Mysterious scratching noise under bathroom floorboards

[Flipjango]

Hi all. Three nights ago we were kept awake all night by a scratching, scraping noise under the floorboards, just in the back corner of the bathroom by the outside wall, under the bath. The area is practically impossible to get to as the floorboards lay in the same direction as the bath so we can't lift any of them to look underneath. We've recently had a new bath installed and there is no side on the bath, and there are several holes cut into floorboards in the area, and we can't see anything at all in the open holes. I searched the whole house and couldn't find a single sign of an infestation (living in old houses in London, I've had a lot of mice over the years so I know what the signs are) - no droppings anywhere, no food nibbled. I even left a loaf of bread out on the counter deliberately to see if I could see anything, but nothing going on. The next day, we went outside, filled every tiny hole in the wall we could find with cement (and there really weren't any), put down rat poison in a few places including any routes that may get to the area, and have put down rat traps baited with peanut butter under the bath. Everything went quiet for two night, though none of the poison was taken and the traps haven't been touched. Then this morning, the noise is back again. The same scratching sound in exactly the same area. Again, no droppings, no food nibbled, and we're doing loads of renovation work so there is quite a lot of dust and debris around the floors, and not a single sign of a footprint or swishing tail. I've lifted a few floorboards up elsewhere in the bathroom and hall, but nothing there either. I'm presuming this is a rat or squirrel (possibly a bird? but the noise is more like a rat knawing, than wings flapping) but have no idea what to do about it. If its stuck and we don't do anything about it I'm guessing it will eventually knaw through the joist that is trapping it and get into the rest of the house, but it seems like the option we are left with to get to it is to cut out a section of floorboard that may destabilise the bath weight. Any ideas? Should I call in the (very expensive) professionals?

 

[Flipjango]

I should add, we could cut a small hole in the floorboard to get to whatever it is, but if its a live Rat/Squirrel, what do we then do to get it out without risking being bitten? One other option we have thought about is sprinkling rat poison between the floorboards, then cutting open the floorboard when it dies to get the body. Other than that I'm at a loss, so any ideas very welcome!

 

[foxhole]

Do you have a cat? seen it lately?
New timbers installed ? , may be wood boring beetle.

 

[Flipjango]

Nope and nope. No pets at all in the house. No new timbers. House is about 80 years old. No damp or anything. But this noise seems way too big for that anyway. It sounds like something with teeth/nails trying very hard to get out.

 

[ladylola]

If you drill a hole it will scare away whatever is making the noise so no worry about been biten.
It's quite probably a mouse and could have gotten in where the bathroom pipes go through the wall, it really is surprising how they can climb and squeeze through tiny holes or gaps.
I'd go with your idea of pouring poison between the boards but wouldn't worry about taking them up afterwards. A dead mouse will soon desicate and won't smell.

 

[Flipjango]

Just spoke to the Rentokil guy who thinks it might be a squirrel. He said if it was a rat or mouse we would see signs of it around the house, and probably smell it too. But he also said a squirrel needs a hole the size of a tennis ball to get in, so I have no idea where it is coming and going from. Guess cutting up the floorboards is the next step.

 

[longdogs]

If you think it's a squirrel why not cut a hole in the floorboard (if possible) and leave a humane trap with some nuts inside