As usual it is not possible to pick just one favorite for each month but this is what I came up with.

January
February
March
April
May
June
July
August
September
October
November
December

Click for bigger

January :Blue jay scores a peanut - South Weymouth, Massachusetts
February :House finch in the snow - South Weymouth, Massachusetts
March :The ospreys return - Bare Cove Park, Hingham, Massachusetts
April :Monomoy National Wildlife Refuge, Chatham, Massachusetts
May :Cormorants - Bare Cove Park, Hingham, Massachusetts
June :Milky Way - Deer Lake, De Motte Park, Arizona
July :Mount Chocorua and Chocorua Lake - Tamworth, New Hampshire
August :Adult loon feeding a loonling - Lake Waukewan, Meredith, New Hampshire
September :Herons in the trees - Great Esker Park, Weymouth, Massachusetts
October :Moon rising - Sargent's Wharf Harborwalk, Boston, Massachusetts
November :Small waterfsll - Ghost Pony Brook, Sussex Branch Trail, Byram Township, New Jersey
December :Bufflehead - Weymouth Back River, Bare Cove Park, Hingham,Massachusetts