There are variety of birds that have the word tit in their name. Such as, but not limited to, bush tits and oak tit mice. In old English tit meant small bird. So bush tit would be bush small bird. Oak tit mouse would be oak small bird mouse.

When I was doing nest box monitoring we ran into multiple mama birds who refused to leave the nest. One time, when the lead lady went to check an oak tit mouse nest we hear hissing. The oak tit mouse mama was hissing. Oak tit mice can hiss apparently