Mobbing (animal behavior)
Mobbing in animals is an anti-predator adaptation in which individuals of prey species cooperatively attack or harass a predator, usually to protect their offspring.
Konrad Lorenz, in his book On Aggression (1966), attributed mobbing among birds and animals to instincts rooted in the Darwinian struggle to survive.
In his view, humans are subject to similar innate impulses but capable of bringing them under rational control (see mobbing).
[5] In North America, the birds that most frequently engage in mobbing include mockingbirds, crows and jays, chickadees, terns, and blackbirds.
Classic experiments on this species by Hans Kruuk involved placing hen eggs at intervals from a nesting colony, and recording the percentage of successful predation events as well as the probability of the crow being subjected to mobbing.
Reintroduction of species is often unsuccessful, because the established population lacks this cultural knowledge of how to identify local predators.
The much lower frequency of attacks between nesting seasons suggests such behavior may have evolved due to its benefit for the mobber's young.
Niko Tinbergen argued that the mobbing was a source of confusion to gull chick predators, distracting them from searching for prey.
This approach relies on the existence of convergent evolution, where distantly related organisms evolve the same trait due to similar selection pressures.
As mentioned, many bird species such as the swallows also mob predators, however more distantly related groups including mammals have been known to engage in this behavior.
Studies of Phainopepla mobbing calls indicate it may serve to enhance the swooping attack on the predators, including scrub jays.
[21] The evolution of mobbing behavior can be explained using evolutionarily stable strategies, which are in turn based on game theory.
Mobbing behavior varies in intensity depending on the perceived threat of a predator according to a study done by Dutour et al.
[23] However, particularly in terms of its surfacing in avian species, it is accepted to be the byproduct of mutualism, rather than reciprocal altruism according to Russell & Wright (2009).
This so-called dilution effect proposed by W. D. Hamilton is another way of explaining the benefits of cooperation by selfish individuals.
Here the idea is that a mobbing bird, by apparently putting itself at risk, displays its status and health so as to be preferred by potential partners.
