Drywood termite detection (window, cleaning, basement, outside)

[cdelena]

The front entry of my home has a threshold window and I noticed a small hole on the inside sill last year during spring cleaning and sealed it. This year I found another hole a couple of inches from the first.

I see no termite tunnels from the earth outside or in the basement but am worried this might be a drywood infestation.

Would drilling into the sill be the way to investigate or is there a less destructive method?

Any experience of expertise you can share on this?

[QIS]

Drywood termites use holes to eject droppings. The droppings are actually made of wood! Look at the surface(s) below and around the holes; do you see any granular materials? They will look like sand only bigger, oblong and wood colored. If you put them in your palm and press on them, they will hold their shape and not smudge.