Life is hard enough having to carve out a means to co-exist among our fellow beings. With every inch gained, it seems that we fall a few back from one instance to another. It’s easy to see cooperation among many species of creatures. You can readily see it if you’re a multi-species owner, i.e., you have cats, dogs, birds, and other creatures within the same household. And while some separation is necessary due to natural aggression, some species do co-exist quite well. It appears that humans, animals, and perhaps every living thing within our biosphere, must defend territories against invasive threats.
A recent study by the University of Chicago and the University of Nebraska shows that birds in the wild recognize other species and choose to form a bond of sorts that helps provide exclusivity to territory and the food within, as well as the element of safety in numbers.
From 2012 through 2015, two graduate students and their professor from the University of Chicago studied the routines of two species of fairy wrens within the Brookfield Conservation Park in South Australia. They discovered through a variety of means that not only do the birds cooperate with each other; they did so in such a way as to enhance the safety of their families over long periods of time. This proved beneficial in many ways. Often, these two species overlapped in territories, which generated a strong need to co-defend those territories against predators that are more aggressive and other unrecognized members of their own species. Recognition is important and governs the space the birds occupy.
During the study, the group observed that the dominant males were more aggressive toward songbirds outside of their mutually shared territories than they were to their fellow inhabitants. They used recordings of other birds and watched as the birds within the territory flew in to investigate the unrecognized sounds. Different times were utilized to determine the birds’ level of aggression and investigation; the dark of the night as well in the light of the day. It would appear that the song of co-habituating species bear some resemblance or marker to effect familiarity versus the tones of a bird several territories away.
These sets of exciting and interesting findings were recently published in the Behavioral Ecology journal of the International Society of Behavioural Ecology, a part of the UK’s University of Oxford. (An abstract of the study can be found here.)
As with people, the animals that surround us exhibit the same kind of group law and protections that prove safe to them. It encourages a comfort derived from having a patrolled and closely protected territory. I have watched black birds group up to pursue and nip at an invading hawk as it flew through the airspace of their homes. Their relentless attacks caused enough consternation of the hawk that it decided that this wasn’t worth the trouble, and so it flew out of range. I also know that this location is home to cardinals, blue jays, woodpeckers, robins, sparrows, and a few other species. In fact, I can recognize some of them as repeat visitors to backyard feeding places.