European Sawfly
Neodiprion sertifer
Notes:

One year the bluebirds did not nest in the yard. The sawflies look back on that as a good year. They covered almost every branch of the red pine.

Normally though, they don't do much damage. I suspect the bluebirds and phoebes have something to do with that.

Photos:
I think the environment should be put in the category of our national security. Defense of our resources is just as important as defense abroad. Otherwise what is there to defend?
Robert Redford
Yosemite National Park dedication, 1985