What creature is living in my window frame?

[Singsongbird]

I can hear a tap, tap, tap noise followed by a muffled buzz repeatedly from my bedroom window frame during the day. Any ideas what it could be? Its not dying as I hear it often so must be happily living there. Would a termite be that loud? I can't see there being space for a bird to somehow fit in but could it make that noise?

Could be wasps, building a nest. They chew wood into pulp to make their nests, my mum had one in her bedroom ceiling once and they're noisy little bastards

Cluster flies?

We had bees nesting in our double glazing. Sounded like you describe.

carpenter bees.

Wasps - they are surprisingly noisy buggers

woodworm?

We are observing your earth.

I've made wasps make a noise like ruffling thin paper.

Death watch beetles got their name because of their tendency to tap, tap, tap. We had them living in our wood cladding. Could it be them? They like to live in damp, slightly rotting wood.

Its a regular sound and the muffled buzzing probably isn't the best description. Its more of a very fast succession of taps which sort of vibrates the sound every now and again.
Thanks for the suggestions - I'll get googling. Hopefully no little green men crawl out tonight @recrudescence.

I would have thought deathwatch beetles unlikely, because they normally attack hardwood timber, which is seldom used in modern houses. I have hardwood external doors, doorframes and sills, and a few of the windowsills, so it is possible (but I don't believe mine have beetle).

According to Wikipedia they like the timber to be 50 years olds or more, damp and somewhat rotting. Modern houses in UK seldom get wood-boring insects because, with modern central heating, good ventilation and building practice, they are usually too dry inside to support insect life. I have had woodworm in sheds and greehouses, though.

It’s probably a queen bee hibernating. She’ll depart when the weather gets warmer.

Woodpecker?

Probably starlings. We have them behind our fascia boards (wooden). It sounds just like you describe. Listen out for any quiet tweeting. There’s lots of tapping and muffled wing-flapping going on around 8am!