You have a +3 bonus to attack and damage rolls made with this magic weapon.  In addition, you have a +3 bonus to attack and damage rolls for your ranger spells, and your ranger spell save DC increases by 3.  If you use this bow against your hunter's mark target, you have advantage on the attack rolls and can add your Wisdom modifier to the damage once per turn.  When you roll a critical hit against the target of hunter's mark with this weapon, add an extra 2d8 piercing damage to the total (the hunter's mark damage is separate from this and is still doubled).

Proficiency with a longbow allows you to add your proficiency bonus to the attack roll for any attack you make with it.

Notes: Bonus: Magic, ranger, Damage, Buff, Combat, Ammunition, Heavy, Range, Two-Handed