Standing tall with their red heads and grey feathers, Sarus Cranes are known to offer good company to the farmers of India, foraging, nesting and roosting in flooded paddy fields in parts of north and west India.

However, farming activities can also pose several threats to the breeding birds, including damage to eggs due to trampling and machinery, and increased risk of predation to Sarus Crane chicks exposed after the harvest.

Why the Sarus is vulnerable

The Sarus is a monogamous bird that nests during heavy monsoonal rainfall. Besides paddy fields, it favours marshlands, lakes and ponds for breeding, since these spots are full of vegetation like reed.

A slow breeder, the Sarus yields only 1-2 eggs at a time. Its high dependence on the landscape and rainfall, besides its slow pace of breeding, has pushed the world’s tallest flying bird into the ‘globally vulnerable’ category. 

However, changes in landscape and rainfall patterns are disturbing the birds’ habitat and mating behaviour.  A study conducted in two districts of Uttar Pradesh found that expansion of towns permanently displaced 0.7 per cent of Sarus pairs annually.

On the other hand, below-normal rainfall in the monsoon can prevent Sarus Crane pairs from breeding or can enhance mortality of eggs and chicks as low water levels increase risk of predators.

How the Sarus Crane is overcoming the odds

A study done by the International Crane Foundation evaluated unseasonal nesting behaviour of Sarus Cranes for 13 years in the states of Haryana, Gujarat, Rajasthan and Uttar Pradesh. The researchers found that the pairs which could not nest successfully, or lost their chicks during the regular breeding period, try to nest again if conditions are conducive. These conditions can be either due to unseasonal rainfall during non-monsoon months or due to creation of wetlands through leakages from irrigation canals or around water reservoirs.

For instance, in Kota district of Rajasthan, Sarus Cranes are known to breed twice per year, including in the dry season (February–May). This occurs because of the canalised system of the Chambal river that delivers water to the cooling plants of a power plant once every 15 days during the summer. The leakage from the canal leads to water flowing into the marshes.

Researchers found that during the monsoon, Sarus Cranes extensively used paddy fields for nesting in Gujarat and Uttar Pradesh, while wetlands such as marshes, ponds, lakes, and reservoirs were the primary nesting habitat in Haryana and Rajasthan. However, all the off-season nesting activity occurred in natural and artificial wetlands, irrespective of the region. This shows that flooding created by monsoon in the fields is adequate for nesting of Sarus Cranes, but during non-monsoon months, wetness in fields is insufficient.

Further, the study found that 68 per cent of the unseasonal nests were initiated due to conditions created by artificial water sources such as reservoirs and irrigation canals. Around 53 per cent were initiated in years following abnormal monsoon years, including years with delayed monsoon, below-normal rainfall, above-normal rainfall, and rain outside of the normal months. Only 21 per cent nests experienced both artificial water sources and followed unusual monsoon conditions, but all nests experienced either artificial water sources or abnormal monsoon conditions.

This is, thus, one of those rare scenarios where man-made structures are helping the procreation of a wild species. However, it is still too early to rejoice, because a few positives are not enough to neutralise our increasingly negative footprint on the habitats of these majestic birds.