QUESTION:
Why is it that the adult penguins with two chicks only feed the
one who gets to them first and they don't take turns with each 
chick in feeding them?

        From Elise H., 6th grade
             Taylor Road Middle School
             Alpharetta, GA
 

ANSWER from Lori Ross,  Research Assistant, Carol Vleck's Team
            Palmer Station, Antarctica
            Wed, 12 Feb 1997 12:23:33 -0500

Dear Elise,

When the chicks of an Adelie penguin are about 21 days old, both of 
the parents leave to feed at sea.  The chicks form small groups or 
"creches" to avoid predation and keep warm.  When an adult returns 
from the sea, it will call for its chicks and a 'feeding chase' will 
comense.  The adult will try to bring the chicks out of the creche 
before it feeds them.  The adult will run out of the colony with 
its chicks in pursuit.  Feeding bouts will occur as the adult 
stops and pecks at the chicks.  These feeding chases may serve to 
reduce the competition between siblings.  The adult may use it as a 
way to gage how hungry a chick is and will thus feed the hungriest 
chick at this feeding.  However, it may also indicate which chick is 
the strongest and has the most chance of survival.  In cases where 
food is scarce this chick may be fed preferentially.  So the chick 
that chases the longest is successful in obtaining more feedings.   
The chases may also reduce the amount of food wasted by the two 
competing chicks by reducing the amount of food dropped as the two 
chicks jostle for the best feeding position. 

Thanks for your question!
Lori Ross