Diets Change

This photo of a red-bellied woodpecker feasting on the fruits of a marlberry (Ardisia escallonoides) was taken by my talented photographer friend, Christina Evans, in her backyard near my former home. It graces the cover of my first book with The University of Florida Press - Native Plant Landscaping for Florida Wildlife, and it demonstrates better than any words I could write that birds change their diet with the seasons. A lot of attention has been raised recently regarding the importance of insects, especially caterpillars, but a living landscape has to feed birds (and other wildlife) throughout the year. A great many birds switch their insect-rich diet from the breeding season to fruit and other things once nesting is finished.
A few years ago, I was visiting a Florida State Park in late November. The parking area was alive with bluebirds. They were feeding on the ripe fruit of flowering dogwoods that had been planted there more for their beautiful spring flowers, I suspect, than for their wildlife value. The bluebirds, however, knew what their true value was. It was the winter food that they provided once the numbers of insects had dwindled that made these trees so valuable.  Caterpillars are a wonderful food source, but foliage-feeding caterpillars generally disappear by late fall and most birds switch to something else.

Flowering dogwood fruit

The yellow-rumped warbler, for example, switches its diet from insects when it arrives here in Florida to one largely based on the fruit of wax myrtles. In fact, its common name once reflected that and I still prefer to call them myrtle warblers. In my former yard, they stayed just long enough each winter to consume every bit of fruit on my wax myrtle (Morella cerifera) shrubs. Then they'd move on. 
Much the same is true for the ubiquitous American robin. The bird that built its nest each year in the red cedar (Juniperus virginiana) outside my living room window in Wisconsin spent its summer pulling earthworms out of our lawn and the lawns of my neighbors. They arrive in Florida by late fall and here they consume fruit.  I saw my first flock of robins at my new home yesterday. As I took inventory of my small wildflower nursery, I saw movement in the mature red cedar that rises up out of one of my next-door neighbor's backyard. As I scanned the tree, I realized that a flock of at least 20 robins were flitting through the branches. Although the tree is too far away to get a really good visual, I suspect that this tree is a female and that the robins were there feeding on the blue-colored "berries." The tree across the street from my front has not had that level of activity, but it is a male. The red cedar that was once so important to my childhood nesting robins had morphed, in a way, here in Florida to an invaluable food source.
Living landscapes need to consider the changing habitat needs of wildlife throughout the year. As I plan for the small woodland that I will install in my new home, I will focus as much on providing winter fruit as I will on creating conditions favorable for the caterpillars most will need in spring and early summer. many of the birds I hope to feed in winter will have moved back north by the time the caterpillars are most needed.

A male hooded warbler feeds on caterpillars during migration and throughout the nesting season. Photo by Christina Evans.