Unlike the Eurasian Kestrel, the larger Greater Kestrel sits-and-waits, not for voles and birds, but for grasshoppers and other invertebrates.
By Rex Graham
Grass fires are irresistible. Greater Kestrels catch so many fleeing grasshoppers, wind scorpions and other invertebrates, small mammals and lizards that they cache food on the ground. They eat it later (after shaking off the ants).
With a wingspan of up to 33 inches (84 cm) the Greater Kestrel is one of the biggest kestrels. The slightly smaller, more colorful Eurasian Kestrel uses updrafts, limited hovering and other modes of aerial hunting at higher altitudes to catch voles, mice and other small mammals, birds and large beetles. Foraging that way requires more energy than sit-and-wait hunting for invertebrates, which, gram-for-gram, offer the same nutritional value as vertebrates.
Greater Kestrel hunting strategy
The lower-altitude Greater Kestrel is often attracted to roadside perches. They don’t scavenge road kill with the crows. Instead, they use the perches as part of an energy-efficient strategy to hunt for grasshoppers, wind scorpions and spiders and termites.
Lizards and other large prey are often presented by males to females spending long hours incubating eggs and attending to chicks. “Vertebrate prey rose in importance during the courtship, incubation and, to a lesser extent, nestling periods,” South African researchers wrote in the Journal of African Ornithology.
The Greater Kestrel is a non-migratory resident of beautiful, arid landscapes of eastern and southern Africa, typically with a few scattered trees or other perches. Ornithologists who study them have the enviable task of spending long hours with binoculars and spotting scopes in grassy, mid-elevation foothills, river valleys and high ridges. Researchers collect pellets regurgitated under roosts and hunting perches to gain a detailed understanding of the kestrels’ diet.