Tree Swallow in May

May is the peak of the birding year. Migration floods the North, dawn chorus is at its loudest, and nesting is underway across most of the continent. By month's end the first broods of the year are hatching in mid-latitudes.

For the Tree Swallow specifically, May is a spring month inside the nesting season — one of the most active and demanding periods of this bird's year. Across the 60 states and provinces where tree swallows occur, what the bird is doing this month depends heavily on latitude — the details below break it down by band.

Southern states

absent

Mid-latitudes

year-round resident

Northern states & Canada

absent

In May, tree swallows are absent in the South, year-round resident across the mid-latitudes, and absent in the northern states and Canada. That north–south split is the defining feature of this month: where you live changes which version of this bird you're looking at.

May is inside the Tree Swallow nesting season — about a month earlier in the South and a month later in the North. Nest: nest box or tree cavity lined with feathers. Clutch 4–7 eggs, incubation 11–20 days, 1 per season.

In the South the season is already underway, while northern birds are still settling territories — a pair in Florida or Texas may be on eggs weeks before a pair in Minnesota or Ontario has even chosen a nest site. During the nesting months, adults switch to protein-rich foods for their young, become more secretive around the nest site, and often visit feeders in quick, purposeful trips rather than lingering.

Tree Swallow nest box dimensions and mounting →

• Flies, mayflies and dragonflies

Tree swallows readily take bluebird-style nest boxes; mount boxes in pairs 15–25 ft apart to share with bluebirds.

Adults feeding nestlings need easy calories. Some species that ignored feeders all winter now visit regularly, and you may see fledglings brought to feeders by their parents.

Full Tree Swallow diet guide → · Best feeder for tree swallows →

In May, the best watching is around food rather than the nest — adults make repeated foraging trips and are most visible at dawn and dusk. Give nesting birds space: if a bird is carrying food or scolding you persistently, you're close to a nest and should back off.

If you have a Tree Swallow box up, watch from a distance for comings and goings — steady traffic means an active nest — the box guide below has the exact hole size and mounting height this species needs.

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