Episode 133 – Fork-Tailed Palm Swift: A Passerine Pirate

“Thank you to Casy for our theme song. Hear more of Casy’s music by searching Casy Michelle on Youtube. Today we’re talking about a bird with a penchant for piracy, but more on that later…”

Birds often display unexpected ingenuity. They’re famous for building nests, and those nests come in all shapes and sizes, from tiny wood-pecker holes to giant, kiddie pool sized eagles nests. You may expect that sticks and foliage are mainstays in bird construction, but one avian family nests with interesting building materials. And one species, get their materials from strange, if not unscrupulous, sources. But sustainably sourced insulation is one recipe for success in Life, Death, and Taxonomy. 

Critter Groups

Swifts (these were some good ones, birds are usually good ones)

  1. Blasting Swarm
  2. Beautiful Belligerence
  3. Screaming Frenzy
  4. Smart Hattle


They live in the marshes and forests of Trinidad, French Guiana, Brazil, Colombia, Venezuela, and Peru. Basically all over northern South America.


They’re about as swifty as swifts get.

Which means they have slender bodies; large, pointed wings; and short beaks.In flight, they look sorta like a moth that’s all stretched out and pinned to a board.

Or a batarang, either one.

I tried looking up a good detailed picture of one, but 80% of the images on Google are of the bird flying and the others are of it neck-deep in its weird little nest.

It has tan to dark-brown feathers on its head and back with cream-colored feathers on its stomach.

And, of course, it has the characteristic forked tail of a forked tail swift. Though it wouldn’t be the first time that something was misnamed.

Though Grima Wormtongue didn’t have a forked tongue in LOTR, which was disappointing.

If I saw one flying overhead, I would assume it was a swallow because of the tail.

Measure Up

Welcome to the beloved Measure Up segment. The official listener’s favorite part of the show! The part of the show when we present the animal’s size and dimension in relatable terms through a quiz that’s fun for the whole family. It’s also the part of the show that’s introduced by you when you send in audio of yourself saying, singing, or chittering the words measure up into ldtaxonomy at gmail dot com. We do have a new measure up intro this week from Wizard Gandalf.


  • 13.2 cm long
  • How many palm swifts go into the length of the Caroni River in Trinidad and Tabago?
  • Hint: It’s the longest river in the country and on the island of Trinidad. It goes through many of the most densely populated areas of the island. The current in the river is apparently strong and it often floods.
  • Answer: 303,030 swifts. The river is 25 miles (40 km) long.


  • 11 grams
  • How many swifts go into the lethal dose of salt?
  • Salt can be removed from your body through sweat and urine and if you eat a salty meal, you can purge it by drinking plenty of water. But taking too much at once can be more than your body can handle.
  • 5.09 swifts! 56 grams is the minimum lethal dose.

Fast Facts

  • Taylor Swift tends to fly low over the marshes and scoop up flying insects.
  • They have a short, buzzing call that sounds like a cicada burp

Major Fact: Pirate Preeners

Many birds make interesting and intricate nests. We’ve already talked about the bower bird that builds a sophisticated stick hut to impress mates. 

But palm swifts build particularly unique nests.First of all they nest in palm trees, as their name might suggest. Swift nests aren’t your typical stick circle that other birds make.

Swifts like to nest on the sides of things. Palm swifts, in particular, nest on the underside of drooping palm leaves.

No stick fort will do when gravity is pushing your house and home to the ground. Instead, swift nests are light in plant material and heavy in saliva.

So, some swifts make nests out of bird saliva entirely. They weave these spit baskets that are stuck to the side of a solid object and put their eggs in them like a pouch. 

If that sounds delicious to you, and you have a few thousand dollars to spend, you can get yourself a bowl of bird’s nest soup.

The soup is an Asian delicacy, which is also said to have healing qualities.

People forage for these nests which are often hard to find and harvest, but demand is so high that a pound of bird’s nest could go for more than $4,000.

How are Palm Swift Nests Different?

But, fork-tailed palm swifts prefer shag carpeting over hardspit floors. 

Their nests are made of some plant material, but it’s mostly feathers and saliva. Not their feathers, mind you, they need those.

Instead, they like to collect the feathers of other birds like pigeons.They also prefer fresh feathers. But this is a problem, palm swifts spend most of their lives in the air.

They may only land in palms to nest, otherwise they’re out and about in the air. How do you get fresh feathers in the air?Some reports suggested that they collect “air-born detritus” or feathers floating around that have been shed from birds.

Feather Thieves

But recent studies report that they launch air-born attacks against other birds to pluck their feathers.When a bird flies close to palm groves, swifts will attack by striking the middle of their backs to pluck a mouthful of feathers. Larger birds barely react, but smaller birds sometimes maneuver to avoid attacks and hide in trees.

They prefer slow-flying birds like parrots and pigeons. Other birds like ducks are more dangerous because of their fast flight and erratic flying patterns. It can take a pair up to three months to construct a nest. It could be that it takes them that long to pirate the feathers. 


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