Cumulative upkeep—Add . (At the beginning of your upkeep, put an age counter on this permanent, then sacrifice it unless you pay its upkeep cost for each age counter on it.)
Enchant creature
Cumulative upkeep (At the beginning of your upkeep, put an age counter on this permanent, then sacrifice it unless you pay its upkeep cost for each age counter on it. can be paid with one mana from a snow source.)
Enchanted creature gets +3/+3 for each age counter on this Aura.
Flying
Rimefeather Owl's power and toughness are each equal to the number of snow permanents on the battlefield.
: Put an ice counter on target permanent.
Permanents with ice counters on them are snow.
. (At the beginning of your upkeep, put an age counter on this permanent, then sacrifice it unless you pay its upkeep cost for each age counter on it.)
(At the beginning of your upkeep, put an age counter on this permanent, then sacrifice it unless you pay its upkeep cost for each age counter on it. 
