Identify Adult Female Rufous Hummingbirds

3.5 to -4" medium sized hummingbird.The females are larger than the males.  Females have bright golden green backs their crowns are a bronzy greenish to olive color. The gorget is heavily spangled with bronzy green speckles. They often have a iridescent red center patch on their throats that appears diamond shaped. There is often a rufus tinge to the lower rump continuing into the tail feathers. There is a band of black on R3-R5 followed by a white tip. R2 is slightly notched with rufous green and black, R1 is green and black tipped. They have a white collar extending into the chest area and then blending with rufous which extends along the sides up into the back. It is very difficult (some say impossible) to tell the differences between Allen's,  Calliope, and Broad-tailed females in the field.