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Sunday, January 26, 2014

Polar Vortex Winter Birds


Male northern cardinal, Cardinalis cardinalis. Click to enlarge.
It was a cold week in New York. As I sat writing at my desk by the window I saw the neighborhood birds in another light. One of the ways birds keep warm is by fluffing up their insulating feathers; they looked like puffballs all week. 

European house sparrow, Passer domesticus. 
They have other ways to keep warm. Their feet are thermally isolated from their bodies by a network of blood vessels that cool outgoing blood and warm the returning flow. They also can stand on one leg with the other inside the warm cover of their feathers. Sone huddle together at night to share warmth. City birds are good at finding warm spots to sleep near like chimneys or lights, and on eaves. An old building I worked in attracted a red-tailed hawk on cold nights; it slept on the sill of a window that was so leaky that the perch was practically toasty. 

Another thing that helps keep birds warm in cold weather is eating high calorie foods. When snow covers the ground, even the most resourceful city birds have trouble finding food. My little porch gets covered with snow but I brush off the dormant planters and put food in them: sunflower seeds, safflower seeds, peanuts, grapes, raisins, perhaps some bits of apple and whole grain bread. Below are summer photos of the neighborhood birds that have been visiting.

The blue jay, Cyanocitta cristata, announces its arrival with chime-like musical calls. A pair have been showing up together all week. They eat seeds and peanuts. Each takes one seed at a time to a perch in the little tree close by. The bird holds the seed in its feet, pecks with its bill, then pulls the seed out, eats it, and comes back for more. Very labor intensive! 
A house sparrow might show up alone but is soon followed by a flock. They eat  everything, including safflower seeds that they are reported to eschew. Maybe Brooklyn's  house sparrows  have a cosmopolitan taste for foreign foods. 
The male northern cardinal preferentially takes whole peanuts. He flies away with them and returns in a few minutes for another. I know when he has arrived because I hear his quiet tick tick tick. After peanuts, sunflower seeds are his next favorite thing. He stabs at grapes eating beak after beak full of fruit. 
The female cardinal has arrived alone or with a male every day. 
White-throated sparrows, Zonothrichia albicollis, normally feed in the underbrush by scratching at leaves. They are good in snow, too, tossing it up with their feet and flapping wings to uncover seeds. A few of them come to my porch to look for food throughout the winter. 
Morning doves, Zenaida macroura, seem passive with the other birds, but make up for it by eating faster. They don't open the seeds before eating them, like most of the other birds. They just peck them up, shell and all, one peck per seed. Very efficient! 
American robins, Turdus migratorius, don't all migrate away for winter. They do change their eating habits. No worms are available. They disappear from lawns and go foraging for dried berries. Click here to read more details in a previous blog. One or two are spending the winter near my place; the apples, grapes, and raisins are for them. And they like an occasional nibble of whole grain bread. 

Sunday, January 19, 2014

Cooper's Hawk

An immature cooper's hawk, Accipiter cooperii. Click to enlarge. 
The cooper's hawk is about the size of a crow. Immatures are mottled brown on top with brown-streaked creamy breasts and yellow feet. Adults are slate-gray above with reddish barred light breasts and red eyes. They are found year-round in all but the coldest parts of the lower 48 United States. Birdwatchers call them coopies.

The bird in the photo was sitting about six feet from the ground in a tree beside a residential street in Cape May Point, New Jersey, on a Sunday afternoon in January.

Cooper's hawks are good fliers, adept at weaving through trees in pursuit of the birds they hunt and kill for food. They are famous for appearing at active bird feeders where they can find prey species. Robins, European starlings, doves and pigeons are among their favorites. They also capture and eat flickers, quail, chickens, pheasants, and grouse. Their diet includes mice, squirrels, chipmunks, rabbits, and bats.

Although most people understand that raptors need to eat, few are willing to contribute to the killing or want to see it happen in their yards. So if a cooper's hawk starts hanging around your bird feeder, capturing the birds that come to eat -- stop putting food out for a few days. The birds will stop coming and the hawk will move on. You can resume feeding when the coast is clear.


Sunday, January 12, 2014

Soft Wax Scale Insects

Soft wax scale insects in the genus Ceroplastes. Click to enlarge.
The little white puffs in the photo don't look like it, but they are insects -- soft wax scale insects. If you pull one off its branch you will see a little gelatinous body under the waxy dome. They remind me of jelly-filled after dinner mints.

Whatever side you look at, wax scales are somewhat featureless. Identifying them often requires magnification, and might require chemical treatment and then mounting on a microscope slide for examination. Another way to identify one is to extract and sequence its DNA; the International Barcode of Life maintains a growing library of DNA reference sequences to identify organisms by comparison. Another clue you can use to identify one is the plant it is eating; they are host specific, that is certain scales eat certain plants.

The scales in these photos are attached to the twigs by tiny strawlike mouths. They suck plant fluids, sometimes so much that they drip sugary liquid from their bodies. Some wax scale species are all female and reproduce parthenogenetically, while others have short-lived males. Females overwinter as we see them in these photos.

If a concerned gardener does not come by and pick them off this plant, the scales will lay eggs that will remain concealed under them until hatching. The hatchlings, called "crawlers" are mobile. They walk on their tiny legs to a new spot, insert their little beaks, and start sucking plant juice and growing waxy coats. Crawlers are sometimes distributed by wind or by unwitting passing animals and birds. In some species, the crawlers settle first on leaves, feed until late summer, and then move to twigs or stems.

The USDA has a website about scale insects called Scale Net. Click here if you have a scale you are wondering about, or if you'd just like to see a few. 




Sunday, January 5, 2014

Peregrine Falcon

An immature peregrine falcon, Falco peregrinus
I saw this falcon at the Edwin B. Forsythe National Wildlife Refuge in Oceanville, New Jersey, on Christmas day, 2013. I would not have noticed it, but an adult peregrine circled around me. I looked at the ground where the adult had swooped lowest and I saw the young peregrine on the ground. I took the photo below. See how well it blends with the background?
This bird hatched in spring 2013. Its cream and brown camouflage will be replaced this comming summer with the famous slaty blue plumage of an adult peregrine falcon.  Click to enlarge. 

The sighting is something to celebrate. Peregrine falcons had been extirpated in the entire eastern United States by the 1960s. Western populations were estimated  to have been at about 10% of historical levels -- there were just a few hundred known nesting pairs left.

A series of conservation laws, culminating in the Endangered Species Act, targeted peregrines for protection. The Endangered Species Act was signed into law by President Nixon on December 28, 1973. Its 40th anniversary has just passed. Protection and recovery efforts are working for the peregrine. The falcon was removed from the federal endangered species list and declared recovered on August 25, 1999. It is still listed as endangered by the state of New Jersey.

Thanks to federal protections and local reintroductions, I saw a peregrine in New Jersey on Christmas. The first pair nested at Forsythe Refuge in 1980. There were about 25 pairs in the state by 2010. Fifty-seven young peregrines were raised there in 2013.

Click here to read the New Jersey Department of Environmental Protection, Division of Fish and Wildlife, report on the Peregrine falcon for 2013.