What are the pigeons eating under oaks

[Lazurus]

I was watching some woodies yesterday on the local estate, they were feeding on a sown pea field, I assumed they were eating the pea shoots, however on further surveillance I noticed they were only feeding under oak trees, nowhere else on the field. I had a wander around and sat under a big canopied oak trying to see what they were eating. now there was some late blossom on the ground but it appears they were after a type of caterpillar that was coming down on a silk rope from up in the oak I watched several of the little paratroopers come down as I sat there - anyone seen similar or where they just eating the fallen blossom and debris from the tree?

[openspaceman]

2 hours ago, Lazurus said:

 caterpillar that was coming down on a silk rope from up in the oak I watched several of the little paratroopers come down as I sat there -

Sounds like tortrix moth caterpillars but I've no idea if pigeons eat them, they do eat acorns of course