I spoke with an older well known mink trapper in my area. He did some bounty trapping for the Game and Fish several years ago to conduct a study of mink decreases in Arkansas, and insisted on being briefed on the findings as a condition. I disagree with the predatory birds. There is enough aquatic habitat and cover from above. It would be easier for the hawks, owls to catch squirrels and rabbits. The report, he said, pointed into the chemicals used by rice farmers, but much like a lot of water polution reports, money cleans the water up pretty well, unfortunately for all of us. I know of a certain film factory, that has cleaned up waste water flowing back into the white river. We used to catch lots of fish at the source of the flowage, you wont catch anything there now. But the water is supposed to be clean enough to drink, but only as the report comes back down hill from the top.

There is enough aquatic cover from above???
There is no cover above most muskrat houses.It is hard for there to be overhead covering,when it goes into the building of their houses.Go through a heavy cattail marsh--where are rat houses located?in open pockets,created by the rats when they build.
Also rats do not live long enough for chemical buildups to affect them.Granted some chemicals may kill them on contact,but their short life span ,keeps chemical buildups in the body from doing most of them in.
Birds of prey learn the waiting game well.It is now pretty common to see hawks sitting patiently above urban bird feeders.They do the exact same thing along rat marsh edges.
Tom Olson

I'll have to agree with bogmaster on this one. Predation from the air seems to be the biggest problem as far as I can see. Lost at least a half dozen rats to owls or birds this year. If a rat wasn't under the water seemed to be the biggest problem. Certain parts of my line haven't shown any real loss of numbers where others are decimated. Most of these are areas with lots of trees along the shoreline be it creek or ponds. Areas without the tree line seem to hold there numbers rather well. So seeing that the use of chemicals has allowed bird numbers to increase it would make sense the prey numbers would drop. I.E. Lynx and snowshoe hares.
Pollution could be a contributing factor not so much from killing the rat but by making the young weak or causing the mothers to abort. The same as the pesticides that make the egg shells weak for birds. Manure run-off has turned into a major problem in some water ways and I've seen some creeks where run off could be a problem.
Seeing their only a lowly muskrat not much will be done by most state agencies. Wolves and and other high profile animals yes but seeing this only affects such a small portion of the sporting community(Trappers). It won't get much for attention until to late.
Bill

I know for a fact the it is birds of prey. I have not gone a day the entire season without seeing an eagle along my best rat marsh. Hawks are in the trees boarding just looking out across. Just last week when running otter sets I found a large buck mink dead on the bank of the reservoir. Skinned him out and almost positive it is a talon mark right in the middle of his back. Not only have the rat numbers dropped in this area but so have the mink numbers I had only seen 3-4 sets of mink tracks through here the entire fall and then I find a dead one. This is in an area where last year it would be hard to go 3 days without finding fresh mink sign, we even spotted 2 mink out on the snow running the edge of the creek.

Well guys, yes birds of prey will take advantage of easy prey like a muskrat in a trap. However if you read again I wrote we lost our frogs and minnows then our mink then our pheasants now our rats. This tumor thing was going on for years then the spotted liver problem started and having helped a fur buyer skin rats the first week each season, I can say there were less and less kits. So they abort or die very young. I am so sorry to hear you fellows are loseing your rats but it's not birds of prey or over trapping or drought, because the rats would always bounce back. It's the bad water even though it looks clean.

The reduction of muskrat populations is not restricted to areas where chemical contaminents may be an issue.Overall raptor populations are much greater now than they were in the past. This is a fact supported by surveys done by folk interested in such things.Large owls (Barred & Great Horned)don't just "take advantage of easy prey like a muskrat caught in a trap".They are flat out killing machines when it comes to small mammals.I cannot see anything being done in the forseeable future to reduce raptor populations.

It was suggested that you contact the apropriate authorities concerning your suspicion concerning chemical polutants but you didn't want to get involved.
If you are so certain that polution of some sort is the real reason why this decline is occuring.Then I will say it again,you need to report it to the agency(s) that deal with such things.I am certain nothing will happen if no one says anything about it.

Henry,I must disagree with you.I trap in ares that are nowhere near chemicals.Many of these areas I have been trapping,hunting and observing for 33 years.
I have watched a change in our rats--as raptor populations exploded,rat movement shifted to almost entirely nocturnal.Not only that,rat movement ,even at night decreased.Now this change was not brought on by any chemicals,it was brought on by increased predation.Now I am not talking oportunistic birds,picking off a few rats in my traps.I am talking entire populations,changing in an effort to stay alive,and it isn't working.Raptor population increases--percentage wise are far out stripping our rats.
Two other factors to also look at:Our ever increasing coon population.I am from Minnesota,the northern half of our state,had very few coon in the 60s and 70s.They started showing up in the mid 80s.Their populations have also exploded.They are oportunistic feeders,and I believe they take quite a few young rats.I catch more and more coon every year at rat houses.And I am not taking those that ar right on shore.Coon are swimming great distances to these rat houses,why?Tender young rats.
The lack of young rats is also greatly influenced by water level spikes---flooding that takes place when the rats are young can wipe out every litter.With our increased amounts of black top and concrete,spring rains and snow melt cause flooding like we have never seen.small rats are poor swimmers.Water spikes--kill young rats.
So you have increased raptor predation,increased coon predation,increased flooding,and decreases in the number of wet lands.
These are the major factors in the decline of our muskrat populations---not chemicals.
Tom Olson

Bogmaster, you mentioned some good points and the raptor problem does exist. Judgeing from the replies it's a series of proplems for the muskrat. The information and replies from several different states speak of a decline. Whatever the reason or reasons, it's a sad time for the muskrat.
Most people wpold rather see a hawk or owl rather than a muskrat hole in their pond. I am afraid we are fighting a loseing battle fellows.

Henry, I have the same dwindling 'rat population here in Dauphin County, Pa.

This has been hashed and rehashed on various fourms. It probably is a combination of things. We do have a lot of hawks and owls and of course they do spray for gypsy moth and black flies not to mention whatever farmers are spraying with their crops. I guess you could even ask what chemicals are being put on the highways in winter. That stuff runs off into ditches and from there into streams and waterway. In the past 10 or so years we've also had a lot of dry summers. A lot of places that held water and where I trapped 'rats are bone dry for much of the year now.

Guess there were never any raptors back in the early 80's when the fur boom was on and everyone had traps out, didn't seem to bother the rat population much back then, I'm not a rat trapper, but I saw a plenty of em on the rivers and everyone that trapped for em brought in a lot. Not now a days for some strange reason. And a report is a report.