[Steve]

Steve asked the Naked Scientists:

We were intrigued by a question posed about certain fossil birds that had feathers attached to their legs and how this could possibly have helped with flight.

However, based on the anatomy of the pelvis and hips, it's been suggested that these birds couldn't put their legs out backwards and so it's difficult to see how the feathers could have assisted in flight.

But our geese can put their legs out backwards! My son keeps geese and we often see them sitting on the ground with their legs stretched straight out backwards.

Best regards

Rory and Steve

What do you think?

[blakestyger]

Some modern birds have leg feathers too - eagles, rooks for example. Of the different types of feather on a bird's body these are contour feathers, much like the ones on its back and head. These feathers (very light and with a central shaft) do not assist in flight; they generally form the outline of the bird and contribute to buoyancy in aquatic species, streamlining, insulation and weather proofing. It's probable that they performed the same function in fossil birds - the problem is that there is an incomplete picture regarding feathers as they appear suddenly in the fossil record with no evidence(as far as I know) of any precursors.

[LeeE]

As blakestyger says, the feathers around a bird's legs do not contribute to flight at all, but help with insulation and help reduce form-drag (drag due to the shape of the object).

There's some good evidence suggesting that at least some of the later terrestrial dinosaurs were warm-blooded and had developed feathers, but this was just primarily for insulation.  For these dinosaurs, the feathers were just a more efficient and more highly evolved type of hair that could cover a greater area of the body than simple hairs - this would have been a significant factor for a creature with scaled skin where hairs cannot grow through the relatively large scales but only between them.

I don't think it's clear yet whether these feathers were hollow, or not, which would have been an important factor for flight (due to weight considerations).  It's likely that these very first feathers had solid shafts and would have been quite heavy.

[Alan McDougall]

 []I dont think so but feathers must have given them the idea