Happy wife, happy life! Humans aren't the only ones to worry about keeping "the wife" happy while she focuses on bringing the next generation of offspring into the world.
When it comes to laying and incubating eggs, female birds of many species put in a lot of time and energy. To help her pull off the task, male birds often will bring her meals. When studying the North Island robin of New Zealand, Dr. Rachael Shaw of Victoria University of Wellington found that the males pay particular attention to what the females are craving, and cater to that desire.
Shaw tested whether or not males watched what the female was asking for when it came to food choices. It turns out the males don't just bring food willy-nilly, but bring what she's craving. According to a news release from the university:
The experiment first involved establishing female robins' eating habits. [Said Shaw:] "I fed the females either meal worms or wax worms, and then gave them the choice between these two types of insect larvae. I found that after the females had eaten one type of insect, they would prefer to eat the other type when given the choice. This means that the female's desire for a particular food is affected by what she has previously eaten."
Based on this, Dr. Shaw then tested if the male would also be able to choose the type of insect his mate was most likely to want (the one she had not just eaten)."
"Regardless of whether or not he had seen what his mate ate first, the male still made the appropriate choices. This suggests that the female is likely to be displaying her current desire in her behaviour, and that the male is using these cues to identify the food that she wants."
Watching the behavior of this songbird species opens up the possibility that there may be other monogamous food-sharing bird species where the mother-to-be makes requests about what she's craving, and the male brings her what she wants.