When is it most useful to "enter" your bird?

Entering a bird in falconry is specifically about training the bird to hunt and successfully capture a particular type of quarry. This process involves introducing the bird to the prey species it will be hunting to build its confidence and instincts around that quarry. When the bird becomes familiar with the behavior and characteristics of the prey, it's more likely to perform well in the field.

While there may be scenarios that can make it important to familiarize the bird with its surroundings or containers, these do not directly correlate with "entering" in the context of utilizing the bird for hunting. The essence of entering a bird lies in its readiness and ability to engage with its intended quarry effectively, ensuring a successful hunting experience.