I live in Henderson Nevada and my sister lives two blocks away (Henderson is a suburb of Las Vegas). My sister has 6 humming birds feeders that she meticulously maintains for her flock of humming birds. She takes the feeders in after night fall and puts them out before sunup on very cold nights.
A week ago around January 15th, the morning temperatures fell to 19 and 20 degrees with the highs for those two days only getting to 35 and 37 degrees respectively. On the two nights/days that it got unusually cold (normal winters it usually only gets into the upper twenties on the coldest of nights) seven of her humming birds died (that she knows of). She found their frozen bodies all over her yard (five female Broad Tails and two male Black Chins). She sees only three humming birds left alive going to her feeders.
Needless to say my sister was heartbroken. Does anyone know of any way to create a warm zone at night for humming birds that they would use to stay warm during cold nights? My sister bought clip-on heat lamps immediately to shine on the feeders during cold nights instead of bringing them in, but has yet see any of the surviving humming birds stay on a feeder after dark. The nights are only about 35 - 40 degrees now.