Hummingbirds will soon begin their migration southward to Mexico and Central America. Believe it or not very little is known about what triggers their winter journey or why the males leave first. Many naturalists and volunteers banded some of these birds and tracked their movement but recording the movement of that same banded bird is a long shot. The average weight of a hummingbird is only around three grams so at this stage in our technology transmitters are just too heavy for the little bird. Some experts believe that the birds follow the insects. As insects retreat southward the hummingbirds follow their source of nourishment. These birds are carnivores after all. These birds can traverse an unbelievable five hundred miles in eighteen to twenty hours. Hummingbirds can average thirty miles per hour during the course of their migration. It's no wonder that a quarter of the males will perish in some stage of the journey. It's also no wonder that these small birds can lose over half of their body weight by the time they reach their winter destination. I will leave my hummingbird feeder out until I am sure they have all left. The birds have to fatten up before they depart. Some will more than double their body weight before their departure. Some ornithologists claim the birds will not leave until the first frost but I have never seen a hummingbird after October first. Clean those feeders and let's fatten up our little friends before they leave.