l 't't
General
Notes
[Auk
The molt of the Emperor Penguin. (Plate 8.)--The changeof plumage through
molt--the sheddingof the old, weather-beatenfeathersand their replacementby
an entirely new suit-occurs in some birds once a year, although in others, at
leastin somepartsof the plumage,it takesplacetwicea year or eventhree times.
The growingof new feathersis a mostseverestrain upon the individual, at times
more detrimental than the temporary absenceof food.
The various degreesof molt arc many. Whereas the molt is sometimesbriefly
describedas a feather-sheddingphenomenonwith the growing of new feathers,
in some forms it includesa general renewal of other parts of the integument.
This occursin somespeciesof the Tetraonidaewhere the long winter clawsarc
shed or worn off as spring arrives. The North American White Pelican shedsthe
horny, ridge-like projectionon the beak that it carriesduring the breedingseason,
and the puffin molts its horny beak-sheath.
The speciesof the family of penguins,Sphcniscidac,undergo a most peculiar
molt. The scaly feathers are not shed in special order but come off in flakes.
The National ZoologicalPark, Washington,D.C., has in its collectionof living
birds three Emperor Penguins (,4ptenodytesforsteri) collectedby the U.S. Antarctic ServiceExpedition of 1939-1941. I was a member of this expedition and
collectedand observedthe Emperor Penguin in Antarctica and have supervised
the care of the speciesin captivity.
The first of these penguinsobtained by the expedition was observedthrough
binoculars,and appeared like a small man dressedin black, standing amidst a
snowstorm. I left the ship and went out on the ice with three membersof the
expedition picking my way through pressureice toward the bird, which proved
to be in full molt. It offered little resistanceas I put a rope around it and
stuffedit into a bag that I then shoulderedand carriedback to the ship. I relate
this story of the capture to indicate that, while molting, the Emperor Penguin
takes little interest in what is going on around it, does not swim, and remains
on the ice.
For a period of twelvemonthsI have recordedthe molts of our three Emperor
Penguinsin captivity. Birds A and B, in January,underwenta partial molt which
lastedsixteendays. Bird C, in February,alsowent into a partial molt terminating
in twenty-fivedays. In March, all three birds went into a completeor full molt
that lasted thirty-two days. Bird B, in August, underwent a partial molt that
ended in twenty-two days. The horny coveringof the lower mandible was shed
during this molt, revealing a new dark yellow sheath. In the courseof these
molts the birds refusedto eat their full ration of fish during the latter stagesof
the transformation,the stagewhen the new feathersare in the process
of forming.
Other activities,such as that of pacing the cagein singlefile and occasionally
swimming,largely ceased.
The sheddingof feathers begins on the postero-ventralportion of the body,
and progresses
in an irregular manner over the body of the bird. As is shown
in Plate 8, the dorso-anteriorregionshold their feathersuntil the last. During
the full molt it is possibleto catch the birds and pull the feathersout in large
handfuls. This 'picking alive' hastensthe growing of the new coat of feathers,
and is desirableif an individual appearsunable to completethe molt and refuses
to resume feeding after a reasonabletime of fastlng.--MALcOLM
DAVIS,National
ZoologicalPark, Washington,D.C.
[Published with the permissionof the Secretary of the SmithsonianInstitution, Washington,D.C.]
T•E
AvI•, VOL. 62
KIMBALL.--LouISIANA
DAVIS.--THE
PLATE 8
HERON
IN VIRGINIA
IN DECEMBER.
MOLT OF THE EMPEROR I•ENGUIN.