Two Insect Gleaners

Today while looking for the crossbills at Valley Forge National Park I got to watch two insectivores with completely different foraging techniques, the Golden-crowned Kinglet and Brown Creeper. Both of whom were identified by call before I could sight either of them. To me their calls are similar; both being very high pitched thin calls, with the kinglet having an even 3 noted call and the creeper usually a single note.

Of all our birds in North America, it is the Golden-crowned Kinglet that relies heavily on a diet of insects – even in winter. They are highly active foragers working their way randomly through a tree, often hanging upside down, lightly flicking their wings as they glean insects from branches. Their tiny thin straight bills perfectly suited for this.

Though they tend to favor spruce trees, in winter one can often find them in mixed flocks with chickadees, titmouse and even creepers moving through a wooded area. Their head pattern is beautiful with a white supercillium and black border, bordering the yellow crown. Today when one came down into a rhododendron bush I got to see the usually concealed central orange patch that lies within the yellow crown. When they really get excited or aggressive this can even be raised.

Very different is the cryptically colored Brown Creeper. Creepers have a very thin de-curved bill that is well adapted for exacting small insects from tiny crevices in the bark. They forage primarily on tree trunks working their way not only up a tree but also along branches, as well as their undersides. Once they near the top they fly down to the base of another tree and repeat the process. Like a woodpecker it has a stiff tail, using the 2 central tail feathers to brace itself as it climbs up. They are so well camouflaged that it often freezes in place at the first sign of danger.

There are only a handful of our hummingbirds that are smaller than the Golden-crowned Kinglet. They are also the smallest bird to endure freezing temperatures without having to go into a state of torpor which is what hummingbirds have to do. They maintain a normal 104F body temperature and along with the Brown Creeper, is one of the few species that huddle together in cavities to keep them warm on cold nights.