The mysterious death of bald eagles: we just discovered what has been causing havoc among the birds of North America for 25 years
For 25 years, avian vacuolar myelinopathy has killed countless waterfowl and raptor in North America. Only between 94 and 99, a total of 56 bald eagles died in Arkansas. However, the researchers were unable to find the key that was hidden behind that strange neurological disease that was especially priming, let’s not forget, with the national symbol of the United States.
Now, as if it were an old serial killer movie, a team of investigators just found the culprit. And the carom is, honestly, quite unexpected.
Birds, toxins and humans
The key seems to be into a new toxin produced by an invasive species of cyanobacteria that has recently been identified. However, it does not occur under normal conditions; only when cyanobacteria are exposed to anthropogenic bromide. When these bacteria colonize a plant, the toxin affects the animals that consume it, but also the rest of the food chain because it bioaccumulates.
I have used the term “unexpected” before and perhaps it is not the most accurate. If we analyze the study published in the journal ‘Science’, we discovered that the two fundamental elements are climate change and human activity. That is to say, the same suspects as always. What’s interesting, though, is that they do it in such a twisted and sharp way that it took 25 years to figure out.
And that bald eagles were very close to extinction at the end of the 20th century and this fact not only promoted the research programs around avian vacuolar myelinopathy, but also motivated the launching of a recovery campaign. Very successful, by the way. What would have happened if the affected had been the ashen coots, the real ducks or the collared jugs? That we probably wouldn’t have discovered this connection yet.
Without the intention of elevating the case to a category and beyond the bald eagles, the truth is that it seems inevitable to think what elements are acting without being perceived causing radical (and irreversible) changes in the planet’s biodiversity. In short, as science sometimes does, it took 25 years for us to discover that we still have a lot to know.
Image | Marco Bicca