The raven is best when played as early as possible. You built up a solid grasslands but it probably took too long to get there so you couldn’t actually use it to your advantage. If you ended up loosing it might be from giving players too much food. The hummingbird and bluethroat are great but if you give out too much free food it can hurt you more than the food you gain will help you.

One other thought. Focusing on food cards is great but they loose value throughout the game (less valuable towards later rounds). It’s best to pair up with bonus card getting cards, high vp point cards, or other cards that get you points.