The norse and germanic year was split between two season, summer and winter. Summer began at the festival of Eostre close to the spring equinox.
This is a celebration of renewal, fertitlity, and rejoicing. The gift of colored eggs can be traced back to this ancient holiday. It was a way of wishing friends and family prosperity in the coming year. Eggs represented new life. The rabbit was regarded as a symbol of this holiday because of it's reemergence at this time of year, and it's amazing procreative abilities.