Army Birding

Out this morning on a BTO Nightingale Survey visit. A large flock of finches flew by at treetop height. I do not get a good view but they were generally dull. However, they were making a distinctive 'buzz' contact call and they were not Goldfinches. I have been through most of my own and online sound recordings but cannot find that 'buzz' call amongst the finches. Any ideas anyone?
Cheers.

Can only think that Linnet or even Redpoll may fit the bill.

Thank you Roger.

I had them down as Linnet at the time but couldn't find that 'buzz' in any of the sound recordings. Don't these birds know how they're supposed to sound?!

I'll keep plodding through the sound recordings for Linnet and Redpoll.

Cheers.