Macrotus - Foraging Habits and Flight of Macrotus Californicus

Foraging Habits and Flight of Macrotus Californicus

The flight of the Macrotus Is remarkable chiefly for its extreme maneuverability. The bat flies fairly rapidly on occasion, but the usual foraging flight is slow and buoyant, and more nearly silent that of most bats. In level flight Macrotus wings make a soft fluttering sound that is less sharp and carrying than the sounds made by the wing beats of most other bats. The method of landing is most interesting. The bat flies six to eight inches below the ceiling and upon the wings making a deep down stoke that is directed nearly straight forward the hind limbs and uropatagium. These movements cause the bat to swoop upward toward the ceiling and as the bat nears the ceiling the wings are pulled back in an upstroke while the bat rolls over 180 degrees so that its back is facing downward and the long legs reach for the ceiling. Stated briefly, then the alighting maneuver consists of an upward swoop and a half-roll, at the end of which the feet wing rapidly toward the ceiling, seize it, and the wings give a final beat to steady the bat. Often these landings must require remarkably precise judgement of speed and distance, as many landings are made in the midst of a fairly closely spaced group of bats. Macrotus has two main methods of launching into flight, by dropping form the ceiling and taking flight after a short downward swoop, and by taking flight directly form the roosting place. The bat often hovers, both when foraging and when flying in its daytime retreat. Macrotus seems to hover easily, and it’s able to hover for several seconds at a time. These bats usually forage within three feet of the ground and often drop down closer to the ground nearer the surface where they can occasionally hover for a few seconds. Even bats released in the daytime flew fairly close to the ground. Leaf-nosed bats seem to be totally insectivorous, and their food clearly reflects the bats’ foraging habits. Some insects regularly eaten by Macrotus are almost certainly taken from the ground or from vegetation. The bats’ stomachs often contain orthopteran insects, noctuid moths and caterpillars, and beetles of the families Scarabaeidae and Carabidae, along with unidentified material. The lists of food items of Macrotus contain a plethora of insects that seldom fly, are flightless, or that fly in the daytime; this constitutes strong evidence that this bat consumes insects that are on the ground or on vegetation. Most leaf-nosed bats forage sometime between one hour after sundown and four hours after sundown, and then retire to a night roosting place. Actually, each bat seems to have a pre-midnight foraging period of roughly one hour. The greatest activity in the early morning seems to occur between two and one half hours before sunrise and thirty minutes before sunrise. Bats generally begin returning with full stomachs to their daytime roosts about two hours before sunrise, and the last bats usually return approximately twenty minutes before sunrise.