What does the term "bloom" refer to in falconry?

In falconry, the term "bloom" specifically refers to a healthy sheen or luster that appears on a bird's feathers. This sheen is often an indicator of the bird's overall health and nutrition. When a bird is well-cared for, receiving proper diet, and living in a suitable environment, the condition of its feathers will reflect this care. A good bloom signifies that the feathers are not only clean but also well-oiled, which helps in water resistance and insulation.

The other options, while relevant to birds and their characteristics, do not accurately describe "bloom." Feather arrangement, color of plumage, and the molting process are all important aspects of falconry and bird care, but they do not correspond to the term "bloom," which is specifically about the appearance and health of the feathers due to proper care and nutrition.