What is the most significant factor influencing how 'friendly' a bullfinch appears to an observer?

Answer

The availability of food.

The availability of food is almost always the most significant factor influencing how approachable a bullfinch appears to a human observer, as their boldness is often conditional on a reliable food source.

What is the most significant factor influencing how 'friendly' a bullfinch appears to an observer?
speciesbirdanimalBullfinchfriendliness