wildlife

Urban Wilds is written by Lela S. Lela lives in Petworth. She previously wrote about bird migration.

Vultures!

I’m writing this post from Florida City, just outside the Everglades, where vultures have developed a taste for windshield rubber. Like New Zealand’s infamous kea, migratory black vultures stopping over near the park are known for their attacks on rubber and plastic parts of cars, ripping out window seals and peeling windshield wipers. It’s gotten so bad that the park offers visitors tarps to shield their car from attacks. We don’t know why the vultures do it especially since they don’t really seem to eat the stuff, just shred it. Maybe just for fun, or perhaps the delicious flavor of sun-warmed vinyl.

DC has plenty of these scavengers – both black vultures and turkey vultures – although in our area, at least, they haven’t turned to gnawing cars yet. Vultures don’t have syrinxes, the bird equivalent of vocal cords, so they don’t sing and limit their vocalizations to hisses and grunts. Both species in our area soar on thermals looking and smelling for lunch. (Black vultures have much poorer senses of smell, and often watch for turkey vultures to identify carrion so they can sail in and steal it. Vultures thrive around cities as well as in the country. In fact, the urban heat island effect generates strong, consistent thermal columns for them to ride, which other soaring birds like red-tailed hawks also benefit from. To tell our two species of vulture apart, look at the way a given bird is flying. Turkey vultures wobble in flight, where black vultures have a stronger, more forceful flight pattern punctuated by several wing beats. Black vultures have tails that look short for the birds’ size, and the underside of their wings appear almost totally black; turkey vultures’ wings are marked by a long stripe of paler feathers toward the outer edge. They’re found all over the DC region, throughout the year.

Photo by PoPville flickr user Mr. T in DC

Urban Wilds is written by Lela S. Lela lives in Petworth. She previously wrote about luna moths.

Migration Season

Between April and June, cued in part by increasing daylight hours, migratory bird species turn from their winter territories and travel en masse to spring breeding grounds. In the Washington area, we see migrants returning from farther south: Kentucky warblers from the Caribbean, yellow-billed cuckoos from as far as Argentina. DC’s official bird, the wood thrush, overwinters in Central America and parts of southern Mexico. Not all birds migrate, and some species are only partly migratory: one population may migrate while another stays put. European Starlings are one of these: we have resident starlings all year, but some travel south for the winter. Spring migration is maybe the best time of year to go birding: this time of year, the migrants sport their often-gorgeous breeding plumage, making them easier to see than during the fall migration, and their sheer numbers make the odds better as well.

Most birds migrate at night, navigating partly by the stars and avoiding diurnal predators. Artificial lights, which now blanket most of the Atlantic flyway, appeared only recently from an evolutionary standpoint, and birds don’t recognize them as something to avoid. When birds fly past an illuminated building at night, they are drawn to the light inside, and can fly straight into windows or glass walls, injuring or killing themselves. A similar thing happens during the day when birds see the sky reflected in a building before them, and fly toward it. This can happen at any time of year, but is most lethal during migration, when huge numbers of birds are flying along routes that take them past some of our biggest and brightest cities. Up to a billion birds die this way every year in the U.S. alone.

A simple fix is to turn out unnecessary lights at night, especially in taller buildings. The volunteer-based organization City Wildlife runs a program called Lights Out DC that encourages Washington business owners to do just that. Volunteers for Lights Out (full disclosure – I’m one of them) walk routes downtown in the early morning during migration season to collect dead and injured birds, determining which buildings are the most dangerous. Turning out unused interior lights is a quadruple win – it saves energy and money, reduces light pollution, and protects birds – but like any behavior change, it happens slowly.

To learn more about City Wildlife, or to volunteer, visit www.citywildlife.org.

Ed. Note: We still have a few spots open for Bird Watching on TR Island May 4th. Please email me at princeofpetworth(at)gmail if you’re interested.

Dear PoPville,

OMG! I saw this in my alley today and it terrifies me. Has anyone else seen one of these mutants? It looks like a squirrel/rat. It hopped like a squirrel and has it’s body but the tail is unmistakenly a rat’s! I spotted it in the alley of 14’th/13th & Irving/Kenyon NW. I think it’s called a Squrat or Sqrat.

Photo by ggallice via wikipedia

Urban Wilds is written by Lela S. Lela lives in Petworth. You can read Lela’s previous post on raccoons here.

Insects are as close as we get to alien life on Earth – skeptics, just google “macro photo insect.” Their lives run on cycles and timing that can seem cruel or bizarre from a mammalian standpoint. We’re about to witness a big upswing in the insect interest factor when Brood II of the periodical cicadas hatches out after spending 17 years underground. Luna moths, among the most beautiful of insects, have a less dramatic but equally exotic life marked by a complex, colorful development and an early death.

The color of pistachio ice cream, with feathery antennae and long ‘tails’ at the bottom of each wing, Lunas are among our larger moths, with wingspans up to five inches. (You may recognize them from a pharmaceutical ad that aired a few years back.) These gorgeous animals, widespread in eastern North America, are hatching now in our area. Luna moths are similar to cicadas in that their adult phase is poignantly short. After hatching, a Luna caterpillar will go through five stages, or instars, as an increasingly large bright green caterpillar. Pupation takes about two weeks. After emerging from their cocoons, the insects immediately begin to breed. A female Luna sends out pheromones that males of the species can pick up, using their antennae, from several miles away, and glues her 200 or so eggs to host tree leaves. They have to move quickly, because Luna moths pupate with a cruelly efficient structure: they don’t have mouths. Once hatched from their cocoon, they only live long enough to breed and lay eggs, and die within a week.

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Photo by PoPville flickr user pablo.raw

Urban Wilds is written by Lela S. Lela lives in Petworth. You can read Lela’s previous post on Eastern Skunk Cabbage here.

Spoiled for choice, I struggled to decide what to write about in this post. I’ve been trying to keep installments focused on current phenomena and species that we have a better than usual chance of seeing in a given month, and spring is prime time for all kinds of nesting and blooming things. Then last week, reeling with serious jet lag, I looked at our cat pawing at my suitcase and saw a large raccoon instead. The hallucination only lasted a moment – but was it a sign? Two days later, jogging in Rock Creek, I ran past a large and very dead raccoon; down at the water’s edge, its little handprints were visible in the mud. I accepted this to mean that although they are with us all year round and not doing anything especially interesting right now, the universe would evidently like a post on raccoons.

Raccoons are smart, adaptable generalists that live equally well in urban and rural habitat. They have a storied history in DC: the Coolidge White House kept two pet raccoons (emphatically not recommended) and trotted them out for Easter egg rolls. A 1998 study found extremely high densities in parts of Rock Creek Park – estimated at 333 raccoons per square kilometer! – and they are widespread throughout the city, sometimes sheltering in abandoned houses. Anyone trying to grow vegetables on their roof will probably have experienced raccoon-related losses: they’re omnivores, and eat everything from crayfish to berries to garbage. They have few natural predators in our area (although Great Horned Owls will prey on baby raccoons) and are probably most susceptible to cars and to a range of diseases including canine distemper and rabies. The one I passed while out jogging was almost certainly a traffic fatality.

Raccoons have an unusually wide range of body weights in the wild, from 4-30 lbs (though more commonly 8-20 lbs, with some freakishly large individuals clocking in at over 60 lbs). It’s not unusual for them to lose up to half their weight in winter: while they don’t hibernate, in cold weather they will sleep for long periods of time to conserve energy. Their tracks, in mud, snow, or sand, are distinctive: both front and hind paws have five digits, and the front paws, usually 2-3 inches long, look very much like little human handprints. Raccoon ‘hands’ are quite dexterous and become markedly more sensitive when wet. The species’ Latin name, Procyon lotor, refers in part of their habit of “washing” their food: a raccoon will carry food items down to a stream or pond to manipulate them underwater. It’s now thought that this is done partly because the raccoon can perceive the food better with wet hands. Their sense of hearing is also excellent: supposedly, they can hear earthworms moving underground, although I’ve been unable to verify this.

You can see raccoons almost anywhere in DC. They’re mostly nocturnal, but roam and browse for food during the day as well.