How an enormous eagle got here to dominate historic New Zealand

The now-extinct Haast’s eagle hunting moa in New Zealand, which lacked other large predators. Today scientists are looking at the ancient history of the islands’ birds to better understand how “natural” biological invasions happen.

Enlarge / The now-extinct Haast’s eagle searching moa in New Zealand, which lacked different giant predators. Immediately scientists are trying on the historic historical past of the islands’ birds to raised perceive how “pure” organic invasions occur. (credit score: John Megahan/CC)

New Zealand has lengthy been generally known as a spot for the birds—fairly actually. Earlier than folks arrived 700 years in the past, the archipelago hosted an idiosyncratic ecosystem, practically freed from mammals. Greater than 200 chicken species crammed a meals internet all their very own. Quite than cows or antelopes, there was a household of flightless birds generally known as moa. And instead of apex predators like tigers, New Zealand had Haast’s eagle.

Ever since a gaggle of farm staff drained a swamp within the late 1860s and uncovered its buried bones, this eagle has captivated researchers. Julius Haast, the explorer and geologist who revealed the primary notes on the species, described it as “a raptorial chicken of huge dimensions.” Immediately, biologists estimate that the eagles weighed as much as 33 kilos—roughly 50 % greater than any raptor identified right this moment. However with a wingspan of solely two to 3 meters—simply past the vary of a bald eagle—this was an oddly proportioned chicken.

The form of Haast’s eagle was one among many puzzles that scientists confronted as they studied this long-extinct species, preserved in only a few skeletons, plus scattered bits and items. For practically a century, there was a debate over whether or not such a big chicken may fly; even after that feud was settled, questions remained about whether or not the chicken was able to killing moa, which in some instances would have been greater than 15 instances bigger than the eagle itself. Now, new scientific strategies, mixed with a clearer understanding of New Zealand’s geological historical past, has positioned the Haast’s eagle amid a a lot bigger ecological dialogue: how species involves “invade” new territories.

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