Some catkins of alder (Alnus
sp.) in the BWCAW were deformed; inspection of this one revealed an exit hole and a tunnel bored through the center of the catkin along most of its length. I'd guess that the borer is responsible for the crooked shape of the catkin, but I can't be sure.
I wonder if this could be the bronze alder moth
, Argyresthia goedartella
. The Info page for that species says: "overwinters as a larva in a shoot or male catkin; inhabited catkins are distorted and frass is ejected through a hole in the side." However, that species supposedly overwinters in the catkins, and whatever made this sign appears to have already left the catkin. (Perhaps it was eaten or parasitized?)