In the mid-20th Century, Dutch scientist Niko Tinbergen studied nesting Herring Gulls. He noticed that newly hatched chicks were fed by their parents only after they pecked at the adults' bills. Tinbergen devised experiments that varied the shape and coloration of the adult's bill. It became clear that the red spot on the adult gull's bill was an important visual cue in a chick's demands to be fed, and thus its survival.
The Little Red Spot on a Gull’s Bill
Written by Bob Sundstrom
This is BirdNote!
[Bugling calls of Glaucous-winged Gulls]
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. [Bugling calls of gulls] Behind that red spot lies a considerable tale – that’s t-a-l-e!
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]. Tinbergen devised experiments that varied the shape and coloration of the adult’s bill. It became clear that the red spot on the adult gull’s bill was a crucial visual cue in a chick’s demands to be fed, and thus its survival. [Begging calls of young gulls]
Tinbergen also made the case that the chick’s 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.
Turns out that it's more complicated than that. But Tinbergen’s 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. [Bugling calls of gulls]
Learn more about Tinbergen’s research — and see a photo of that red spot — on our website, BirdNote.org. I’m Mary McCann.
Bird sounds 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.
BirdNote’s theme music was composed and played by Nancy Rumbel and John Kessler.
Producer: John Kessler
Executive Producer: Dominic Black
© 2015 Tune In to Nature.org October 2014/2015 Narrator: Mary McCann
ID# 100407redspotKPLU gull-04b