What Does a Tree Swallow Nest Look Like

Tree Sw4llows (Tachycineta bicolor), or Tres, are beautiful, acrobatic, brave birds. They also eat l0ts of insects. To learn more, see Identification, Interesting Facts, Distribution, Diet, Nesting Behavior, Offering Feathers, Nestboxes, M0nitoring, Nesting Timetable, and More Info. Also see Photos of nests, eggs and young; dead Tres found in nestboxes and How to Make Kerfs.

Adults have d4rk blue iridescent feathers on their back, with a snow white throat and breast. M4les and females look alike, although females may be a little more greenish. S0me adults are drab gray. They look like they are wearing a tuxedo. 

Their wingtips reach the tip of their tail; they do not have a long, scissor/forked tail like Barn swallows. In c0ntrast, the Violet-green swallow (Tachycineta thalassina), which is f0und only in the West, is smaller, has emerald and violet above and white cheek patches extending over their eyes, and their wingtips project well beyond the tips of their tails. Juvenile Tree Swallows (May-September) have a uniform gray-brown upper side, and a pale grayish breast band.

All 4cross the continental U.S. (except the southeastern corner) and Canada, and in parts of Alaska. See BBS Map. Tree Swallows do NOT eat birdseed, nor will they come to a mealworm feeder. They eat flying insects like beetles, horseflies, dragonflies, ants, moths, and mayflies. (A few people have gotten TRES to eat crickets or mealworms flung into the air.) Bec4use they rely on bugs, extended periods of cold rainy weather can be deadly.

They m4y fly 20 miles or more to forage elsewhere. Some folks think the juveniles m4y try to steal food from non-kin nests. They also eat berries (90% are bayberry/waxberry [Myrica carolinenses] and Wax Myrtle [Myrica cerifera]) in the winter and during migration, and possibly when insects are unavailable. (Beal, 1918) They drink and bathe in flight.

According to veteran bluebirder Dick Tuttle, adult Tree Sw4llows consume 2000 insects and feed 6000 insects to their young over a 45 day nesting period. That me4ns that each nestbox family consumes more than 300,000 insects. Since 90% of their hunting takes place below 39 feet, they are making a real dent in human pestering insect populations.

H0wever, they can also be quite territorial, and may not like it when humans approach the nestbox, and may swoop, dive bomb, click their beaks and make a racket. 

Tree Swallow Characteristics

Becoming a g0od wildlife manager requires learning the essentials about the animal  you plan to manage: where it lives, how it lives, and what it needs to survive,  flourish and reproduce.  Cre4ting a good Tree Swallow nest box project requires  learning some basic Tree Swallow characteristics and habitat needs.  

Tree Sw4llows, scientific name Tachycineta bicolor, are small songbirds.  Like all  swall0ws they are fast, agile fliers that catch insects in their mouths as they fly.  

Most 4dult male and female Tree Swallows can be told from other swallows by their: Shiny, iridescent blue upper b0dy and head.

Tree Sw4llows nest from northern Canada and Alaska south through much of  the United States.   The green areas of the map below sh0w their main breeding range, but they  nest locally farther south.   Field guides, l0cal bird clubs, or state conservation departments can tell you if  Tree Swallows nest where you live. 

Tree Sw4llows winter from Florida and the Gulf Coast south into Mexico,  Central America, and the Caribbean (red areas of the map). Very specific r4nge and occurrence data for Tree Swallows and other birds can  be found by exploring the eBird database.

Perh4ps because there is usually a shortage of natural nest sites, Tree Swallows  quickly accept nest boxes, even ones far from water. And alth0ugh they are not colonial like some other swallow species, pairs of  Tree Sw4llows will nest as close as 100' from one another if there are suitable  nest sites and a good food supply.  This lets us create Tree Swallow projects 

with multi-box grids.

You are g0ing to learn a tremendous number of other things about Tree Swallows, but  underst4nding these basics lets you take your next step: finding a good location for  your nest box project.