I've noticed a very reduced population here as well. Years ago the few marshes we have around were dotted with huts. They are few and far between now. The waterways here have good habitat thanks to farm programs that have reintroduced wetlands and grass strips along creek channels. But the muskrat population still does not bounce back. The same creeks I trapped as a boy only produce a few rats each year. My kids think I'm crazy when I tell them the numbers I used to catch back then. I have thought for years that it was from chemicals in the water. I wish there was a study done on the subject.

Just a closeing note. I did report the sick muskrats to our game protector and told him my experances and thoughts in reguards to the water.
He agreed but told me "to go against big companys or developers because of a few muskrats, I just may get my head chopped off." It's money first and enviorment second.

HI,was reading old news and todays I'm an old time trapper and have to agree with you about the rats being less than 30 years ago. Theory I have heard is the herbicieds, phorous, and pesticides farmers use now cause rats to be steril, thus very few mice or mediums. This
wasn't the case back then as you could count on 10% mice or mediums from your catch.
This year i caught 2 small rats out of 60, does this prove that rats aren't reproducing?

Also reading old news, I ran across snares for rats.
This is very interesting as I read pros and cons
snares will rust from the inside out?
Will muskrat oil applied in a soak work?
They have oil sacks just like beaver when you skin them save the oil sacks (along with the carcass for food or bait).
Freeze them for later when you clean snares soak them in the oil sacks , I know it takes
alot but you will be surprized how fast they add up.
Here in Ohio we sell the carcasses to whom ever wants them (helps with gas money ).
Just my thoughts.

Here in eastern WI from my experience over the 15 years I trapped rats quite extensively I would say our population is about 1/3 of what it was in the early 90s and that is with less trapping pressure. I have joined in many posts on several forums as to reasons why. I will just state that they are many and varied and probably all have some validity.

Bryce

I have noticed up here in Maine we are loosing vegitation. Our cat tails are being replaced by some purple flowers. The rats seem to be dieing off as fast as the cat tails. we havent noticed a surge in Mink eather. Though the population of Bald eagles has risen along with other birds.
( owles, hawks, crows and ravens.)

What ever the reason is I don't know but we have a fraction of the numbers we used to have.

Down here you can't hardly find s muskrat any more. The nutria has crowded them out. Perfect example why not to introduce a non-native species into the wild.

I haven't seen much rat sign at all in certain areas that used to really produce. Did good on mink this year though. It dosen't make sense to me if the rats aren't there why would there be so many mink ?

While there are many circumstances that indeed lower our rat populations----other than loss of habitat,Raptors are where I point my finger.While hawks and eagles take some daytime rats.It is the devil of the night---The Great Horned Owl that I lay the majority of the blame on.
Tom Olson

I think you're right about the owls, in fact I think it's much more than that though. Between the owls, mink, hawks, and any other predators that kill muskrats, that, with good habitat becoming less and less,soon we're not going to have any.