed a “beaver deceiver” (a pond leveling device, comprising large tubes inserted through a dam so that water would continue to flow through).

It appears that the beavers found the water flow too noisy, so each evening they would mud up the fencing around the deceiver intake so that no water could enter there. The humans would take away the mud; the beavers would put it back. The humans moved the pond leveling devices to deeper areas, but with heavy rainfall, the waters would rise very high.

Finally, in early autumn, the HOA had much of the wetlands drained. This was done to avoid killing the beavers by driving them further downstream to find another area where they could build dams to establish a new pond territory.

The beavers in a large pond that remains rather full have not moved; they are still felling trees, presumably to reinforce their lodge and to have some food supplies in stock for the winter. They also need to keep chewing as their teeth never stop growing. When they remove trees, they leave stumps of about 6-12 inches behind. I’ve seen some of these tree stumps, such as a tulip poplar, sprouting branches again. So the beavers’ tree clearing does not have the same effect as clear-cutting done by humans.

   

  

I thought that the drained wetlands at Pokeberry Creek might be the end of my beaver observation opportunities, but then I discovered that another wildlife and recreational park was facing challenges from beaver dams. Sandy Creek Park had had beavers some 5-6 years ago and at that time the mammals were removed (killed). The park manager wants to avoid that now if possible, but the dams need to be controlled since they are causing flooding onto paved pathways which help make the park accessible to persons living with disabilities.

A wildlife biologist visited the park to assess the potential success of a pond leveler there; because the pond in question is rather deep, they may have more success with a beaver deceiver. I’m guessing it will also depend on how the noise levels evolve with the new flow of water into the nearby creek. If they can install a silent outflow pipe, the intervention may be successful.

In November, I found that beavers were also busy at a third natural area that I visit often, the Brumley Nature Preserve North. The rodents are busy in two of three ponds there. The volunteer trail steward periodically breaches the dam at one pond so that the water can continue flowing downstream. When the pond water level remains high enough, the beavers seem to be more lax in repairing the dam.

  

At the other pond, the water level has stayed fairly consistent with all the rainfall our area has had in the past months and no beaver engineering seems to be happening there. As there is no obvious stream flowing into that pond, if we have a dry summer, the beavers may have to abandon that home as the pond could dry up as happened during a drought period last year. There was an interesting development at this pond, however. It involved one particular beaver who recently spent afternoons for a couple weeks swimming laps for hours.

I was quite surprised to see him (it could be female but somehow I thought of this individual as a male who was hoping to attract a mate), since beavers often prefer not to be out in the open during the day. He even emerged from the water from time to time, but always on the other side of the pond.

 

It didn’t matter whether the day was sunny or colder, gray and overcast. Sometimes, it seemed that he was taking a quick power nap.

  

The beaver would make small circles, large circles, go to the shore for a quick rest and then resume laps.

One day, I saw him swim toward the lodge and I was able to see inside above the underwater entrance. He didn’t stay there long though and soon came out again to exercise.

This beaver seemed to be quite relaxed, swimming around and around, except for when walkers came by with dogs. He definitely did not care for the canines; when they appeared, he often would begin slapping his large, flat tail on the water and then diving noisily under water before emerging again nearby.

These tail slap warnings and dives showed off his webbed hind paws.

It was interesting to hear how very loud the tail slaps can be. The beaver will also vocalize its distress.

At one point, some visitors to the reserve allowed their dog to jump into the pond and the canine swam close to the beaver lodge. (Dogs are supposed to be kept on leash but a number of pet owners ignore the sign stating this. When I mentioned that dogs running loose also disturb ground-feeding birds, the response was: “Too bad for the ground birds!”) That very much disturbed the beaver, who slapped his tail again and again.

After that incident, I only saw the beaver having afternoon lap sessions a couple more times. He seems to have given up the practice or is now restricting his swims to very quiet times. I can understand if the animal is trying to avoid stress and distress; that’s one reason I go out for nature walks, too. But I was glad he ventured out for a while so I could see him fairly close on several occasions.

Happy New Year to you all – hope your 2019 is happy, healthy and filled with nature’s beauty!

An under-appreciated bird?

In the area where I live, many birders are thrilled when spring migration begins and the wood thrush (Hylocichla mustelina) arrives. They find its song especially appealing and exclaim over the fact that they had the privilege of hearing the wood thrush in their yard or in the woods.

 

 

While it’s a nice song, however, I find that I’m more attracted to our winter visitor, the hermit thrush (Catharus guttatus), perhaps because this species seems less afraid to emerge from the vegetation when people are around. I find its song quite nice as well, even though it doesn’t seem to have as many trills in it as the wood thrush.

 

   

The past couple years, I seem to have been seeing the hermit thrush more and more often. Presumably, this is not because there are more of them but because I have grown a little more adept at spotting and identifying birds as time has passed. The past six weeks, I’ve seen them in various places and have very much enjoyed each spotting.

On the 15th of December, during a walk at Mason Farm Biological Reserve, I spotted one eating berries with gusto.

 

       

Ten days later, birds in different parts of the reserve came out on twigs, observing me as much as I was observing them. On the 2nd of January, one caught my eye when s/he was bobbing its reddish tail up and down. It gave me a good view of the bird’s underside, which looked nicely cushioned. That part of the tail is the most colorful part of the bird, which otherwise is a rather muted light brown with a cream-colored, lightly spotted breast.

   

On the 4th of January, we had a light smattering of snow and I saw a hermit thrush in a crepe myrtle tree, an unusual sight in my yard as their visits are usually few and far between. The next day, the bird returned to the red cedar trees (Juniperus virginiana) to make a few meals of the nicely ripe juniper berries.

  

The snow melted quickly but the bird was back the next day for more berries; fortunately, the American robins and cedar waxwings had not eaten them all.

  

In the spring and summer, the hermit thrush’s diet consists mainly of insects and sometimes small reptiles and amphibians. In the winter, they turn to eating berries and fruit. Here, a thrush at the Brumley Forest Preserve had been foraging on the ground and found a seed or fruit.

Back at Mason Farm, the 21st of January was a stellar day for seeing hermit thrushes; I must have seen at least six in different parts of the woods. At one point, I had stopped to listen to a downy woodpecker (Picoides pubescens) calling and then noted a thrush sitting on a sapling branch near the walking trail. S/he flew down to the path to forage and suddenly another one flew in landing atop the first thrush! The attacked bird spread its tail feathers on the ground while the other one glared at it.

The Cornell Lab of Ornithology notes that hermit thrushes may respond to predators by crouching and pulling in their heads; perhaps this was an adaptation of that response.

I always think of these little beauties as being peaceful birds so seeing one challenge the other in such a physical way was a real surprise. Then as suddenly as the attack had happened, all was sweetness and light as the two birds began foraging on the path about 2-3 feet from one another. The downy woodpecker even joined them on the ground for a little while.

  

The oldest recorded hermit thrush was almost 11 years old. Perhaps their generally sweet disposition helps them survive.

   

Depending on whether these birds are fluffing their feathers against the cold, they can either look like a sleek and slender avian or a puffy little ball of feathers. In both cases, I think they look quite appealing.

  

Whatever shape they take, I do look forward to seeing more of these lovely, usually demure and delightful thrushes!