Why are Ruby-crowned Kinglets generally not regular visitors to standard bird feeders stocked with large seeds?

Answer

Their diet is specialized toward protein and fats found in moving insects, not dry grains

Because their diet consists almost entirely of live, small invertebrates, they are typically not interested in standard feeders offering seeds like sunflower or thistle.

Why are Ruby-crowned Kinglets generally not regular visitors to standard bird feeders stocked with large seeds?
foodbirdKinglet