Cormorant "wing drying"

[George Hogg]

Anyone recall the research which found cormorants holding out their wings are not drying them but generating muscle heat to counteract the chilling effect of cold fish in the stomach?
The researchers fed cormorants fish of varying temperatures and birds fed warm fish never "dried" their wings!
Personally I can see much more sence in this theory than a water bird continually needing to dry itself....George

[faz]

hmmmmm but if they got no oil on feathers for water proofing ?

[John D]

Hi George,

From all the things I've read about cormorants it has been clearly stated by all associated authorities that 'cormorants stand with outstretched wings in order to dry them'.
To date I haven't seen any reference that suggests anything different.


John D
Zenfolio | John's Wild World

[George Hogg]

Agreed that is the current thinking but we have all seen cormorants with wings outstretched in conditions where there isn't a hope of them drying.
It just does'nt hold water if you excuse the pun!..George

[Picidae]

Birds use wing spreading for various reasons and you need to look at the specific ecology and species physiology to give a clue as to behaviour:

You may find this excerpt interesting:

Spread-Wing Postures

Btw: Contrary to 'popular' belief, it's not an oil deficiency that necessitates the wing drying in Cormorants, but the feather structure itself, which helps to reduce buoyancy and enables deep fishing. It may be the case that the wing spreading in Cormorants and the flat tail also help with land balance. I would suggest, given the need for reduced buoyancy by the reduced air pockets under the outer feathers of a cormorant, part of the wing 'drying' process could be to realign the feathers after a dive to ensure that any pockets of air in ruffled feathers is from them (weather irrelevant) - obviously the latter requires the drying process to do this!


The ''research'' you mention sounds flawed anyway - warm (dead!) fish float, so there would have been no need for Cormorants to dive deep (become totally submersed for extended period in order to retrieve the fish and therefore no need for wing drying)

EDIT: I've found the ''research'' reference you mention - I think it's largely discredited and a non-starter imo - the cormorants in the 'test' were in a zoo, they didn't dive for the fish and didn't get wet in the process!

http://www.cefe.cnrs.fr/esp/publis/D...JAB%201995.pdf

Crucifixion of the cormorant - Science, News - The Independent

[Picidae]

Oops: typo errors in my above paragraph, it should read thus:


Btw: Contrary to 'popular' belief, it's not an oil deficiency that necessitates the wing drying in Cormorants, but the feather structure itself, which helps to reduce buoyancy and enables deep fishing. It may be the case that the wing spreading in Cormorants and the flat tail also help with land balance but that's more open to debate. I would suggest though, given the need for reduced buoyancy of Cormorants due to their fishing ecology, enabled by limited air pockets under the feathers combined with the individual feather structure, part of the wing 'drying'/spreading process could be to realign the feathers after a dive to re-air them, thus restoring the insulating air pockets under the feathers. (weather irrelevant) - lots of reading here if you're still interested:

Pelicans, cormorants and their ... - Google Books

Incidentally, you are wrong to say the test birds 'never' spread their wings - the ones that ate warm fish didn't do it as frequently - none of the test birds became fully water logged when taking a bath either and not all the birds swam after food.