New birds?

I don’t know if new birds have moved into my neighborhood or if the old birds change their tune as the summer progresses. It seems as though I would know what’s going on, but I’m hearing birds that I don’t recall hearing before. And I can’t get a view of them.

I’m hearing three “new” songs:

1. Jimmy, jimmy, jimmy.
2. Teacher, teacher, teacher.
3. Tweet, tweet, tweet.