House Wrens

By Karin Bolcshazy

My neighbor has several bird boxes in her yard and regularly hosts wrens who build their nests inside to raise their young. The House Wren common in Pennsylvania is a small brown unassuming bird measuring about 3-5.1 inches in length with a wingspan of 5.9 inches and weighs 0.3-0.4 ounces.  Both males and females look the same. But don't let the drab appearance fool you - House Wrens make their presence known with incessant singing and chatter. They are widespread across North America and South America. In winter, House Wrens reside in the Southern US and Mexico. They make their way north in spring, eventually ending up covering most of the Continental United States and parts of Southern Canada.

You are not likely to find them at your bird feeder, since they are insectivorous, eating mostly insects and other invertebrates that move along the ground such as beetles and spiders. They have also been known to eat flying insects such as dragonflies and moths.

Wren breeding season starts in late March and into early April. House Wrens aren't too particular about where they build their nests. They prefer cavities in trees for ultimate protection from predators, but love man-made nesting boxes even better. During mating season, the male picks a few spots he deems appropriate for nesting and places a few twigs into the cavity. When the male finds a prospective mate, he takes her to show off his potential nesting locations. If the female approves of the nesting location, she will start to build her nest. Male wrens place twigs in up to twelve different nesting locations to ensure that the female will like at least one! Wrens are very territorial -if House Wrens find another nest around their nesting grounds, they will destroy it along with the eggs in an attempt to monopolize all of the nesting sites in their territory.

House Wrens raise two broods per season A female house wren lays between 2-6 eggs per brood. The incubation period lasts between 9-16 days. After the brood hatches, the babies remain in the nest for up to 17 days. During this time, both the male and female hunt for food to bring back to the nestlings. As the nestlings grow, they start to develop feathers and will start to open their eyes.  After 17 days in the nest, they are ready to leave.  Once they leave, the male house wren continues to feed fledglings for up to two weeks. Often, he's putting in a double shift making a new nest for a second brood while feeding young fledglings.

If you want to attract house wrens to your backyard feeders, opt for peanuts, dried berries, or even mealworm suet when insects aren't as plentiful in the cooler months.

Sources: birdwatchinghq.com; songbirdhub.com; Wikipedia