Grouse are hetero

And the males are handsome in their dark plumage. But don’t make the mistake of Googling ‘black cock’ to check that fact. 

Careful, Mutters.  GLAAD says of the term "homosexual":

Homosexual
(see Terms to Avoid) Outdated clinical term considered derogatory and offensive. The Associated Press, The New York Times, and The Washington Post restrict usage of the term.

As a result, heterosexual must also be problematic, whether in long form or abbreviated, and whether applied to humans or birds.

Maybe ask Warren for further guidance.