So far this fall my short water line has only been Fair. Mostly d u e to some of my private land spots h a d dried up. We had been in a summer to early fall drought and eliminated some of my private land trapping areas thus my rat numbers were down a little. Three of my usual stops are on a small Creek called iron Creek. It is a slow moving very Mucky bottom Creek that runs through Farm country. It has plenty of vegetation including Cattails and wild rice some boggy areas and normally is good for 30 to 50 rats and always some mink. With a lot of the little puddle tributaries that drain into it drying up I thought there should be even more rats in the main Creek this year and should be as good if not better trapping then usual. My three stops on this Creek are about a mile apart and this year I could not catch even one muskrat or mink off of this Crick. There was not any fresh sign but normally I don't look for it because the rats are always there y e a r in and y e a r out. I have trapped this c r i c k since the 1970s off and on the past 10 years consecutively. My sets are usually bottom Edge and blind Culvert sets at Road intersections and if there is any fur movement at all I will have catches. I am no biologist but I would think even some sort of disease wouldn't have completely killed every rat on the creek. It has just come to my attention that the Wisconsin DNR water Department has been poisoning invasive cattails on some of the areas located partly on some of the headwaters of this Creek that was done this spring. I don't know if this could be a Cause or not just looking for any input anybody might have about this issue. I have been trapping muskrats for many decades and this is certainly a puzzling mystery to me.

I've seen very good fishing ponds killed off by spraying cattails. Just because people are educated doesn't mean they're smart.

Hmmmm poison

I have trapped 4-7 miles of a wadable river since the late 1980s. This river is in red clay soils, reed canary grass borders, typically rock and hard bottomed in about 80% of the area I trap. Over those 30 plus years I average about 20 rats per mile of stream with 12 on the lower end and 30 on the upper. I had a period from about 2000-2010 when the rats were on the low end every year.
This year as you experienced most of my sloughs and small marshes dried up and the feeders were so shallow that I felt the rats would have migrated to the river. (Those who survive the trip over land.) Well I found the rat population to be the lowest I have ever seen. I trapped about 1/3rd the stream I normally trap and caught less then 20 rats and they were smaller, thinner skinned with less fat than normatl. I guess not a bad time to experience low numbers but still it shows when we have low water we have low rats. I had one area that had about the same number of rats as normal.

Bryce

I wonder if you got spanked?

Clarify please I am ignorant

Bryce all other areas I trapped this fall some were even very marginal conditions but still had water had trappable populations of rats it was only on this specific Crick there did not seem to be any rats at all.

I would guess the food source is no longer there or a better food source has been found elsewhere.

Real good food source again this year just like every year with cattails swamp grass and wild rice and still plenty of water in this Creek on the part that I trap.

I don't know the area you trap but I have been to several areas in WI that were drier then normal but almost every place had more water then we did here. We have been drier than normal since late September of 2021.
I noticed that trapping through the ice this last winter that the water level was falling below the ice that formed. It just got worse from there.
As I have stated in other posts all the marsh area where I trap the cattails were all brown. I don't know the life cycle of our native cattails so I don't know why there were no green cattails at all. Don't know if the cattails don't have active good roots when they are all brown and thus less rat food.
Bryce

No mink along with the lack of rats usually leans towards otter showing up. They can clean a creek system of both in a hurry.

I had a stretch of creek here that yielded a dozen or so mink and quite a few rats a few years ago. The next year, one mink and hardly a rat. That's when I started catching otter. They are expanding and when they do, everything else gets gobbled up...especially in a stream setting. Set for otter if you can there.

The middle stop on this Creek had the usual otter sign which is their year after year and is nothing out of the unusual I have caught otters at this stop before

Could very well be the otter, as they are voracious on about anything in the ecosystem.. an otter won’t hesitate to feast on a mink either. Do you also have more hawks and owls than usual ? Can’t rule out disease either. Muskrats have been disappearing in alot of places,,, most dnr departments have done studies,,, but can’t seem to find anything conclusive

We had our highest rat populations 2-3 years ago after 4 wet years since the late 1970s and earlly 80s. Predation with species like rats is only a real issue when they reach a critical mass number due to habitat losses in my opinion. Preditor numbers are high when prey numbers are high and they follow that trend it is just that the predators are a season or two behind so that is why we can see these huge spikes in prey numbers before the predators rebound from the down years.
I thnk most of us are totally unaware of how significant movements in rat populations we can have from season to season within the year. If one has access to very large marshes say 2-10k in acres one can see where rats will have moved in mass. In a big marsh they can move and be in water the whole while, Dried up sloughs, shallow feeders, dried up ditches those rats have a lot of exposure.

Bryce

Thanks for everybody's input. One thing I would like to clarify is that I did not intend to do any DNR bashing. The headwaters of this Creek are not the only place the DNR has done Cattail spraying this summer in our area. Just trying to get some definitive answers. So the mystery will continue. Thanks for everybody's help.

Likely to be the poison like you said. We had the worlds greatest numbers of muskrat along with likely the highest population of otters for years, our muskrats only went away after we started killing beaver year round and the nutria came.

Byrce's comment describes me: I thnk most of us are totally unaware of how significant movements in rat populations we can have from season to season within the year.

Its fairly intuitive to me when it comes to year-over-year but within the year, including this year- I trapped a lot of old sign where there was definitely a migration that occurred within the year but I was about 2 campfires behind them.

I have been trapping these rascals for a very long time and I am continuing to learn more about them. I am not a college educated biologist but have trained a few of them about trapping them. When I was a State Conservation Officer, in my training class of 25, only 2 others had ever trapped. Most of these people had a college education pertaining to wildlife and biology.

One thing that I did learn from the books was that muskrats can have 3 litters per year, and the first litter can have a littler that same year. When I lived in the Big Marsh area of Lake Erie, I saw firsthand the 3 litters per years. I also observed that low water, high water, or lack of food in any particular area can/will interrupt this breeding cycle. They may no longer breed more than once a year and cycle may move from April and May to June or even July.

Another thing that low water causes is when the rats move because of low water, they accumulate in smaller areas, that can realistically hold 20 rats and 40 end up there. This is when mother nature steps in and disease pops up from nowhere and wipes out 99% of the population. When the rats accumulate in a particular area, so do the predators. Raptors, owls, eagles from the air, mink, otters, and raccoon from the ground. Another predator that kills young muskrats are geese. I have seen on several occasions, geese chasing after very small swimming muskrats, catching them and killing them. On one occasion, the goose then ate the young rat.

I am not saying, that the above is what has or is happening, only that these are my personal observations over the many years I have trapped and observed muskrats and their habit and the reactions to their environment, and what different conditions can and do cause.

Garry-

Thanks g a r r y. One other predator that I have come across in the Mississippi back Waters area that I have just started trapping recently are northern pike. 2 years ago in late summer some of the nicer northern pike that I was bringing home and cleaning had muskrats in their stomach about the size of a chipmunk but definitely muskrats. It must have been like the third litter and were being eaten by the Northerns.