The tree swallows are back; actually some of the first males to arrive have been back for several weeks. Those adventurous males have the opportunity to claim the best territories and nesting sites – but they also risk being caught by a period of cold damp weather which they may not survive.
A few days after the males arrive, the females return from their wintering areas – the females that are gray on their backs and wings where the males are iridescent blue –
The birds pair up following high speed courtship flights –
The newly-formed pairs begin to explore cavities that might be suitable for the nest where they will raise their young. Sometimes those nest cavities are in dead trees, preferably close to water. The tree cavities usually are those that had been excavated by woodpeckers since tree swallows are unable to create their own cavities.
Occasionally the nest cavities are in wooden fenceposts –
But increasingly tree swallows nest in boxes that people have placed in suitable locations –
In mid to late summer all swallows, including tree swallows, gather in large flocks as they prepare to head south once again. Occasionally those flocks gather to bask on a sunny roof and soak up some rays.
More commonly we see them gathered on utility wires awaiting the moment to take flight –
But those flocks are months from forming, for now we can enjoy seeing the newly arrived tree swallows flying above fields, lakes, ponds and large streams in their eternal quest for insects.