Bird masturbation is common

A new study analyzed 120 bird species from 22 major groups.

The phrases “stroke the cock” or “jerk the bird” are often used as euphemisms for masturbation, but a new study suggests the act of self-pleasure is widespread among birds.

In a May 31 study published in the journal “Ecology and Evolution,” researchers found that masturbation among birds is “strongly phylogenetically conserved”—suggesting it’s an ancient behavior that runs along the evolutionary family line.

The act is more common in males, though it occurs in both sexes. It also happens across age groups, indicating that it isn’t a way for younger birds to “practice” before mating.

Researchers also found that birds with multiple mating partners are more likely to masturbate—compared to those that form long-term pair bonds. This supports the idea that going solo might help increase reproductive success, particularly in species with intense competition over fertilization.

For males, masturbation may help flush out old sperm—replacing it with newer, more viable sperm for mating. For females, it may increase sexual arousal—making it easier to mate with non-partners.

Solo sex is also more common in the wild than in captivity, challenging the assumption that it’s a stress response or abnormal behavior among caged birds. Researchers noted that bird keepers often suppress it through punishment, changes in diet or care, and even drugs and surgery.

“Instead, it is part of a wider repertoire of sexual behaviours exhibited in birds,” they said, adding that masturbation commonly serves as an “outlet for increased sexual arousal, a means of increasing reproductive success through postcopulatory selection, or both.”

The study analyzed 120 bird species from 22 major groups, drawing from existing research, online observations, and bird experts’ surveys.

For years, different researchers have noted that masturbation is common across the animal kingdom, including primates, tortoises, dolphins, elephants, camels, and porcupines.

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