Thursday, October 27, 2022

Do Birds Grieve?

Environmental & Science Education, STEM, Brain, Biological Evolution, Biodiversity, Wildlife, Nature, Behavior

Ed Hessler

"Do Birds Feel Grief?" was the headline of the birding column by Val Cunningham for the StarTribune, October 5. The article is protected by a subscriber's paywall.
Cunningham was asked whether birds mourn after a cabin owner told him that following the death of one of a pair of barn swallows, "the other swallow then seemed to be holding a vigil, sitting halfway between its dead partner and its nest for some time."

It is now known that bird brains are not simple but complex and more "human like than once thought," e.g., see this article in Scientific American for a review of two scientific papers. In the essay, Cunningham calls our attention to Tim Birkhread's book "Bird Sense: What It's Like to Be a Bird" and also draws attention to one species in particular before returning to the behavior of the barn swallow: crows.

Crows are sometimes seen to congregate around a dead crow, a behavior that many of us have observed. What's up? Attributing grief or other motivations to crows is difficult to investigate scientifically if the aim is to collect empirical data strong enough to provide evidence of a behavior.

So, I take a sharp turn, deviating from the question of grief, and turn to a special issue of the Philosophical Transactions of the Royal Society B. The theme was "Evolutionary Thanatology: Impacts of the Dead on the Living in Humans and Other Animals. The entire issue is accessible with PDFs for each paper. 
There you will find a research article about crows and the other research articles are diverse and fascinating. John Marzluff, quoted by Cunningham (see below), is a co-author of the research paper which is not about grief but about the somewhat common behavior of crows gathering around a crow corpse.Here is the last paragraph but I urge you to look at--there are pictures, graphs, etc., as well as a description of experiments. I think you'll appreciate the challenge of planning and carrying out the experiments, designed to provide evidence. I subdivided this paragraph for easier reading.

"This study is the first to demonstrate that American crows occasionally make contact with dead conspecifics. The nature of contact in crows can be exploratory, aggressive or sexual.We show that such behaviours are both atypical and, with respect to sexual and aggressive behaviours, seasonally biased. We suggest that rather than information acquisition,food or territoriality, contact with crows is attributable to an inability among some birds to process conflicting stimuli resulting in inappropriate or conflicting displacement activities. 

"Similar aggressive and sexual behaviours have been anecdotally observed among cetaceans, non-human primates and elephants. It remains unknown, however, whether our findings apply to these animals. A crucial distinction between our study and the vast majority of observations among mammals is that most interactions involving mammals were between familiar individuals. The potential myriad ways this may affect the response of either mammals or birds are unknown. Given that crows maintain permanent pair bonds that can span over a decade, it is possible that responses to familiar individuals contrast with our findings, particularly with respect to affiliative behaviours. 

"Understanding whether these differences exist and what form they take (which may be investigated in experiments employing sedation) will help us better elucidate the significance of death on group members and partners, and help guide best practices when we are confronted with animal death in captive settings."

FYI: Raw data associated with this manuscript are available.

The Marzluff quote in Cunningham is worth repeating for two reasons. It notes the complexity of the bird's brain/nervous system and is an insight into biological evolution. "'Birds certainly possess the capacity to mourn -- they have the same brain areas, hormones and neurotransmitters as we co, they can feel.'" To which Cunningham added "but that doesn't mean we know when it's happening."

The human habit of projecting motivations and behaviors onto other humans as well as non-humans is almost a default response. I appreciated what Laura Erickson had to say; it bears ourclose attention. "'The complexities of how our own species feels grief are hard enough to tease out. It must be very complicated for scientists to break down grief into its components for any other species.'"(My emphasis)
Thanks Val Cunningham for another provocative, informative column.

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