The Social Network…of Birds

Two bee-eaters appear to be sharing a meal in their aviary.

These two bee-eaters sharing a meal in their aviary are part of the same social network.

The age of social networking has the world communicating through cyberspace on just about anything. We are now connected to a network of people on Facebook and Twitter with whom we tune in daily to see what our friends are up to. In the past hour, my friends on Facebook looked at the nutrition facts on a candy bar (Is that really a good idea?), posted a CUTE photo of a clouded leopard (thanks to my “friend,” San Diego Zoo Global), and humorously referenced her boss mistaking a Kanye West song for the ‘80s hit single “Ghostbusters.” This is my social network.

Scientists are developing new methods to understand how people are influenced by their social network. Who we are connected to in the virtual world and in real life influences different aspects of our own lives, such as whether we vote in elections, our happiness, our weight, and whether we catch the flu or acquire other diseases. In collaboration with James Fowler, Ph.D., a professor at the University of California, San Diego, we are also trying to learn how connectedness influences the spread of disease in bird populations.

Avian mycobacteriosis is a bacterial disease of birds caused by Mycobacterium avium and other related species of mycobacteria. This is a challenging disease of birds, because whenever a case arises, we do not know how far an infection has spread through a group of “connected” birds sharing the same aviary. Traditionally, disease acquisition has been attributed entirely to contact with other infected birds; however, recent studies conducted by the Wildlife Disease Laboratories, a division of the San Diego Zoo Institute for Conservation Research, show that the environment may also be playing an important role in the spread of this disease. So, which is more important, the social network or the environment?

A powerful method of untangling this dizzying question is a social network analysis. Years of careful record keeping has created an archive of data documenting each bird’s aviary and enclosure-mates. These data can be used in conjunction with health history to determine whether the occasional cases of avian mycobacteriosis we see are attributed to a bird’s social network or its environment history. What makes the problem interesting is that the network is dynamic. Similar to how I might change my Facebook network by adding or dropping a friend, one of our birds might change social networks when she moves into a new enclosure to be closer to her new boyfriend (i.e., she drops her old bird “friends” and adds a new bird “friend”). Evaluating these dynamics through time is where social network analysis is remarkably powerful. Ultimately, we hope to uncover the relative contribution of mycobacterial infections due to both the social network and the environment.

We are just beginning this fascinating journey into understanding the influence of social networks on disease dynamics in our animals, so you will have to stay tuned to find out the answers. These answers will allow us to develop better disease-management protocols to mitigate risk to birds at the San Diego Zoo and San Diego Zoo Safari Park, as well as in conservation programs around the world.

Carmel Witte is a researcher with the San Diego Zoo Institute for Conservation Research. Read her previous post, Cutting-edge Science in Historical Surroundings.

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