I was thinking along those same lines but thought why limit it to just state, why not put all the whabird search criteria in the menu. Look at this for example
http://www.whatbird.com/wingedtoolbar/rev2.jpg
You can see the family attribute is selected and its waiting for a family to be selected. What happens next has several possibilities.
1. Narrow the drop down list so it shows just those birds selected with the attribute-value menu. Then you can select any bird in the list and it would open that species account page for you like now. (Note I show the attribute:value in the combo box so its clear what has been selected even when that menu is closed.
2. Open the search page on whatbird,com with the birds that resulted from the attribute-value selection (for example all the birds in California).
For this to be realistically useful it would be limited to just ONE attribute-value ssearch election. To add yet another choice would make the entire interface much more complicated. Not that it cant be done or that its a bad idea. Its just a much larger and more complex job.