Foods Evey Canary Breeder Should Avoid Feeding To Their birds March 30, 2019 Every Canary pet owner should avoid some foods that is not designed for your bird's digestive system, these foods including: Celery Onions Iceberg lettuce Tomato Avocado Apple seeds Mango. Chocolate Candy Mushrooms Salt Caffeine Breads Cookies Cake Canaries are seeds eaters and they also benefits from some greens, fruits and some occasional egg food.