A Winter Warbler

It may still be the dead of winter, but when today’s temperatures crawled into the 50’s and the snow began to melt, a warbler I came across got me thinking several months ahead. It will not be long before spring is here and we get to see our spectacular wood warblers once again in bright plumages as they wing their way to their northern breeding grounds.

The warbler I saw is unique amongst our wood warblers. While most all warblers head to the neo-tropics and warmer climates of Central and South America for the winter, the Yellow-rumped Warbler is an exception and has actually been here all winter. It is a common winter resident perfectly adapted to colder climates wintering as far north as coastal Maine.

All wood warblers are insect eaters on the breeding grounds but in winter Yellow-rumps, or “butter-butts” as they are affectionately called in the field, are the only warbler species able to survive when there are few insects around. They have a slightly stouter bill and a digestive system unique amongst warblers that allows them to eat hard waxy berries such as bayberry, wax myrtle, poison ivy, juniper and eastern red cedar throughout the winter.

The bird I saw today was not the prettiest in its drab winter plumage (top photo), but one could clearly see where it gets its name from. Interestingly it is not the only warbler with a yellow rump. Magnolia Warbler has a yellow rump the same size but that tends not to be as conspicuous. Yellow-rumps flitter about and flick their wings, maybe not as much as a Ruby-crowned Kinglet but enough to expose their rumps to a greater degree than a Magnolia would.

As the days get longer and the temps continue to climb our drab looking bird will slowly turn into a stunning breeder like the one in the lower photo; join returning migrants and head for coniferous forests as close as the New Jersey highlands to raise another brood. Can’t wait!