Can anyone give me some good sets to catch flying squirrels? I believe I have the converted barn sealed up pretty good now. The apartment is built on the second floor and is literally an apartment built inside the second floor hay loft. Any help is appreciated.

Location, location, location

I once had a job where they were running the soffit. I squeezed in there and set traps next to the knee wall. For a week nothing. Squeezed back in and moved the traps to the other side of the 2x4 into the actual soffit and cleaned them out in a week. Three and a half inches was the only difference.

Toilets, blind corners on their runs, entry point. The places you know they will be.

I seal all the entries I find except one. I then set a colony trap over that one. Inside, I set rat size snap traps baited with peanut butter and sunflower seeds. It does not take much of a crack for them to get through.

X2 on seal up. That job I mentioned the client opted not to seal, after my third round of trapping in two years I put it to them seal up don't call. They sealed.

Seal up. Colony trap over primary, sometimes two. If trap fills up, you know you found all the entries. If not, keep looking.
Exceptions are a building with so much damage, or a porous barn that is impossible to seal. Rat snaps are last resort. I never single catch cage trap.

I think I have it sealed up, but there's no way of knowing for sure. I had a one way funnel set up on where I thought they were going in and out, but that obviously wasn't the only hole. Went back through and went over barns exterior again and found another entry point. Sealed it up and saturated the attic with baited snap traps.

Don't overlook ground level openings. Doesn't happen often but I've had them use the sill on old homes at least 4x.

I've used two complete rolls of 36"X36' galvanized hardware cloth covering this barn, inside and out. Owner installed trail camera in the hopes of seeing where they might be getting in and out, but still have not caught them on camera. My last resort is to put poison in the attic. Has anyone had any success using it on flying squirrels? The owner has poison bait stations on the ground and in the car port, for rats or mice. Have had the flip and slide mouse traps out for a couple weeks and haven't caught anything in a week or so. First two day caught twelve mice in them.

You may want to show up as the sun starts to set. Set up a chair outside away from the structure and have a good set of binoculars. Watch for them to emerge and glide out as it gets darker. This will tell you for sure where their hole is. A bit time consuming,but sounds like you're at that point.

Good luck

I don't know of any rodenticides labeled for flying squirrels. They may exist, but I haven't seen it on any labels.

Is there a chimney? I've had multiple houses where flyers were getting into chimney and through a gap somewhere out of sight. If so, cap it.

You need to find the likely entries and access points as they get into places that can be extremely difficult to find at times. I have had my share of challenges over the years. I always got them figured out.

Sometimes you need to be very critical of what you think they can get thru with regards to the configuration of a hole size. The angle you look at a potential hole of entry can make all the difference in making that determination.

The ends of roof ridge caps are very suspicious on all flyer jobs for me. I have seen far too many poor installations by roofing companies over the years.

Also, it seems to be a more common easy chew in point for those little buggers. These now near standard cobra venting ridge installations are notorious for bat and squirrel entries. From my experience.

Check all along the running sides of the ridge cap for any irregularities or gaps that have developed from the nails pulling away from the roof ridge cap edges.

I've sat and waited for them to emerge, with no luck. The apartment is literally a house built inside the hay loft of the barn. The 2X6 (roof and ceiling) rafters were not sealed up very well and that was the first place I looked for entry points. The metal roof has nailer's on top of the rafters that the roof is screwed to. I have sealed between each nailer and the roof line. Going back again to go over everything and try to find any possible hole I missed before. This will also be the third time I have to open the rafters I sealed with hardware cloth to destroy the nest.

Take some pictures so we know what kind of mess you're dealing with. Sometimes fresh eyes can help.

I often used one or two trail cameras in attics when I was having problems finding an entrance. Sometimes I found other critters too. The cameras have taken pictures of flying squirrels, gray squirrels. mice, roof rats, opossums,and one time a chipmunk.

I still remember quite clearly the first time I saw a chipmunk climbing a large brick chimney when I was doing a walk around bat inspection on a large home. It entered and disappeared at the meeting of the chimney and the soffit jointure.

I wouldn't have believed it or pondered the possibility before I saw one that day disproving my previous ground dweller only theory.

The old guy that first trained me told me my first day that no matter how much I think I know, that animals will keep proving me wrong by doing unexpected things. He was wrong about a lot of things, but that one he was right on, lol.