Light levels: Most bat species have poor eyesight and rely on echolocation to navigate and find prey. During the morning and evening, when the light levels are low, bats may have difficulty seeing and hunting for food.
Predators: Many of bats' natural predators, such as birds of prey and snakes, are active during the morning and evening. By avoiding these times, bats can reduce their risk of predation.
Competition for food: During the morning and evening, many other animals, such as birds and insects, are also active and competing for food. Bats may find it more difficult to find enough food during these times.
Thermoregulation: Bats are warm-blooded animals, and they need to maintain their body temperature within a certain range. Flying during the morning and evening, when the temperatures are cooler, can cause bats to lose too much body heat.