It is usually used to describe someone who doesn't eat very much or who just picks at his or her food during mealtime. Actually, this comparison to a bird's eating habits is only partly true, because birds can eat large amounts of food. It is true, though, that many birds are very particular about the foods they eat. Just like you and me, birds have foods they like and foods they don't. I hate to eat beets.
Some birds are seed eaters and actually enjoy some seeds much better than others.
Some birds are insect eaters, while others prefer eating fruit, nuts, or berries. There is a fun experiment you can do to see which birds eat certain foods. You can use whatever foods you want, just make sure the foods are safe for birds to eat and that each dish offers some- thing different. Take a pad of paper and start listing the birds you see that visit each dish. Be sure to write the date, time of day, and weather conditions when you make an observation.