Birds putting rocks in ground feeder

I have a ground feeder which is frequented mainly by house sparrows, jackdaws, rooks and pigeons. I have noticed that when it is empty or low, the jackdaws/rooks will place rocks in it. It's a rock garden, so the feeder is surrounded by them. I have tried searching for why they might be doing this but so far haven't found anything. Is there a reason? Are they 'trading' rocks for food possibly?

  • i'd guess they're trying to raise the water level up.

    i have crows which are always putting bread they've got from other gardens in my water bowl. then they come back later and take it away again, presumably after it's been softened up

    [edit... sorry, i. misread that and thought you were talking about a water bowl on the ground. I haven’t got a clue why they would do it for food!]

  • Do they use the stones to stand on if the feed is low instead of reaching over the edge of the feed tray ?
  • Not that I have seen, they just leave the stones there shortly before flying off. I think you might be right though, although I haven't noticed them having any issues reaching over the edge of the feeder, I struggle to think what else it could be! I have seen house sparrows standing in the feeder, but the stones are far too big for them to pick up and I'm not sure that the rooks/jackdaws would do that for their benefit.
  • Hi there! I am searching for an answer to this exact question.

    We have blue jays and wood peckers that frequent our ground feeder. When the bowl starts to look close to empty, a rock from our landscaping appears in the bowl. The more the food disappears, the more landscaping rocks appear in the bowl. I'm talking five little 2-inch rocks in the bowl!

    I have heard that ravens/crows leave gifts for humans that feed them, so I am wondering if they are thanking me or actually reminding me to fill up their bowl! I'll add this happens every single time the bowl is low on food.

    Placing the rocks in the bowl so they can reach the food does make sense to me, but they keep putting rock after rock in the bowl? Birds are amazing. :)