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It’s not just humans who get pregnancy cravings. The females of one bird species also seem to get an itch for certain foods when they are incubating eggs – and their partners are able to pander to their dietary whims.

“For the first time, we tested whether and how males cater to the specific desires of their mates in the wild,” says at the Victoria University of Wellington, New Zealand, who led the study conducted at Zealandia, a nature sanctuary in the city.

The researchers tested 16 pairs of New Zealand robins (Petroica longipes) while the female was incubating. Females were fed mealworms and two types of insect larvae under two conditions: when a male could see what his partner ate and when he couldn’t.

The female birds generally preferred a food type if they hadn’t eaten it recently. The males somehow knew what food the females wanted, even when they couldn’t see what they were being fed by the researchers. When a male robin held a preferred food item, his partner begged more intensely for it prior to or during food sharing.

Subtle signs

The study demonstrates the subtlety with which a mated pair of birds conveys important information crucial to successful breeding, says at the University of Washington in Seattle.

“This study is the first to confirm in the wild that not only the hunger of the female, but [also] the specific preference for food type is conveyed to the male, and that this information is most likely encoded in the vigour of her begging behaviour,” he says.

This suggests that females can somehow signal their current desires to their mates, enabling males to cater to female desire in the wild.

This is important because in monogamous species such as New Zealand robins, food sharing by the male is vital to help the female offset the energetic costs of reproduction, such as egg laying and incubation. The male’s ability to give his mate what she wants could be an important factor in determining the success of a pair, as well as influencing whether they stay together, says Shaw.

This discovery raises the possibility that many other species might be capable of doing the same, she adds.

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