Craving crawdads in Carolina – a buffet for night herons

Many people in the USA, especially but not only in the South, grow up knowing what crawdads (Cambarus bartoni) are. This was not the case for me. My immigrant family pretty much stuck to the dietary customs of their own and their friends’ home countries (The Netherlands, Belgium, Germany). Like pumpkin pie, sweet potatoes and okra, crawdads were not on those menus and so it was only recently that I actually learned that these crustaceans are the same thing as crayfish, of which I had heard as a child.

This year was my time to learn more about these members of the arthropod family who are related to lobsters – it turned out they were thriving in a pond created through a man-made wetlands installed between a shopping mall and several apartment complexes. I learned about their presence when local birders alerted one another that the crawdads were attracting a family of yellow-crowned night herons (Nyctanassa violacea).

Hoping to spot the herons, I also visited the wetlands and first noted the crayfish remains scattered around near the pond. Shortly thereafter, I came across one crossing a path in another local nature park (photos above and below). It was interesting to see how the crawdad first stayed stock still as I neared and then stood tall on its legs as its tail propelled it backwards while it made a dash for the nearby pond.

The crawdad females lay hundreds of eggs; scientists do not yet know how long they incubate before birth but estimate it takes somewhat longer than a month before they hatch. In North Carolina, there are almost 50 species of these animals and several species are found only in this state.

The crayfish at the wetlands must have had a successful year because the place became a real buffet for various birds. Both adult and young night herons stayed near this pond for quite a long time before leaving to migrate to more southerly climes for the winter.

The adult herons were attractive with their boldly patterned heads.

 

 

   

They kept up their looks through regular preening.

 

 

Sometimes, they emerged from the pond weeds to perch on a snag while peering into the water on the lookout for a meal.

 

It was interesting to learn that while the adults have yellow legs most of the year, their legs can turn red or pink during breeding season.

 

 

In my experience, the younger herons were a bit less shy and didn’t fly off so quickly when I neared.

 

One in particular decided to take the sun in mid-August, adopting a pose that I more often see taken by great blue herons and which I’ve nicknamed the “flasher stance.”

     

The young birds, like their parents, stalked the pond vegetation on the lookout for crawdad snacks.

They also showed the herons’ taste for other food such as snails, earthworms and insects.

 

The night herons, for which most birders visited the wetlands, weren’t the only birds at the buffet, however. Red-shouldered hawks (Buteo lineatus) also showed a fondness for the crustaceans.

 

 

 

The herons weren’t always alert to their presence. One adult, for example, decide to fly to a low perch when chased away from a tall snag by a hawk. S/he settled in for a bit of preening but was then rudely chased off by the same hawk. (That hawk was later harassed by a group of crows, who chased it away in turn.)

Other herons who were interested in outdoor crayfish dining during the humans’ Covid epidemic, included the great blue herons (Ardea herodias).

 

 

Green herons (Butorides virescens) visited the pond regularly as well, eating small fish in addition to the other wetland delicacies.

 

 

 

 

 

 

Belted kingfishers (Megaceryle alcyon) were busy flying to and fro over the length of the pond, but I didn’t see them carry off any crayfish so they must have been focused on fish.

 

A great egret (Ardea alba) was a regular visitor, too, stalking different areas of the pond.

The adult night herons obviously thought it was interesting to watch the egret’s foraging technique.

Other regular visitors to the wetlands included a flock of Canada geese, American and fish crows, Northern mockingbirds and wandering glider dragonflies (Pantala flavescens).

 

There were so many animals feeding on the crawdads this summer that the female crayfish must have had a lot of success with their offspring reaching maturity. The last reported sighting of the yellow-crowned night herons at the wetland was 24 October, but I’m guessing that they will be leaving soon and the pond will not be so busy this autumn. The crayfish population had to have been reduced mightily over the summer season, so it will be interesting to see whether it rebounds and attracts crowds of birds — and birders — next year!

Helping monarch butterflies thrive

If you follow news about nature, you may have come across warnings that the monarch butterfly (Danaus plexippus) has been in rather dire straits for many years now.

 

These lovely orange and black butterflies live from 6 to 8 weeks when they are adults engaged in reproduction. Those who live in the Eastern USA participate in a multi-generational migration process between Canada and central Mexico. The last generation to emerge in late summer is able to delay its sexual maturity to undertake the last leg of the migratory journey (called reproductive diapause) and may live up to 8 months. Individual butterflies may travel as far as 1200-3000 miles to get to their warmer over-wintering grounds.

 

Since the 1980s, the Eastern US monarch population has declined by about 80%, mainly because the only food source for their caterpillars has been disappearing. Milkweeds used to grow abundantly in agricultural areas and along roadsides and ditches, but people have been eradicating the plants from fields and using herbicides and mowing to remove them along roads.

Climate change has also affected the butterflies’ breeding and migratory patterns so that reproduction has been reduced.

One way to help out the monarchs is to plant native (not exotic!) milkweeds in your own yard and any other natural spaces to which you have access. I’ve been doing it around my home and as a volunteer for the Mason Farm Biological Reserve. This year, I was lucky enough to be a beneficiary of a milkweed give-away organized by some local high-school students, so I had two types of the plants in my yard.

 

The ones that I had originally planted were common milkweed (Asclepias syriaca). These plants have large globular clusters of flowers that range in color from pinkish to purple. They do not have blooms their first year but that doesn’t stop the caterpillars from eating their leaves.

 

Butterfly weed (also known as butterfly milkweed; Asclepias tuberosa) is a bit more delicate and “exuberant” in appearance, with small clusters of orange, reddish and yellow flowers. These were the plants that I was gifted by the students and I was happy to see them grow quickly to exhibit their beautiful blooms.

According to Wikipedia, the butterfly milkweed is not a preferred plant for the monarch but this year the butterflies seemed much more attracted to it than to the common milkweed. After a few visits from some butterflies, I began seeing caterpillars and at one point counted 17 crawling up and down the various plants.

They were especially prevalent on the butterfly weed in my front yard and were munching the plants to bare stems very quickly.

 

       

To make sure they had enough food, I transferred some of them to the common milkweeds in my back yard – these were larger plants with much broader leaves and I thought this would ensure their healthy development. Frass (poop) was being left on the remaining leaves and the ground surrounding the plants.

 

It was rewarding to see three caterpillars make it to the chrysalis stage; the other caterpillars crawled away before I could see where they went, and I didn’t find them suspended from any plants. The first one had attached itself to a bare sapling and, unfortunately, the next day it had disappeared, leaving only the silken thread by which it had been suspended.

The caterpillars store milkweed glycosides in their bodies, making them toxic to many other animals. They still have many predators, however, including wasps, spiders, other insects, lizards, toads and mice. I resolved to save at least one chrysalid if I could.

I got to see the second chrysalis being formed (see the video, which is a little shaky at times). When the caterpillar is ready to undergo the pupation stage, it attaches itself to a plant stem by making a silk pad as an anchor (called a cremaster). Then it inserts the hooks at the end of its abdomen into the pad and hangs down. When the caterpillar forms a J shape, this signals the change to a chrysalis will soon be underway.

Starting from the head, the outer skin is shed, rolling up as the new covering develops. The shed skin may remain at the silk pad or fall off.

 

Slowly the stripes of the caterpillar disappear, and the chrysalis takes on a shiny even green hue, with some golden accent spots.

 

I kept that chrysalis, as well as a third one I saw the next morning, in my house and waited for them to darken. This signals the butterfly is almost through developing inside.

One morning I found the newly emerged monarch from the second chrysalis drying its wings. I took it outside so that it could fly free and then begin its trip to Mexico. (I also took the third one outside when it darkened but the twig holding it disappeared.)

 

You, too, could contribute to their propagation by planting some milkweed if you have an area for this. Autumn is the best time to plant seeds, but you can try it in the spring as well. Common milkweed typically doesn’t flower during its first year, but butterfly weed will give you flowers in its first season; the latter plants may be slow to emerge at first.

Both of these milkweed varieties are perennials so be sure to remember where you planted them. Common milkweed may spread out with time, while butterfly weed remains where you put it.

 

Other flowering plants will attract the adult monarchs, too, for nectaring, such as asters and lantana.

 

And then sit back next year and wait for the monarchs to arrive, happy in the knowledge that you have contributed to maintaining a favorable environment for their survival.

More ideas on how you can participate in the drive to save this iconic butterfly are detailed on a U.S. Fish & Wildlife Service website: https://www.fws.gov/savethemonarch/

 

What gets a birder really going? A rare bird!

People who are “into birding” are excited when they see a new bird for the first time. Many keep “life lists” – an account of each different species they have actually seen worldwide, in their country, in their state or province, or perhaps in their yard. When they see a new species, birders say they got a “lifer” – a first-time sighting in their life. Quite a few of these birders then decide to enjoy a reward – a lifer pie!

This past week, I was lucky enough to get a lifer, thanks to alerts circulated in the birding community. Doc Ellen Tinsley, the North Carolina Piedmont area’s main bald eagle researcher, also looks for other species when she goes out to see the eagles she knows. On 27 September, she was at the Jordan Lake Dam, where she often sees eagles whom she has come to recognize and know. Since it is the migration period for many birds that breed up North, she was also watching for warblers, a popular type of songbird because they are often beautifully colored.

She counted herself very lucky when she spotted a yellow striped bird that she had not seen before. After getting a confirmation of its scientific identification, she notified area birders that she had spotted a Kirtland’s warbler (Setophaga kirtlandii) and it was still foraging so people might be able to see it if they came to the Dam.

Until recently, the Kirtland’s warbler was considered an endangered species as it requires a very specific habitat in jack pine forest to breed. It depends on areas affected by fire; about 6 years after a conflagration, the space will be regenerated with small trees, shrubs and open areas that are favorable for its nests. When trees grow to about 10-16.5 feet high (3-5 m), the warblers leave to find a more suitable living area.

Compared to other birds, the Kirtland’s has the most restricted geographical breeding area of any bird in the continental United States. In the 1970s and 1980s, only about 167-200 males were counted in annual surveys. Conservationists in Michigan, Wisconsin and Ontario, Canada, collaborated on protecting the Kirtland’s environment and achieved success. This warbler has now been re-designated a threatened rather than endangered species. There are currently about 2,300 breeding pairs who migrate south to spend the winter in the Bahamas.

 

These birds’ diet comprises mainly insects and small fruit such as blueberries. Occasionally, they will catch an insect on the wing but more usually they glean pine needles and other vegetation for their meals. Spiders, moths and flies constitute part of their diet. Adults will also ingest pine sap.

 

 

These birds place their nests on the ground, underneath the small jack pines. The males will feed the females while they brood and both parents bring nutrition to the hatched offspring. In the past, brown-headed cowbirds often laid their eggs in Kirtland’s warbler nests and this contributed to their endangered status. Elimination of cowbirds from the environment for many years has now reduced the threat.

“As a condition for the warbler’s delisting, the USFWS, U.S. Forest Service, and the Michigan Department of Natural Resources signed a memorandum of understanding that the agencies will continue habitat management at sufficient levels to ensure a continued stable Kirtland’s Warbler population. Keith Kintigh, a forest conservation specialist with the Michigan DNR, says his agency will plant 1.8 million jack pine seedlings per year going forward to help maintain the 38,000 acres of suitable jack-pine habitat needed to keep the warbler population above the 1,000-breeding-pair threshold for recovered status.”
9 January 2020; https://www.allaboutbirds.org/news/kirtlands-warbler-delisted-after-47-years-of-conservation-work/

It’s likely that at least 100 people have traveled to Jordan Lake Dam to see this female bird. She was very popular because she didn’t particularly hide as some birds do. (She was sometimes a bit hidden by the pine needles, but that was because she was constantly moving about in the trees.)

She was foraging for insects along rocks bordering the dam area and in nearby trees, which gave the birders an opportunity to memorialize her visit with photos. Much of the time, she was seen in the company of a male bird of the Cape May species, who look similar (left).

The Kirtland warblers’ areas in Michigan and Wisconsin are closed to the public when they are breeding. They are rarely seen so there are guided tours in those two states to enable people to spot them.

 

Doc Ellen provided area birders with a wonderful opportunity to admire this rare bird! A much needed bright spot in a year that has been fraught with calamities.

 

Sunning snappers, cavorting cooters and spirited sliders – unexpected behavioral encounters

All wildlife fascinates me. It’s always a delight when some animal exhibits behavior in my presence that I haven’t seen before. Turtles have not been the most likely candidates in this regard for me, however. That changed this year in two cases (see further below). Mostly I see them basking on logs in bogs, ponds and lakes, like these yellow-bellied sliders (Trachemys scripta), either alone or in the company of other creatures.

Painted turtles (Chrysemys picta) also like to sun and can be seen in the same environments.

Seeing turtles cross a walking path as they search for a place to dig a nest for their eggs is not unusual.

I’ve come across a red-eared slider (Trachemys scripta elegans) also on the march, apparently having just completed a nesting site.

There are seven species of cooters (Pseudemys) in the southeastern USA and it can be difficult even for experienced naturalists to distinguish them. They are all large turtles at full growth, with a carapace measuring some 13 inches or more.

 

The turtle that many more people see, including in their yards, is the lovely Eastern box turtle (Terrapene carolina). During nesting season they are often on the move and several people I know will stop and “rescue” them as they cross busy roads.

The other day, I stopped traffic on a busy neighborhood road when I spotted a box turtle crossing. Drivers of cars going both ways kindly came to a halt as I carried the turtle to the side of the road where it was headed. It was about the 5th time this summer and fall that I had stopped for a box turtle and I always hope that the reptile will go on to have a long and healthy life.

This summer I also rescued a box turtle that I found resting on water weeds in my pond. I had always thought that these terrestrial turtles would drown, so I got the reptile out. There is a small log sticking up out of the pond, which is how I think the turtle got in, but I wasn’t sure it could climb up again.

I did find out later from my friend Lucretia that box turtles are able to swim, despite not having webbed toes like aquatic species.

The box turtles vary a lot in coloring, but the turtle below has to be the most strikingly colorful one I have come across so far. It made me think of a young person who went a bit wild with the make-up.

The slider turtles can also have some beautiful coloring.

One bit of behavior that I don’t expect from snapping turtles (Chelydra serpentina) is the basking behavior exhibited by many other species. Nevertheless, in June I found one apparently enjoying a sojourn in the sun in a pond kept filled by the local beavers.

Usually, I see snappers with their heads tucked in, but they certainly do earn their scientific name of serpentina (snake-like) as their necks are very long!

And that brings me to the really unexpected behavior that I recently saw while watching turtles. One day, about 20 turtles were swimming and gliding around a pond, close to the surface. Two in particular were not only swimming, however, but also seemed to be playing. After asking for help in identifying them in a reptile-oriented Facebook group, it was suggested they were either sliders or cooters. Both were very large.

They were not near one another but in their own space, showing similar behavior. They would surface, swim along with their bodies stretched out to the limit and then bring up their hind or front legs and slap the surface of the water repeatedly. Then after doing this several times, they would suddenly rise up a bit and splash their whole bodies down into the water, making an even larger spray of water.

A fellow photographer suggested they might be mating or defending territory, but I think they were actually playing.

Some readers might think that makes me very anthropomorphic, but scientists are studying the concept of play in reptiles and one researcher, Gordon Burkhardt, has said that rejection of the idea of reptiles playing has to do with how play is defined.

He has proposed a definition that would make it entirely possible to think of reptiles playing:

“play is repeated, seemingly nonfunctional behavior differing from more adaptive versions structurally, contextually, or developmentally, and initiated when the animal is in a relaxed, unstimulating, or low stress setting.”

It should be noted, too, that websites dedicated to people who own reptiles as pets include articles on how they can stimulate play – and thereby well-being and health – among their animal companions.

I’ll be keeping a more watchful eye on turtles from now on; who knows what other interesting behaviors might be observed? And it would be just nice to think that a turtle whose remains we find in the woods could have had an enjoyable and not just “mechanical” (pre-programmed) life.

As Brian Doyle wrote in Martin Marten:

“The fact is that the more stories we share about living beings, the more attentive we are to living beings, and perhaps the less willing we are to slaughter them and allow them to be slaughtered. That could be.”

 

 

 

When it’s time to eat your own skin

Several years ago, I bought a couple hard polyethylene pond liners and dug two large holes in my clay and rock-filled back yard. I wanted to have a pond area and figured that two big tubs would be easier to manage and clean than maintaining an in-ground pond. So far, that has been the case except for the fact that I couldn’t keep any fish – a great blue heron managed to eat all the fish I had over the course of about 2-3 years.

That doesn’t mean my pond is not populated, however. Indeed, all the water sources in my yard have residents. Some are unwanted – for example, the mosquito larvae that I admittedly kill with mosquito dunk. The Cope’s gray tree frogs (Hyla chrysoscelis) have a preference for my rain barrels. Somehow they manage to crawl inside even when a lid is on and they deposit hundreds of eggs per season.

   

Fortunately, not all of the frog eggs hatch or my yard would be overrun and the sound in the evenings would be overwhelming. Even the half-dozen or so current adults manage to produce quite a loud concert series – I’m surprised neighbors haven’t asked me to do something to tamp down the sound!

I used to have bullfrogs in my container ponds but haven’t seen them this year. Instead, my neighbors have been lovely green frogs (Rana clamitans). One grew to a very large size and he was joined by two others of a bit smaller stature.

They aren’t very noisy, mostly croaking in the late afternoon. It must have been that sound that attracted another neighborhood resident whom I spotted one day sitting on a nest box next to the pond. The red-shouldered hawks (Buteo lineatus) have spent time watching the pond before when in the mood for frog legs; this was a young hawk who had obviously been in the pond as evidenced by his wet plumage.

The pond was quiet for a few days and I thought the hawk must have had a good meal. And then, slowly, the frogs began to emerge again. There are three that sit on the rocks surrounding the larger pond although one is a bit smaller. This makes me think the hawk might have gotten one but that a juvenile frog was now accompanying the larger pair.

   

When my pond “greenies” croak, they don’t seem to get very large inflated vocal sacs. At the NC Botanical Garden, fellow photographer Mary showed me a green frog that she had been photographing and he croaked a couple times. It went too fast to get a good shot so I offered to make him “talk” by croaking at him. My pathetic attempt at imitating him really was quite pitiful, but amazingly did evoke a response. His vocal sac didn’t get really large either though.

One day, I spotted one of the yard frogs sitting on a rock, opening and closing its mouth without making a sound.

 

When I looked more closely, it seemed to have some membrane hanging on its side.

Then I saw that it was partly in the frog’s mouth and the amphibian was tugging away at it. I wondered if he was sick.

It turns out that he was perfectly healthy and staying that way by eating his own skin! These amphibians regularly shed their skin because it would otherwise harden and make it difficult for them to absorb oxygen while underwater, where they spend a considerable amount of time. So periodically, they scrunch themselves together and then stretch to break the skin so that it can be pulled off, leaving supple skin behind to better enable the “breathing” method called cutaneous gas exchange.

But why do the frogs then eat their skin? It actually has many nutrients, including calcium and proteins. I have no idea if the skin has any taste and whether they enjoy ingesting it. It seemed to be a bit of a laborious process when I watched this frog go through the process. Added to that is the fact that they actually use their eyeballs to push food down their throats and you discover that our froggy friends have quite a unique digestive process!

 

Outside my yard, I’ve not seen too many frogs this year. There was a lovely little Northern cricket frog (Acris crepitans) out and about on one of my walks.

More recently, I’ve been seeing Fowler’s toads (Anaxyrus fowleri) in the woods and parks.

 

     

At the NC Botanical Garden, I had the chance to see some rather large tadpoles sharing a pond with smaller ones.

It was interesting to see that the tadpoles first develop their hind legs and then their front legs before eventually losing their tails.

Finally, one more type of interesting creature I’ve been observing lately on walks are land snails. They don’t really belong in a blog that is about amphibians but it’s unlikely I’ll be writing one about mollusks any time soon. So, I’ll leave you here with a few photos of what I thought were some snails with beautifully spiraled shells. Have a good day or evening!