Have you ever wondered how wild birds cope with baking hot afternoons and freezing cold mornings? Our new study has taken a close look at one of Africa’s most familiar birds – the helmeted guineafowl – and uncovered surprising answers about how they deal with extreme temperatures.
The helmeted guineafowl (Numida meleagris) is a common sight across sub-Saharan Africa’s savannas and semi-arid regions. They are instantly recognisable with their spotted plumage, bony helmet, bare blue head, and loud cackling calls. These birds are famously social, often seen roaming in noisy flocks.
Helmeted guineafowl can endure air temperatures from -4°C up to 40°C in South Africa.
The idea that animals huddle to stay warm – known as social thermoregulation – is well documented in mammals and birds like penguins. This theory proposes that animals huddle together to conserve heat in cold conditions, but is this what guineafowl are doing?
Together with colleagues in Spain, we set out to find the answer because understanding whether birds group to keep warm or for other reasons helps ecologists uncover the true drivers of social behaviour. This can also inform how species will respond to changing climates and help guide conservation strategies.
We studied a wild population of guineafowl in South Africa’s Madikwe Game Reserve, a protected area near the Botswana border. It’s known for its sharp daily temperature fluctuations during winter, with cold, frosty mornings dropping to 0°C and sweltering afternoons reaching up to 40°C.
To spy on the birds without disturbing them, we set up a live-streaming webcam at a busy waterhole, recording their behaviour over an entire year. We watched how group size, body posture and daily routines shifted with the seasons and weather.
What we found was striking.
Our study challenges some common assumptions about how animals survive in extreme climates. Guineafowl don’t rely on cuddling for warmth like some penguins and some species of monkeys. Rather, they use behaviour – adjusting posture, timing their activity and changing group sizes according to food and safety needs – to navigate life’s temperature extremes.
This strategy may help them cope with the growing unpredictability of climate.
When they get together, it’s to exploit a food patch and nurture their offspring within close-knit social groups while foraging, or to fend off predators during coordinated mobbing behaviour.
What we found
The evidence we gathered shows that the guineafowl did not form bigger groups when temperatures dropped. There was no evidence they huddled together to stay warm. Even at night, when they roosted in trees, they perched in small family units – just two or three birds per branch.
Our findings suggest that the reason guineafowl form groups has more to do with food and safety.
During the dry winter months, when seeds and vegetation are scarce, the birds form large foraging flocks to help find food and stay safe from predators. More eyes mean better chances of spotting danger. This supports the widely recognised “many eyes” hypothesis, which shows that individuals in larger groups benefit from improved predator detection. But once the rains return and food becomes more plentiful and spread out, the guineafowl split into pairs or small groups to focus on breeding.
While group size wasn’t tied to temperature, the birds used clever body postures to handle both heat and cold. On chilly mornings below 17°C, they puffed out their collar feathers and tucked their bare necks deep into their bodies, creating a rounded, fluffy ball that trapped heat.
On warmer days, they stood tall with their necks fully extended, legs exposed, and feathers sleek to release excess heat. When temperatures soared above 30°C, they opened their beaks to pant, spread their wings slightly away from their bodies, and exposed bare skin to cool off, much as a dog pants on a hot day.
One of the most delightful behaviours observed was “sunning”. On frosty winter mornings, guineafowl would fly down from their roosts and stand facing the rising sun, fluffing their feathers and soaking up warmth before starting their day. It’s a simple, effective way to heat up after a cold night.
Another surprise was how rarely the birds drank water. Despite living in a dry environment, only about 2% of observed guineafowl visits were to the waterhole. In wet seasons, they likely get most of their moisture from eating green plants and insects. In the cold, dry season, when food is drier, drinking increased slightly, but still far less than expected.
They drank even less when it was both hot and windy, possibly because the noise of the wind makes it harder to detect predators when standing out in the open. Avoiding water during hot periods is usual among helmeted guineafowl, which typically avoid exposing themselves during peak heat due to increased predation risk and the physiological stress of extreme temperatures. Most galliforms (gamebirds) and terrestrial species favour early morning or late afternoon activity patterns, limiting mid-day exposure.
Every evening, the flock gathered at the same familiar “launching pad” near the waterhole and flew into nearby trees to roost. But once again, warmth wasn’t the reason for this behaviour. They roosted to avoid ground predators, not to share body heat. I have seen them for many years going into trees when predators or dogs chase them, unlike spurfowl and francolin just flying further on.
Why insights are useful
This research carries important lessons for understanding animal adaptation. Rather than relying on group warmth, guineafowl show how behavioural flexibility, adjusting posture, timing and habitat use, can buffer them against harsh conditions. It highlights how survival depends not just on temperature or water availability, but on having access to diverse habitat types: open grasslands for foraging and trees or dense bush for roosting and safety.
As climates shift and ecosystems change, understanding how animals like guineafowl cope with extremes will be crucial for conservation planning.
