It's that special time of year, just a few weeks of balmy green May, when the warblers migrate through our area. Warblers are tiny, active birds which live half of the year in South and Central America, and then make the long journey up into the northern United States and Canada, where they make their nests and breed. They appear just as the leaves of the deciduous trees are almost all out, and the tree-flowers are blooming. Warblers eat caterpillars, insects, and other things which only are available at this time of year. If the warblers come too soon or too late, they won't have anything to eat. So it is all precisely timed.

Their songs are not really warbling at all; they are more like squeaky whistles and tweeting, often so high that older people might not hear them. But though they are high-pitched, they are also loud, and in the early morning bird chorus they hold their own. It's hard to tell one warbler song from another unless you are an advanced bird expert. They all seem to sound like zweet zweety-zweet zweet until you make the ultrasonic distinctions.

I would never claim to be an "advanced" birder, though I am an experienced one. I have friends who have seen thousands of species and go on foreign tours just to go birding in some exotic jungle. I am a backyard or park birder. I have a "life list" of species seen, but am not fanatic about adding to it. But I do like to go out searching for warblers when I hear their piercing songs because warbler-watching is such a challenge. It's certainly not like seeing robins or jays or crows or sparrows, who are always easily visible in the city environment. The warblers are elusive. They hide among the fresh green leaves and they are so light and agile that they barely jostle the branch they perch on. Also, most of them prefer to move around in the very tops of the trees, so you have to bend your head back at an uncomfortable angle just to spot them. Some birders call warblers "neck-breakers!" Some other warblers take a lower space, and can be equally elusive in the underbrush or smaller trees closer to the ground.

I find warblers both by the sound and by the movement. Once I see a tiny flutter in the treetop, I snap my binoculars to attention and try to follow it. Most of the time I am rewarded with a second's glance at a flash of color among the emerald leaves. That is enough for me to make a sight ID. Some warblers are a bit bolder and easier to see than others. The glorious American Redstart can put on a show, fanning his orange and black wings and tail on an exposed branch. But other tiny flyers like the Magnolia Warbler only appear for a few seconds at a time in between the leaves, its vivid black and yellow stripes like a road sign in the forest. And there is one warbler, the Blackpoll Warbler, who is almost impossible to see, because it creeps along branches rather than perching in the leaves, and its black and white stripes are good camouflage against the tree bark.

The different warbler species have their fly-through schedule in different weeks, or waves of migration. The first to arrive are the Yellow-Rumped Warblers who usually show up in late April. They don't have to migrate as far as the other ones, because many of them winter in the southern United States. After them come the Redstarts, the Yellow Warblers, and their relatives. Later, the rarer and harder-to-see species flit through, hidden among the leaves. Last, in late May, come the Blackpolls. They are the rear-guard of the migrating warblers, and when I hear their nearly ultrasonic high calls, I know that warbler season is almost over.

If I hear a warbler song, and I have time, I rush out of my dwelling with my binoculars and look into the trees. I also make some birding time in local parks and even parking lots near forests. I have had plenty of birding success peering into the woods in the parking lot of my old workplace in urban Tysons Corner, Virginia. It is a great satisfaction for me to spot the brilliant color of one of these living flowers among the foliage. I also know that these birds, while not yet "endangered," are threatened by habitat loss in their southern winter residences. Some years I hardly see any at all. But this year so far is a good year for them, and just now the fresh trees are filled with the sounds of bright visitors.

Posted at 3:52 am | link