flocks, though not very numerous, seem always to be about.

Sparrows crowd every hedge and field, their numbers are incredible;
chaffinches are not to be counted; of greenfinches there must be
thousands. From the railway even you can see them. I caught glimpses of
a ploughed field recently sown one spring from the window of a railway
carriage, every little clod of which seemed alive with small birds,
principally sparrows, chaffinches, and greenfinches. There must have
been thousands in that field alone. In autumn the numbers are even
greater, or rather more apparent.

One autumn some correspondence appeared lamenting the scarcity of small
birds (and again in the spring the same cry was raised); people said
that they had walked along the roads or footpaths and there were none in
the hedges. They were quite correct--the birds were not in the hedges,
they were in the corn and stubble. After the nesting is well over and
the wheat is ripe the birds leave the hedges and go out into the
wheatfields; at the same time the sparrows quit the house-tops and
gardens and do the same. At the very time this complaint was raised, the
stubbles in Surrey, as I can vouch, were crowded with small birds.

If you walked across the stubble flocks of hundreds rose out of your
way; if you leant on a gate and watched a few minutes you could see
small flocks in every quarter of the field rising and settling again.
These movements indicated a larger number in the stubble there, for
where a great flock is feeding some few every now and then fly up
restlessly. Earlier than that in the summer there was not a wheatfield
where you could not find numerous wheatears picked as clean as if
threshed where they stood. In some places, the wheat was quite thinned.