Carolina Wrens Expanding North

Most people who have ever put up a bird nesting box know the house wren, the tiny, super active brown bird with the cocked tail who sits and sings his bubbly song incessantly. Thinking of it now on a dark, frigid early morning, I long for the warming winds of late April, when this bird will return from the south.

A few fortunate people in the Connecticut River Valley have a wren or two in their yard now, including a gentleman from Greenfield who has written me a note about a pair at his feeder.  However, his birds are not house wrens. They are Carolina wrens, and even in January when the sun brightens the snow this wren will sing its loud, clear rolling song. If you have heard the tufted titmouse belt out his two-note song over and over, then just add a third note and you have the song of the Carolina wren.

This wren might be added to the list of species that do not migrate and have expanded their range north into New England in the last forty years, but it does not quite qualify.  The Greenfield writer asks why not, because a pair are spending the winter in his yard for the second year in a row.  He has seen the red-bellied woodpecker, which is on the list, only once ever.

The difference is that the Carolina wren has been trying to move north for a long time, and has not made much progress. The few individuals we have with us are perpetual pioneers, always setting out to colonize the new frontier, but always getting massacred by the resisting natives, ice and snow.

Between 1963 and 1968 there were no Carolina wrens found on the May census conducted by the Allen Bird Club. I can remember waiting for hours in a cold car to see one at a feeder in March of 1969, but it was not until August of 1974 that I heard and saw my first in the Stebbins Refuge of Longmeadow.  New England had begun then to enjoy a series of mild, open winters.

From 1969 to 1975 as many as six Carolina wrens were present for the census.  Then several hard winters kept numbers to one or none for seven years. Starting in 1986, very mild winters took over, and census counts swelled slowly until 21 were counted in May of 1992. That December on the Christmas count there were 49 tallied.  Then another hard winter or two ensued, until in 1996 only two were on the census and six on the Christmas count.

In order to survive the winter, a Carolina wren must be able find larva on the ground beneath the leaf litter. It is simply not adapted to finding them on the bare tree trunks or branches. It does eat some seed, but that is not the mainstay of its diet, even in winter, so only suet or peanut butter would help it through the bad times. The only place in New England that this species has been able to persist in any numbers is within a few miles of the coast from New York City to Cape Cod.

The Carolina wren is one of those species that will be "driven in to feeders" when the snow and ice takes over. Two days ago I received two photos showing an individual as it clung to a tree trunk and perched on some suet.  It is distinctive with a rich brown back, light undersides washed with rusty color, thin bill and cocked tail, and the prominent white stripe above the eye.

The owner of the feeder was none other than the Agawam hostess of the famous rufous hummingbird.  I have rather sad news to tell about the hummingbird. No, Rufie is not dead or gone. To the contrary she is as lively as ever in her Northampton greenhouse.  A little too lively it seems. Her territorial instincts were just too strong. She found a way around the divider that separated her from the male that had been sharing her quarters. The caretaker was out and within a few hours the male lay dead on the floor, a victim of a rivalry as intense as any could be.