House Wrens (Troglodytes aedon) are small, active birds often found in backyards and various habitats across North America. They are known for their enthusiastic songs and their prolific nesting habits, frequently utilizing diverse cavities for their broods.
The Core Diet: What House Wren Babies Eat
House wren nestlings primarily consume a diet of soft-bodied invertebrates. This diet includes various insects and spiders such as caterpillars, beetles, grasshoppers, crickets, flies, moths, daddy longlegs, and earwigs. They may occasionally consume millipedes and snails.
The selection of soft-bodied prey is important because it is easy for the young wrens to swallow and digest. Caterpillars, for instance, are a highly nutritious staple chosen by many bird parents for their nestlings.
How Parents Provide for Their Young
Both male and female house wrens tirelessly forage to feed their nestlings. They deliver food frequently, with observations showing parents feeding older nestlings approximately 25-30 times per hour, or even more often. These feeding trips can occur as rapidly as every couple of minutes from dawn until dusk. Parents may also feed grit and small bits of shell to their young starting around day three.
Parent wrens maintain a clean nest environment by removing fecal sacs. These sacs are gelatinous packages containing the nestlings’ waste, making them easy for the parents to carry away from the nest. This practice helps keep the nest hygienic and reduces the scent that could attract predators.
The Importance of Their Natural Diet
The invertebrate-rich diet is important for house wren nestlings due to its high protein, fat, and moisture content. Protein is fundamental for the development of body tissues, strong feathers, and muscle formation. Feathers, over 90% protein, require significant protein for proper growth and insulation. Insects are an excellent source of protein, with some insect meals containing 37% to 65% protein.
Fats provide energy for feather development and contribute to proper feather coloration. The moisture in insects also helps hydrate the young birds. This specialized diet supports the fast growth rate of altricial birds like wrens, enabling them to fledge within 12-18 days after hatching.
When Humans Should (and Shouldn’t) Intervene
Do not feed wild baby wrens or any wild birds human food. Human foods lack the specific nutritional balance required by wild birds and can lead to malnutrition, developmental issues, or illness. For example, bread offers no nutritional value and can cause deficiencies.
If a baby wren appears to be in distress or truly orphaned, contact a licensed wildlife rehabilitator. These professionals provide the specialized care, appropriate diet, and medical attention wild birds need. Attempting to care for a wild bird yourself can be detrimental to its survival and is often illegal without proper permits. If the bird is a nestling (featherless or eyes closed) and the nest can be located, carefully place it back in the nest, as parents will not reject their young due to human scent.