In the Wild
House wrens prefer to feed either on the ground or in low bushes. They are shy about approaching backyard feeders, so they make do almost entirely with insects on plants or in the soil year round.
Carolina wrens prefer to feed above the ground, snagging insects from plant surfaces. About 90% of their diet is this protein. In the winter they turn to berries, nuts and seeds on plants when insects are less abundant. They will eat poison-ivy berries.
The food preferences of winter wrens are less known because of their shy ways. Researchers conclude that they eat insects almost exclusively, but occasionally will sample red cedar berries.
At the Feeder
Wrens in general do not visit feeders, but Carolina wrens can be enticed by a suet cake. They and the occasional house wren also enjoy nutmeats (especially pecan), black oil sunflower seed, peanut hearts and some fresh fruit such as bananas. They have been known to try dry pie crust, bread and cottage cheese, too.