On 23 March 2017 I banded two Golden-crowned Kinglets. Both birds were males. This fact may surprise some birders, who assume yellow-crowned birds are females. In fact, the orange crown of this male kinglet is hidden under the yellow feathers. If you look closely, you can almost see an orange hue under the yellow crown.
Golden-crowned Kinglets winter further north than Ruby-crowns. The species tolerates night temperatures below -40 degrees C. At such temperatures, Golden-crowns may huddle together, but they are not known to become torpid (Swanson et al. 2012).