UFO ?

Can you help identify this bird?

I put up a new birdfeeder filled with Nyjer seeds to see what they might attract. After a few days this little bundle appeared

Pics not great as they were shot through the window.

From a distance, first thought it might be a female Chaffinch - now thinking probably House Sparrow? long time since I actually saw one

Just posting in the hope someone recognises it

Unlike the Blutits and Chaffinches, it didn't dart about but sat on the perch for ages.
quite Zen like, looking around and having an occasional nibble.
It didn't seem interested in other foods (peanuts, sunflower seeds or mealworms)

I didn't want to disturb it so was unable to move in closer to get a better shot.

Have seen it once since this shot was taken (Backblip)
The behaviour was exactly the same as before.
It sat on the Nyjer perch for almost 10 minutes, not at all phased by the antics of the other birds (who don't seem interested in the Nyjer seeds)