Sex and the Birds: 3. Fidelity and Promiscuity

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Most birds are monogamous, forming a pair during one or more breeding seasons or even for life LINK. And for a very long time, people believe that monogamous birds are the epitome of fidelity.

In Chinese culture, the Mandarin Duck (Aix galericulata) is often featured in paintings. Also featured in Chinese weddings, these ducks symbolise wedded bliss and fidelity LINK. Similarly, swans, immortalised in stories, songs and poetry, have also long been viewed as a symbol of fidelity and enduring love. They mate for life and are believed to remain faithful until death. Should one of the pair die, the other is believed to often live alone, never mating with another. Doves are another symbol of fidelity – that is why a pair is often released at weddings.

These long-held myths have now been exploded with the introduction of DNA fingerprinting. In an Australian study on Black Swans (Cygnus atratus), researchers found that these swans are in fact “feathered philanderers” and that males “enjoy flitting from one nest to another for trysts with a string of females” LINK. In fact, a clutch of cygnets can be fathered by as many as three fathers.

So the so-called monogamous relationship of many birds is actually social rather than sexual monogamy. What this means is that either or both of the pair will sneak away to indulge in extra-pair mating.

According to ornithologists, male birds are hardwired to spread their genes. Female birds on the other hand try to select the best male for their chicks. But, as we all know very well, this can be tricky. Thus the females widen their options by mating with other males.

YC Wee
Singapore
October 2013

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