I bought this because the larger birds such as jackdaws were eating the hanging fat balls and also were managing to swing on the open fatball feeder. It has only worked to a certain degree as they find their beaks are long enough to get inside but they have more difficulty in balancing. The blue, great and coal tits all love it as they can sit inside and eat to their heart's content.
Used this about a week ago on a stoned parking area surrounded by rough grass and now all the weeds have turned yellow and will not be here much longer. Used in a watering can with a weedkiller arched rose and found the preparation easy. Would recommend.