Thistle Bird Feeder How do the birds know that there is thistle in the feeder?

Question by Pick A Winner: How do the birds know that there is thistle in the feeder?
As soon as I fill up the feeder the birds show up. How do they know it is there?

Best answer:

Answer by Mike S
Visual imagery most likely

What do you think? Answer below!

Tags:bird, Birds, feeder, know, there, Thistle