Hi Richard. I'm glad to hear that you're making sales with your birds. Wildlife is not the easiest subject matter to license!!
I had a fresh look at Measures for the past year. I agree, 'foliage' is borderline.
Bird Singing: 10 searches - 1 sales, so I wouldn't exclude it.
Bird Feeding: 16 searches - no sale reported, so I wouldn't exclude it either.
Passerines: 1 search - 0 sales. I used to include it, but don't bother anymore.
I would disagree with you about location. If you ask anyone for help with an ID, the person will get very upset if you haven't mentioned location. It could be a regional search, like 'Birds of Queensland', 'British Bird'. You're right, the city is over the top.
Having said all that, I was flummoxed in the past to see a repeated search for a single keyword 'Wildlife'. Strange I thought, they don't know what they want?? Until I licensed a turtle that had been searched using this exact term. It turned out that the Guardian has a weekly photo gallery 'Wildlife'. They're not fussed about what animal/country, provided the image is eye catching. So much for our efforts!!
Nice talking to a fellow bird photographer.