I’ve seen several pictures of pigeons with, basically, large wing feathers on their feet, apparently called muffs. This link implies that it’s mainly a trait bred by humans for show pigeons, but does it ever occur in the wild? What impact does this have on flight?
One reason I ask is that there’s currently a lot of debate surrounding a dinosaur (Microraptor) with this same arrangement (which was apparently standard for the species, long foot feathers known from many specimens and some other unrelated species), how it factors into the origin of flight (if at all), etc. Any and all cites discussing this phenomenon in modern birds would be much appreciated, Google is failing me big time in terms of scientific discussion of the topic.
Are you thinking the foot feathers of a pigeon might be a genetic holdover from earlier species like microraptor?
As far as effects on flight, I’m not sure you could compare the two. Microraptor probably did unpowered gliding only, where the foot feathers were mostly kept out of the way when covering long distances and were mainly employed at the last second to help it change attitude for grabbing onto a tree trunk or vertical surface with all four limbs. Pigeons have powered flight, keep their feet in a different posture, and don’t need to change attitude to land because they prefer horizontal surfaces and only use two limbs to hold on.
I’m not sure how the feathers could be kept out of the way, unless there’s some kind of unique muscle system in the foot. Wing feathers are folded by tucking the wrist–obviously it couldn’t tuck the foot in the same way against the body.
Most models of Microraptor flight tend towards the biplane model. There’s a whole Nova special on it available online featuring wind tunnel tests, if you’re within the US.
However the final solution doesn’t make much sense. The tucked-back canopy position for the feathers and the biplane configuration are mutually exclusive unless the feathers were individually mobile.
I don’t think the feathers are necessarily a genetic holdover, but I haven’t been able to find anything about their development or behavioral effects, whether they occur in the wild and how that impacts survivability, etc.
I just clicked on one link, the Russian Tumbles (as opposed to a Parlour Tumbler, which is a whole 'nother bird). Tumblers don’t fly, they tumble. Birds like Tumblers (and some others of the Darn Odd Group) are unable to clean themselves.
Danr hard to get any sort of Tumbelr nowadays, by the way.
That PBS show is the main source I had in mind when replying. The wind tunnel tests showed legs back to be better for gliding than the biplane mode. In that position, the foot feathers are out of the way and not being used for flight. The conclusion in the PBS show seemed to be that microraptor may have used the back leg feathers for the final maneuver before landing, but not for flying in general.
I’m afraid the reason for this is that very little research has actually been done regarding the flight characteristics of feathered legs in extant birds, much less extinct ones. Even among those modern forms with feathered legs (and toes!), the form and arrangement of the feathers is very different from those found in the likes of Microraptor. The actual mode of attachment of these feathers to the body (in Microraptor and related forms) has also not been investigated to any great degree, so we can’t even really tell if they formed viable flight surfaces (Chatterjee’s reconstructions are based on the assumption that they did, but this has not been conclusively demonstrated yet).
So, sadly, the whole topic is largely speculative at this point.
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