There are two types of sparrows in the UK; house sparrows and tree sparrows. Only the former is found in the west of Scotland ie West Dunbartonshire, although the latter is found south of the border and in much of the east of Scotland.
HOUSE SPARROW : Passer domesticus
This species is common around West Dunbartonshire.
We may be more familiar with sparrows bobbing around on the ground, perhaps under a cafe or picnic table. Within trees they seem to take on a more elongated form as they stretch for berries or, in this case, into a bird feeder.