I trapped in 6 different swamps here in WI this winter till close. The one with the least amount of rats had those, shrimp. There were quite a few ducks tho. The one with the most rats was full of snails. (Unusual observations)

IMO one can judge the condition of the marsh by the condition of the rats, size and shape. Couple days after break up all bets are off
If I could figure out how they can loose that much weight that fast, I wouldn’t have to trap.

Might have to throw out some rat traps along this creek, less than 24 hours.

That is interesting. Nothing like making a new toilet station that is handy. What is that old saying about a port in a storm.