So in that context, I had the opportunity to go to South Korea a few years ago and there I saw the awesome migration that happens around the Yellow Sea. It’s a remarkable thing to see. You have a backdrop of a very first world country with high-rises all over the place and tens of thousands of shorebirds and other birds in the air, often many flocks being chased by Peregrine Falcons. I just wanted to raise this context as part of that, that is, while we were there, we saw the final stages of the building of the so-called Saemangeum Seawall which has shut off the most productive wetland in all of Asia and is causing really grave consequences to these huge numbers of migratory birds that are going through the Yellow Sea: shorebirds, waterfowl, herons, and others. The shutting off of the important migratory areas by land reclamation is going on throughout the Yellow Sea. It really represents ground zero for problems with migratory birds worldwide.
So, seeing the multitudes of birds in the sky in this modern-day context where, surrounded by millions of people, these wetlands until recently have still been very productive and very powerful in their gathering of abundance. Seeing all that, seeing the spectacle and the challenges of migratory birds in the context of avian flu risk was just really an impressive and challenging set of observations for me.
What migration or flight would you like to witness in the field and why?
Zack: I want to take us back in time. For us in North America, the quintessential migration that we all missed was that of the Passenger Pigeon. That was a remarkable bird that would migrate in the millions across our eastern deciduous forests in search of mast. Mast is that phenomenon where any group of trees produces abundant fruit and nuts at the same time. They do that to attract potential dispersers and they do it in copious numbers. It’s a time (from early descriptions of this by our early settlers in this country) where the skies would literally darken with passenger pigeons. One could watch them horizon to horizon fly in the millions. This was probably the most abundant bird on the planet. They would see where funnel clouds of other birds were literally dropping out of the sky toward patches of abundant seed provided by the mast.
For me, this was the quintessential migration. Migration for so many of us is a spectacle of abundance, so visible, and here was the most abundant bird on the planet coursing over intact forests gathering nuts and they would darken skies for days. They were so numerous they would land on these immense branches of old oak trees and break them with their weight. For reasons that include the magnificence of abundance, conspicuous migrations (they moved by day), and the phenomenon that was really singular, I missed by only about 250 years — the chance to see passenger pigeons.
Why do you think that journey has changed so much? Why will we never see them?
Zack: Well the passenger pigeon is extinct and it’s felt that the felling of our eastern deciduous forests — not that we remove all the trees, but we removed enough trees that this ecological phenomenon, this one of mast, the coincident massive fruiting of tree, was completely disrupted. So the interesting paradox for us in conservation and ecology is that even when this bird was in the millions down from billions, its fate was already sealed for extinction because they were intimately tied to these massive trees and their incredible timed phenomenon of relieving seeds and nuts at the same time. Eastern forest Passenger Pigeons were part of an intact massive phenomenon that with the felling of our forests in the early 1800s, that bird went from being the most abundant migratory bird to one of the most dramatic examples of extinction.
What we learned after the fact is that it was an unintentional result, this particular example of extinction. Not that we have applied these lessons! But it’s really interesting to me that it was about abundance and once you lost enough of that abundance of mast and of this highly social migratory bird, it’s whole lifestyle was completely disrupted. They could not longer find the hyper-abundant foods in their hyper-abundant flocks. Once you disrupted that, it was in hindsight, a one-way journey to extinction.