This is bird note.

A rakeish eye-catching crest really sets some birds apart.

Picture the blue jays of the east.

Or Stellar's jays of the west.

A jays crest is made up of a slender array of feathers on top of its head.

These feathers are a bit longer and can be spiked up or slicked back,

depending on what the bird is trying to communicate.

When jays are sitting on eggs feeding their young or hanging out with their mate,

their crests my low.

But in the case of heightened arousal like in courtship or conflict,

a jays sharply raised crest tells a tale.

The same goes for northern cardinals and perhaps most crested birds.

Even birds without crests like crows or sparrows sometimes puff up their short crown feathers.

Why some species have crests and others don't?

Remains a complex evolutionary question dating back to the dinosaurs.

For bird note, I'm Michael Stein.

Support for bird note is provided by Sarah Murner and Craig McKibben from Seattle, Washington

and generous listeners from around the world.