Improving Our Bird Brains, Part 4: Ibis

Thoth, with his ibis-shaped head. Art by Jeff Dahl, CC BY-SA 4.0.

Lodging is expensive in Florida, and when my wife and I were vacationing there, we always had a big bill. This put us in good company with the ibis, which also has a big bill.

In fact, it’s a big, long, curved bill, and the most distinctive feature of an ibis, other than its strange name. Hey Jason Frels, just try to make a pun out of “ibis”. I challenge you.

The ibis uses its curved bill to probe around the bottom of shallow waters, hunting for crayfish. And its bill is sensitive, which allows it to hunt by feel, as it cannot see those little mudbugs skittering around in the murky waters. This is a highly effective way to hunt, for these birds , although I imagine it must lead to a few surprises now and then.

Even though the ibis prefers crawdads, it’s also willing to eat just about anything, including fish, crabs, and insects. It tends to locate fish in willow ponds, and crabs in mangrove forests.

There are many species of ibis found throughout the world, in both temperate and tropical climates. The African sacred ibis was worshiped by ancient Egyptians, and was associated with the deity Thoth.

Thoth is depicted as a man with an ibis’ head, including that weird, curved bill. This god was thought to have created writing, mathematics, time, the moon, and magic. And so you see, having a bird brain can actually make you smart.

Legend has it that the Northern bald ibis was one of the first birds to be released by Noah, from his ark. I can understand why, as Noah probably got tired of looking at this ugly-assed bird. What a scary sight!

The Northern bald ibis. Yeah, if I was Noah, this would be the first bird I’d eject from my ark to go search for land. And probably on day 1 rather than 41. Photo by Richard Bartz, aka Makro Freak, CC BY-SA 2.5.

The ibis found in the United States is known as the American white ibis, and it’s much better looking than Noah’s ibis. Its most common habitat is in Florida, but it can also be found in coastal areas as far north as Virginia, and as far south as Texas. Outside the U.S., its range extends even further south, through Mexico, and as far down as Ecuador.

A male white ibis can weigh nearly three pounds, while females tend to be much smaller, at less than two pounds. Ibis get up to 28 inches long, with a wingspan of up to 41 inches.

They’re known as the “white” ibis, but this is false advertising, as they’re not pure white. They actually have black wingtips. However, they tuck these wingtips out of sight while on the ground, so you can’t see them unless they’re in flight.

Is the plural “ibis” or “ibises”? I think you can use either, though I prefer “ibiseseseseses.” This is a flock of ibiseseseseses in flight above the Everglades, showing off their black wingtips.

Also, some young ibis are not white, but can be gray or brown, while slowly transforming to white as they molt, over the first two years of their life.

Two juvenile “white” ibis apparently hunting for crabs in a mangrove forest on Long Key, Florida. The one on the left has lost most of its brown feathers, while the one on the right has a ways to go before it can start looking like a grownup.

Ibis tend to reproduce more during droughts than during wet years. That’s because droughts make bodies of water more shallow, which increases the availability of their favorite food, the crayfish. I guess like with people, good food can lead to good sex.

But it’s tricky business, becoming a new ibis. Up to 75% of their eggs are robbed by crows, gulls, raccoon, and rat snakes, and half the chicks that manage to hatch are killed by additional predation. But if one is lucky enough to reach adulthood, it can expect to live up to 16 years or more in the wild. Unless an alligator gets it.

The pollutant methylmercury affects the mating behavior of ibis, turning many of them homosexual, and causing parents to abandon their nests. It doesn’t kill them, but it does lead to less reproduction and reduced populations of this bird.

But so far the American white ibis is not considered to be a threatened species. Therefore, thankfully, we can expect to enjoy this beautiful bird with its big, curved bill, for many years to come.

An ibis in Key West, tempted by food and using its math skills to calculate its chances of avoiding capture.

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