Yes, but with limits. Finding exact or near-duplicate images is much easier for software than understanding image content at a human level.

What you describe—recognizing that different photos all contain parrots despite changes in color, pose, or background—is difficult. Computers are generally much better at matching images that are the same or very close variations of the same photo.

From the answers given:

• VisiPics can find duplicate or loosely similar images, and lets you adjust how strict the matching is.
• LibPuzzle is an option if you’re comfortable with programming.
• Imense was mentioned as software that works with Adobe Bridge.
• Picasa had an experimental duplicate-finding feature, but it was aimed more at duplicates than true “similar subject” searching.

So the short answer is: software exists for duplicate and near-duplicate detection, but true subject-based similarity search (like “find all parrots”) is much harder and may not work the way you expect.