Squirrels in High Places

There is Republican primary coverage on television. Through the window near the TV, I see a squirrel  tightrope walking on the porch fence.

The juxtaposition reminds me of Ronald Reagan and the White House squirrels. He fed them, and they reportedly gathered outside the Oval Office and looked in at White House doors and windows, anticipating treats. The President brought back acorns for them from Camp David, the presidential country retreat in Maryland. The Reagans' 1984 Christmas card, a painting by Jaimie Wyeth, called "Christmas Morning at the White House," shows a squirrel leaving a trail of footprints in snow on its way to the White House door. (Click here to look at one that's being sold for $85.00!)

The relationship of the White House squirrels with other human occupants has been both good and bad. In 1921, President Harding's first lady, Florence, championed animal welfare, including the protection of squirrels on the White House grounds. President Truman fed the squirrels while taking his meals outside on the south porch. The nation was charmed when in 1949 a five-year-old visitor expressed concerns about the White House squirrels, and Truman appointed him to feed them (at no cost to the taxpayers). The story appeared in newspapers across the country; click here to read one.

The chummy relationship came to an abrupt end with the Eisenhower administration. Eisenhower was a golfer. When he had a putting green installed on the lawn a short distance from the Oval Office, the squirrels started burying nuts there. Eisenhower was reportedly infuriated about all the holes and bumps. After attempts to scare the squirrels away failed, a few were trapped and released somewhere else. Boy did he get in trouble for that! His opponents in Congress depicted him as an enemy of wildlife. The squirrel trapping campaign was suspended.

During the Carter administration, the National Park Service studied squirrels in downtown Washington. They found that Lafayette Park, the seven-acre park across Pennsylvania Avenue north of the White House, had an extremely high number of squirrels -- more than 100 -- probably supported by the constant stream of squirrel-feeding and snack-dropping tourists.

The George H.W. Bush years were challenging for the squirrels -- the Bush family dog, a Springer Spaniel named Millie, habitually chased the squirrels. During the Clinton years, when squirrels attacked the White House tulips, the gardeners placed peanut-filled feeders on the South Lawn and in the Rose Garden to draw them away from the flower beds. Like deja vu, George W. Bush's dogs also chased the White House squirrels.

I wonder how the squirrels are getting on with the Obamas. Is Bo a squirrel chaser? The President mentioned the squirrels last year during an East Room ceremony celebrating America's Great Outdoors -- you can watch the video clip by clicking here. (Sorry about the ad before the clip.) But does he feed them?

The American Crow

The American Crow, Corvus brachyrhynchos.

In one of Aesop's Fables, a thirsty crow finds a tall pitcher with water in the bottom, beyond its reach. The crow drops pebbles into the pitcher to raise the water level, and drinks.  The moral of the tale is that necessity is the mother of invention. Another message is that even the ancients realized that crows are smart.

One of my favorite scientific debates is about a smart thing that crows do. Some scientists think the birds drop nuts onto roads from the air so that cars will crush them open; other scientists insist that crows are dropping nuts on hard roads surfaces to break them as they always do, but that cars are coincidental and not part of the nut-cracking plan.

Regardless of how the car debate is resolved, there is no question that crows drop nuts from the air to break them open. And it's more complicated than you might expect. Nuts may not crack on the first drop, but they weaken with each drop and break open eventually. Nuts break differently when dropped on different surfaces. Another crow might dash in and steal the broken nut.

A scientific study compared the way crows dropped hard California walnuts and softer English walnuts. (You can read the original paper by by clicking here.) The scientists observed and documented that crows drop harder nuts from greater heights, drop the same nut from decreasing heights on subsequent drops, and drop both kinds of nuts closer to hard roads. If other crows are watching, they drop from lower altitudes, on guard for possible thieves. How smart is that!

Stiff bristly feathers on the beak. 

The American crow is a large glossy black bird up to about 20 inches long. Its bill is heavy, shiny, and black; the top of the bill near the face is covered with stiff short bristly feathers. In adults, even the inside of the mouth is black. It calls a familiar caw-caw-caw. It breeds from central Canada south through most of the United States.

Crows spend winters in most of the parts of their breeding range inside the United States. During winter when less of their natural food is available they are more likely to visit landfills and dumpsters. They masterfully exploit urban food sources. They don't just eat trash -- they open lunch bags and unwrap the contents. I have watched them around outdoor lunch tables and trash cans at the Bronx Zoo. They pecked open unused ketchup packets, up-ended unfinished milk containers to drink the remains, and stuck their heads inside discarded potato chip bags to finish off the crumbs.

One study found that crows spend more time watching for danger while foraging around denser human populations than in rural areas; they share vigilance by forming groups and may depend on that more in cities, where line-of-sight can be short. I can attest that they are hard to photograph; they seem only casually aware of me, but I never seem to be able to get close. As I advance, using maximum stealth, they find interesting things to do just a few steps further away.

Click to enlarge. 

There is a nursery rhyme called Counting Crows, in which the number of crows you see predicts a future event. There seem to be endless version. Here is one --

One for sadness, two for mirth;

Three for marriage, four for birth;

Five for laughing, six for crying;

Seven for sickness, eight for dying;

Nine for silver, ten for gold;

Eleven for a secret that will never by told. 

Right-footed Pigeons

The pigeon, also called rock dove or rock pigeon, Columba livia. 

They paddle with staccato feet 

In powder-pools of sunlight...

                                                              from Pigeons by Richard Kell

In the 1950s a scientist named Harvey Fisher was using pigeons to study landing forces. He noticed that the birds did not always land on both feet simultaneously. Sometimes they extended one foot or the other to absorb the force of the landing. This inspired Fisher to watch his flock of 11 experimental pigeons land 7,259 times.

He found that seven of them were right-footed, three so strongly so that they landed on the right foot over 90% of the time. Three of the birds were left-footed. One bird had no preference -- it was apparently ambipedal.

He published his observations in 1957 in  the ornithological journal, The Wilson Bulletin. You can read the original paper by clicking here.

I'm keeping a landing log of a few distinctive pigeons in my neighborhood. I'll let you know.

Hmmmm....which foot to use, which foot to use...

Sparrows in the Snow

An English sparrow, also called house sparrow, Passer domesticus, in Brooklyn snow yesterday. 

Ever wonder how birds survive the cold winter weather? There is no question that it is hard for them, but they have some adaptations that get them through it.

Their feathers insulate them against the cold and the oils that they spread on them while preening add waterproofing. But their feet are bare ! you are saying. Like in a heat-exchange system, their blood passes through side-by-side capillaries on the way to and from the legs; incoming blood is warmed and outgoing blood is cooled. Less heat is lost that way. And they sometimes stand on one foot with the other tucked up in the feathers.

They puff up their feathers, which traps some insulating air. They can huddle together. They can sit in the sun. They find wind-sheltered places like the broad-leaved evergreen bush near my porch fence in the picture below. They sometimes perch on warm human structures, like chimneys and outdoor lights. I knew a red-tailed hawk that regularly slept on the windowsill of an old building in Manhattan -- heat leaked from the rickety windows and made it a good place to spend a cold night.

The sparrows outside my window remind me of a poem called Winter Birds, by Andrew Downing. Here is part of it:

Warm sheltered corners the cattle have chosen,
Shivers the pine in its evergreen leaves;
Pools by the roadside in wrinkles are frozen--
Bayonet icicles hang from the eaves.
Five English sparrows, defying the weather,
There in the pathway a conference hold;
Ho! merry midgets in doublets of feathers!
Why do you rally out there in the cold?

Little you care for the riot and rattle--
Little you heed--let the mercury fall!
Brave little fighters, go on with your battle--
Here is a friend who will welcome you all!
Fly to my window--I'll feed every comer--
Hail to the comrades that constancy show
Loving and loyal, in winter and summer--
With us, alike, in the heat and the snow!

The Double-Crested Cormorant

"That bony potbellied arrow, wing-pumping along implacably, with a ramrod's rigid adherence, airborne, to the horizontal, discloses talents one would never have guessed at." 

from The Cormorant in Its Element by Amy Clampitt. 

Double-crested cormorants have seen hard times. In the 1960s they were threatened across the United States by the use of the pesticide DDT, along with Peregrine Falcons and Bald Eagles. Thanks to a federal ban on DDT and the passage of the Clean Water Act, cormorants have recovered. They showed up in New York Harbor in 1985. Now I see them often in the East River. There are usually a few loafing on the pilings at the southern end of the waterfront promenade on Pier One in Brooklyn Bridge Park. 

Double-crested cormorants, Phalocrocorax auritus, on pilings in the East River near the Brooklyn shore at Brooklyn Bridge Park. 

Double-crested cormorants are large, slender, short-tailed, birds about 30 inches long. Their necks are kinked. Their eyes are blue. Their bills have a hook at the tip. They have an area of bare bright orange skin on the face and throat. Adults are black with a greenish sheen. Immature birds are gray on the neck and breast. 

They dive underwater to chase fish, swimming after them and grabbing them with their bills without spearing. Some of the cormorant's feathers are specially structured to decrease buoyancy so they can dive efficiently. The special feathers get wet during dives; cormorants typically sit in the sun with wings spread to dry them after diving. Just the outer feathers get wet, so the cormorant is still well insulated by a layer of air next to its skin and able to dive in cold water. 

Cormorants swim low in the water and sometimes all we see of one is its head and neck. They dive from the surface, propelling themselves with their feet. They can dive to about 25 feet and stay under for more than a minute. They eat smaller fish while underwater, but sometimes bring big ones to the surface. You may see them slap a fish on the water surface, and then toss it in the air to swallow head first. 

Double-crested cormorants often fly close to the water. 

Click on the photos to enlarge. 

Oh, and don't get too close. The double-crested cormorant is famous for its vomit defense. If you threaten it, it may throw up on you. 

American Kestrel

The American kestrel, Falco sparverius.

I saw a bright male American kestrel land on a utility pole yesterday in Brooklyn Bridge Park. The American kestrel is the smallest falcon in North America. It is also the most numerous, most colorful, and most widespread. Although it is only the size of a robin, it is as deadly to its prey as any falcon– it swoops from the sky to catch and kill live insects, rodents, and small birds.

The kestrel in the photos is a male. He is between eight and ten inches long. Female kestrels are slightly larger. Both genders have two vertical black stripes on white faces, black talons, dark eyes, and reddish brown backs and upper tail surfaces. Males have bluish grey wings.

As I watched, the kestrel hunted using a sit-and-wait strategy: it perched high, bobbing and turning its head to scan the ground below for prey. Had it found something worthwhile, it would have swooped down to grab it with sharp talons. Kestrels are fast, graceful, and deadly. They sometimes also hunt by hovering stationary in the air, looking down. And they fly distinctively -- pointing their wings down and back with each stroke as if rowing, interspersed with periods of fast stiff-winged glides, until soundlessly falling upon prey. 

It is not unusual to see a kestrel flying over a New York City street with a mouse dangling from its talons. Kestrels can find lots to eat here, and plenty of places to live. They are secondary cavity-nesters; they build nests in cavities, but they do not excavate them. They use holes made by woodpeckers, naturally occurring holes in trees and cliffs, and spaces in buildings and other man-made structures.

American kestrels are in New York year round. They breed across the United States, Canada, and Mexico. In winter, the northern-most breeders migrate south and some that breed further south migrate as far as Central America.

I have seen kestrels flying down Broadway in Manhattan, sitting on windowsills of fancy apartment buildings, and perching on traffic lights at busy intersections. When I drive on the New Jersey Turnpike I see them perched on utility poles scanning for prey in the short grass on the shoulders of the highway. The one in the photos is the first I have seen in Brooklyn's new park. I hope is stays.

 

The American kestrel is also called the sparrowhawk.

Happy New Year!

   The neighborhood red-tailed hawk on the last day of 2011.             Click on the picture to enlarge it.

I wish everyone a year filled with fabulous urban wildlife sightings!