Can anyone suggest which model would be the best to detect wildlife.  Specifically:

• Can focus motion detection on a specific area (activity zones)
• Will detect smaller creatures (ducks in my use case)
• Ideally battery powered

I live on a lake and have a woodduck box a bit off shore and I want to capture video when there is activity near or on the box.  Most motion detection cameras look for motion anywhere in the field of view and waves and other activity on the lake have them triggering all of the time.