Wildlife Watching Wednesday: The Graceful Tree Swallow

By: Tom Berg

Tree swallows are a common sight from spring throughout the summer in many areas as they expertly flit and fly over ponds, lakes, marshes and fields.  These small, streamlined birds migrate back northward throughout the U.S. from their overwintering areas in Central America and Mexico to nest and feed here throughout the warm weather months.

Male tree swallows are a beautiful iridescent blue on their backs, shoulders and head with black wings and a bright white belly.  Females are not quite as bright, but the blue is still evident on them as well.  Juveniles are mostly brown on top.  Like most swallows, they have long pointed wings and a very short bill.  Tree swallows have a short, almost square tail – which helps distinguish them from another common swallow, the barn swallow, which has a deeply forked tail.

Tree swallows feed extensively on small flying insects they catch in their beaks in mid-flight.  Mosquitoes, flies, winged beetles, mayflies – they eat them all.  The acrobatic maneuvers of tree swallows are amazing to watch as they zip back and forth in pursuit of their next meal.  They are extremely common around lakes and wetlands where water-borne flying insects are plentiful.

As their name implies, tree swallows are closely associated with trees.  They prefer to nest in tree cavities, often in dead trees such as flooded standing timber in reservoirs, swamps and along the banks of creeks and rivers.  They also make use of artificial nest boxes when they are available, especially those meant for bluebirds.  Both species prefer nest cavities with exactly the same size hole.

These small swallows return to their nesting grounds earlier than any other swallows, so sometimes they must eat plant foods like buds, berries and seeds to help them survive if bugs are scarce during a cold spring.  After the breeding season, tree swallows head south in huge flocks.  Some migrating flocks have been observed with hundreds of thousands of birds in them.  It takes a lot of bugs to feed that many tree swallows!

Have you had a great out experience? Join Global Outdoors and write a review to tell everyone about it! We’re building the home for trusted reviews of outdoor experiences, outfitters, and guides.