The rites of your circle grant you the ability to transform into more dangerous animal forms. Starting at 2nd level, you can use your Wild Shape to transform into a beast with a challenge rating as high as 1. You ignore the Max. CR column of the Beast Shapes table, but must abide by the other limitations there.
Starting at 6th level, you can transform into a beast with a challenge rating as high as your druid level divided by 3, rounded down.
At 2nd level, you gain the ability to summon a spirit that assumes an animal form: as an action, you can expend a use of your Wild Shape feature to cast the Find Familiar spell, without material components.
When you cast the spell in this way, the familiar is a fey instead of a beast, and the familiar disappears after a number of hours equal to half your druid level.
When you choose this circle at 2nd level, you gain the ability to use Wild Shape on your turn as a bonus action, rather than as an action.
Additionally, while you are transformed by Wild Shape, you can use a bonus action to expend one spell slot to regain 1d8 hit points per level of the spell slot expended.