The female great-horned is back on her nest as of 31 January, which means that we will soon be hearing the “barking” of angry crows. Read hear for a description as to why birds mob.
Mobbing is a common occurrence for many species of birds that can be initiated for different reasons. Protecting a nest of fledglings would trigger a mobbing of a large predatory bird that might fly in thinking that the baby birds would be an easy meal. When the predator is spotted, a few birds will let out an alert call and bring other birds together to distract and confuse the threat to the point where it eventually leaves. Another reason that birds might mob is because they are trying to teach their young who the “bad guy” is. The “bad guy” could be a bird of prey, an animal or even a human. When any of these bad guys have been spotted nearby, the young watch the mobbing and learn what they should do if a predator comes near them. Finally, birds could be mobbing as a means to protect one another. One example of this would be what Stanley Temple, a wildlife ecologist, encountered firsthand: “On one occasion, one of his red-tailed hawks caught a crow and brought it to the ground. The screaming of the captured crow sounded the alarm for the crows in a huge nearby roost and “they descended like a black tornado on the hawk,” and the captured crow got away.”
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Note: The quote was taken from the website below and is part of Stanley Temple, a wildlife ecologist at the University of Wisconsin-Madison’s research.