Ahmedabad study unlocks new truth about stunning bird formations in the sky

What makes this pulsing, twisting organism change its shape? Scientists who study starling murmurations have put forward several theories over the years. Researchers from Ahmedabad University have now established a correlation between the size and shape of the murmurations and the threat and proximity of a predator in the sky.

The study, the first of its kind in India, has been published in the April issue of Integrative and Comparative Biology (ICB), the internationally reputed journal of zoology, organismal biology and comparative physiology that was originally known as American Zoologist.

The paper, authored by Venu Divin and Jitesh Jhawar of the School of Arts and Sciences at Ahmedabad University, has quantified the shape dynamics of rosy starling flocks in the presence and absence of predators – and concluded that a predator’s presence has an influence on the geometry of murmurations.

Videos and photographs were taken from the top of a building rising over canopy height, and the murmurations were classified in various shape categories. (Express)

Starling murmurations, which are typically seen at dusk for a few minutes to up to an hour, are common in the autumn and winter across Europe and North America. India sees some spectacular murmurations as well, and Gujarat is the best known hotspot, with the standout site being Jamnagar’s Lakhota Lake.

The rosy starlings seen in India are different from the European variety of the species. The birds breed in Central and West Asia and Eastern Europe, and start migrating to the Indian subcontinent from around July-August to winter until March – making an unusual west-east journey rather than the north-south one that most migratory species make.

The birds forage only on trees and not on ground. Flocks have been seen in Gujarat from around the end of July this year. Besides Gujarat, starlings are also seen in Rajasthan, Karnataka, Keralam, Chhattisgarh, Telangana, and Andhra Pradesh.

The study was carried out on campus at Ahmedabad University from January 2, 2025 to February 13, 2025. Videos and photographs were taken from the top of a building rising over canopy height, and the murmurations were classified in various shape categories. The data were collected over 28 days, from one hour before sunset until five minutes after all the birds had moved to their roosts.

“We recorded details…including the shape of the flock, the approximate number of individuals in the flock, the time of observation, the direction of the flock, whether merging or splitting occurred, the shape shift, and the presence of any predator near the flock…,” the authors have noted in the paper.

A total 3,023 flocks were recorded during the sampling period, and 12 distinct canonical shapes were identified, including “Small Road”, “Small Oval”, “Globular”, “Wave Shape”, “Ovoidal”, “Snake” and “C-Shape”.

The most common avian predator at the study site was the black kite (Milvus migrans). The study recorded 181 instances in which a predator was present within 10 metres of a flock of rosy starlings.

In the absence of a predator, flock shape frequencies were dominated by “Small Oval” (27.9%) and “Mini Flock” (27.7%) formations. However, in the presence of a predator, the “Small Road” shape became overwhelmingly dominant, accounting for 71.3% of observed shapes.

The study recorded 181 instances in which a predator was present within 10 metres of a flock of rosy starlings. (Venu Divin, Ahmedabad University)

“The Small Road formation has a relatively large surface area and pointed ends at the front and rear, features that may facilitate higher flight speed,” the study notes.

“Compared to spear-shaped formations, such configurations may offer advantages that allow faster escape.”

However, the change in murmuration displays was not consistent or predictable. “Although black kites were present in the study area on most days, predator presence alone did not consistently trigger murmuration displays. This observation contrasts with the common assumption that predator presence directly induces murmurations,” the authors note.

The findings of the study are consistent with those of research on European starlings that suggest murmurations are more likely to occur when flock sizes exceed the threshold of approximately 400-500 individuals.

Explaining the significance of the study, Jhawar told The Indian Express, “From the perspective of group living [of birds], this study has broad implications. So far, group living studies have been done in labs; there are very few group living studies directly from the field. This study is one of its kind in that sense. We have shown that group living can be studied in this way [as well].”

He added that the study of shapes is also rare in the wild. “There are very few such studies, especially in the wild. If their behaviour is to be predicted in future, these types of studies are needed. Until we understand these dynamics, we will not be able to predict their responses in their natural environment. The collective response is important because often species do not respond individually,” Jhawar said.