Cobwebs

The triangulate household spider, Steatoda triangulosa.

The triangulate household spider above is a female. Like all spiders she has eight legs and two body segments. Her large round abdomen is decorated with brown triangular spots. She is about 1/4 of an inch long, with bands of darker color at each of her leg joints.

She has just settled into a spot close to the ceiling light outside of my bathroom. She has been there for three days, moving only slightly to change position. Day and night, she hangs upside down from her almost invisible web.

The spider below is a male of the same species. He lives in the vicinity of a framed photograph that hangs in my hall. Triangulate spiders are among the most common harmless household spiders of North America. They were introduced from Eurasia.

Triangulate spiders (and other cobweb spinners in the scientific family Theridiidae) make webs from short stands of sticky spider silk arranged irregularly. Their webs are not the pretty symmetrical kind that garden spiders make, but they work just fine.

Triangulate spiders hang upside down waiting for insect prey -- ants, fleas, ticks, and other tasty things. They rush over to wrap up ensnared prey in more silk, and eventually kill and eat them.

The cobwebs that triangulate spider spin probably got their name from an Old English word for spider, attorcoppe, which was eventually shortened to coppe and led to coppeweb or cobweb. Fans of J.R.R. Tolkien will remember when Bilbo the Hobbit tried to enrage the giant spiders of Mirkwood by jeering at them: "Attercop! Attercop!...you are fat and lazy, you cannot trap me, though you try, in your cobwebs crazy!"

Abandoned cobwebs gather dust and gradually become more visible. I don't knock them down unless they are empty, not wanting to interfere with the capture and consumption of insect pests. No good housekeeping seal of approval for me -- I harbor cobweb spinners!

The Bird King

Troglodytes troglodytes, the winter wren.

I saw this little wren in Cadman Plaza Park in Brooklyn, New York. He was on the ground, hopping in and out of sight under a row of shrubs. He perched momentarily on a low branch and then dove into the underbrush.

Don't feel bad if you have never seen a winter wren. Even though they are common, they are tiny. They weigh less than half an ounce and are only about four inches long. We often only notice them as they scurry away under bushes. It is easy to mistake them for mice.

The winter wren usually holds its short tail cocked upward. The bird is warm brown with dark narrow bars on wings, tail, and back. It has a light stripe above the eye. Its chin and throat are grayish brown. Its short round wings allow it to take off quickly and to maneuver around in the close environment of brush and bush.

In North America, winter wrens breed in northern Canada and then move south into most of the United States to spend the winter. They live in habitats from remote islands to crowded cities, but they prefer conifer forests. The winter wren is the only wren that is also found outside of North America, in Europe, Asia, and Africa.

Although winter wrens eat insects, they are able to find enough food in cold weather by foraging on bark and fallen logs. They are usually not social during the day, but may spend nights huddling in groups in snug cavities; it is warmer that way.

The winter wren is famous for singing. Only the males sing, but unlike many birds that sing only during breeding season, winter wren males sing year round. The little wren puffs his chest, cocks his tail, tilts his head back, and sings a long stream of musical trills. Follow this link to watch a wren singing on YouTube: http://www.youtube.com/watch?v=5EAzaDSN70o

Now about the title. According to folklore via Aesop's Fables and Grimm's Fairytales, the winter wren is the very unlikely King of the Birds. Apparently it was decided long ago one day when the birds were talking about who should be king. They agreed to decide by a flying contest and they all took off skyward. Over time they dropped back one by one, first the little birds, then the heavy birds, until eventually only the eagle was left.

But no! A little winter wren (called simply the wren in Europe where it is the only one) was hidden in the eagle's feathers. The wren won on a technicality -- being on the eagle's back and therefore higher, or in another version, by jumping off and flying upward after the eagle finally got tired. The wren reached heaven and proclaimed his victory with song. (The moral is that cleverness is superior to strength.)

The birds were upset and demanded a redo. They decided to see who could go deepest underground. They all started digging and tired themselves since most were not really made for the work. The winter wren popped into a mouse hole and won again. He sang his victory song again. The birds were really mad, but tired. They posted an owl to watch the mouse hole and went away to rest. The owl fell asleep. The wren got away, but to this day feels uneasy and stays hidden in the bushes. The owl, humiliated by failure, no longer goes out in the daylight and gets revenge by eating mice...

In England, the Queen of the Fairies was thought to shapeshift into a wren called Jenny. Lots of nursery rhymes feature wrens. Here is a sampling.

This one, which captures the wren's typical resting habit, is best read aloud: 

          Little Jenny Wren

          

                                                       A little Jenny wren, 

                                                       was sitting by the shed.

                                                       She wagged her tail,

                                                       and nodded with her head.

                                                       She wagged her tail,

                                                       and nodded with her head. 

                                                       As little Jenny wren,

                                                       was sitting by the shed. 

This one refers to the winter wren's fecundity. A pair of winter wrens can raise two 1-9 egg  clutches in a year. 

The Dove and the Wren

The Dove says coo, coo, what shall I do?

I can scarce maintain two.

Pooh, pooh! Says the Wren, I've got ten,

And keep them all like gentlemen. 

And here is one that refers to the winter wren's drab plumage. 

When Jenny Wren Was Young

'Twas once upon a time, when Jenny Wren was young, 

So daintily she dance and so prettily she sung,

Robin Redbreast lost his heart, for he was a gallant bird, 

So he doffed his hat to Jenny Wren, requesting to be heard. 

"Oh, dearest Jenny Wren, if you will but be mine, 

You shall feed on cherry pie and drink new currant wine, 

I'll dress you like a goldfinch or any peacock gay, 

So, dearest Jen, if you'll be mine, let us appoint the day."

Jenny blushed behind her fan and thus declared her mind: 

"Since dearest Bob I love you well, I'll take your offer kind. 

Cherry pie is very nice and so is currant wine, 

But I must wear my plain brown gown

And never go too fine."

The last dragonflies of the year -- or are they?

Green darner dragonly, Anax junius. 

I watched this green darner dragonfly couple laying eggs in the new pond at Brooklyn Bridge Park. The male is in front, clasping the female by the head. They mated just a few minutes before.

They worked like a couple on a bicycle-built-for-two, taking a few synchronized steps forward or back as she found spots she liked. Her abdomen has a sharp tip to make little slits in aquatic vegetation. She makes a slit, places an egg, and then they move on. The couple flew from branch to branch, scattering their eggs.

This is the beginning of a dynasty for that pond. The eggs will soon hatch into larvae that will spend the winter (and several more years and developmental stages) actively hunting under water. Dragonfly larvae are voracious predators of other aquatic insects; in a pond too small for fish, the dragonflies will be top predators.

Green darners are the largest, most abundant, and most common dragonfly in North America. Adults are about three inches long with a four-inch wing-span. They have green bodies, yellow leading edges on their wings, and a blue-yellow-and-black bull's eye mark on the "forehead" between the eyes. The male has a handsome blue abdomen.

Green darner adults are so good at catching and eating mosquitoes that they are commonly called "mosquito hawks."

Some populations of green darners migrate south to warm areas at summer's end. Their descendants fly north in spring. Adult populations of northern residents and migrants spend the mosquito days of summer side by side. Larvae are at work below the water's surface year round.

And starting this year in the new pond at Brooklyn Bridge Park!

Not a mosquito...

Good news! This is not a giant mosquito! It's a crane fly in the family Tipulidae, one of over 1500 kinds in North America.

The one in the photo is a female. You can tell because her abdomen ends in a point. She has a sharp looking organ there called an ovipositor that looks dangerous but is only used to lay eggs, not to sting. 

Some crane flies have wings that span over two inches. They all have a v-shaped groove on their back. Like most flies, they have paired halteres, club shaped organs that stick out of their sides just behind the wings. Halteres are the vestigial remains of a pair of wings lost over evolutionary time. (Most of the other insect groups have two pairs of wings.) 

Flies are usually so small that you need a magnifying glass to see their halteres, but on big crane flies they are proportionately large. You can see them in these photos. Halteres wave around during flight and act like gyroscopic stabilizers. But halteres don’t help big awkward crane flies go any faster so they are easy prey for birds, frogs, fish, and other insects. 

The next time a crane fly enters your home you can relax. It's not a mosquito. It won’t bite. Phew.

Green Eyes!

The Eastern Box Turtle

Terrapene carolina, eastern box turtle

Box turtles are small, typically about 4 or 6 inches long, and they take a long time to get that big. Their average life span is about 50 years, with some individuals living past 80. That's a blessing and a curse.

They don't reach sexual maturity until around age seven. Mature females only lay about 6 soft leathery eggs each year, in spring or summer. She covers them with dirt and then she leaves. The eggs take a long time to develop, hatching in late summer or in autumn. Meanwhile, raccoons, skunks, and foxes dig them up and eat them. So few offspring are born and populations replace themselves slowly.

A box turtle can pull in its head, legs, and tail, and then close the shell completely; the lower half is specially hinged to allow this. But their shells don't protect them from everything. During the past century their preferred habitats or woodland and wetland were converted to farms and then into suburbs. More roads mean more car fatalities for box turtles.

The turtles are terrestrial, usually found in grass or woods, not water. They are not good swimmers. On hot days they may cool off in mud or even soak at the edge of a shallow pool, but they avoid deep water. Hatchlings and youngsters are very shy; they stay in the undergrowth and are rarely seen. Eastern box turtles ranges from Massachusetts to Florida west to the Mississippi River, and north to the Great Lakes. The one in the picture was crossing a path in a New Jersey park on a hot September day in 2010.

They eat insects, worms, slugs, fruits and berries, mushrooms (even some that are toxic to humans), plants, and carrion. Those that live in the cold north hibernate in the ground during winter by digging into loose soil. The colder it gets, the deeper they go.

The eastern box turtle in the picture has bright orange markings on its typically tall dome-shaped shell. Individuals may also be yellow, tan, brown, or olive. Males are brighter than females and are famous for their bright orange or red eyes (brown in females). Adults are brighter than youngsters. So the turtle in the picture looks like an adult male. Their pretty colors work against them. Poaching for the domestic and international pet trade threatens them.

Box turtles were added to the CITES list in 1994 -- the Convention on International Trade in Endangered Species of Wild Fauna and Flora -- the agency closely regulates exportation and commercial trade. Many states legally prohibit collecting box turtles from the wild too. So step away from the turtle! Put your hands up!

The Stinging Rose Caterpillar

The stinging rose caterpillar, Parasa indetermina. 

There are not very many caterpillars that look like Christmas candy. But stinging rose caterpillars come in red, orange, and yellow with purple and cream pinstripes. I think of them as cherry, orange, and lemon. They are about an inch long -- bite-sized --  and flamboyantly decorated with spine clusters and spiked horns.

But they are far from delicious. In fact, you can't even touch them. Their pretty spines can break off and cause an irritating skin rash, a hypersensitive reaction, and other complications  serious enough to be called stinging rose caterpillar poisoning.

An attacking bird that gets a painful mouthful of one of these will probably remember the mistake and avoid gaudy caterpillars in the future. Wearing bright colors as a warning about how dangerous you are is  called aposematic coloration; it is common among insects.

Stinging rose caterpillars can be found on many familiar woody plants like apple, cottonwood, hickory, dogwood, redbud, sycamore, and on blueberry and rose bushes. The two pictured here were having a meal of bayberry leaves by the side of a road in Cape May, New Jersey.

There is more information about urban insects in my book,  Field Guide to Urban Wildlife, which will be published by Stackpole Books in spring 2011.

Halloween Pennant Dragonfly Mating Wheel

Halloween pennant dragonflies, Celithemis eponina.

This dragonfly couple was mating by the side of a pond in Cape May, New Jersey. It is not immediately clear what’s going on or who is doing what. Which one is male? Female? What’s with the head-grabbing?

They are in a common dragonfly reproductive pose called a mating wheel.  The male is the one holding on to the stick. He prepares to mate by producing sperm from genitalia at the tip of his abdomen, and then transfers it to receptacles under his belly. 

Then he flies off to find a female. He grabs her by her head with clasping hooks at the end of his abdomen that precisely fit females of his species. They fly around at this stage, attached claspers-to-head, in a position called a mating chain. (The male flies while the female dangles.) 

Eventually they land. In the photo, the female is curling to pick up the sperm with genitalia at the tip of her abdomen. They remain in the wheel (some call it a heart) for about 15 minutes. 

The Halloween pennant is a common dragonfly in eastern North America. It is named for its colors and for posing with its bright wings streaming behind. It eats mosquitoes, gnats, and flies, which it catches in the air in a sort of basket formed from its six spikey-haired legs. 

There is more information about urban insects in my book,  Field Guide to Urban Wildlife, which will be published by Stackpole Books in spring 2011.