Monday, March 22, 2010

Did the Crazy-Bad Winter Hurt the Robins?


(The following piece originally appeared March 1 in the Voice newspapers of Takoma Park, Silver Spring and Kensington in Maryland. I write the monthly Sligo Naturalist column for the Voice. The snow has melted in the last 21 days. But the memory of that snow lingers on, and on, and on... and the questions I get about robins persist, too. So I thought better late than never to post it here.)

Things are slowly emerging from the snow and like urban archeologists we see some of our missing stuff out in the sooty, icy drifts, where things became immobilized several weeks ago by the twin blizzards. (Oh, so that’s where the other snow shovel went. And hey, I was wondering where the purple sled had gone. I think that shiny thing is an earring… we’ll just have to wait until it melts a bit more to get it out…maybe this ice pick from the kitchen will help to dislodge it…)

When I walk the dog, I mostly find litter, smashed into the frozen banks where it blew during the high windstorms. Loads of beer cans and beer bottles, fast food wrappers, dozens and dozens of plastic bags – I pick them all up while I walk the dog and arrive home with a sack full of trashy storm souvenirs.

One night I looked out before going to bed and saw a bright red, disposable plastic cup on the sidewalk. By the time I got out there in the morning to pick it up, some one had used it to carve a smiley face completely of circles in the grimy, grey snow bank by the curb. Wise guy.

While we continue to wait for the snow to vanish (and despair that another storm might drop more upon us in March), people desperately cling to signs of spring. We are not a region that is accustomed to real winters. We usually have a lot more thaw periods in January and February than we got this year. We want proof this will soon end.

Everywhere I go, for instance, people want to talk about robins. Why have such huge flocks descended on their yards? Why are they eating all of the holly berries? Are they okay? Will they freeze or starve because they can’t eat enough worms from the frozen ground?

I have theories, and a few scientific answers.

First of all, the robins that we are seeing out there are not that unusual. They often flock together in winter before dispersing to mate in the spring. A few years ago, during a very mild early March, I looked out to find more 30 robins were gathered around the birdbath, noisily drinking and bathing. Flocks are not that unusual.

People keeping telling me that they’ve never seen them in such huge numbers, but I keep wondering if that’s because we were all stuck at home more with out much to do during the long weeks of blustery February. Also, robins are pretty good at blending in most of the time, but I think the unusual abundance and persistence of snow has made them more visible. The brown and orange feathers really contrast against the white snow this year.

There are always robins that spend the winter with us here in Maryland. Although it seems we were all taught to look for robins as “the first sign of spring” there is little to back up this harbinger. Some robins move back and forth. We may be looking out the window right now at a bird which is on its way northward to a place in New England where it will spend the summer. But there are some robins that stay here during each winter.

Robins like to eat berries in the winter, but then switch to worms in the spring once the ground softens. It could be that the real sign is not the robins themselves but the worms they are finally able to eat. But since we get so many mild winters here it is possible to actually see them eating like that, even in the January, so even this is not an accurate assessment of spring’s arrival.

Robins also like to stay in the tops of trees during winter, although during storms they may spend more time near the ground due to wind. So during the storms we may have seen them down at the ground more.

Many people have also asked me if the robins are here early this year because of climate change. I’m glad to hear the question. I’ve been worried that maybe people would be inclined to think this winter’s storms offered some kind of proof that climate change was no longer a concern. (Don’t get me started on a rant about the Fox News foolishness of that very unscientific, anti-intellectual way of thinking. It is not pretty and usually involves bellowing on my part. Instead, you can check out this link to a story about climate change and the snow which appeared in the New York Times for some interesting information. )

There are not really that many straightforward answers specific to robins, however, because the research on these birds and climate change is pretty thin at this point and robins are considered a species of low conservation concern. There are a lot of them around, and they tend to thrive in urban and suburban areas. No one is really thinking that they’ll go extinct or anything if climate change occurs.

It is generally assumed that the impact of climate change for many bird species, including robins, will be to change the birds’ range. They may, for example, appear farther north earlier in the spring and the areas they inhabit in the southern part of the US may recede as the average temperatures continue to rise each decade. Some work a few years ago indicated that some western robins were migrating southward sooner in the Rocky Mountain regions as food became more available to them earlier each spring. But a 2004 study which analyzed fifty years of data about birds in North America found that unlike other bird species such as sparrows, the date the robins laid their eggs and the clutch sizes of the eggs did not really change significantly over the years included in the research.

I guess it is also important to realize that one year of observation does not constitute a trend. So even if the birds did do something unusual this year, it would not necessarily signal a massive change in the entire species’ behavior.

I like the robins, though, and I am glad to see them, even if they don’t have a really strong connection to the beginning of spring. As I stand outside picking away at the ice fossils on the edges of my garden, I like hearing their song mix with the flute-ish call of the blue jays, and the busy chatter of the chickadees that are searching for nesting spots. I think I’ve learned to train my ear to hear those things over and above the noise of sirens, beltway traffic, and helicopters. And maybe that’s why everyone else is so focused on the robins around here, too -- they’re familiar, and easy to remember. Their ability to pull out the worms when the ground warms is reassuring no matter when you witness it.

No comments: