Jackdaws are not exactly my favourite bird (one must live with birds to know them, and we know the black ones!) and I can understand farmers getting incensed about them to the extent of building jackdaw traps in their fields.
I once lost a fine crop of peas through their raids, not knowing that black cotton would have kept them off (and pigeons too) just as well as it served to protect gooseberry bushes from sparrows. At the weekend I stopped to watch a company of jackdaws feeding on a rough field, for, although they plague me in all sorts of ways, I am continually fascinated by them. The great banquet on this occasion appeared to be spiders; however, I couldn't get close enough to see all that went into the crops of the birds. The feast may have included that tiny red mite that has been a great nuisance to some people here this summer, housewives included.