Birds Turning Geothermal Pools into Feather‑Cleaning Spas
Humans have been soaking in warm water for centuries to feel better, but a recent study from the University of Otago suggests that some avian species might be doing the same for a very different reason. Researchers observed several bird species near geothermal sites in New Zealand and found that the birds spent considerably more time grooming and bathing in the sulfur‑rich steam than they did at ordinary locations. The implication is that these feathered visitors could be using the natural heat and chemical properties of the springs to rid themselves of parasites and possibly harmful microbes.
Why the Steam?
The idea originated when Ceridwen Fraser, a scientist familiar with Antarctic penguins, noticed those cold‑adapted birds perched in steaming hot‑water vents. "It seemed odd for animals that thrive in icy conditions to seek out a sauna," she recalled. Since sulfur is a well‑known agent for controlling insects, fungi and other parasites, Fraser hypothesised that the birds might be exploiting the same property.
Fieldwork in Rotorua
To test the hypothesis, the team set up observation stations around Rotorua on New Zealand’s North Island, a region dotted with geysers, hot pools and vents that release sulfurous gases. Over a four‑week period they monitored six bird species – black swans, Canadian geese, Australian purple‑crowned lorikeets and three gull species – both at geothermal sites and at control locations without any heat or steam.
In total, the researchers logged 334 distinct sightings, amounting to nearly 2,900 minutes of watch time. Each bird was followed for up to ten minutes, during which the scientists recorded every activity: resting, foraging, swimming, and, most importantly, feather‑maintenance behaviours such as preening and bathing.
Clear Patterns Emerge
The data revealed a striking contrast for certain species. Black swans and several gull types devoted significantly more time to activities associated with parasite removal when they were at geothermal spots. They preened more frequently, often dipping their beaks into the hot water before smoothing their plumage. This pattern was not as evident in the Canadian geese and the Australian lorikeets, which appeared to use the warm areas mainly as feeding grounds rather than grooming stations.
Fraser explained, "Our results indicate that birds may be able to shed some parasites or disease agents by exploiting geothermal environments. It shows that wildlife is not always helpless in the face of such threats." However, the study also acknowledges that direct measurements of parasite loads were not taken, so it remains uncertain whether the birds actually emerged with fewer parasites after their steamy sessions.
What Remains Unclear
Because the researchers did not quantify the number of ectoparasites on the birds before and after the visits, the claim that the hot springs function as a genuine treatment remains provisional. Moreover, not all species responded uniformly; some seemed indifferent to the steam, focusing instead on the abundant food that often gathers around warm waters.
Consequently, the authors describe their findings as an intriguing indication rather than conclusive proof. Further work involving parasite counts and perhaps experimental exposure to sulfur‑rich water will be needed to confirm whether these avian “spa‑goers” are truly benefitting from the geothermal baths.
Regardless of the final verdict, the study adds a fascinating layer to our understanding of animal behaviour, highlighting how wildlife can creatively exploit natural resources to address health challenges.
Source: https://scientias.nl/sommige-vogels-nemen-mogelijk-een-spabad-tegen-parasieten/#respond