Zazu is on the brink! Southern yellow-billed hornbill that shot to fame in The Lion King is being wiped out by climate change, study warns
- Scientists studied breeding success of birds in Kalahari Desert from 2008-2019
- Nest success declined by 41%, while average chick number went from 1.1 to 0.4
- When the average air temperature went above 96.2°F (35.7°C), there were no successful breeding attempts at all
With its long yellow and down-curved beak, most Disney fans will instantly recognise the southern yellow-billed hornbill as Zazu from The Lion King.
But the stunning bird is at risk of being wiped out by climate change, according to a new study.
Researchers from the University of Cape Town studied the effects of high air temperate and drought on the breeding success of the birds in the Kalahari Desert from 2008-2019.
Their findings reveal that breeding output ‘collapsed’ during this time – with an increase in temperature to blame.
Researchers from the University of Cape Town studied the effects of high air temperate and drought on the breeding success of the birds in the Kalahari Desert from 2008-2019. Their findings reveal that breeding output ‘collapsed’ during this time – with an increase in temperature to blame
With its long yellow and down-curved beak, most Disney fans will instantly recognise the southern yellow-billed hornbill as Zazu from The Lion King
The Southern yellow-billed hornbill
The southern yellow-billed hornbill is a socially monogamous species.
The female seals herself into the nest cavity and stays there for an average of 50 days to brood and care for chicks.
The only opening is a narrow vertical slit, through which the male feeds the female and chicks.
This type of nesting largely protects from predation, which means that breeding success depends primarily on other factors such as climate and food availability.
For example, yellow-billed hornbills initiate breeding in response to rainfall, which corresponds with the hottest days of the year.
This makes it difficult for them to shift breeding dates outside of the hottest periods.
Previous studies have shown how animals living in the Kalahari Desert are suffering the consequences of global warming.
For example, a previous study revealed how multiple bird species are now breeding earlier and for a shorter time.
In the new study, the team set out to investigate the impact of climate change on yellow-billed hornbills over a 10 year period.
‘There is rapidly growing evidence for the negative effects of high temperatures on the behaviour, physiology, breeding, and survival of various bird, mammal, and reptile species around the world,’ said Dr Nicholas Pattinson, first author of the study.
‘For example, heat-related mass die-off events over the period of a few days are increasingly being recorded, which no doubt pose a threat to population persistence and ecosystem function.’
The researchers studied the breeding success of pairs of southern yellow-billed hornbills in wooden nest boxes at the Kuruman River Reserve, and compared their findings with climate trends for the region.
Their results showed that as the maximum air temperature increased, the breeding output collapsed.
‘During the monitoring period, sub-lethal effects of high temperatures (including compromised foraging, provisioning, and body mass maintenance) reduced the chance of hornbills breeding successfully or even breeding at all,’ explained Dr Pattinson.
When comparing the first three seasons (2008-2011) to the last three (2016-2019), the researchers found that the average percentage of occupied nest boxes declined from 52 per cent to just 12 per cent.
Nest success (successfully raising and fledging at least one chick) also declined from 58 per cent to 17 per cent, while the average number of chicks decreased from 1.1 to 0.4.
And when the average air temperature went above 96.2°F (35.7°C), there were no successful breeding attempts at all.
Worryingly, current warming predictions indicate that the entire breeding season will eclipse this temperature by 2027.
When the average air temperature went above 96.2°F (35.7°C), there were no successful breeding attempts at all. Worryingly, current warming predictions indicate that the entire breeding season will eclipse this temperature by 2027. Pictured: Kalahari Desert
‘Much of the public perception of the effects of the climate crisis is related to scenarios calculated for 2050 and beyond,’ Dr Pattinson said.
‘Yet the effects of the climate crisis are current and can manifest not just within our lifetime, but even over a single decade.
‘Despite no striking large die-off events, our prediction in this study is that southern yellow-billed hornbills could be extirpated from the hottest parts of their range as soon as 2027.
‘Sub-lethal consequences of high temperatures may drive local extinctions by resulting in recruitment failure (ie no young animals joining the population) and changes to the ecosystems on which we all depend.’
Climate change is causing some Amazonian birds to SHAPESHIFT
Climate change is shape-shifting the bodies of birds in the Amazon, the world’s largest rainforest, a concerning new study shows.
Researchers have found several bird species have become smaller with longer wings over several generations in response to hotter and drier conditions.
Smaller bodies are more efficient at dissipating heat, while bigger wings reduces the amount of metabolic heat generated to stay aloft.
Affected species include the golden-crowned spadebill, the gray antwren, McConnell’s flycatcher and the dusky-throated antshrike.
Adapting to shifting environmental conditions may include ‘new physiological or nutritional challenges’ for birds, say the scientists, who claim to have eliminated other factors that may have influenced these changes – in other words, there’s no doubt climate change is to blame.