Is there a consensus on whether or not Mice climb downspouts to gain access to a roof? Do you think they can climb a gas fireplace galvanized pipe? Trying to determine if the noise inside a gas fireplace pipe and a mouse in the house are connected. I’m leaning that the noise in the pipe was a bat and that the mouse is unrelated. What do you guys think?

I doubt that they can climb a galvanized pipe, but have heard of other remarkable feats such as them climbing vinyl siding that I have a hard time believing. Supposedly there's a video of them climbing the siding.

We do have a video of them running around on a roof.

So as to not fall victim to hearsay:
1. I’ve personally watched a mouse zigzagging in all directions on a smooth concrete wall.
2. I was shown a video of a mouse triggering a WiFi doorbell when its tail swung through the view of the motion sensor as it sat on top of the doorbell. The doorbell was mounted on a wall with brick siding.
Neither of these will be surprising to most here, but it is confirmation of their abilities on two surface types. In both of the above cases, the material was porous enough for a mouse to easily grab and walk vertically. The smooth concrete wall really surprised me because it felt smooth to the touch.

I’m highly confident that a mouse could not climb the outside face of a downspout. I’ve looked at the tapering gap between vinyl siding and a downspout and have wondered if a mouse could navigate it. My conclusion has always been ‘no,’ and I’ve never had to go back and exclude a downspout because mice keep getting in after all other exclusion work was completed. In other words, I have plenty of customers who are mouse-free and I did not exclude their downspouts. This isn’t proof, but it is a large sample size that would seem to deny that mice scale the siding/downspout gaps.

Everything was quiet last night. So either the mouse came out the vent in the gas fireplace (and was killed by the client) which means it got on the roof and up the stovepipe and down into the air intake. Or, it was something else that died in there and the mouse is unrelated. I took the cap off and looked down the pipe, but there is an elbow so I couldn’t see the bottom. A bit of a mystery but a screen on the pipe will solve it either way.

Mice can make entry and climb some things that if you didnt see it yourself you probably wouldnt have thought they could do it.

They can use their backs to press against an area to help support their footing while climbing as you can in some situations.. I do believe they can climb the interior of a drain spout along the seam to the gutter which gives them access to the roof and eventual access to the attic which you know the rest of the story after that happens. Many gutters are lined to a degree with debris sticks, leaves, seeds etc. which further helps to assist their ability to climb obviously.

I have seen mice on power lines overhead near a structure which leaves me to believe they came up a power pole which are easily navigated due to their rough surface or entered the line to cross from the house to another building.

Bob, I’m intrigued to hear more about how you arrived at this conclusion. Is based on some direct observations? On indirect observations that were stitched together? On mice continuing to get into a building until the downspout bottoms were excluded?

I’d love to know more!

I would not put anything past a mouse! JMO

I have spent many years on ladders and have observed many mice running the roof lines, in gutters, run down into corner gutter drops once startled by my presence not to return while I was working there. I have seen them run in and out of dormer corners that were being treated for squirrels or bats. I assumed thru these observations that they have found some way to navigate the drops in some cases. I have also seen black rat snakes doing the same thing over the years.

Thanks for the thoughts. On a related note: will 1/2” x 1/2” GAW wire mesh reliably exclude mice?

We never trusted 1/2" for mice, or bats. Go with 1/4". Call backs suck.

That’s kind of what I thought. Might keep our most but not all. I buried this stuff in sand and then covered in washed rock. I wasn’t sure 1/4” would hold up long term in this application. I guess I’ll find out.

1/4 inch vinyl coated wire will last many years under ground and at ground level.

I've watched chipmunks, red and grey squirrels climb up the inside of downspouts. Don't doubt that mice could, just haven't caught 'em at it yet.

If a rodent's skull can fit through an opening, the rest of it can too.