These are all off the cuff ideas that I haven’t looked into, but I think are promising.
I would try to see if you can recover exif data from the images first. Camera manufacturer is pretty standard (e.g., iphone, android, Nikon, etc), and will allow you immediately filter out a huge percentage of the possible observations.
Next I would do a bit of GIS work and look for observations that occur near a road. This won’t help you for obscured observations, but by virtue of being a doorbell camera, it should be near a house, and therefore a road. Openstreetmap is where I would look first for road vectors.
You can also filter by taxa of course. Looking at your project, it is largely mammals and birds. That will narrow the total pool down quite a bit as well. No need to look at plants or marine life.
You can use cheap LLMs to surface observations that have notes which seem promising, instead of simple word matches. If you hate LLMs, you can take an embedding approach and calculate similarity then manually review. Simply filtering out blank notes would remove most anyway.
Another LLM approach is to pass the image to another small and cheap vision enabled model and ask if it looks like it was taken by doorbell camera or trail camera, since the two appear quite similar. I think you would be surprised how effective these image classifiers can be.
I would use all of these ideas to just reduce the total number of observations to review, because eventually you will want to verify them.
All of these ideas are well within the capabilities of frontier AI right now to help you setup the tooling to make this possible. As for the actual grunt work of classifying everything, local models that can run on well spec’d laptops are sufficient, and you can do it with your own machine. Just pay power!
Hope there’s something useful here for you.