What are "shock marks" on an eyas hawk's tail most likely the result of?

"Shock marks" on an eyas hawk's tail are typically caused by a combination of factors linked to the young bird's development and environment. These marks can result from the stress experienced when the hawk is taken from its nest, as this sudden change can lead to physical manifestations like feather damage or discoloration, often referred to as shock marks. Additionally, if the parents are unable to provide sufficient food during critical growth periods, the stress and nutritional deficiencies can contribute further to these marks. External parasites can also affect young hawks, as they may cause irritation and stress, leading to feather damage.

Thus, shock marks can be a reflection of multiple stressors impacting the health and well-being of the eyas. This understanding illustrates the intricate relationship between the hawk's environmental conditions, parental care, and the challenges posed by external factors, making "all of the above" the most comprehensive answer.