What do you call birds that hatch in an undeveloped state, being reliant on their parents for food?

Birds that hatch in an undeveloped state and rely on their parents for food are classified as altricial. This term refers to the young of many avian species that are born relatively helpless, with their eyes closed and feathers not fully developed. These chicks typically require extensive care from their parents, including feeding and protection, until they grow stronger and more capable of independent survival.

In contrast, precocial birds are those that hatch in a more advanced state, often able to walk or swim shortly after birth. Nestlings refer to young birds that are still in the nest, which can include both altricial and precocial species, while fledglings are birds that have developed enough feathers to leave the nest but may still depend on their parents for support. Thus, the specific characteristics of altricial birds highlight their dependence on parental care in their early stages of life.