Wandering albatrosses are the bird species with the greatest wingspan (on average three metres) and can live up to 50 years.
78 days of incubation and long periods of fasting
They typically mate for life and breed every two years with the same partner. After the female has laid a single egg, the prospective parents spend the next 78 days – one of the longest incubation periods among birds – taking turns incubating the egg while their partner flies out to sea in search of food. Such a foraging trip lasts on average 12 days, during which the parent remaining at the nest must go without food. This can have a negative effect on the animals’ physical condition, which generally deteriorates the longer the partner is away.
A research team led by the University of Liverpool has now found that wandering albatrosses with older partners tend to spend less time foraging than those with younger partners, meaning their partners spend less time without food. The researchers suspect this may be because the birds are able to gauge how long their partner can go without food. Since older birds are better able to withstand the strain of a longer fast, their partners may return more quickly – a behaviour that ultimately benefits both parents, who depend on each other when raising their offspring.
«Albatrosses cannot be single parents»
«On paper, this behaviour looks very caring: one parent sacrifices feeding time to protect the other. In reality, this behaviour benefits both parents. Albatrosses cannot be single parents; the conditions are too harsh. If one parent demands too much of the other, they lose the chick, which is catastrophic for both partners», explains the lead author of the study, Finn McCully, a doctoral candidate in environmental sciences at Liverpool.
«Our results suggest that the birds have a way of recognising how much pressure their partner can withstand. This familiarity may develop over the years they spend breeding together and learning each other’s limits. So if you are a wandering albatross and your partner is a little older and can no longer recover as well from a long fasting period, it is in your own interest to take extra measures to keep them fit.»
While earlier research suggests that wandering albatrosses adapt their own foraging behaviour as they age, this is the first study to show that the age of one’s partner can also play an important role in these behavioural changes.
«We thought that the birds would pay more attention to their own age than to that of their partner when making decisions, so these results were truly unexpected. Our findings show how complicated the lives of animals can be and that nature is full of surprises,» McCully concluded.
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