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Sunday, December 19, 2010

Winter Geese

There are lots of geese in American cities and suburbs. We see them grazing on lawns and flying overhead. Most of them are Canada geese, big birds 30 to 40 inches long that can weigh up to 20 pounds. The Canada goose has a black head and neck, grayish brown chest and body, a white patch under the tail, and a distinctive white chinstrap mark. I will say a lot more about Canada geese in a later post, but today I want to point out a similar looking but less common relative, the Brant goose.

Canada Geese, Branta canadensis, sporting handsome chinstraps. 














Brant geese are only about 25 inches long and weigh around three pounds. They are just a bit larger than mallard ducks. The Brant goose has a black head, neck, and chest. Seen from a distance it looks dark overall. Closer inspection shows a brown back, lighter underparts, and a patch of white below a short black tail. Their bills are relatively short. The broken white patch on a Brant's neck looks like a necklace or an incomplete collar. (Brant can be singular and plural like sheep, but it is also ok to say Brants.)

The Brant goose, Branta bernicla














Brant are primarily saltwater geese so they are not usually found far inland (although they take occasional forays to agricultural fields to snack on grains and grass.) They usually eat marine plants like eelgrass, sea lettuce, and other seaweeds. They have special glands that filter salt water from their systems and enable them to live on salty plants.

Brant geese breed far away in the northern tundra. They migrate thousands of mile to spend the winter along both coasts of North America. So if you see geese offshore during winter, take another look -- they might be brant. I took these photos of Canada geese and Brant in the same spot on the Brooklyn side of the East River near Fulton Ferry Landing under the Brooklyn Bridge. (The East River is a tidal estuary so it is comfortably salty for the Brant.)















Brant are accustomed to rough ocean water. I watched them doing something that Canada geese wouldn't even think about doing -- diving into the foamy waves caused by boat wakes crashing on rocks near the shore.

Sunday, December 12, 2010

The yellow-rumped warbler

Dendroica coronata, the yellow-rumped warbler.













With ornithological practicality, the little warbler with a bright patch of yellow feathers at the base of its tail is called the yellow-rumped warbler. It is one of a group of small, primarily insect-eating birds called the wood warblers. We mainly see wood warblers passing through New York City in spring on their way to northern breeding grounds or heading south in autumn. 

They are about five inches long, stripy brown, weigh less than half an ounce, and have patches of yellow on rump and sides. In summer they are brighter and have white patches on the wings and face. 

Some yellow-rumped warblers spend the winter in New York. (Others can be found in winter throughout the northeast, across the southern half of North America, in Mexico, and throughout Central America.) You might see yellow-rumped warblers in places as varied as forest edges, coastal shrubs, or backyards and parks. 

The one pictured here was foraging about a month ago at Alley Pond Park in Queens in New York City -- at the nexus of the Cross Island Parkway, the Grand Central Parkway, and the Long Island Expressway.  Yellow-rumped warblers are clearly not troubled by traffic! This bird might have been evaluating the neighborhood as a winter retreat, or just stopping off to eat something on its way south. It may in fact be visiting a feeder in Miami right now, or even feasting on tropical caterpillars in Guatemala. 

But if it stayed its diet would change from mostly insects to mostly fruit. The yellow-rumped's digestive system is even uniquely adapted to allow it to eat bay berries and wax myrtle berries. Not surprisingly, one of its other common names is the myrtle warbler. 

Yellow-rumped warblers are famously clever foragers. They flit from tree to tree, gleaning insects. They pick insects out of spider webs and off water surfaces. The one in these pictures was taking advantage of another bird's work. See the rows of holes in the tree? They were made by a yellow-bellied sapsucker. The sapsucker is a kind of woodpecker that specializes in drilling holes in trees, eating some of the live cells, and licking up tree sap with its bill inserted in the hole. Sapsuckers always make their holes in neat rows like those shown in the photos. Insects get accidentally trapped in the sticky sap at the holes. Other kinds of birds visit sapsucker holes to snack on sap and sticky insects. 
































Oh and bird watchers call yellow-rumped/myrtle warblers butter butts

Sunday, December 5, 2010

Born in the summer of 2010

It's 30 degrees and windy in New York City today. As I scattered seeds on my Brooklyn porch for the birds this morning I couldn't help thinking about the coming winter and how it will impact the birds. Some of them, like the northern cardinals and the pigeons, will stay here through the winter; they are called residents. Others, like robins and blue jays, have mixed feelings about leaving; some of them migrate but some don't. Still other birds, like winter wrens, migrate to here to spend the winter from even colder places further north. Regardless of the migration plan, winter causes upheaval; the birds face either a long cold season or a long round trip.

The baby birds pictured below were all born this summer in New York City despite noise, pollution, and about eight million people. Despite all that and snow, ice, and freezing temperatures, or a trip to Florida or Mexico, they will be here next spring to start families of their own.

A family of Canada geese, Branta canadensis, in the East River.
















This baby rock pigeon, Columba livia, was born
on a Manhattan building ledge.
 














Baby American robins, Turdus americana, look like
adults with spots.This one was born in a tree behind
the Metropolitan Museum of Art. 
















These Mallard ducklings, Ana platyrhynchus, were
born by The Pond in Central Park, across the street
from the Plaza Hotel. 















This baby blue jay, Cyanocitta cristata, was born
on Manhattan'supper west side in Central Park near
the Shakespeare Garden. 















This baby northern cardinal, Cardinalis cardinalis,
was born in my condo garden in Brooklyn.

Sunday, November 28, 2010

White-throated Sparrows



The white-throated sparrow, Zonotrichia albicollis.
















White-throated sparrows are back and they love black oil sunflower seeds! Three of them have been coming to my Brooklyn porch for breakfast all week.

Most white-throated sparrows spend the summer breeding season in Canada. Then they migrate south to spend the winter in the eastern and southern states, on the west coast, and in northern South America.

I usually hear white-throated sparrows rustling in the leaves before I see them. They forage for insects and seeds in brush piles and under bushes. They flick their heads to toss leaves aside. They use both feet to scratch backward and then jump on anything they scare up. They spend a lot of time on the ground, hopping instead of walking.

Their habitat is usually described as woods and forest edges, but they like parks too and they are at home in extreme urban landscapes like New York City where they forage side by side with house sparrows. The white-throated sparrow is brown above and grey below, like a house sparrow, but it is distinguished by a striped head, a yellow spot between the eye and the bill, and, of course, a white throat.

White-throated sparrows come in two genetically determined color varieties. One has bold white markings and the other has muted tan stripes. The color forms are maintained by a complicated set of mating preferences. Males prefer white striped females but females prefer tan striped males. White striped birds are more aggressive, so white striped females may have a competitive edge in pairing with  sexy tan striped males. The gene pool refills with both kinds.

Sunday, November 21, 2010

Spider Business

Remember the spider I wrote about last week? The one that makes cobwebs on my ceiling? She had an eventful week!

First, she shed her skin! She molted! On Monday morning, there seemed to be two spiders where there had been one. Closer inspection revealed this:

Female triangulate spider, Steatoda triangulosa, with her newly shed skin. 
















That's her old skin on the right. It's stuck in her invisible web on the ceiling next to the light outside my bathroom. Notice how the spider's new legs are almost transparent? After spiders and insects and other things with external skeletons shed, they are softer, lighter colored, and more flexible than usual -- like soft-shelled crabs. They are actually incapacitated while they wait for the new skin to harden. Our girl sat still next to her old skin from Monday through Thursday, while her new skin dried, hardened and darkened. The new skin has tiny folds that expand to accommodate her new bigger size. Apparently my home provides enough insect prey to support a growing spider. Come to think of it, I haven't seen any other insects in here lately.

Then, she got a boyfriend! On Tuesday morning there really were two spiders where there had been one! He is on the left in the photo below.
















All I saw of their relationship was the two of them sitting motionless side by side, but chances are good that there are spiderlings in our future. To mate, a male spider spins a "sperm web," and deposits sperm in it using sex organs on his rear abdomen near his silk spinning organs. Then he takes sperm from the web with a pair of organs near his mouth, called pedipalps. When he gets the chance, he inserts his pedipalps into paired sperm receptacles under the female's abdomen. Both genders have pedipalps, which look like very short legs -- females use theirs for touching things and handling food. Mature male pedipalps have enlarged ends that look like tiny boxing gloves.

By Friday morning the female's new skin had hardened. She had a spurt of activity and ran around for a few feet in all directions in her new outfit. She returned to the center, near her old skin, and approached the male. They faced each other with their front legs spread wide. When they both suddenly and unexpectedly fell from the ceiling, I squeaked and ran away. We all recovered quickly. They climbed up threads. I went back to watching them. They went back to sitting motionless.

On Saturday morning the male was gone.

Things are back to normal. But the female is bigger and possibly inseminated. If she has eggs she will spin a protective case of silk and hang it in her web. We'll know before long!

Sunday, November 14, 2010

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!

Sunday, November 7, 2010

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."


Sunday, October 31, 2010

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!


Sunday, October 24, 2010

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!





Sunday, October 17, 2010

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!


Sunday, October 10, 2010

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.

Sunday, October 3, 2010

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.

Sunday, September 26, 2010

Migrating Monarch Butterfly Spectacle -- not just in Mexico!

A monarch butterfly, Danaus plexippus.













I was in Cape May Point, New Jersey, on Saturday, September 18th, expecting to see migrating hawks. Many birds follow the Atlantic shoreline south during autumn migration. As New Jersey gradually narrows into a tip at its southern end, migrants end up concentrated at the “point” with the Delaware Bay in front of them -- across their path. They sometimes wait a day or two for a north wind to help them across the water. The place can fill up with eagles, hawks, and songbirds. It’s a great place for autumn bird watching.

But this year butterflies stole the show. Monarch butterflies also get funneled to New Jersey’s point. On Saturday there may have been a half a million big orange and black butterflies in the tiny town of Cape May. Butterflies filled the sky. They hung from the flowers and trees. It looked like the town had been transformed into a Walt Disney movie. 

Gathering in a roost for the night. 













On Sunday morning, the wind was just right. The butterflies headed out in orange clouds across the bay. They passed by for hours. It was spectacular.

They are going to Mexico. As unlikely as it sounds, each tiny individual from the summer’s last generation flies the whole distance or dies trying. For some that is a distance of over 3000 miles. They can fly at about 12 miles per hour, for about 50 miles per day.

Once they get to Mexico, they spend the winter in a dormant state in chilly mountain refuges. The migrating generation lives about seven months, which is much longer than the few weeks typical for monarchs born in spring or summer. The migratory generation doesn’t finish developing sexually until the spring following migration. Then they rouse, mate, and start coming back north.

But they don’t have to fly all the way back. The return flight is generational. Individuals fly part of the distance, lay eggs on milkweed plants, and then die. The eggs hatch into caterpillars that eventually become adults that fly further north to lay eggs of their own. After a few generations, each traveling further north, the continent is repopulated all the way to southern Canada. Before you know it, a migratory generation is born and it’s time to migrate again.



Populations from eastern North America fly to Mexico. The western ones tend to end up in southern California.  In cities all over the continent we can glance out of our office windows, even on high floors, and see the big orange butterflies passing by. The last of them will go by around Halloween; they have to beat the first frost. 

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. 

Sunday, September 19, 2010

Sparkling Birds














I took this photo of the World Trade Center Light Memorial this year on 9/11. The normally still columns were filled with thousands of shifting silver dots of light that glittered as they moved. At the time I didn’t know what they were.

They turned out to be migrating birds!

Hundreds of thousands of birds fly over New York City each autumn on their way to their southern winter homes. Light from the sun, moon, and stars helps them navigate. But artificial lights can interfere with their natural abilities to find their way. Unlike most autumn migrants, the birds that flew down Broadway on the night of 9/11 did not pass overhead unseen; instead they flew into the memorial lights. They became disoriented and stayed there, circling, illuminated like silver sparks. 

The lights were turned off five times during the night for 20-minute periods to allow the birds to fly away.

But migrating birds are still in danger. Brightly lit buildings confuse them too; many birds die every year when they fly into office building windows. The phenomenon is gaining recognition and famous sites like the Empire State Building and the Chrysler Building dim their lights from midnight until dawn during fall migration. It saves a lot of birds. Let us hope that it catches on.

You can read more about it here:  'Lights out' help migratory birds


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

Sunday, September 12, 2010

The Buckeyes are Leaving

The buckeye butterfly, Junonia coenia


Buckeye butterflies are passing through New York, heading south. I keep seeing them in the open sunny places that they like -- lawns and parks, roadsides, empty lots, and fields of weeds.

They are heading to the warmer places where they live year round like the southern United States, Mexico, and the Caribbean. Every spring some of them return to repopulate the northern United States and parts of Canada. Their southbound autumn flight is particularly noticeable along the coasts where at times they seem to be everywhere.

Adult buckeyes are about two and a half inches across. They are brown and tan, with a pair of orange bars on each forewing, and a series of large “eyespots” that may scare off predators when the wings open suddenly to reveal them.  (Oh no! Says the attacking bird -- some giant thing is looking right at me!) The caterpillars vary from dark greenish to gray or black with orange and yellow lines and rows of fancy spikes.

The buckeye caterpillar -- slim and stylish. 
 The butterflies sip nectar from asters, chicory and peppermint flowers, and some others. The caterpillars are especially fond of the foliage of plantains, snapdragons and toadflax.

Most of us are familiar with sexually dimorphic species, like lions or cardinals, where males and females look different. But buckeye butterflies appear in different forms in different seasons. The buckeye’s wings are tan underneath in spring, but red underneath in autumn; the change is probably linked to lower temperatures and shorter days. The difference is so pronounced that scientists call the forms by different names -- linea for the tan one and rosa for the other. 

Saturday, September 4, 2010

Don't touch the parsley worms!

Black swallowtail caterpillars are called parsley worms because they are commonly found on plants in the parsley family, Apiaceae, which includes carrots, fennel, dill, hemlock, Queen Anne’s lace, parsnips, anise, and coriander. I found this caterpillar in the Shakespeare Garden in New York City’s Central Park where it was sharing a fennel plant with  two other parsley worms and a host of wasps and bees.

The black swallowtail caterpillar, Papilio polyxenes.


It is easy to see some features of caterpillar anatomy on a fat three-inch long specimen like this. It has three pairs of tiny true legs near its head, on the right. The four pairs of feet in the middle and the pair at the rear end are called prolegs; they have rows of hooks called crochets on the tips that help them hang on. But one of its most interesting features is usually hidden.

It has an osmeterium, also called a “stink gland,” which it can use to startle and repel would-be attackers. (Other kinds of swallowtail caterpillars have them too.) When I gently tapped this caterpillar, it instantly reared up on its proglegs, stuck out his bright yellow osmeterium, turned to touch me with it, and just as quickly pulled it back inside its slot above the face.

The caterpillar's forked yellow osmeterium is usually hidden. 







The bad smell this left on my finger was impressive. The smell is usually described as that of rancid butter, but it is an angry insect version of rancid butter that seems much worse to me. So I learned a lesson; don’t touch the parsley worms. And if I were a caterpillar predator I would definitely look for a better-smelling meal. 

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. 

Sunday, August 29, 2010

Wow -- that's a great egret!

The great egret, Ardea alba.

This bird has lots of names. It’s called the common egret, large egret, American egret, and white egret. And it's no surprise that many people have noticed the elegant and beautiful bird; it is more than three feet tall and has a wingspan over four feet.


The great egret is white with a yellow beak and black legs and feet – a combination of colors that distinguishes it from other herons and egrets you may encounter. It flies with its neck folded back, flapping deeply and slowly. 

It is often seen wading in shallow water or in mud, stalking its prey – frogs, snails, fish, insects, crayfish, and similar small things. This one often hunts in New York City's Central Park at the narrow end of The Lake just north of the Bank Rock Bridge. 

The great egret is found throughout the southern states and in estuaries and wetlands on both coasts during some part of the year, breeding mainly in the east but with exceptions. Some pairs breed in isolated spots and others in colonies. They build big nesting platforms of sticks, usually in trees, but also on the ground or in shrubs. Typically they lay three pale blue-green eggs. Males and females look the same. In breeding season they develop long plumes on their backs, which they erect and spread like big lacy fans.

The beauty of their plumes caused big trouble for them in the 19th and early 20th century. They were very popular decorations for ladies' hats. Wild bird hunting was unregulated then. Millions of egrets and other birds were slaughtered for their plumes and feathers. Common egrets were hunted to the edge of extinction. 

Public outcry saved them just in time and led to legislation that protects wild birds to this day. The Audubon Society was formed around then -- they incorporated in 1905; they led the cause, and later adopted the great egret as their symbol.

The great egret population has recovered and is doing well; its range in the United States is expanding.

Our taste in hat decorations has improved too.





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

Sunday, August 22, 2010

Eastern Tiger Swallowtail







It is easy to mistake this tiny caterpillar for a dried up bit of bird droppings. Clever disguise! It helps the little guy get through the treacherous early stages of caterpillar life when many are snatched up and eaten by birds.

A closer look reveals the caterpillar behind the disguise. This one is feasting on a lilac leaf. Eventually it will grow into the beautiful eastern tiger swallowtail butterfly, Papilio glaucus.

This one is a female -- the males have a few small spots of blue where she has those extensive blue patches on her hind wings. Take a close look and you will see that her wing edges are damaged; she may have escaped a bird  attack, or been tossed by rough winds.  As butterflies age their wings get worn and tattered.

Eastern tiger swallowtail butterflies sip nectar from a variety of flowers, including wild cherry and lilac blossoms. They don't mind urbanization so we see them in city parks and yards, and sometimes flying incongruously through the concrete canyons. This one was visiting the Shakespeare Garden in Manhattan's Central Park.

Sunday, August 15, 2010

Fennel time!

Fennel, Foeniculum vulgare 














A handful of crushed fennel leaves smells deliciously of celery and licorice. 

There is a little patch of fennel among the flowers growing on the extension of Middagh Street that passes over the Brooklyn-Queens Expressway near my home. The plant is tall with pretty feather-like foliage. Its tiny yellow flowers are borne in little bouquets that are technically called compound umbels, like the flowers of parsley and carrots.  Fennel is one of the main flavors in the cordial Absinthe, and it is used in herbal medicine too. The seeds are used as a spice, and some of us eat fennel bulbs and leaves as a vegetable. 

But we are not the only ones who like fennel. Wasps love it! 

On a sunny day a seemingly endless parade of exotic looking insects visits fennel blossoms, each more elegant that the last: thread-waisted wasps, potter wasps, mud dauber wasps, a good compliment of honeybees and bumble bees, and lots of fancy flies come in for a tasty sip of fennel nectar. 

Here are photos of a few recent visitors.



Isodontia elegans -- a "grass-carrying" wasp. 






They got the common name "grass-carrying" because they incorporate grass into their nests. 

Another Isodontia species. 

Polistes dominula -- the reviled European Paper Wasp. 







The European paper wasp is a relative new comer to the United States, introduced from Europe and first recorded in the northeastern United States in the 1980s. It has already gained a bad reputation as a cranky wasp that becomes aggressive toward humans with very little provocation. 

Sceliphron ceamentarium -- a black and yellow mud dauber wasp. 


Eumenes fraternus -- a potter wasp.








Visit this link to see how the potter wasp uses that fancy tail end to build a pot-shaped nest out of mud: 


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. 

Sunday, August 8, 2010

The Ailanthus Webworm Moth

Ailanthus altissima, the tree-of-heaven.























You may have seen this weedy looking tree growing in a vacant lot, or an alley, or in the space between sidewalk slabs. It thrives in cities and seems able to grow almost anywhere, even out of the sides of abandoned buildings. It has a strong smell that stays on your hand when you crush a leaf.

It's a Chinese native that was  introduced to the United States in the 1700s. It became naturalized and can now be found growing wild all over the country. This is the famous tree that Betty Smith wrote about in "A Tree Grows in Brooklyn."

The ailanthus tree has its own moth, Atteva aurea, the ailanthus webworm moth. The moth holds its wings rolled and close around its body while resting, so it looks a little like a long beetle.

Atteva aurea, the ailanthus webworm moth.













Like many other insects, this one was named after the food it eats -- ailanthus leaves. The "webworm" part of the name refers to its lifestyle during the caterpillar stage. The "webworms" spin silk webs on ailanthus trees and live in groups while eating foliage, like more familiar tent caterpillars.

Ailanthus webworms at home in their silk web.












Like the ailanthus tree, the ailanthus webworm moth is an introduced species. Except for populations native to southern Florida, ailanthus webworm moths came from Central and South America, where they feed on a tree that is closely related to the tree-of-heaven.

The introduced ailanthus webworm moth switched its diet to the introduced ailanthus tree and they took off together across the country.

How convenient!

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. 

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