1. The ability to filter birds by size.
In the Attributes section of the search engine, in the Basics attribute group, you can select one or more of the following: 3-5 inches, 5-9 inches, 9-16 inches, 16-32 inches, 32-72 inches. The ability to select more than one size is key if you weren't able to measure the bird with a ruler.
2. A gallery that displays thumbnails of birds that fit criteria entered. This would allow quick comparison and identification.
In the Matches section of the search engine, at the bottom of the section there is a radio button where you can select either Text of Icons. Selecting Icons gives you the thumbnails you want. You can't show icons if you are entering part of the bird name, i.e. if you are doing a text search, but it works fine if you are using attributes to narrow it down.
"A bird does not sing because it has an answer. It sings because it has a song."
--Chinese Proverb