Study says birds are selfish, but are they really?
A new study examines the behavior of babblers that decide to go it alone.
With a flock of birds, a group member can often be seen perched up high acting as a lookout while the rest of the pack forages for food on the ground below. When a predator approaches, the lookout sounds the alarm.
To the casual observer, it may appear that the lookout is acting for the good of the greater group, but a new study suggests that the lookout – called a sentinel – may actually be working first and foremost for itself.
Dr. Roni Ostreiher and Professor Aviad Heifetz have been studying birds at the Shezaf Nature Reserve in Israel for almost 30 years. In a paper published in the Royal Society Open Science journal, they share their findings that among certain babbler groups, sentinel behavior is motivated by the songbird's own interests, and not the good of the group.
Babblers live in groups of about 20, and most of the time, there is a sentinel that assumes a lookout position for several minutes while the group is foraging. Babblers are very territorial; the sentinel is not only keeping watch for predators but also for other babblers that don’t belong to the group.
The flocks that the professors from the Open University in Israel studied were fitted with colored rings so that individual birds can be easily identified.
While sentinel behavior among groups of birds has been observed extensively, Ostreiher and Heifetz recently began researching the sentinel behavior of floaters – individual birds that have either been cast out or for other reasons decide to go it alone. What they found was that floaters also engage in similar lookout activities and will sound an alarm call if a predator approaches.
This suggests that while the group benefits from having a lookout, the instinct to act as the lookout is motivated not by the group but by self-preservation. The sentinel may simply be trying to scare away a predator instead of warning his buddies down below.
It might be easy to understand that when a floater displays sentinel behavior, the bird is acting for itself. However, birds in groups may have less selfish motives since the birds appear to alternate as lookouts. “There are some adult group members who act as sentinels more often than others. As far as we understand, acting as a sentinel is not a duty. The motivation is internal, and those who sentinel less often are not punished,” Ostreiher told From the Grapevine.
He also noted that the sentinel’s primary purpose is to gather information about its surroundings – the presence of a neighboring group, changes in food sources and even weather – not keeping lookout for approaching raptors and predators.
“We do not know what motivates them to stop foraging and climb up to a tree canopy and start to sentinel,” Ostreiher added. He and Heifetz are now focused on understanding what happens after an alarm call is sounded.
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Related Topics: Animals