BirdNote; When Does a Crossbill's Bill Cross?

BirdNote®

When Does a Crossbill’s Bill Cross?

Written by Bob Sundstrom

This is BirdNote.

[Red Crossbill calling]

If you were to look at the beak of a baby loon or young crossbill, you’d have to wonder just what kind of bird you were seeing. Because their beaks look nothing like the beaks of their parents.

Red Crossbills are a striking example of how some young birds must grow into their adult bill shape.

[Red Crossbill type #2 calling, https://macaulaylibrary.org/asset/82851841#_ga=2.199924331.491525157.15…, 0.24-.26]

A young crossbill starts life with a wedge-shaped beak. As it grows up and starts to feed itself by removing conifer seeds from their tough packaging, the tips of its bill begin to grow rapidly — and then they cross.

[Red Crossbill type #2 calling, https://macaulaylibrary.org/asset/82851841#_ga=2.199924331.491525157.15…, 0.24-.26]

By the time the bird is a month and a half old, it’s been twisting its bill again and again, always in the same direction, as it extracts hard-to-get seeds. The tips of its bill become fully crossed — kind of like when your parents warned you that if you keep making that face, it’s going to stick that way.

[Common Loon call, https://macaulaylibrary.org/asset/116589201#_ga=2.43202272.491525157.15…, 0.03-.05]

And take loons. These birds begin life with stubby bills that slowly develop their full dagger shape.

Or flamingos. A baby flamingo has a beak that looks more like that of a goose. But as the bird grows, the beak starts to curve into that strangely bent flamingo beak we all recognize.

Despite some awkward teenage phases, all of these young birds eventually grow into — and come to rely on — their unique beaks.

[Common Loon call, https://macaulaylibrary.org/asset/116589201#_ga=2.43202272.491525157.15…, 0.03-.05]

For BirdNote, I’m Ashley Ahearn.

Today’s show brought to you by the Bobolink Foundation. ###

Producer: John Kessler

Executive Producer: Sallie Bodie

Editor: Ashley Ahearn

Associate Producer: Ellen Blackstone

Assistant Producer: Mark Bramhill

Bird sounds provided by The Macaulay Library of Natural Sounds at the Cornell Lab of Ornithology, Ithaca, New York. Red Crossbill ML82851841 recorded by G Chapman, 0:05 - 0:55. Common Loon ML116589201 recorded by D Everaert 0:55 - end.

BirdNote’s theme was composed and played by Nancy Rumbel and John Kessler.

© 2020 BirdNote February 2020

ID# RECR-02-2020-02-11 RECR-02 Narrator: Ashley Ahearn

[some background on crossbill beaks] https://judyhoy.com/f/red-crossbills

https://www.summitdaily.com/news/summit-outside-the-unique-beak-of-the-…