Feeding ecology and diet

Horseshoe bats are aerial foragers, catching flying prey on the wing, and some are also gleaners, snatching stationary prey from branches, foliage, stones, or the ground. Many are clutter foragers, using their broad, short wings and high echolocation frequencies to fly slowly and maneuver through dense vegetation. Many species also "flycatch" or "perch-hunt" by hanging from a perch and making rapid sallies to snatch prey detected flying past. Some species can hover. Horseshoe bats usually hunt within 16.5-19.5 ft (5-6 m) of

A greater horseshoe bat (Rhinolophus ferrumequinum) catching a moth in flight. (Photo by Stephen Dalton/Photo Researchers, Inc. Reproduced by permission.)

the ground, and will also feed on the ground. Prey can be caught in the wing membrane and may be stored for brief intervals in cheek pouches. The relatively short tail and small tail membrane are not large enough to form a pouch for holding insects. When a large insect is caught in flight, it may be tucked into the wing membrane under the arm while the bat manipulates it with its mouth.

Horseshoe bats begin foraging later in the evening than most bats and often return to the roost, or to a feeding perch, to eat captured prey. Such perches can often be located by the piles of insect fragments that collect on the ground beneath them. In general Rhinolophus species are solitary hunters, while Hipposideros species forage in small groups. Like many other bats, horseshoe bats generally have regular feeding territories or hunting areas, and greater horseshoe bats may hunt regularly around the periphery of the same trees, low bushes, and buildings. Blyth's horseshoe bats have small, well-defined foraging territories near their roosts. They explore the foliage of trees, making frequent stops to pick insects off leaves. Some species are attracted to insects flying around lights and may enter buildings in search of prey. Hildebrandt's horseshoe bat hunts on the wing during the early part of the night, after which it flycatches throughout the night. The rufous horseshoe bat adopts a similar feeding strategy. The greater horseshoe bat changes its foraging habitat seasonally, hunting in woodland in the spring and over pasture in late summer. This behavior is linked to prey availability: the ambient temperature in woodlands is higher than that over open ground, leading to higher insect numbers in spring, while Aphodius dung beetles, a favored prey, increase in pasture during the summer as cattle dung accumulates.

Echolocation pulses are emitted through the nostrils with the mouth closed. The echolocation calls are of high duty cycle (56-60%), are of constant frequency with a short frequency drop at the end, and are often exceptionally long (20 to over 100 ms) in duration. To a certain extent, frequency can be used to identify a species, since individual species emit signals over a characteristic limited frequency band. Signal intensity (loudness) 4 in (10 cm) in front of the bat has been recorded at 27.0 N/m2 in the greater horseshoe bat and 2.0 N/m2 in the Mediterranean horseshoe bat R. euryale. The former species can differentiate between two identical targets, one placed as little as 0.47-0.51 in (12-13 mm) in front of the other, while the latter can detect a 0.12 in (3 mm) wire at a range of 4.6 ft (1.4 m) and a 0.002 in (0.05 mm) wire at 8 in (20 cm).

Prey items include Lepidoptera (almost entirely moths, including microlepidoptera), Coleoptera (including cockchafers and dung beetles), Hemiptera, Diptera (including mosquitoes and craneflies), Orthoptera (grasshoppers), Hymenoptera (wasps), Isoptera (termites), and spiders. The greater horseshoe bat drinks during low-level flight or while hovering.

A greater horseshoe bat (Rhinolophus ferrumequinum) chasing a moth in flight. (Photo by Animals Animals ©S. Dalton, OSF. Reproduced by permission.)

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