Signs of Summer 10: Eastern Towhee

Photo by D. Sillman

Eastern towhees (Pipilo erythrophthalmus ) are one of Deborah’s and my favorite birds of summer. We met our first towhee in 1984 out on the old farm we rented in northern Allegheny County. A pair of them set up their nesting territory in the woody thickets that bordered the long, rutted, gravel path that was our only way in and out of the hollow where our farm house and barn were situated. We frequently walked down the path to get to the hiking trails and pipeline cuts that ran up into the wooded ridges to our south and whenever we did we were chirped and chittered at by the flashing male towhee. Initially we had to go to our Peterson Field Guide to figure out that he was, as they were called then, a rufous-sided towhee. They were on the same page as the rose-breasted grosbeak which was just after the page with the blue grosbeaks and the indigo buntings, three birds that we also had the great pleasure of seeing on the farm that summer. It was a wonderful place for birds!

At first I thought the towhee, in spite of its obvious field guide location among the sparrows, was some sort of robin or related thrush. It was smaller than a robin but so much larger than a sparrow that it really took some intellectual discipline to accept the kind of bird that they were! Their beaks, once you got a good look at them, were obviously cone-shaped and very non-thrush-like, but it made me glad to see later on as I read about them that they are frequently called “ground robins” (which, if you think about it, is a very strange name! I mean what should you then call regular robins that are mostly found on the ground?).

Photo by D. Sillman

Towhees are birds of thickets and edges. They build their cup-shaped nests on the ground under the protective cover of dense branches and vines and frequently dig the nest down into the covering leaf litter for better concealment. They typically feed in the surrounding leaf litter, too, using a two footed scratching technique to fling the dry leaves about to uncover a wide variety of insects and other invertebrates. In fact, one of the best ways to find a towhee out in the field is to listen for loud, energetic scratching under the bushes!

Towhees also eat a wide range of seeds and fruits and have even been known to consume small lizards and snakes! They also have been observed raiding the nests of other birds to eat eggs and nestlings, but, hey, no species is perfect, right?

Towhees are subject to intense nest parasitism by brown headed cow birds (Molothrus ater). In some areas over half of the eastern towhee nests will have cowbird eggs. The towhees, though, do not seem to able to recognize these foreign eggs and spend a great deal of their reproductive energies feeding and rearing these brood parasites.

Eastern towhees in their northern ranges migrate relatively short distances either between sheltered local habitats or milder, southern regions. They have relatively short wings and are not strong fliers. They dart about from ground to low shrub branches in a very characteristic flapping and gliding flying pattern.

Photo by D. Sillman

We regularly see eastern towhees up at Harrison Hills Park when we are out doing our bluebird nest box monitoring. The extensive shrubby areas in the park are ideal for this species, and we are frequently hear both the underbrush scrapping and scratching and also the distinctive “cherrit!” (often sounded out in field guides as “drink your teeeeee!”) of the very territorial males.  The males seem especially interested in us as we walk past or through their territories. They keep a close eye on us and shadow us along our way.

Interestingly, eastern towhees mark out much larger territories than they actually require in order to provide adequate food supplies for their nestlings. They are extremely aggressive against any other towhee that might venture into their territories and have a wide range of displays and postures (frequently involving the flashing of the white tips of their wings) by which they express their anger and outrage! Not surprisingly, towhees are very solitary birds and seldom seen in flocks, but there is a marvelous name for these seldom seen aggregations! A group of towhees is called a “tangle” or a “teapot” of towhees.

Photo by J. Mayer, Flickr

Towhees can nest two or sometimes even three times in a season. A parental pair stays together for a given spring or summer but then the mating pairs re-shuffle for the next season. The female builds the nest with only minimal assistance from the male. It takes her about five days to complete the nest (a complex mix of sticks, rootlets, grass, bark, and leaves, and lined with soft grass and animal hair (paper and other human materials may even be incorporated into the nest materials).

Two to six creamy white, brown spotted eggs are laid in each clutch. As previously mentioned, nest parasitism by brown headed cowbirds is very high and overall nest predation by chipmunks, raccoons, and a variety of snakes is also quite severe. Nest success rates of less than 20% have been regularly reported. The Cornell Laboratory of Ornithology reports that there are approximately 28 million eastern towhees in North America and that their population has declined by 49% between 1966 and 2015. Loss of brushy habitats (due to human development of sites and also to ongoing forest succession) and the impacts of cowbird parasitism are given as the main causes of these population declines.

I am very happy to report that for the second summer in a row Deborah and I have a towhee residing in our yard! We see him regularly at our front yard bird feeder and also under our arbor vitae and spruce trees digging through the leaf litter. For the past three years I have raked my autumn leaves under these shrubs and trees to give shelter to insects and to generate a food source for foraging birds (not to mention possible overwintering habitat for tree frogs!). Maybe these leaves are the key to drawing towhees in close to our house! They are a truly welcome addition to our local fauna!