That would be the crop it isn't found in all birds and even fewer create a "milk" in the crop for the young (pigeons being one).
Something was upsetting the blackbirds that are nesting in a conifer below my window this morning might have been a magpie trying to get in. Parents are still taking food back though.
Forgot to mention saw my first Swifts of the year last week and the number of swallows has gone up as well.
09-May-2016 20:41:48