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!

Growing up barred – Part 1: becoming independent

From the ages of about 8-19 years, I lived in a house that had a nice backyard and was not too far from some neighborhood woods with a creek. As a child, I read under backyard trees, planted a flower garden and played in the woods with friends. While I became familiar with squirrels, robins, frogs and some bugs and loved being outdoors, I didn’t spend lots of time looking for wildlife. And I never saw an owl in the wild.

Now decades later, I’ve had the good fortune to learn a good deal about various members of the wildlife community while spending time finding and watching them. And in the past couple years, I’ve been privileged to see owls up close in the wild; for example, the owl below was perched next to a pathway at dusk when I walked by a few days ago.

This past summer was unique for me, however, because I was able to observe a pair of juvenile barred owls (Strix varia) at the Mason Farm Biological Reserve as they set off on their life’s journey outside the nest. I’d like to share a bit of what I saw with you in a three-part blog. This one is about them finding their independence. The next two will focus on their grooming and interactions.

Barred owl pairs usually bond for life; if one mate dies, the survivor will seek another partner soon after. They tend 2-4 eggs, which hatch after 4 weeks’ brooding and the young leave the nest after four or five weeks. They remain dependent on their parents for food for some time after that even though they may be almost as large as the adults at 16-25 inches in length (40–63 cm); their wing span can stretch up to 3-4 feet (38-49 in, 96–125 cm).

When I first spotted the young owls in June, they could already fly. Nevertheless, they did need to find their balance occasionally as they perched and moved along branches and snags.

 

The owlets were making a keening noise the first time I saw them. At first, I didn’t recognize it, and I thought perhaps some small mammal was in distress.

Eventually, the plaintive call helped me locate them above me in a tree. This particular call apparently is used by the babies to call to their parents. I figured mom or dad was close by as the owlets kept looking upwards and eventually the parents did fly in with a meal – crayfish as far as I could tell.

 

On several occasions over the next 6 weeks or so, I would hear the owlets making that keening call and staring upwards. I figured the parents were nearby, but they were obviously just keeping an eye on their offspring and not feeding them (at least not when I was there).

It was time for the young ones to learn how to get their own meals.  Although barred owls usually hunt at dawn and dusk, the young owls were busy looking for food during the day. The mammals they eat include voles, mice, shrews, squirrels, rats, rabbits, bats, moles, opossums, mink, and weasels. Birds are also a food source and their prey may include woodpeckers, grouse, quails, jays, icterids, doves, pigeons, cardinals, cedar waxwings and grackles. They also eat amphibians, reptiles and insects (e.g., snakes, slugs, lizards, frogs and toads, salamanders, crayfish, turtles, scorpions, beetles, crickets, grasshoppers) and it was the latter group of prey animals that I saw the owlets hunting. Here for example, it appears one young owl had caught a crayfish.

One day, one of the pair was grasping a twig in its beak; I’m not sure what it was doing but it seemed to have some purpose. Perhaps it was testing how strong its beak was.

  

That a strong beak can be an asset became apparent on another occasion. One of the juvenile owls suddenly flew from one tree on the other side of a water ditch to one above my head. There was much rustling of branches and leaves and when I got into a spot where I could see the bird, it became obvious s/he had caught the largest stag beetle I had ever seen at Mason Farm Biological Reserve. It appears that the giant stag beetle (Lucanus elaphus) drinks tree sap, which must have been what it was doing when the owlet got hold of it. The problem for the owl was how to eat the beetle when those large pincers were in the way.

     

The owl would try to grab hold of a pincer but lose its grip; s/he would turn the beetle around but was having a very difficult time getting those defensive appendages off. This went on for quite a long time, which made me feel a bit sorry for the beetle.

 

Finally, the owl had success and was able to settle in for a crunchy meal.

 

They expel the indigestible parts of their prey in owl pellets that they cough up regularly. Here you see the contents of one a friend found under a favorite perching branch at the reserve.

Another day I saw one owlet suddenly fixate on the water ditch.It turned out that quite a large rat snake (Elaphe obsolete; Pantherophis alleghaniensis) was swimming by. The owl watched it carefully as it climbed out of the ditch and eventually crossed the adjacent walking path, never making a move to tackle the reptile. I had remarked on this encounter to the reserve’s land manager, who said it was probably a smart move on the owlet’s part, since the snake was large enough that it could have wrapped around the owl’s head and choked it.

The young owls seemed to have learned a lot about life as a predator as they grew older. It was fascinating watching them explore their world.

Next up: how the owlets cared for themselves.