Geese are primarily herbivorous birds. They exhibit remarkable adaptability in their dietary habits, foraging extensively in both aquatic and terrestrial settings. Understanding their natural diet is important for appreciating their ecological role and ensuring their health when human interaction occurs.
Natural Foraging
Geese spend a significant portion of their day actively foraging for food. Their diet mainly consists of plant materials, with grasses forming a substantial part of their intake, including species like Kentucky bluegrass, ryegrass, and clover. They prefer short, fresh grass and are commonly seen grazing in fields.
Beyond terrestrial vegetation, geese also consume aquatic plants. They can be observed dabbling or tipping their heads underwater to reach submerged vegetation such as pondweeds, water milfoil, duckweeds, and sedges. They also pull roots and rhizomes from the silt, incorporating plants like wild celery and cattails into their diet.
Seasonal changes shift their foraging focus. In fall and winter, geese increase their consumption of seeds and grains, including wheat, maize, barley, oats, and beans, to build up carbohydrate reserves for warmth and migration. They also occasionally eat berries and fruits like apples and grapes when available. While primarily plant-eaters, geese supplement their diet with small invertebrates such as insects, snails, and worms, particularly during breeding season or for growing goslings. This small animal protein intake contributes to their overall nutritional needs, though it constitutes a minor part of their overall diet.
Harmful Foods
Providing geese with human foods like bread and crackers can be detrimental to their health. These foods offer minimal nutritional value, being high in carbohydrates and empty calories, akin to junk food for these birds. When geese fill up on these items, they neglect to seek out the natural, nutritious foods their bodies require, leading to malnourishment.
One serious condition linked to an improper diet, particularly one high in protein, carbohydrates, or lacking specific vitamins and minerals like D3, E, and manganese, is “angel wing.” This developmental deformity causes the wing joint to twist, preventing the feathers from lying flat and rendering the bird unable to fly. While more prevalent in young, rapidly growing geese, the condition is irreversible in adult birds.
Beyond nutritional deficiencies, feeding geese human food can lead to other problems. Moldy food can cause aspergillosis. Uneaten food left in the environment can rot, leading to bacterial growth, water pollution, and the attraction of pests. Furthermore, a reliance on human handouts can cause geese to lose their natural fear of people, potentially leading to aggressive behavior and increased vulnerability to dangers in human-populated areas. Some foods, like dairy, avocado, white potato, green tomato, eggplant, pepper, fruit pits/seeds, raw beans, raw nuts, onions, chocolate, and caffeinated items, are also toxic and should never be given to geese.
Responsible Feeding
For those who feed geese, selecting nutritious alternatives to harmful human foods is important. Safe options include cracked corn, whole oats, defrosted frozen peas, and chopped leafy greens such as romaine lettuce, kale, cabbage, and spinach. Small amounts of cooked rice, sweet potato, carrots, broccoli, cucumber, watermelon, cantaloupe, and certain berries without seeds or pits can be occasional treats.
When providing food, do so in moderation, as a supplement, not the bulk of their diet. Scattering food on the ground, rather than throwing it into the water, helps prevent water pollution and the growth of harmful bacteria like botulism. Geese naturally prefer to feed on land, so spreading small, bite-sized portions in an open area is beneficial.
Ethical considerations are important in feeding wild animals. Regular feeding can inadvertently create dependency, leading to altered natural foraging behaviors and potentially causing geese to become overly reliant on human handouts. This can result in localized overcrowding, increased competition for food, and a higher risk of disease transmission among bird populations. Many wildlife experts advise against feeding wild animals entirely, encouraging natural foraging.