Nature is all about survival in the animal kingdom. Hummingbirds are no different. It may surprise you to know that a high number of young hummingbird hatchlings don’t survive. Studies that have been done on fledgling success, those hummingbirds that make it from hatching to full feathering, range from 17% to 59% of the number of eggs which had been laid.
There are a number of explanations for the high rate of hummingbird mortality. The number one explanation is the various predators of the hummingbird. A hummingbird mother will try fiercely to defend her eggs or young, but even so it is quite often with out success.
Other explainations also include the following: bad weather such as extreme cold or heat, heavy rains or even high winds. Accidents also help to account for the high mortality rate of hummingbird fledgling death.