By Faridat Salifu
Intensive agricultural landscapes in South Africa’s Western Cape may be undermining the breeding success of the country’s national bird, the Blue Crane, according to new research.
The study warns that wheat-growing regions that appear suitable for the species could actually be reducing its long-term survival.
Researchers from the University of Cape Town and the International Crane Foundation partnered with the Endangered Wildlife Trust to investigate breeding patterns across different habitats.
Their findings show that cranes nesting in the Western Cape’s wheatlands are producing significantly fewer chicks than those in other regions.
The research suggests these farming landscapes may function as an ecological trap, a habitat that appears attractive but ultimately lowers survival or reproductive success.
The study was published in the Ostrich: Journal of African Ornithology.
Scientists compared breeding outcomes in the Overberg and Swartland wheatlands with populations in the Karoo and eastern grasslands of South Africa.
They found cranes in grassland and Karoo habitats bred more frequently and successfully than those in agricultural areas.
Pairs in natural habitats produced close to one fledgling per breeding attempt.
By contrast, breeding pairs in wheatlands produced roughly half that number.
Around two-thirds of crane pairs in the Karoo and eastern grasslands successfully raised at least one chick.
Only about 40 percent of pairs in the Overberg and Swartland achieved the same outcome.
Lead researcher Christie Craig said the findings are concerning because the Western Cape wheatlands host some of the highest densities of Blue Cranes globally.
She warned that persistently low breeding productivity could explain recent population declines in the region.
The team also analysed winter flocks to determine how many young birds were entering the population.
Between 2019 and 2021, juveniles accounted for only about four percent of winter flocks in the Overberg and 3.6 percent in the Swartland.
Those figures represent roughly half the proportion recorded three decades ago.
Craig said the decline in recruitment suggests fewer young cranes are surviving to adulthood.
She noted that when fewer chicks fledge and fewer juveniles join the population, it becomes increasingly difficult for populations to sustain themselves.
Although the species has adapted to farmland, agricultural landscapes can introduce hidden dangers.
Harvesting operations can destroy nests during the breeding season when wheat fields are cut.
Disturbances near nesting sites may also increase predation by birds such as the Pied Crow.
Field observations also suggest chicks may die from hazards common on farms.
These include entanglement in fencing, drowning in water troughs and food shortages.
Craig said further research is needed to better understand the causes of chick mortality in these environments.
Despite the challenges, researchers emphasised that farmers remain central to conservation efforts.
Most breeding cranes occur on farmland, making collaboration with landowners essential.
Potential solutions include reducing disturbances near nests, modifying water troughs so chicks can escape and adjusting fencing to prevent entanglement.
Craig said working with farmers to balance conservation and agricultural needs will be critical to safeguarding one of South Africa’s most iconic bird species.
