This is bird note.

You might be surprised to learn that many birds have a sense of smell,

and the odors that birds make can act as mating signals for some species.

The source for many of these scents, says biologist Daniel Whitaker,

are the microbes that live in birds' pre-noil,

which they use to keep their feathers in good condition.

It turns out that the arpeggio gland, which is the gland that secretes pre-noil,

is home to a really diverse community of bacteria,

and a lot of those bacteria are odor-producing.

So, when birds rub pre-noil into their feathers,

they're also spreading fragrant beneficial bacteria.

For birds such as dark-eyed juncos, the pungent odors can help attract potential mates.

Daniel and other scientists are studying how the genes that regulate birds' immune systems

might help control these microbes.

So, there's some really interesting work going on about immune system genes,

like the major histocompatibility complex,

which is involved in regulating parasites and bacteria that come into the body.

It's thought that that gene complex will affect the bacteria you carry,

which will affect your scent.

So, I feel like this has the potential to be this unifying set of information

to help us understand how we get from animals' immune system

to the bacteria they carry to the scent to how they attract other individuals.

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