Saturday, September 26, 2009

Gray Birch: Bird Magnet

Saturday, September 26, 2009
A male Baltimore oriole stops by one of our gray birch clumps.

We planted some gray birches (Betula populifolia) on our southeastern Ohio ridgetop farm about a decade ago. Julie was the one who wanted birches specifically, since they reminded her of the New England woods where she'd spent her college and post-college years. Being an artist, she loves birches for their visual appeal: pale bark dotted with black, bright green leaves that turn golden in autumn. In winter, when the birches, like most other deciduous trees, are completely leafless, the stark white trunks flecked with black seem to fit perfectly—almost beautifully—into the stark landscape.
Beautiful even during the leafless winter months.

Gray birch does not occur naturally in our area. In fact the only birch native to our part of Ohio is the river birch. Our dry ridge is not the preferred habitat for the gray birch, but they are short-lived trees anyway, so when they begin to age-out, we plant a few new ones.

Though we planted them for their aesthetic value, little did we know what bird magnets these trees would be. We've planted them in clumps of two or three all around the yard and it's rare to look into one of these clumps and not see a bird. I've watched migrant warblers, orioles, tanagers, vireos, cuckoos, and thrushes drop out of the sky into the birches. My guess is that, when flying over, they recognize the birches' shape, color, or foliage.
Yellow-billed cuckoos seek caterpillars in our birches.

What do the birds get from the birches? The primary thing is food. Birches seem to attract a lot of insects—insects that eat the leaves, live in the bark, bore into the wood. Insects that hatch from the foliage, caterpillars that munch on the soft green leaves. Our chickadees, titmice, and nuthatches seem to love the trees as stopover points as they come and go to the feeders. The loose bark of the birches is a good place to lodge a seed so it can be hammered open by a tiny bill. But I've also seen warblers grabbing ants from the birch bark, squishing them, and rubbing them through their feathers.

A black-throated green warbler anting in one of our gray birches.

Sapsuckers seem to be drawn to our birches and their rings of small sap holes are easy to spot on every large trunk.

As the gray birches age, some of the branches lose their leaves, much like and aging man begins to lose his hair. These bare sticks are perfect perches for ruby-throated hummingbirds and insect-hawking flycatchers. They are song perches for blue-winged warblers, and indigo buntings that next in the nearby edge habitat.
Springtime birch buds go nicely with the first singing American robin in our yard.

Even when a birch tree is dead it still provides for the birds. Flickers dig ants from the rotting stumps. I gather the dropped branches together to weave a brush pile near the feeders before the first snowfall blankets the ground.

Our willows and ashes and oaks and maples and mulberries and tulip poplars and sycamores and box elders and sassafrases and red pines are wonderful, bird-friendly trees. But none of these seems to draw the birds in every month of the year like the gray birch does.

Here are a few images of fall warblers in the gray birches from last week.
A magnolia warbler.

Blackburnian warbler in fall plumage.

A very dull fall-plumaged blackpoll warbler

A pair of bay-breasted warblers dropped into the dead top of a birch just after sunrise.


On September 26, 2009 at 4:28 PM Julie Zickefoose said...

A wonderful paeon to my favorite tree. Perhaps in mid-winter you'll do another post about the siskins and goldfinches that love its seeds, and the way the tree sparrows and juncos gather them off the snow below.

On September 27, 2009 at 10:26 AM Tom said...

Bill- I love your blog. The next few sentences are going to be written by a "science chimp", not me. Or maybe Jimmy Mac took over my keyboard for a second. Ohio does have five native birch species- although river birch is the only one documented from Washington County- the others are swamp (pumila), yellow (alleghaniensis), sweet (lenta), and gray birch (populifolia), which is pretty frequent up in the extreme NE part of the state, especially in bogs.

Many of the gray birches that are planted are the european white birch, Betula pendula, and this one escapes. It has been giving us botanists nightmares in northern Ohio for decades trying to determine if something is the native gray birch or the european species. Probably way more than you wanted to know!



On September 28, 2009 at 11:36 AM Bill of the Birds said...

Thanks for the clarification. I needed to make my point about native versus non-native birches more betterish. All I was trying to say was these trees did not get here on their own—at least not on my dry ridgetop, but that birds know the birch and are attracted to it.

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