|Tufted Titmouse on Seed Cylinder Feeder|
Titmice as the plural is the most accepted use even though is not etymologically consistent. I went to Cornell Lab of Ornithology’s Tufted Titmouse webpage at http://www.allaboutbirds.org/guide/Tufted_Titmouse/id and they use titmice repeatedly.
I would use titmice but I can’t see that using titmouses would be wrong. Any bird or word experts want to chime in and make a comment?