The colour of fox eyes can vary depending on many things.
A. The colour of the spotlight being used; HID, halogen or coloured filters will have an effect on the retinal reflection colour you see. B. The age of the fox may have an effect. C. How directly the fox looks at the light. D. The distance between your eyes and the light source (reflective angle) can affect the colour.
What colour am I looking for?
Usually greenish yellow. However white, orange and even red eyes can be a fox. Cats, sheep, cattle and dogs can share the same colour as foxes. The space between the eyes can sometimes determine whether or not it’s a fox. The movement of the eyes is the next thing to look for. You may see a fox or a cat blink. A fox’s eye may move quickly whereas most other animals don’t move so quickly. A fox may only give a quick glance compared to a sheep for example. A fox may be seen apart from a mob of sheep, but sometimes within the mob but moving differently to the sheep’s eyes. Because other creature’s eye reflections are similar to fox, you must identify the animal before shooting. Cats, sheep, cattle, wolf spider and fox eyes can look similar in colour.
Deer have particularly bright eyes. They group together quickly and move quickly when startled. Animals with a more red appearance are kangaroo, possum and rabbit.
When you purchase a new rifle or have your rifle re barreled, like many many machines, there is an important run in or break in period. After mounting your scope you need to sight in the rifle. Use this opportunity to run in the barrel. It is a little extra trouble but it pays dividends later on. Regardless of how smooth your new barrel looks, there is microscopic roughness that needs to be worked smooth. This roughness will collect copper or lead fouling every time the rifle is fired. Removing this will ensure the best chance of getting the best accuracy potential from that barrel.