‘From changing their calls in loud traffic to seeing ‘status’ through stripes, birds keep surprising us’

Trevor Price has been studying birds in the Himalayas since 1985 — and they still surprise him. The ornithologist tells TE about his research. ‘We study birds of the Himalayas and, in particular, look at two aspects. First, we ask why the eastern Himalaya has many more species than the Western Himalaya.Second, how are birds dealing with climate change and other human-driven impacts/’Importantly, well before we humans came along, ripping up trees and making malls on meadows, birds had learnt to deal with changing climes. Price says, ‘Birds go back a long way. The last famous mass extinction 66 million years ago had a huge impact on them because that wiped out many dinosaurs, pterodactyls, etc. After that, birds radiated a lot but 34 million years ago, it suddenly got much colder. Massive ice sheets started to form in Antarctica. Global wind patterns changed, turning northeast India into rainforests. It’s likely that caused birds from Indonesia to enter the Himalayas. These have subsequently evolved into almost half of all bird species, showing climate change effects.’ Birds continue to adapt today. Price says, ‘My colleague at the Wildlife Institute of India, Tushar Parab, and I have written about how the call of the yellow-browed leaf warbler bird has changed in just the last 40 years. This is amazing as we’re looking at 20 million birds, changing their language in just a few decades. This little warbler breeds in the Himalayas and goes northwards into Siberia but it spends its winter in India. It transits through Delhi, which is extremely noisy. We think the warbler has changed its call because of Delhi’s loud traffic — the new call can be more easily heard against that noise than the old call.’Some changes are harder. Price remarks, ‘With climate change, we will see whole new routes of migration. A classic example is birds from Germany that once wintered in a warmer Africa but with the expansion of the Sahara out toward the south now, they are really suffering.’ There is no end, thankfully, to the ingenuity of birds though because, as Price adds, ‘However, some German birds have actually learnt they could fly to England instead where they now spend their winter as an option to Africa because the winter in the United Kingdom is sufficiently mild and they can even find some fruit there.’All that entails crystal-clear vision — Price, who has closely studied the evolution of colour vision in birds, elaborates. ‘Birds can see into the shorter ultraviolet (UV) wavelength better than humans as well as seeing further into the red or long wavelength. Humans have three different colour photoreceptors and we can tell reds, greens and oranges apart quite well. But birds, with four types of cone cells, can see a wider spectrum of colours and certainly look further into the UV and the infrared. It’s very difficult to study and understand this but one of the interesting things we’ve discovered is that in quite a few species, female birds have different colour vision than males. They see the world in a different way than males do. They can certainly tell a lot of colours apart. In some areas of the wavelength spectrum, particularly between the greens and blues, females might be able to tell colours apart better than males — one possible reason is that females choose males and they all want the brightest, most colourful one because that bird will have the highest fitness, be likely most free from parasites, etc. So, it’s a premium on females to be able to tell different shades of blue apart — males,’ says Price, with a gentle grin, ‘Are much less discriminating.’There are other surprises. Price describes intense climate change in the Himalayas and outlines rainfall and hailstorm patterns in the region, ‘If nesting birds there have laid eggs and there’s a hailstorm, generally, they fly down the mountain and wait it out and then, they come back and sit on the eggs. If they come back, say, two days later, all that happens is the chicks in the egg stop growing for that duration — they resume when the parent is back and hatch just a few days later than they would have. Now, with significant seasonal shifts taking place, the birds are breeding earlier. Then, these massive hailstorms happen but the chicks have already hatched and the parents can’t feed or protect them — that’s when you lose them.’So many of our actions — from wasting energy mindlessly to demanding neverending rivers of goods, which means more and more deforestation — have tragic impacts on others. These remain largely hidden from our eyes, however, except for research by scientists like Price. Their work goes a long way in both bringing home the facts to us — as well as, in some cases, changing ground reality. Price says, ‘The Amur falcon carries out this astonishing 22,000-km-long migration. It breeds in China and as winter approaches, it leaves and spends about a month in northeast India. Then, it flies all the way to Africa for the rest of the winter and returns to China afterwards. Now, earlier, people in India were catching the falcon and eating it. However, thanks to the determined efforts of conservationists and some great publicity campaigns, the falcon has become a big tourist attraction. Many people travel to see flocks of falcons over the reservoirs. This success story, turning a grim picture into a bright one, highlights hope for India and the world. More and more people are appreciating these birds and want to preserve them. They pay to see them, so people are economically better-off protecting the birds than just eating them.’The surprises aren’t over. Price mentions, ‘We once did research on the little yellow patch on the wing of the warbler I mentioned — in that study, we painted the yellow patch to make it bigger. It turned out if you did that, the birds got larger territory. If you painted the patch green, so it looked like the rest of the bird, they got smaller territories. It’s like in the army, where the bigger the stripe you’ve got, the more senior you are. That really astonished me, highlighting the complexities of these birds. They’re just about six grams, the same as a box of matches, and yet, they live in the middle of freezing cold snow, wait for this to melt before they build nests, produce new generations and then fly all the way to southern India for winter, returning again to the freezing cold. The thought of this could exhaust many humans — but they do it, despite being so tiny. They are,’ says Price, his voice warming as he likely thinks of all the birds he has seen 1985 onwards, ‘truly surprising beings.’