Climate change cause for more ‘divorces’ in sea birds - Study

More number of black-browed albatross — the sea birds known for monogamy — are separating these days due to the challenge of long-distance travels and reduced food availability, states Science American magazine, attributing the altered behaviour to rise in sea temperature.

“Few animals seem more affectionate than black-browed albatross. These large seabirds, whose dark eyebrows shadow their eyes like mascara, are socially monogamous and often mate for life,” Science American recently noted.

The study suggests climate change could be the reason for “marriage trouble” in albatrosses. Usually, only 1% of albatrosses separate after choosing their life partner, but researchers now say the percentage of separation has gone up to 8%.

“Monogamy and long-term bonds are very common in albatrosses. It serves a practical purpose; in that, it helps build trust as the pair alternates between taking lengthy food-gathering trips and egg-incubation duties. Trust is the hallmark of their relationships too,” Francesco Ventura, a researcher at the University of Lisbon and co-author of the study, told theswaddle.com.

Ventura said that rising sea temperature due to anthropogenic (man-made) activities could be the reason for the drastic change in the behaviour of this bird.

The study, published in the Proceedings of the Royal Society B, observed 15,500 breeding pairs in the Falkland Islands in the Atlantic Ocean over a period of 15 years.

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The research’s introductory note states that individuals (male or female albatross) were more likely to divorce after breeding failures. However, regardless of previous breeding performance, the probability of divorce was directly affected by the environment, increasing in years with warm sea surface temperature anomalies – a factor which also increased the probability of switching mates in females in successful relationships.

The study says that “environmentally driven divorce may therefore represent an overlooked consequence of global change”.

To gauge this trend of “divorces” better, researchers considered two environmental factors critical to an albatross’ life — wind speed, and sea surface temperature. Warming oceans mean less food for the birds, which means they need to travel farther and struggle more in search of food. The study concluded that the stress of less food availability may drive them to conflict, resulting in relationship discord.

Harsher environment was found to increase stress hormones in albatrosses, which could be another reason for more couples splitting up.

Just as in case of humans where stress and longer working hours result in conflicts among couples, albatrosses too were found to respond to stress, caused mainly by fast changing environmental factors.