European starlings are the iconic murmurating species, but they are not the only birds that form these swirling, shape-shifting aerial displays. Starlings perform the most visually dramatic murmurations, typically at dusk before settling into communal roosts, and the phenomenon has been studied in starlings more intensively than in any other bird. Yet similar coordinated flocking behavior shows up in other species, and the reasons behind it turn out to be a tangle of anti-predator defense, social negotiation, and possibly information exchange that researchers are still working to untangle.
Starlings Are the Textbook Example
When most people picture a murmuration, they are picturing European starlings (Sturnus vulgaris). These pre-roost displays can involve anywhere from a few dozen to many thousands of birds, twisting and pulsing across the sky in fluid formations before dropping into their overnight roosting site. The displays tend to happen in autumn and winter, when starlings gather in large communal roosts, and they are most visible at dusk against a fading sky. A large citizen-science effort in the UK confirmed that these pre-roost displays are one of the best-documented examples of collective animal behavior in the natural world.1PubMed Central. Birds of a feather flock together: Insights into starling murmuration behaviour revealed using citizen science
What makes starling murmurations so striking compared with other flocking events is their sheer fluidity. A flock of a thousand starlings can reverse direction, split into sub-groups, compress into a tight ball, and then expand again, all within seconds, without any single bird acting as a leader. The coordination looks choreographed, but it emerges from each individual reacting to its neighbors.
Other Birds That Form Murmurations
Starlings get the spotlight, but coordinated aerial flocking occurs in quite a few other species, even if these displays are less often called “murmurations” in casual conversation.
- Dunlins and other shorebirds: Small sandpipers, especially dunlins (Calidris alpina), fly in dense, synchronized flocks that flash light and dark as the birds bank in unison. Researchers studying starling escape behavior noted that a distinctive vertical, elongated flock shape previously described only in dunlins also appeared in starlings under pursuit.2bioRxiv. Starling murmurations under predation
- Jackdaws: Corvids in the genus Corvus are not usually associated with murmuration-style displays, but jackdaws (Corvus monedula) form coordinated transit flocks whose internal dynamics closely resemble those of starling murmurations. Analysis of jackdaw flight data confirmed that the same topological interaction rules seen in starlings also govern jackdaw flock structure.3Royal Society Publishing. Topological interactions account for border dynamics of murmurations and transit flocks
- Swallows and martins: Tree swallows, purple martins, and barn swallows form large communal roosts during migration, and their morning departures create radar signatures visible across huge distances. Weather surveillance radar has been used to detect and track these communal roost departures across the Great Lakes region of the United States over two decades.4PubMed Central. Quantifying long-term phenological patterns of aerial insectivores roosting in the Great Lakes region using weather surveillance radar
- Red-billed queleas: Found in sub-Saharan Africa, queleas form some of the largest bird flocks on earth, occasionally numbering in the millions. Their wheeling aerial maneuvers before roosting closely parallel starling murmurations in form, though they have received far less scientific attention.
- Waders in mixed flocks: Knots, sandpipers, and plovers sometimes form tight, synchronized flight groups over estuaries and mudflats, especially when a raptor appears. These displays share the rapid directional changes and wave-like behavior seen in starling flocks, though they tend to be smaller in scale.
The underlying point is that coordinated flocking is not a quirk unique to starlings. It appears across taxonomic groups whenever large numbers of birds share roosting or foraging habitat and face pressure from aerial predators. Starlings simply do it at a scale and frequency that makes the behavior impossible to miss.
How Individual Birds Coordinate Without a Leader
One of the most common questions about murmurations is straightforward: how do thousands of birds move together without crashing into each other? The answer lies in what researchers call topological interaction. Rather than tracking every bird within a certain radius, each starling appears to pay attention to a fixed number of neighbors, roughly six or seven on average.5Cell Press (Current Biology). Murmurations If those six or seven neighbors shift direction, the focal bird shifts too, and that adjustment cascades through the flock.
This neighbor-counting rule, as opposed to a distance-based rule, turns out to matter a lot for how the flock behaves at its edges. Modeling work shows that topological interactions naturally produce the kind of dynamic, churning borders observers see in real murmurations, whereas distance-based rules do not. And the pattern extends beyond starlings: jackdaw transit flocks show border dynamics consistent with the same topological interaction model.3Royal Society Publishing. Topological interactions account for border dynamics of murmurations and transit flocks
The practical consequence is that a behavioral change by one bird on one side of the flock can propagate across the entire group almost instantly. A landmark study reconstructing the three-dimensional positions and velocities of individual starlings found that velocity fluctuations are correlated across the full extent of the flock, no matter how large it is. The range of correlation scales with the flock’s overall size rather than being fixed at some set distance.6PubMed Central. Scale-free correlations in starling flocks In plain terms, a flock of fifty birds and a flock of five thousand both respond as a single unit, because each bird’s adjustment ripples outward through the neighbor network until the whole group has reacted. The researchers described the flock as behaving like a critical system, poised to respond maximally to outside disturbances.
Predator Defense Is the Leading Explanation
Ask most biologists why starlings murmurate and the first answer will be predator defense. Starling flocks are regularly targeted by raptors, especially peregrine falcons and sparrowhawks, and the murmuration appears to make it dramatically harder for a predator to isolate and capture a single bird.
Recent fieldwork using a robotic falcon to pursue starling flocks documented the range of collective escape maneuvers starlings deploy. Researchers chased flocks of roughly 20 to 2,000 birds for pursuits lasting about 20 seconds to two minutes on average. The flocks responded with a varied repertoire: collective turns, splits, flash expansions, compaction into tight balls, agitation waves, and a behavior called “blackening,” where the flock appears to darken as birds bank in synchrony. Multiple escape patterns often appeared simultaneously within a single flock during a single pursuit.2bioRxiv. Starling murmurations under predation
The diversity of these responses is itself thought to be part of the defense. A predator that approaches the flock might encounter a sudden split, then a compacting, then a turn, in rapid succession. This unpredictability likely overwhelms the predator’s ability to lock onto a target, an effect sometimes called the confusion effect. It is not just about being hard to catch; it is about being hard to even choose which bird to chase.
Beyond Predators: Social Functions of the Pre-Roost Display
Predator defense is compelling, but it does not explain everything about murmurations. The displays often begin well before any predator appears and sometimes continue for 20 or 30 minutes. If safety were the only goal, the birds could simply drop into the roost quickly. The persistence of the display has led researchers to explore other functions.
One long-standing idea is the information centre hypothesis, which proposes that communal roosts serve as hubs where birds that had a poor foraging day can identify and follow successful foragers the next morning. Under this hypothesis, the murmuration could function partly as an advertisement, drawing birds in from surrounding areas so the roost grows large enough to serve as an effective information-sharing network.7Oikos. Beyond the information centre hypothesis: communal roosting for information on food, predators, travel companions and mates? The idea has been tested most rigorously in vultures, where GPS tracking confirmed that uninformed birds at communal roosts do follow informed roostmates to previously discovered food sources.8PubMed Central. Social foraging and individual consistency in following behaviour: testing the information centre hypothesis in free-ranging vultures Whether the same dynamic plays out at starling roosts is less well documented, but the parallel is suggestive: large, conspicuous pre-roost gatherings could help birds locate roosts and, by extension, foraging partners.
Warmth is another practical factor. A communal roost of thousands of birds generates meaningful heat on cold winter nights, and the murmuration may help coordinate which birds settle where. There is also a growing view that the display involves social negotiation over roosting positions, since birds closer to the center of a roost are safer from nocturnal predators than those on the edges.
Vision, Not Sound, Drives the Coordination
Given the speed at which turns propagate through a murmuration, you might assume the birds are calling to each other. They are not, at least not for directional coordination. Research comparing the roles of acoustic signals and movement cues in group coordination found that starlings in murmurations copy the flight direction and speed of nearby individuals through visual tracking rather than vocalizations.9Royal Society Publishing. The relative contribution of acoustic signals versus movement cues in group coordination and collective decision-making In a fast-moving, densely packed flock, vocal communication would be unreliable: the noise of thousands of wingbeats and the simultaneous calls of many birds would make it nearly impossible to locate which neighbor is signaling what.
Starlings do have sophisticated visual systems, and studies of their head movements show that they copy the timing of their neighbors’ lateral scans, placing those scans closer together in time than chance would predict. They appear to monitor nearby flockmates using their peripheral vision rather than their high-acuity central vision.10ScienceDirect. Social birds copy each other’s lateral scans while monitoring group mates with low-acuity vision This strategy makes sense in a murmuration context: if you are flying wingtip to wingtip with six or seven neighbors, using your peripheral vision to track them frees your central vision for watching the sky ahead or spotting a predator. The fact that head-scan timing is socially contagious may also accelerate how fast threat information spreads through the flock, since a neighbor’s sudden head turn could trigger your own before you even see what alarmed them.
Energy Costs and the Role of Orientation Waves
Murmurations are visually dramatic, but the birds are not performing aerobatics for fun. Flight is metabolically expensive, and spending 20 minutes in a dense, fast-turning flock costs energy a starling could otherwise conserve. This raises the question of whether the flock dynamics themselves reduce energy costs in some way.
Computational modeling of starling flocking has explored this angle. One model built around orientation-based social flocking, where birds align with their neighbors’ body orientation rather than just their heading, found that the resulting flight paths used significantly less energy for turning compared with classic simulation approaches. The model also produced emergent orientation waves, the rippling patterns of directional change visible in real murmurations, without any predator present.11ScienceDirect. Flock2: A model for orientation-based social flocking The implication is that the way starlings coordinate their movements may inherently minimize the energetic cost of rapid turns, meaning the murmuration is not as wasteful as it might look from the ground.
That said, the energy-saving effect seems to apply mainly to turns and directional changes within the flock. Nobody argues that murmurating is cheaper than simply perching. The display still represents a real investment, which reinforces the idea that it serves important functions, whether anti-predator, social, or both, that justify the metabolic expense.
How Scientists Actually Watch Murmurations
Studying a murmuration is not easy. You are dealing with hundreds or thousands of small, fast, visually similar animals in three-dimensional space. Early studies relied on video and manual tracking, but the field has been transformed by two technologies.
The first is stereoscopic 3D computer vision. The STARFLAG project, based in Rome, pioneered this approach by using multiple synchronized cameras to reconstruct the positions and velocities of individual birds within large flocks. This is how the topological interaction rule and the scale-free correlation findings mentioned earlier were obtained. Without the ability to track individual birds in three dimensions, researchers would still be guessing about the internal structure of the flock.
The second is weather surveillance radar. Communally roosting birds produce distinctive radar signatures when they depart en masse at dawn, and machine-learning algorithms can now automatically detect and track these departures. Radar-based monitoring has been used to locate previously unknown roost sites and to quantify long-term patterns in roosting behavior for species like swallows and martins across the Great Lakes region.4PubMed Central. Quantifying long-term phenological patterns of aerial insectivores roosting in the Great Lakes region using weather surveillance radar A separate system applying machine learning to weather radar images has been used to detect communal bird roosts across the entire United States, providing large-scale data about habitat use and movements during the non-breeding season.12Proceedings of the AAAI Conference on Artificial Intelligence. Detecting and Tracking Communal Bird Roosts in Weather Radar Data Radar does not capture the fine-grained dynamics of a murmuration the way 3D cameras do, but it reveals the big-picture ecology of communal roosting at continental scales, something no camera setup could accomplish.
Why Murmurations Inspire Drone Engineers
The rules governing starling murmurations have caught the attention of engineers designing autonomous drone swarms. If you need dozens of unmanned aerial vehicles to fly together through cluttered environments without a central controller telling each one what to do, the starling playbook is appealing: simple local rules, robust collective behavior, fast obstacle avoidance.
Researchers have mapped the behavioral patterns of starling flocks, including collective movement, evasion, and local-following behavior, onto fixed-wing drone swarms to improve their ability to dodge dynamic obstacles in complex environments.13PubMed Central. Starling-Behavior-Inspired Flocking Control of Fixed-Wing Unmanned Aerial Vehicle Swarm in Complex Environments with Dynamic Obstacles The appeal is not just aesthetic. The scale-free correlation property, where information propagates across the whole group regardless of size, is exactly the kind of responsiveness drone engineers want. If one drone in a swarm detects an obstacle, the ideal outcome is for the entire swarm to react coherently and immediately, much as a starling flock reacts to a falcon.
The biomimicry work is still in relatively early stages, and real drone swarms operate under constraints starlings do not face, including communication latency, battery limits, and regulatory restrictions on autonomous flight. But the direction of the research underscores how much the natural phenomenon has taught us about decentralized coordination more broadly, with applications reaching well beyond ornithology into robotics, traffic management, and network design.
When and Where to See a Murmuration
If you want to watch a murmuration yourself, your best bet in Europe and much of North America is late autumn through early spring, when starling numbers peak at communal roosts. Look for large congregations arriving at a roost site about 30 to 60 minutes before sunset. Favored roost locations include reedbeds, under bridges and piers, in woodlands, or on buildings in urban areas. The displays tend to be most spectacular on calm, cold evenings when large numbers of birds converge on a single site.
In the UK, well-known murmuration hotspots include the Somerset Levels, Brighton’s Palace Pier, and Gretna Green in Scotland. In North America, starling murmurations are common in agricultural areas and cities across the eastern and midwestern states, though they are less reliably massive than in parts of Europe. For shorebird murmurations, tidal estuaries and mudflats at high tide can produce impressive coordinated flights of dunlins and knots, especially when a raptor triggers a panic response. These are harder to predict but well worth seeking out if you spend time in coastal habitats during migration season.