Photographing black coloured birds at long distance on a very dull day is not a great idea.
Last Summer the large fields at the foothill of the site of Maiden Castle Dorchester were adorned with the colour yellow, (masses of sunflowers.)
Sunflowers are grown for the seeds and farm animal fodder.
Last week I visited the area and the it was black rather than yellow.
Large flocks of Rooks have now taken up the challenge of digging the ground and searching for food and hiding some.
They certainly have the correct beak for the job.
Rooks are 'wrongly' much maligned regarding their feeding preferences.
They are not the nest robbers like the other members of the Corvid family and eat, insects seeds and vegetables. However they will eat carrion. So they do a lot of good in reality.
Another habit they have is to 'Cache' food, hiding it in the ground and remembering where they buried it.
Remember for ID purposes,
Rooks together, Crows on their own.
Unless they are Jackdaws of course, but they are much smaller.
Rooks are quite tolerant of other species, but they do enforce a pecking order.
Flying around the field and stopping to feed at vacant spots were several black-headed gulls in their Winter plumage.