Was this from a bird?

Observation - Was this from a bird?. Description: It was a flat bug type thing and immediately I thought it may be a 'louse' from a bird as we found a dying swift last year and this had similar on it. I am unable to find a picture to match and can't seem to find a word that will be picked up in the searc

It was a flat bug type thing and immediately I thought it may be a 'louse' from a bird as we found a dying swift last year and this had similar on it. I am unable to find a picture to match and can't seem to find a word that will be picked up in the search option. It was brownish grey, not smooth and about the size of my little finger nail and oval-ish in shape. I was unable to get a photo.