Rosa Rubicondior: Unintelligent Design - Flightless Birds Still Have Feathers for Flight

When birds lose the ability to fly, their bodies change faster than their feathers - Field Museum

As though designing birds with wings that they can't fly with wasn't stupid enough, it seems creationism's idiot designer designed them with flight feathers too. That is, if you believe the childish nonsense of special creation of species without ancestors, which is a central superstition of the creationist cult. And presumably, because it's also central to the cult that species don't evolve, it must be assumed that every extinct species was created without ancestors too, so they can't have evolved from ancestors either.

Which makes it all the more puzzling that a study has shown that as flightless birds became flightless over time, they tended to retain feathers that were characteristic of flying birds, and in particular, those of their flying relatives.

In other words, as flightlessness evolved, the last thing to change were their feathers.

Which begs thew question why creationism’s putative designer gave flightless birds feathers that looked as though they had been inherited from flying ancestors.

Of course, there is a rational explanation for this, and it doesn't involve magic creation by a blundering idiot behaving like a mindless process operating without a plan.

Tell me about flightless birds, with examples, please. Flightless birds are birds that have lost the ability to fly through evolution. This adaptation usually occurs in environments where flight is no longer necessary, such as predator-free islands, or where other modes of movement (running, swimming, or diving) provide better survival advantages.

Key Adaptations of Flightless Birds

Reduced or absent keel (breastbone): The keel anchors strong flight muscles in flying birds. In flightless birds, it's either reduced or missing.
Stronger legs: Many flightless birds have powerful legs adapted for running (e.g., ostriches) or swimming (e.g., penguins).
Denser bones: Unlike the lightweight, hollow bones of flying birds, flightless birds often have denser bones, making them heavier.
Smaller or vestigial wings: While some retain functional wings (e.g., penguins use them for swimming), others have significantly reduced wings.

Examples of Flightless Birds

Ratites (Large, Flightless Running Birds)

Ostrich (Struthio camelus) - The world's largest bird, found in Africa. It is the fastest-running bird, reaching speeds of 70 km/h (43 mph).
Emu (Dromaius novaehollandiae) - The second-largest bird, native to Australia. It is a strong runner and can sprint at speeds of up to 50 km/h (31 mph).
*Cassowary (Casuarius spp.) - Found in New Guinea and northern Australia, cassowaries are dangerous birds with dagger-like claws used for defence.
Rhea (Rhea spp.) - Native to South America, rheas are smaller than ostriches but still large, reaching speeds of 60 km/h (37 mph).
Kiwi (Apteryx spp.) - Small, nocturnal, and endemic to New Zealand. Kiwis have long beaks with nostrils at the tip, unique among birds.
Penguins (Flightless, Aquatic Birds)
Emperor Penguin (Aptenodytes forsteri) - The largest penguin, native to Antarctica, known for its endurance in extreme cold.
Adélie Penguin (Pygoscelis adeliae) - A smaller Antarctic species that is excellent at swimming and diving.
Little Blue Penguin (Eudyptula minor) - The smallest penguin, found in Australia and New Zealand.
Other Flightless Birds
Kakapo (Strigops habroptilus) - A nocturnal, flightless parrot from New Zealand, critically endangered and known for its strong scent.
Takahe (Porphyrio hochstetteri) - A large, flightless rail endemic to New Zealand, thought extinct until rediscovered in 1948.
Flightless Cormorant (Phalacrocorax harrisi) - Found in the Galápagos Islands, this bird has adapted to a swimming lifestyle.
Steamer Duck (Tachyeres spp.) - A group of ducks from South America, some of which are completely flightless.

Extinct Flightless Birds
Dodo (Raphus cucullatus) - A famous flightless bird from Mauritius, driven to extinction by hunting and introduced species in the 1600s.
Great Auk (Pinguinus impennis) - A flightless seabird from the North Atlantic, hunted to extinction in the 19th century.
Moa (Dinornithiformes) - Giant flightless birds from New Zealand, driven to extinction by human hunting around 1300 CE.
Elephant Bird (Aepyornis spp.) - Once the largest bird in history, native to Madagascar, extinct due to human activity.

The discovery was made by a team of researchers led by Evan T. Saitta of the Field Museum of Natural History, Chicago, IL, USA. They have just published their findings in the journal Evolution and explained it in a Field Museum press release:

When birds lose the ability to fly, their bodies change faster than their feathers
More than 99% of birds can fly. But that still leaves many species that evolved to be flightless, including penguins, ostriches, and kiwi birds. In a new study in the journal Evolution, researchers compared the feathers and bodies of different species of flightless birds and their closest relatives who can still fly. They were able to determine which features change first when birds evolve to be flightless, versus which traits take more time for evolution to alter. These findings help shed light on the evolution of complex traits that lose their original function, and could even help reveal which fossil birds were flightless.
All of the flightless birds alive today evolved from ancestors who could fly and later lost that ability.

Going from something that can't fly to flying is quite the engineering challenge, but going from something that can fly to not flying is rather easy.

Evan T. Saitta, lead author.
Life Sciences Section
Field Museum of Natural History
Negaunee Integrative Research Center, Chicago, IL, USA.

In general, there are two common reasons why birds evolve flightlessness. When birds land on an island where there aren’t predators (including mammals) that would hunt them or steal their eggs, they sometimes settle there and gradually adapt to living on the ground. Since they don’t experience evolutionary pressure to stay in flying form, they gradually lose some of the features of their skeletons and feathers that help them fly. Meanwhile, some birds’ bodies change when they evolve semi-aquatic lifestyles. Penguins, for instance, can’t fly, but they swim in a way that’s akin to “flying underwater.” Their feathers and skeletons have changed accordingly.

Saitta is a paleontologist who often studies non-avian dinosaurs (the branches of the dinosaur family tree that do not include modern birds). However, when he arrived at the Field Museum for a postdoctoral fellowship, he was struck by the Field’s collections of over half a million birds.

I suddenly had access to all these modern birds, and it made me wonder, ‘What happens when a bird loses the ability to fly?’ And because I'm not an ornithologist, I went in and measured as many features of as many different feathers as I could. So it was a highly exploratory study in that sense.

Evan T. Saitta.
Saitta examined the preserved skins of thirty species of flightless birds and their closest flighted relatives and measured a variety of the birds’ feathers, including the microscopic branching structures that make up feather plumage. He also examined specimens of other, more distantly related species to represent more of the bird family tree.

Previous research has revealed how long ago different species of flightless birds branched off from their flying relatives. The ancestors of ostriches, for example, lost the ability to fly much longer ago than the ancestors of a flightless South American duck called the Fuegian steamer. Saitta found that these species’ feathers are very different.

Ostriches have been flightless for so long that their feathers are no longer optimized for being aerodynamic.

Evan T. Saitta.

As a result, their feathers have become so long and shaggy that they're sometimes used in feather dusters and boas. But even though Fuegian streamers can no longer fly, they lost this ability relatively recently, and their feathers remain similar to those of their flying cousins. Saitta says he was surprised by how long it seemed to take flightless birds to lose the feather features that would have helped them fly. It didn’t seem to make sense why a flightless species would “waste” energy growing a bunch of feathers optimized for an activity that it no longer did, or why feathers no longer required for flight wouldn’t be freed up to evolve into a wide variety of forms. However, Saitta says, his postdoctoral advisor, Field Museum research associate and former Field curator Peter Makovicky (now at the University of Minnesota’s Bell Museum), had another perspective.

Pete pointed out that when trying to understand why a modern bird looks the way it does, you can’t just think about natural selection or relaxation thereof. You have to also consider developmental constraints. Feathers are complex structures that have a really well-defined developmental sequence that’s hard to change. And when birds lose flight, those feather features disappear in the opposite order that they first evolved.

Evan T. Saitta.

When bird embryos develop feathers, those feathers increase in complexity in the same general order that those feather features first evolved in dinosaurs. After losing the ability to fly, birds lose those feather features in the opposite order that they first evolved. It’s like remodeling a house-- it’s faster and easier to change elements that went in last, like the wallpaper, than it is to tear down a load-bearing wall and rebuild it into something new.

Some more recently-evolved feather adaptations, like the asymmetry in the flight feathers that allows birds to fly, are easier to change, and thus disappear relatively quickly once birds no longer need to fly. But overall, the basic feather structure is like those load-bearing walls. It takes a lot of evolutionary time for the underlying development of a standard feather to be transformed into producing something like a plume-y ostrich feather.

Saitta and his colleagues also found that certain larger features changed relatively quickly once a lineage lost the ability to fly.

The first things to change when birds lose flight, possibly even before the flight feathers become symmetrical, is the proportion of their wings and their tails. We therefore see skeletal changes and also a change in overall body mass.

Evan T. Saitta.

The reason behind this, says Saitta, may be the comparative “costs” to grow these features. When animals develop, it takes a lot more energy to grow bones than it does to grow feathers-- so evolution “prioritizes” changing the skeleton before the majority of the feathers.
Let’s say a bird species lands on an island where they are able to safely live on the ground and don’t need to fly anymore. The first things to go are going to be these big, expensive bones and muscles, but feathers are cheap, so there’s less active selection to change them.

Evan T. Saitta.

It’s like how if you auto-paid your $1,500 monthly rent on an old apartment that you no longer live in, that would have a bigger effect on your bank account than forgetting to cancel a $5-a-month subscription. For newly flightless birds, maintaining a flight-friendly skeleton is a bigger unnecessary cost than keeping some of their old feathers around unaltered. Insights from this research could help scientists trying to determine whether a fossil bird, or a feathered dinosaur that isn’t part of the bird family, was able to fly.
Flight didn’t evolve overnight, and flight, or at least gliding, was possibly lost many times in extinct species, just as in surviving bird lineages. Our paper helps show the order in which birds’ bodies reflect those changes. Unless you have a fossil whose ancestors, even older fossils, have been flightless for a very long time, you might not see too many changes in their feathers. You might first want to look for changes in body mass, the relative length of the wings. Those change first, and then you can perhaps see changes in the symmetry of the feathers.

Evan T. Saitta.

Saitta’s research corroborates previous studies that have shown that a bird’s flight feathers become more symmetric after flight loss.
The good news is that because I came at this question from a different angle, we got results that are very consistent with a lot of the previous research, but I think maybe a little bit broader than if I had approached the question with a more specific focus.

Evan T. Saitta.

Abstract
Feathers are complex structures exhibiting structural/functional disparity across species and plumage. Flight was lost in >30 extant lineages from ~79.58 Ma–15 Ka. Effects of flight loss on senses, neuroanatomy, and skeletomusculature are known. To study how flightlessness affects feathers, we measured 11 feather metrics across the plumage of 30 flightless taxa and their phylogenetically closest volant taxa, with broader sampling of primaries across all orders of crown birds. Our sample includes 27 independent flight losses, representing nearly half of extant flightless species. Feather asymmetry measured by barb angle differences between trailing and leading vanes decreases in flightless lineages, most prominently in flight feathers and weakest in contour feathers. Greatest changes in feather anatomy occur in older flightless lineages (penguins, ratites). Comparative methods show that many microscopic feather traits are not dramatically modified after flightlessness compared to body mass increase and relative wing and tail fan reduction. Changes involved with greater vane symmetry show stronger shifts, however. Relaxing selection for flight does not rapidly modify feather flight adaptations, apart from asymmetry. Developmental constraints and relaxed selection for novel feather morphologies may explain some observed changes. Macroscopic changes to flight apparati (skeletomusculature, airfoil size) are more evident in recently flightless taxa and could more reliably detect flightlessness in fossils, with increased feather symmetry as a potential microscopic signal. We observed apical modification in later stages of feather development (asymmetric displacement of barb loci), while morphologies arising during early developmental stages are only altered after millions of years of flightlessness.

Evan T Saitta, Lilja Balaji, Jonathan S Mitchell, Peter J Makovicky
Feather evolution following flight loss in crown group birds: relaxed selection and developmental constraints Evolution, 2025;, qpaf020, https://doi.org/10.1093/evolut/qpaf020

© 2024 Oxford University Press on behalf of The Society for the Study of Evolution (SSE).
Reprinted under the terms of s60 of the Copyright, Designs and Patents Act 1988.

Findings like this serve to illustrate the stark difference between what a utilitarian process like evolution produces and what an intelligent design process would be expected to produce. This is how we can tell than there is no intelligence involved in evolution.

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