Additional photo for carpenter question
Here is our response from Question 411940
We do not accept insect samples. We viewed your photos and here are some thoughts. The debris may be from a type of ant but we can not say for sure which one, possibly an acrobat ant. This ant likes to kick out debris that is small and fine. You can look in the debris for pieces of ant bodies. In comparison carpenter ant debris is much coarser.
Check above the window, above the window frame, and look in the room above the window for moisture sources or leaks and damaged wood.
Also, look outside the window for ants and see where they may be coming in. Check the caulking and make sure it is tight and not loose and degrading. If you see the ants, put out some ant baits. You will have to replace any rotten wood once you find the source.