House Sparrow © Bill Gibbons 2011

Sparrows are everywhere here in the Bronx. Only the pigeons out number them. They are an invasive species, brought here from England in the nineteenth century; some say to help control insect populations, others so that immigrants from Europe could enjoy the presence of a familiar bird in their new home. Whatever the reason, the Sparrow has thrived and is now the most numerous songbird in the US. It has driven out some of the local species, notably the Bluebird, as it is an aggressive defender of its territory and because it stays put all winter long, so that when migratory birds return in the Spring the Sparrows are already well established.

Though its numbers are declining from the highs of the early twentieth century, it is doing much better here than in its original homeland. The English sparrows have been disappearing. Scientists aren’t sure why, but it may be because of a parasite has been undermining their health. Luckily American sparrows are not yet affected by it, but changing lifestyles among the human population have reduced its numbers here. In the days when horses were the main form of transportation, Sparrows enjoyed easy pickings among the oats spilled from their feed, or left undigested in their manure. Since the advent of the automobile, that food source is gone, making survival a little more difficult for these birds. Still, walk through the park and you will see plenty of them, picking over the ground or flocking in trees and shrubs.

Humpback Whale © Bill Gibbons 2011

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Lately we’ve been hearing more and more about the return of whales to New York Harbor. Right Whales, Humpback, Fin, Sei, Minke and Blue whales have all been spotted in the waters around the city. It’s a wonderful sign of the good effects of cleaner water.

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The humpback is said to be the most frequently spotted. It was common in the area in the nineteenth century. In Moby Dick, Herman Melville has this to say about it. “The humpback is often seen on the northern American coast. He has been frequently captured there, and towed into harbor. He has a great pack on him like a peddler; or you might call him the Elephant and Castle whale. At any rate, the popular name for him does not sufficiently distinguish him, since the sperm whale also has a hump though a smaller one. His oil is not very valuable. He has baleen. He is the most gamesome and light hearted of all the whales, making more gay foam and white water generally than any other of them”

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So it seems that in Melville’s day the humpbacks in the harbor would have been greeted by harpoons. Perhaps that’s why they made themselves scarce, or became scarce. The whaling ban is a good thing, but it’s hard not to admire the whalers of old. There’s a big difference between hunting from a row boat as they did in Melville’s time and shooting rocket propelled harpoons from a factory ship, and though the depredations of the early whalers harmed their prey, there is a nobility in their contests with the giants of the sea. It was much more of an equal contest in those days, one that the whale could win.

Beaver © Bill Gibbons 2011

Now that beavers have returned to the Bronx river we can enjoy the sound of their tail slapping here in the city. There are two of them setting up home in the section of the river that winds through the Botanical Garden and the Bronx Zoo. Their presence is a welcome sign that the river cleanup efforts have borne fruit. If they begin breeding the river will soon be home to a host of busy beavers, all dreaming of damming it.

A walk along the banks of the river in the Botanical Gardens reveals evidence of their work. Trees with the distinctive marks of the beaver’s teeth. The half gnawed trunks were coated with a layer of creosote, presumably to deter the beavers from completing their work and building a dam while destroying some of the Garden’s precious trees.

Beavers pursue their own agenda, and so do we. And while we delight in the evidence of natural life all around the city, we claim the territory as our own. The beavers are a wonderful addition to the river, but they will have to be managed, for they will surely try to lay claim to the river by damming it for they are builders, just like us!

The beaver’s industry is well known and its effects are easy to see. He shapes the streams and ponds he inhabits, building dams to raise the water level, creating many ponds along the course of slow running streams. He likes his lodge surrounded by water, a moat protecting a safe home, its underwater entrance well hidden. There is no mistaking the signs of the beaver’s work. The trees that he fells are marked by the pointed stumps he leaves behind. This rodent can grow surprisingly large sometimes topping 40 pounds. He lives off the bark which he strips from the branches of the trees he has felled to bring them within reach of his industrious incisors.

Daphnia swimming in a pond. © Bill Gibbons 2011

There are plenty of tiny creatures living in the city who pass their lives invisible to our eyes. Daphnia are one of them. I’ve found them in Van Cortland lake in the Bronx, but they can be found in just about any fresh water.

Daphnia is small, about a millimeter long and almost transparent. It is boneless, like all crustaceans, supported by a hard outer skin which it must shed or molt to grow. While it’s just visible to the naked eye as a fast moving dot, under the microscope its structure is revealed. Magnified, we see an elongated sphere, transparent and slightly yellowish. The outer shell, called a carapace, wraps around the body like a cape, a characteristic of its Order, the Cladocerans. Its head is covered by a helmet of the same material. The carapace is open towards the front, and we can see leaf-like legs waving rapidly. This rapid movement keeps water circulating around the gills attached to the legs and draws a current between the two halves of the shell that sucks plankton and bacteria towards the mouth.
Like all crustaceans, Daphnia has four antennae. Because the legs are hidden beneath the carapace and so can’t help it swim, two of the antennae have evolved into long “arms” adapted for swimming. The remaining two are tiny sensors. The swimming antennae propel the water flea through the water in characteristic jerky pulses. It puts its fast and erratic swimming to good use when it has to escape from predators. Most Daphnia are female and carry their young in a brood chamber on their backs while they mature, releasing them when they molt. At the front, between the two halves of the carapace, daphnia has four pairs of legs and an abdominal claw. The legs draw in and filter water and the claw cleans debris from inside the covering. She cannot choose what comes in with the current created by the legs. She must form it all into a pellet and taste, ejecting it with the claw if foul tasting, or chewing and swallowing if good.

A surprise visit by a hawk.

I see a number of hawks around the area, but still it was a surprise when I found this one perched outside my window a few months ago. It’s wonderful to see these noble birds so close to home. When they are wheeling overhead the pigeons try to keep a low profile.

Canada Goose, Branta canadensis © Bill Gibbons 2011

I was watching a wintery pond at the NY Botanical garden. It’s almost barren at this time of year forcing the ducks and geese that live there keep a sharp eye out for food. If one of them finds something all the others swim over to have a look and squabble over the find. On this afternoon a muskrat had found something to eat and sat on the bank holding it between his forepaws and eating. Two geese noticed and swam over to have a look, the bolder of the two coming closer and closer to the muskrat, finally reaching forward and trying unsuccessfully to wrest the morsel from his paws. The muskrat was unperturbed, and just kept on eating without moving an inch. I had the impression that these animals knew each other well, and that the goose had tried before but his bill was no match for paws when it came to holding food. Mr. Muskrat finished his meal, jumped into the water and swam across the pond before diving below the surface.

The Canada Goose is a large bird that seems as much at home in a city park as in a wild pond. Their distinctive honk is easy to recognize and their V shaped flight formation a sure sign of the changing seasons. Many of them spend the winters in the United States and fly north to Canada in the summer. They need a lot of food and feed for up to 12 hours a day, eating a variety of vegetation including green leaves and grain, and occasionally small fish and insects.

These large birds can weigh up to 15 pounds and are often aggressive. When full grown they are rarely preyed on, though they were hunted almost to extinction by humans in the 19th century, their numbers have increased as hunting is both more regulated, and less popular that it once was. Nevertheless they are still eaten by coyotes, red foxes, wolves, owls and eagles. Coyotes are fond of their eggs. Both the male and female geese guard the nest and groups of geese will gather together in a creche to protect their goslings. It is amusing to watch the young birds following their parents single file. At any sign of danger the adults will hiss a warning before attacking. The goslings become fledglings after about two months and will remain with their parents for a year, before leaving to find a mate for life.
Canada Geese migrate to warmer climes in the fall and return north in the spring. These strong fliers, reaching speeds of up to 50 miles an hour, can fly over 500 miles in a single day. The preparation for migration begins in the summer when geese shed their old feathers or molt. They cannot fly for almost a month after molting while their new flight feathers grow in. As the summer ends they eat as much as possible to build up a reserve of fat to sustain them during their long flight. Migration begins in late August or early September, depending on how far north the birds are. They usually take the same route each year, even stopping at the same ponds to rest on their way, Their characteristic flight formation saves energy for the flock. The strongest birds take the lead while others follow, catching the draft of the leaders. These lead birds change places from time to time to allow them to rest. The flock may fly as far as 2,500 miles during their migration.
In the Spring the geese fly north again, taking a more leisurely trip than they did in the fall, stopping often to feed and rest along the way. Nesting and egg laying will take place as soon as they reach their destination. They will often reuse a nest from previous years, re-lining it with down. The female lays about a half dozen white eggs and will incubate them for a month. The female will only leave the nest briefly to feed while the gander guards the nest. The goslings leave the nest as soon as they are born and follow their mother to the safety of the water. As they swim the goose takes the lead, followed by the goslings and the gander brings up the rear, guarding the family. Even so, only half the goslings are likely to survive. They remain with their parents for a year, and are ready to mate when they are three years old

This beetle is a ferocious predator ©Bill Gibbons

This Beetle, a ferocious predator and skillful diver, makes its home in ponds and still waters throughout the North East. Born from an egg in springtime, the larva is as deadly as the adult. Hollow, piercing jaws allow him to inject digestive fluid into his victim through the jaws, and suck out the liquified innards. Clinging to a stalk or stick the victorious larva will raise his prize above the surface of the water. The prey, perhaps a fairy shrimp, is pale and wriggling, but as the poison fills its body it darkens and grows still, shrinking and blackening as its vitals are sucked out. After a minute or two the larva will cast aside the black husk of its dinner

The larva of the Predaceous Diving Beetle © Bill Gibbons 2011

The larva will grow for a year before burying itself in the mud of the bank and forming a pupa, to emerge as an adult in about a week. It is much changed, stocky where once slender, hard where soft. The rear legs are fringed with hairs that allow it to move quickly through the water. The piercing jaws have now become biting and tearing, but the adult is as fierce as the larva, eating tadpoles and small fish, even darting out from its hiding place to take bites out of large fish. This beetle breathes through its anus and traps air under its wings to carry below on foraging expeditions. It rests with its tail poking through the surface to breathe, taking in the sights through huge compound eyes, alert for signs of dinner or danger. It’s hard carapace gives it some protection, and its nasty taste will make some fish spit it out, but still, it is vigilant. Danger is everywhere.

The adult beetle. © Bill Gibbons 2011

When the season is right the beetle’s thoughts turn to love. The females are more choosy than the males and will try to avoid coupling by rapid and erratic swimming. The males of some species have evolved suckers on their legs to allow them to hold firmly to reluctant partners. After the romance, the female lays fertilized eggs inside the stems of underwater plants. When the they hatch the larvae are small and vulnerable, less than a millimeter in length, and are eaten by crustaceans, fish, tadpoles, and even by their older brothers and sisters. Meanwhile they eat whatever they can sink their jaws into, rushing to put on the weight and size that will give it some protection from predators. Throughout its life the beetle will be prey as well as predator. Of the 500 eggs laid by each female, only a few will become adults and breed. The rest will be eaten. The adults are strong fliers, and if the pressures of predation or hunger make the pond inhospitable, they will fly away in the moonlight, searching for the glint of water in the night to guide them to another home.