A colorful bird that shot to fame in The Lion King is being wiped out by climate change, according to new research.
Global warming is reducing breeding success of the southern yellow-billed hornbill.
It is commonly seen in scrub and dry woodland areas of South Africa.
Typically on a safari, you will see yellow and red-billed hornbills – like the Disney character Zazu.
In the animated musical, he is the most trusted advisor to Simba’s pride of lions.
First author Dr. Nicholas Pattinson, of the University of Cape Town, said: “There is rapidly growing evidence for the negative effects of high temperatures on the behavior, physiology, breeding, and survival of various bird, mammal, and reptile species around the world.
“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.”
His team studied a population of southern yellow-billed hornbills at Kuruman River Reserve in the southern Kalahari Desert between 2008 and 2019.
Chick numbers collapsed during the 12 years due to rising air temperature. Data was exclusively collected from pairs breeding in wooden nest boxes.
The same phenomenon was identified from analyses of long-term trends and individual breeding attempts.
First author Dr. Nicholas Pattinson, of the University of Cape Town, said: “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.”
Yellow-billed hornbills are monogamous and will live in breeding pairs or small family groups.
They have a very distinctive cluck-clucking call. When a single bird starts clucking, very soon the entire group will join, creating a cacophony of bird sounds. Its calls also include whistles, grunts, cackling, and gritting.
It is one of the first studies to research the impact of the climate crisis on population-level breeding success over a longer timescale.
Global warming is worsening the harshest conditions in the world’s arid regions – increasing the frequency and intensity of droughts.
The animals that inhabit them are already suffering the consequences. Many bird species are affected. They are breeding earlier and for a shorter amount of time.
Dr. Pattinson said: “There is rapidly growing evidence for the negative effects of high temperatures on the behavior, physiology, breeding, and survival of various bird, mammal, and reptile species around the world.
“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.”
Yellow hornbills are cavity nesters. The female seals herself in 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.
When comparing the first three seasons between 2008 and 2011 to the last three from 2016 to 2019, the average percentage of occupied nest boxes plunged from 52 to 12%.
Successful raising and fledging of at least one chick fell from 58 to 17%, and the average chicks produced per breeding attempt decreased from 1.1 to 0.4.
No successful breeding attempts were recorded above the threshold air temperature of 35.7°C.
Breeding was negatively linked with the hottest days. These effects were present even in non-drought years.
The findings underline the fast pace at which the climate crisis is taking place is having severe effects for charismatic species over alarmingly short time periods.
Current warming predictions at the site show the hornbill’s threshold for successful breeding will be exceeded during the entire season by around 2027.
Dr. Pattinson added: “Much of the public perception of the effects of the climate crisis is related to scenarios calculated for 2050 and beyond.
“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 extinction by resulting in recruitment failure – with no young animals joining the population – and changes to the ecosystems on which we all depend.”
The study was published in Frontiers in Ecology and Evolution.
