A large flock of pigeons leaves Nepali researchers wondering what happened

KATHMANDU – In December 2022, Hiru Lal Dangaura, Vikram Tiwari and Subam Chaudhary were watching a colony of vultures in the western plains of Nepal, when they saw an amazing sight: a large flock of pigeons. There were so many birds that the mist spread across the sky, creating a shifting canvas of gray and white. Observers remember hearing the rhythmic flapping of wings and soft chirping of the birds, as they watched in wonder and fascination.

The discovery of the flock, estimated at around 6,500 pigeons on December 14, and 7,500 the following day, has been described as unusual and has baffled local researchers and bird watchers alike, Dangaura and colleagues wrote in a recently published study. in a Nepalese Journal of Zoology.

“We have never encountered such a large gathering of pigeons in our activities,” Dangaura, a project officer at the NGO Bird Conservation Nepal (BCN), told Mongabay.

This marking coincided with the time when in the plains they began to irrigate their land for winter wheat.

“When water enters the fields, birds’ prey such as worms and insects come to the surface. “The pigeons we have seen eat those kinds of prey,” said Dangaura.

The flock is made up of South-Central Asian species of the common pigeon, Columba palumbus casiotis, which the study authors identified in the birds’ cinnamon-colored necks. Pigeons are not considered an endangered species, as they occur in large numbers over a wide range, from Europe to West Asia and North Africa. In Nepal, the pigeon is a migratory species, and is often seen during the winter season.

“However, we have never seen such a large flock,” said ornithologist Krishan Prasad Bhusal, who was not involved in the research.

“The high number of this species observed by our team exceeds any known record of this subspecies,” the study authors said. The largest previous flock seen by ornithologists in Nepal was around 300.

And for these particular subspecies, the herd size is unprecedented throughout its range in this part of the world, the study said. Another important observation of the species, which the authors found on the population science platform Bird, showed flocks of 500 pigeons in India and 250 in Pakistan. Small herds were recorded in southern Iran (40) and northeastern Iran (100).

The European subspecies, C. p. quality, however, has been observed in large flocks of about 50,000 birds, said study co-author Anand Chaudhary. He added that he believed the birds they saw on the plains of Nepal were likely on the Central Asian Flyway, a migration route used by large numbers of birds to dive and nest across Eurasia, the Arctic Ocean, the Indian Ocean and related island chains.

Various factors such as food availability, weather conditions, animal avoidance and social attraction can lead to such a large number congregating as they pass through Nepal, Chaudhary said.

“We don’t know [for certain] what brought herds in such numbers to Nepal,” he said. There hasn’t been much research on how these birds use flight.

Dangaura said changes in climate and environmental variability such as wind and rainfall patterns due to global warming could be a factor.

“We also considered possibilities such as major floods occurring in Pakistan in the summer of 2022,” the study authors said. Although most of the flood-hit areas are not wintering grounds for pigeons, their habitats could be affected by the heavy rains that spread across the country, the study says.

“However, linking the floods in Pakistan with the destruction of common insects in Nepal is not speculative,” it notes. Add such migration may be common for small species, but may not have been recorded before due to the limited number of bird watchers and ornithologists in the region of South and Central Asia.

Chaudhary said the findings call for greater efforts to monitor and conserve birds in the Central Asian Flyway, as well as assess potential climate impacts.

However, Bhusal said he doubts the pigeons were in the Central Asian Flyway, noting that they frequent waterfowl and birds of prey such as vultures. He admitted, however, that more research is needed to clarify the question.

Meanwhile, Dangaura and his team are eagerly awaiting the arrival of the coming winter to see if the pigeons return in large numbers like last year. They tried to count them the last time around, he said, and this time the plan is to get a better understanding of what is really going on.

Advertisement image: A large flock of common beetles was seen in western Nepal in December 2022. Image courtesy of Hiru Lal Dangaura

Abhaya Raj Joshi is a Nepali staff writer at Mongabay. Find him at 𝕏 @arj272.

In Kathmandu, when the hawk is gone, the pigeons come out to play. And the dirt

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Quote:

Dangaura, HL, Tiwari, V., Chaudhary, S., Dangaura, KD, & Chaudhary, A. (2023). Common Wood Pigeon Record Numbers (Columba palumbus casiotis) was seen in western Nepal in December 2022. Nepalese Journal of Zoology, 7(1), 60-64. doi:10.3126/njz.v7i1.56311