The majority of nidicolous animals are altricial. Examples of precocious but nidicolous species include many gulls and terns. Although there is much overlap between altricial and nidicolous species, the terms are not identical. Examples of nidicolous species are most mammals and many species of birds. This nest-dwelling behavior is described as endophilic or nidicolous. Some species of "Gephyromantis" have direct development or nidicolous tadpoles. Many gulls and terns are precocial but nidicolous. Newly hatched chicks are covered with long white down and are largely helpless (nidicolous). Altricial and nidicolous, their eyes are open at birth. Newly hatched chicks are covered with whitish down, and are blind and largely helpless (nidicolous). Incubation is completed in some 17 days, and the nestlings are altricial and nidicolous. The hatchlings are altricial and nidicolous and are fed by both parents. Newly hatched chicks are covered with long white down, and are largely helpless (nidicolous). The chicks are altricial and nidicolous, with both adults feeding the nestlings and fledglings. Young are semi-altricial and nidicolous, requiring warmth, nourishment and a high level of parental care.