Nuthatches of the Pueblo Mountain Park

“Hey, look at that bird - it’s walking upside down on a tree.” If I had a dollar for every time I heard someone say these words, I could buy an MPEC membership at the coyote level, at least! Without looking, it is easy to tell that the bird is a nuthatch. Of all bird species - and there are a lot of them - it is only members of the genus Sitta, commonly known as nuthatches, that display this unique habit. Some birds often walk “up” a tree trunk, but only nuthatches walk “down.” Of North America’s four species of nuthatches, three of them are found in the western United States. The Pueblo Mountain Park is home to all three. This speaks to the diversity of the park’s ecology because habitat descriptions for each of the three species are somewhat different. The remaining species of North America’s four nuthatches, the Brown-headed Nuthatch (Sitta pusilla), is only found in the eastern United States. Worldwide, there are twenty-four species of this interesting genus of birds. Of all three nuthatches, it is the handsome White-breasted Nuthatch, with its bright white underside and black cap, that is probably seen most often crawling down and around the trunks of park trees. At six inches long, it is the largest of North America’s nuthatches; the books say it prefers mature deciduous forests. Like other nuthatches, the White-breasted is searching for insects and other invertebrates when poking around a tree with its long narrow bill. All nuthatches also eat seeds and nuts, especially in winter. An interesting behavior of Sitta carolinensis is known as “bill sweeping.” Usually with an insect or other invertebrate in its bill, it will sweep the bark around its nest cavity with the insect, possibly trying to prevent detection by predators by masking its own scent. Several times on a spring hike, I will detect a small “knocking” that sounds like a muffled woodpecker. Looking in the general direction of the sound, I’ll find a snag with one or more holes in it. Before too long, a little head pokes out of one of the holes and drops a billful of wood chips. More often than not, the poking head will belong to a Red-breasted Nuthatch doing the final touches on a nest cavity. Like most nuthatches, the Red-breasted can excavate its own nest cavity or use an existing one. At about four and a half inches long, the Red-breasted is the middle sized of the three nuthatches found in the park. Less round than its larger cousin, it is easily identified by its orangish underside and dark eye-stripe. Although it is the only species of nuthatch that sometimes moves south in large numbers during winter, the park’s population of Sitta Canadensis can be found in the park all four seasons (as are the other two). A common sound of the Pueblo Mountain Park is the duck-like yank of this little bird. It prefers coniferous forests and is often seen, or heard, in the park’s Douglas fir stands. Like the White-breasted, it also seeks to protect its nest, but instead of using insects, the Red-breasted Nuthatch smears sticky resin around the cavity entrance. The small and social Pygmy Nuthatch is often heard from the tops of ponderosa pines as a group busily looks for food with a continuous clamor of high-pitched chirps and pips, like a group of talkative kindergarteners all talking at once. At three and a half inches long, Sitta pygmea has a gray-blue back and a buffy white underside. Its small size has led to a unique combination of survival mechanisms for very cold nights: it allows its body temperature to drop, it roosts in a site like a tree cavity, and it always roosts with other birds, with up to 100 birds in one roosting site. So close is the relationship between the Pygmy Nuthatch and ponderosa pine forests that the Pygmy is considered an “indicator species” of these forests. This means that the presence or absence of Pygmy nuthatches is used to evaluate the ecological health of a given ponderosa pine ecosystem. It is less common in forests heavily managed for timber. Since ponderosa pine forests are often heavily logged or threatened by logging, the Pygmy nuthatch is listed in several states as a species of special concern. So far, it seems to be holding its own in Colorado. So, if you want a lesson in identifying species of nuthatches, the Pueblo Mountain Park is the place to come. We commonly see them on our Guided Hikes. And if you are not up for being out in the cold, all three species are frequent visitors to bird feeders, so you can observe them at our feeders from the warmth of the MPEC Interpretive Center.