I have done ADC work for over 30 years but this one has me stumped:
It is in my own house. The family room has a sheet rocked cathedral ceiling. About 3 years ago this started, a clunking sound ( just 1 clunk) maybe once a week in a spot above my head at about 10:00 PM. As time went by it became more and more common, going to several times a week to almost every night. Now the sound can be heard several times a night starting at about 4 PM during daylight. When it first started I thought it was a bird (maybe owl) landing on the roof but it is not. I have went over the outside of the house many times there are no holes or openings. No mouse droppings in the rest of the house or attic. Always the same clunking sound, never a running or scampering sound. I put trail cams to cover all parts of the outside of the house, no pictures of anything. Rainy or snowy days there is rarely a sound. I am about ready to open the ceiling to get at it but that would be a major project. My firewood is outside near the chimney, I keep rat and mouse poisen out there year around, often finding dead deer mice on the lawn.
In the picture the sound comes from about 2 feet in from the roof line just above the window and 1 foot below the beam.
Any ideas what it is? It is not bats, bees, squirrels, coons or birds.

I've seen sometimes a branch or something hitting the house causing a odd sound. Even utility wires.

Another thing I've seen is a piece of vinyl siding or other type of siding expanding or contracting causing a noise.

Duct work?

Some noises can turn out to be mechanical in nature. I have encountered that several times in my work. Other times if it is late evening it may be flying squirrels / bats if it is an animal noise.

3 years? If it was Wildlife or pest related you would have figured it out by now. It's mechanical. Time of day, 4pm start, would probably coincide with temp. Your roof or siding is contracting as it cools. Rainy or snowy days, the roof is already cool, not cooling from the heat, so no contracting. Do you have solar panels in that spot on roof? Like Bob, I've seen some weird mechanical type issues.

When I was a kid, we had a similar thing going on. It turned out to be a loose set screw on the squirrel cage blower, where the motor would kick on, but it had slack before the shaft could turn the cage, causing the boom that traveled thru the duct work. Is the noise heard anywhere else in the house. another consideration is an "Oilcan" effect, where the duct work will flex in that spot, making the noise.

I've seen sometimes a branch or something hitting the house causing a odd sound. Even utility wires. Not this no trees or wires near here.
Duct work? Closest duct work is 6 feet from the spot of sound. No blowers in this section of ceiling. No solar panels.
I guess it may be a temperature related expansion but it seems odd as I hear it when it is 90 degrees and sunny then also when it is 10 degrees and cloudy. Only just lately has it occurred before dark.
Right now I hear it and it has been a steady temp of about 60 all day, just getting dark now.
BTW house was built in 1995, no noises until 3 years ago.

Eric

I agree on expansion. Probably a ring shanked nail popping in and out of the sheeting/rafters.

Eric