Autumn is a good time for seeing large numbers of birds. The breeding season is over and both adults and juveniles are grouping up. The birds in some of these flocks will remain together for the next few months now and in effect are winter flocks. Flocks

Autumn is a good time for seeing large numbers of birds. The breeding season is over and both adults and juveniles are grouping up.

The birds in some of these flocks will remain together for the next few months now and in effect are winter flocks.

Flocks of tits now scrutinising woods and hedgerows for food will constitute many of the same birds in winter, perhaps gathering a few new recruits as autumn progresses.

However, some of the flocks consist of birds that will soon be on their way to Africa and have gathered together to make the most of their last few weeks or days here with us.

I watched swallows coming in over my local quarry workings and gravel pits on a recent evening.

Smaller groups in the 300 or so birds I saw would have spent the day feeding over meadows, but this large gathering was a roost gathering to give them safety in numbers.

It was quite a scene to see the sky filling up as birds arrived from all directions and then watch them drifting around over the roost site they had chosen in the form of reed-filled channels on the gravel company's extraction site.

Even more impressive was possibly the biggest flock of yellow wagtails I have seen in Britain.

I took a stroll along the Earith end of the Ouse Washes and had enjoyed seeing a few of these spritely insect-eaters springing off the bank ahead of me and foraging below the cattle grazing the lush vegetation on the washes.

There came a point, though, and I am not sure why, when seemingly every yellow wagtail in the area chose to take to the air.

Clearly, a huge number had remained hidden among the vegetation, but a wheeling mass, calling sharp 'sweep' calls, was in the air before me.

I counted the birds in tens to try to get an accurate count and the final total of 200 was really something special for a bird that has declined significantly in recent years.

On the same day, I noticed a few moderate sized flocks of wood pigeons and stock doves starting to form in the stubble fields.

These flocks will grow and grow and by next month will be numbering several hundred.

Groups of six and four turtle doves had joined the resident birds to fatten up on spilt grain before departing on their hazardous journey to Africa.

These would be the last turtle doves of the year for me.