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The call of the towhee

Just the other day someone asked me to name my favorite hike in the Santa Monica Mountains. Instantly my mind envisioned a place that I have gone to day after day, year after year. I have spent hours in this place mapping the landscape, learning the plants, researching the animals. But then I realized that to a newcomer this place holds nothing spectacular. It does not hold the red sandstone of Red Rocks State Park or the wildlife of Malibu Lagoons or the striking rock pools of Malibu Creek State Park.

But this place is my favorite because it is home. In exchange for impressive vistas and unique landforms, this spot holds smells that are as familiar as my grandmother’s kitchen. The soft leaf duff is as comfortable as an old worn chair.

The birdsong is as soothing as favorite songs playing on the stereo. It is especially the sound of the birds that welcomes me home. Recently I have been most touched by the calls of the towhees. The throaty buzz of the spotted towhee Pipilo maculatus, or the high-pitched note of the California towhee Pipilo crissalis represents a release from the stress of the day and a return to peace.

Spotted and California towhees both belong to the family Emberizidae, a large group consisting of small to mediumsized songbirds. Most birds in this family are brown or streaked with rounded wings and conical bills. In North America there are 18 genera and 50 species of Emberizidae. Towhees are the largest birds within this family, having a stout bill and long tail.

Towhees are ground dwelling birds often found in dense shrubbery and brushy habitats. While they are usually solitary, they pair monogamously during the breeding season, becoming territorial. Nests are designed as an open cup constructed from grasses. Often the nests are found deep within vegetation or on the ground. When born, the young are nourished and cared for by both parents.

Two towhees

The California towhee is a common brown bird with red/cinnamon color on its undertail coverts, throat and face. It grows to a length of 9 inches with a wingspan of 11.5 inches. This bird ranges the length of the California coastal mountains and southward into Baja. The spotted towhee contrasts sharply from the California towhee with its black head, white belly, red flanks and white spotted black wings. It is about the same size as the California towhee. This bird is also found in the California coastal mountains but ranges eastward to the Midwest.

Beyond the towhee calls, another sound associated with towhees is the noise of their foraging. This is often heard as a repetitive scratching noise in the underbrush. Towhees use a “double scratch” method to uncover food. They jump forward and rake the earth back, pushing leaf litter aside to attain access to the soil surface. When raking the ground the towhee positions its head directly over the exposed dirt, ready to pounce on available food.

Diet affects anatomy

When breeding, towhees will forage for insects. Interestingly though, in the winter months, their diet turns toward seeds. To aid in this dietary change, a morphological shift can be seen in their digestive tracts. In California, it has been found that towhees’ intestines lengthen during the nonbreeding months. This allows food to be retained longer, an advantage when processing plant materials. During the breeding months the intestines shorten to accommodate the more easily digested insect diet.

Another morphological shift is seen in bill length, especially in spotted towhees. During the winter the bill is shorter than in summer months. This is due to changing foraging habits. In winter the bill is worn down by the consumption of seeds and grit. When the diet changes in the summer to softer insects, the bill is able to grow longer.

Other adaptations of towhees are observed in the entire Emberizidae family. Although each species is indiscriminate when foraging for insects, each is adapted for specific seed types. The conical bill found in Emberizidae is suited for seed husking. Emberizids with larger bills are readily adapted to plants with larger seeds and thicker husks but are poor candidates for manipulation of smaller seeds. The reverse is true for emberizids with smaller bills. Consequently, habitats that support vegetation with large seeds sustain larger emberizids. Extrapolating this information, one can predict which species of Emberizidae lives in the surrounding habitat by knowing the size of local seeds.

But perhaps the most poignant bit of knowledge brought to me by the towhees is the clarity of “home.” Home was once defined by a structure or family, but it now encompasses so much more, engages all of my senses. I wonder, what is home to you?

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