WORD OF THE DAY
Why birds on the edge stay there: Study sheds light on murmuration mysteries
New research finds that sharp flock borders arise from simple rules of interaction—not from complex survival strategies
They twist and turn across the sky in dense, whirling formations—murmurations of birds that seem to move as one, captivating watchers and puzzling scientists for decades. Now, a new analysis suggests that one of the most mysterious features of these aerial displays—the behaviour of birds at the edges—may stem from accident rather than intent.
A study examining the flocking patterns of jackdaws has found that the sharp borders of murmurations, and the way certain birds linger at the edges, can be explained by the mathematical rules that govern how individuals interact with their neighbours.
Scientists have long noted two peculiar features of flocking birds: those on the outer edges tend to remain there longer than expected, and the border of the flock appears remarkably well-defined, almost as if deliberately maintained. Previously, it was thought that these edge behaviours might have evolved as adaptive traits—perhaps allowing certain birds to spot predators more easily or respond faster to threats.
But according to the new study using stochastic (random) models of animal movement, these patterns emerge naturally when birds follow what are known as topological rules—coordinating their movement with a fixed number of nearby neighbours, regardless of the actual distance.
In contrast, the same striking edge behaviours did not emerge when birds interacted using metric rules, where coordination depends on who is physically closest. The findings were further supported by existing GPS tracking data from jackdaw flocks, which revealed patterns consistent with the topological model.
“What’s fascinating is that these highly structured, seemingly purposeful formations might actually be the result of very simple interaction rules,” said Rothamsted’s Andy Reynolds who conducted the analysis. “The sharpness of the border and the persistence of edge birds aren’t necessarily deliberate strategies. They’re just what happens when the system runs on topological interactions.”
The study adds to a growing body of evidence that complex group behaviours—from fish schools to insect swarms—can arise from surprisingly minimalist rules. It also raises questions about how much of animal group behaviour is shaped by evolution, and how much simply falls out of physics and geometry.
Murmurations, often seen in starlings but also performed by other species such as jackdaws, have long drawn both artistic and scientific fascination. While their precise function is still debated, they are believed to offer protection from predators and help in roosting.
This new research doesn’t rule out the idea that edge behaviours might be beneficial—but it suggests they may not have evolved for that purpose. Instead, they might be a fortunate accident of nature’s algorithm.
Rothasmted studies swarming behaviours in nature because they provide scientists with important information on how the various pest species that affect our crops might behave. By mathematically modelling what holds a swarm together, strategies can be developed that improve our ability to predict, monitor and control the movements of insect pests.
Journal
Journal of The Royal Society Interface
Method of Research
Computational simulation/modeling
Subject of Research
Animals
Article Title
Topological interactions account for border dynamics of murmurations and transit flocks
Article Publication Date
6-Aug-2025
On-board camera footage offers bird’s eye glimpse into seabird flights and feeding behaviour
Scientists have captured unique on-board footage of Indian Ocean seabirds speeding just above the waves to catch flying fish on the wing.
Lancaster University
image:
Image of a red-footed boobie catching a flying fish on the wing. This is a still taken from video footage recorded by a camera mounted on a red-footed boobie in the Indian Ocean
view moreCredit: Dr Ruth Dunn
Scientists have captured unique on-board footage of Indian Ocean seabirds speeding just above the waves to catch flying fish on the wing.
The footage, obtained by lightweight bird-borne cameras formed part of a study of the lives of seabirds in the waters around the remote archipelago they call home.
Two red-footed boobies - a tropical cousin of the more familiar gannet – were carefully fitted with the tiny cameras to record how they catch their favourite food; flying fish. Of 15 capture attempts, 14 were towards flying fish while in flight and one was an underwater dive.
This is the first such on-board footage revealing that flying fish are caught on the wing.
“The cameras recorded footage of the birds catching flying fish just above the surface of the water, while on the wing,” said Dr Ruth Dunn, a Visiting Researcher at Lancaster University and lead author of the study. “We suspected this happened, but this is the first time that we’ve had bird-borne footage like this showing them foraging and catching fish mid-air. It could suggest they are catching a significant portion of their diet in this way.”
In addition, the research team used small GPS and accelerator tracking devices on 18 more red-footed boobies in the remote Indian Ocean archipelago to show how they use the wind to travel hundreds of kilometres over the deep blue open ocean to hunt fish.
Red-footed boobies have long narrow wings relative to their bodies enabling them to glide quickly and efficiently in high crosswinds. The study showed they prefer tailwinds and crosswinds, especially on their outward journeys towards their feeding areas.
Red-footed boobies hunt in the open ocean and do not stick to specific feeding sites because their prey can be patchy and moves around. The researchers show the birds’ selection of favourable winds allows them to conserve energy while travelling and searching for food.
By selecting favourable winds, the birds reached higher speeds without needing to increase flapping. The researchers believe that the birds may have adapted this behaviour to the unpredictable, patchy food options available to them.
The trackers showed that the birds were more likely to continue to hunt in windier conditions and less likely to rest. This is possibly because when it is windier the flying fish stay in the air for longer which provides better opportunities for the birds to catch them.
“We found that the birds foraged in windy conditions and we think that this might be because flying fish are able to glide in the air for longer in these conditions, making them more accessible to the boobies,” said Dr Dunn.
Understanding how the behaviour of birds, and other flying species, are influenced by winds is of growing importance at a time when global airflow patterns and intensities are shifting due to climate change.
The red-footed booby findings contrast to those by other researchers studying some albatross species, which find it harder to catch prey in windier conditions.
The researchers believe their findings will help provide a clearer picture of how red-footed boobies will fare in a changing world.
“This is the first step in helping us to understand more about how wind influences the behaviour and distribution of tropical seabirds,” said co-author Professor Stephen Votier, from The Lyell Centre, Heriot-Watt University’s global institute for Earth and marine sciences. “By gaining a clearer understanding of such environmental effects will enable us to predict how they will cope in the future.”
The study, which was supported by the Bertarelli Foundation, involved researchers from Lancaster University, Heriot-Watt University, the University of Exeter, and ZSL.
Their findings are outlined in the paper ‘Commuting in crosswinds and foraging in fast winds: the foraging ecology of a flying fish specialist’ which is published in Proceedings of the Royal Society B.
Journal
Proceedings of the Royal Society B Biological Sciences
Method of Research
Observational study
Subject of Research
Animals
Article Title
Commuting in crosswinds and foraging in fast winds: the foraging ecology of a flying fish specialist
Article Publication Date
6-Aug-2025
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