[EBB Sightings] grosbeaks

Dear Birders:

In anticipation of a Rose-breasted Grosbeak visiting my feeder again this 
summer, I've been reading up on grosbeaks.  My interest in the family has 
been heightened also by a possible field trip in August with the Central 
Sierra Audubon group to the Pinecrest area (Sonora Pass road) where Evening 
Grosbeaks are often seen.

But now I discover that they aren't members of the same family after all --  
our Black-headed Grosbeak and the Rose-breasted Grosbeak are listed as 
members of the cardinal family while the Evening Grosbeak resides in the 
finch family.  What determines these family assignments in what I assume was 
the pre-DNA era?

Phila Rogers