Sunflower Hearts have everything birds require; high-energy, high-calorific value, they're safe and nutritious. People who feed birds love them too because they’re so easy to feed and they attract lots of garden bird species. Over the years I’ve fed them from bird feeders, bird tables, ground feeders, window feeders, softfood feeder, from my hand and sprinkled direct on the ground. The results have always been the same: birds love them.
Do they love Sunflower Hearts more than peanuts? That’s a different question. Having observed Blue Tits choose between Sunflower Hearts and peanuts, I would say that peanuts win every time. But that’s a Blue Tit. Put Sunflower Hearts anywhere near a Goldfinch and that’s all they’ll ever want to eat again. In my garden, Goldfinches select Sunflower Hearts over Niger Seed and that happens in Bill Oddie’s garden, too. That’s not the case in every garden, though.
Sunflower Hearts have overtaken peanuts because they feature in many of today’s high energy mixes. Haith’s wouldn’t make a high calorie bird food mix without them.
Here’s more about Sunflower Hearts.