Is it a 20th century invention and nature name? I wondered. I mean, it does seem like that now, but I think it's more clearly a surname-name-turned-firstname. I get zero nature image from
Brooke.
It has been "regularly if infrequently" used since the 1920s at least, according to my favorite name dictionary. When I googled I found
Roberta Brooke Astor, who went by
Brooke and was born 1902 (although she wasn't famous until much later).
I'm challenging all who read this post to find earlier Brookes or
Brooks!