Summary: Hasegawa et al. (2013)

The sensory trap hypothesis proposes that courtship behaviour of males that mimic food-begging behaviour of offspring is a consequence of signal evolution. This results from males attempting to match stimuli that stimulate the female response in other contexts (for example, in parental care). As a result, females respond and male mating success increases. To humans, male courtship behaviour in many birds appears similar to food-begging behaviour of chicks. It is unclear, however, whether this behaviour does actually elicit a parental care response by females during courtship, indicative of a sensory trap. Hasegawa et al. (2013) studied barn swallows Hirundo rustica gutturalis and found that males make enticement calls that are structurally similar to nestling begging calls. When they played back these vocalizations to females during courtship, they observed females responding, even when nestlings were not present. Hasegawa et al. (2013) suggest that this represents a sensory trap, whereby a males mimic a signal which evokes a female response for an alternate behaviour (in this case, parental care).