I got both tree swallows and a colony of purple martins in my back yard along with some barn swallows in my barn.
 The tree swallows I have in my boxes are the male ismuch darker than the female and I know some or a few yrs old.  I dont know the life span so might be new ones taking over older ones boxes each year. :)
 I can take some pics when the rain is over if you need any for comparsion. :)

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