The Theo L. Carson Nature Center is on South Platte River in Littleton, Colorado (northwest corner of Sante Fe & Mineral).  They have a diverse display of animals from the area in the main building and very helpful volunteer staff.  It's a 'must see' for residents of the Denver area.  They also have a nature walk which will take you on a VIP birding trip around Cooley Lake (a wildlife area closed to the general public).  The walks are offered the 2nd Sunday of every month.  Advance reservations are requested at 303-730-1022.  There's no fee to visit the nature center or take the Cooley Lake walks.  They also have great educational programs for children and adults.  (See official site at: "Carson Nature Center & South Platte Park")

Belted Kingfisher

Green-winged Teal (Anas crecca)