The yellow-billed hornbill could disappear from the Kalahari, and global warming is to blame

Yellow-billed hornbill. Photo: Faansie Peacock

A sustained rise in global temperatures could see the southern yellow-billed hornbill disappear from parts of the Kalahari Desert in southern Africa by 2027, according to a study by the University of Cape Town.

The bird is best known for its unusual breeding and nesting habits in which the female locks herself into a cavity and stays there for about 50 days to hatch and care for the chicks. The creature is also closely related to the red-billed hornbill, on which the character of Zazu in “The Lion King” was based.

Southern yellow-billed hornbills struggle to reproduce above certain temperatures as they face greater difficulties in foraging and lose weight. A comparison of two three-year periods, between 2008 and 2011 and 2016 and 2019, showed that the number of nest boxes occupied at a site in the Kuruman River Reserve in South Africa dropped to 12% from 52%. , the researchers said. The average number of chicks per breeding attempt fell to 0.4 from 1.1.

Meanwhile, temperature data for the region dating back to the 1960s for the region did not show significant changes until the summer at the turn of 1996-1997, said Nicholas Pattinson, study author and researcher at UCT. The average daily maximum average temperature has risen by about 1 degree Celsius every decade since then, according to the paper.

“There is rapidly growing evidence for the adverse effects of high temperatures on the behavior, physiology, reproduction and survival of various species of birds, mammals and reptiles around the world,” Pattinson said.

“Southern yellow-billed horn beaks could be eradicated from the hottest parts of their range as early as 2027.”

The study, one of the first to research the impact of rising temperatures on a species’ reproductive success over a longer period of time, shows that global warming increases the risk of further extinctions and a decrease in biodiversity. Above a daily maximum temperature of 35.7 degrees Celsius (96.3 Fahrenheit), there have been no successful breeding attempts among hornbills. Based on current global warming trends, that temperature will be exceeded for the birds’ entire breeding season by 2027, the researchers said.

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