Hello Adriano,
Thanks! That seems to have done the trick!
At first it didn't work at all, but then I deleted the filter from the birds view that I had given the argument birds_category to and created another one, this time leaving the default argument. Once I switched the argument in the filter, it worked fine.
It's not as fancy as the one in the example I was trying to follow earlier, but it certainly was MUCH easier and is quite effective.
The only problem is that if I choose a filter item, my menu highlight in the main menu goes off. Do you know of a way to work around that? Any ideas would be greatly appreciated!
Becky
http://featheredfriendsaz.com/birds/?wpvspecies=Macaw