Which term refers to a young bird, especially in the context of falconry?

The term "eyas" specifically refers to a young bird, particularly in the context of falconry. This term is used to describe a nestling or juvenile bird that has not yet fledged, meaning it has not yet developed the fully formed wings or the ability to fly. In falconry, understanding the lifecycle and terminology related to birds of prey is essential for proper training and care.

The other terms listed relate to different stages or characteristics of birds: "haggard" refers to a hawk that has reached adulthood and is no longer in the eyas stage; "passage" refers to birds that are in their first year of life but have already left the nest; and "fledgling" describes a young bird that has developed feathers and is capable of flight but is still dependent on adults for food and guidance. Each of these terms serves a different purpose in falconry nomenclature but does not have the same specific meaning as "eyas."