It seems to me that High Pass sharpening with birds works a lot quicker and more accurate when you simply use a mask and paint in the parts you want sharpened. Or better yet, make a selection of the bird first, turn that into a mask and work from there. Using the eraser tool doesn't seem effective for birds, where you often want the whole background soft and OOF to make the bird stand out. Erasing the HP filter would then mean that you have to painstakingly remove all the sharpening around the bird with all its feathers etc. Not very effective I would think. Unless I'm missing something.
Personally I use layers and masks and sharpen with Smart Sharpen. It's quick, accurate and gives excellent results. You have all the control you would want, it's reversible, you can modify the mask etc.