TO MIGRATE OR NOT TO MIGRATE

A MATTER OF NUMBERS 

- DILIP D'SOUZA

There's something compelling about bird migration. The way birds return to the same spot year after year, the dis-muscle for long flights, why such long flights at all.

Some years ago, I watched a short film about captive-bred whooping cranes. Being so, they don't know how and where to migrate. So humans taught them, by flying along the route in a micro-light aircraft, the eager bird students trailing behind. Just thinking of the sheer human audacity of teaching this (bird) life skill is a reminder of the how remarkable the instinct to migrate is.

Then there's a bird that, in 2020, flew from Alaska to New Zealand. Non-stop. We know it did because of the satellite tracking device fitted on the bird. This is a distance of over 12,000 km, and this little bar-tailed godwit touched down 11 days after it took flight. So, it kept up a steady 45 kmph across a vast ocean with no land for hundreds of miles in any direction. The 12,000 km is a new world record, and it was set by a relatively nondescript, relatively small (about 300 gm) shore-bird.

All this might fill you with wonder, as it does me. How do you teach something that is normally pure instinct, and teach it across species boundaries? How does a small bird find the energy and strength for a 12,000 km flight?

But as interesting as those conundrums are, something else that migrating birds do is possibly worrying. Simply because they travel these great distances, they carry and spread micro-organisms across the world. Some of those can be dangerous to humans. Of course this isn't new knowledge-we've known it for a while. But now, there's a phenomenon that even birds might need to take into account: climate change.