Birds actually don't have much in the way of taste buds or a sense of smell, which is why substances such as hot pepper powder can be added to their food in an effort to keep squirrels out of it. Birds have outstanding hearing and vision, however, which is how they find their food. Robins, for instance, can hear earthworms burrowing in the ground, and raptors flying high in the sky can spot a mouse among the vegetation on the ground.
A vulture can't locate a dead animal if the carcass is hidden from the bird's view. Can't smell it, no matter how "ripe" the carcass might be. So to a crow, one green sprout is much like another. The bird will pull it out of the ground and decide to eat it or not, but the decision will be based on whether the animal recognizes the sprout as "food".
"Isn't it enough to see that a garden is beautiful without having to believe that there are fairies at the bottom of it too?" - Douglas Adams