CURWOOD: Its Living on Earth. Im Steve Curwood.
[MUSIC: BIRDNOTE THEME]
CURWOOD: The way animals behave is a constant source of fascination for some observers and an interest for scientists. And as Mary McCann explains in todays BirdNote, careful observation can help solve mysteries.
[GULL CALLS]
BIRDNOTE/GULLS BEAKS
http://birdnote.org/show/little-red-spot-gulls-bill
The Little Red Spot on a Gulls Bill
[Bugling calls of Glaucous-winged Gulls]
MCCANN: You may have noticed on a trip to the shore or at a waterfront restaurant where gulls gather that many gulls have a bright red spot near the tip of their otherwise yellow bills.
Herring Gull (Photo: mongolito404; Courtesy of BirdNote)
[BUGLING CALLS OF GULLS]
MCCANN: Behind that red spot lies a considerable tale thats t-a-l-e!
MCCANN: In the mid-20th Century, Dutch scientist Niko Tinbergen studied nesting Herring Gulls. He noticed that newly hatched gull chicks were fed by their parents only after they pecked at the adults bills
[BEGGING CALLS OF YOUNG GULLS]
MCCANN: Tinbergen devised experiments that varied the shape and coloration of the adults bill. It became clear that the red spot on the adult gulls bill was a crucial visual cue in a chicks demands to be fed, and thus its survival.
A mature Herring Gull looks out over the water. (Photo: Timelapsed; Courtesy of BirdNote)
[BEGGING CALLS OF YOUNG GULLS]
MCCANN: Tinbergen also made the case that the chicks attraction to the red spot on the bill was instinctive. This conclusion came at a time when there was furious debate among experts about whether such behavior was learned or innate.
MCCANN: Tinbergens gull research helped lay the groundwork for the science of animal behavior, and in 1973 earned him a Nobel Prize. And it all started with that little red spot.
An adult Herring Gull displays its iconic red spot. (Photo: roamingwab; Courtesy of BirdNote)
[BEGGING CALLS OF YOUNG GULLS]
MCCANN: Im Mary McCann.
###
Written by Bob Sundstrom
Bird audio provided by The Macaulay Library at the Cornell Lab of Ornithology, Ithaca, New York. Calls of Glaucous-winged Gulls recorded by A.A. Allen. Begging call of Glaucous-winged Gulls recorded by E.S. Booth. Herring Gulls recorded by Martha Fischer.
Producer: John Kessler
Executive Producer: Dominic Black
2014 Tune In to Nature.org October 2014 Narrator: Mary McCann
Herring Gull chicks peck at an adult in the hopes of a meal. (Photo: Tony Morris; Courtesy of BirdNote)
CURWOOD: Youll find photographs of gulls and their red spots – at our website, LOE.org.
[BEGGING CALLS OF YOUNG GULLS]