Bluebirds! Season 6. Episode 1. Murder in Box 10.

Tree Swallow, Charles River Peninsula, Needham, MA

The tree swallows are back. A dozen or so. They are so early that eBird flagged them as rarities. Not this year. In some places tree swallows have been back for a week already. Also flagged as rarities: three singing fox sparrows, a species that usually doesn't show up until April.

Tree Swallow, Box 7, Charles River Peninsula, Needham, MA

The tree swallows are already checking out nest boxes

House Sparrows, Box 7, Charles River Peninsula, Needham, MA

which has brought them into direct conflict with house sparrows.

Tree swallow and house sparrows, Box 7, Charles River Peninsula, Needham, MA

Not shown above is the pair of brown-headed cowbirds that landed briefly on the same box before flying off to plan mischief at box 9. I'm not sure what I would do if a cowbird laid an egg in a house sparrow nest. I suppose I would have to let the egg stay and force the sparrows to raise it. Box 16 (not shown) is again the object of direct conflict between sparrows and bluebirds.

Box 10, Charles River Peninsula, Needham, MA

I moaned when I got to Box 10. Little gray feathers filled the cracks of the box, fluttering in the breeze. Not a good sign. And indeed, when I opened the box a little bird body tumbled out--a black-capped chickadee. It had died violently. Who did it? Who can tell? It may have been a rival chickadee for all I know.

American Kestrel (left) and Blue Jay (right), Charles River Peninsula, Needham, MA

Today's special guest was an American kestrel. They usually show up around Easter each spring, raising the possibility that they might stick around and breed. Not this time. Unseen in the photo above are two dozen more blue jays that took turns dive-bombing the tiny falcon until they finally drove it off.