- Nina Leopold Bradley: Let me tell you how we got onto this whole idea of keeping records.

Phenology is a way of seeing the earth.

The fact that you keep records all of a sudden changes the way you see the natural systems around you.

My father was Aldo Leopold, and my father wrote, "Keeping records enhances the pleasure of the search and the chance of finding order and meaning in these events."

We spent all our weekends at the shack out here on the Wisconsin River.

I can remember to this day, standing in front of the shack when the first cranes went over.

They were almost extinct in this area.

Dad was so excited.

He said, "A crane sounds like a frog with a sore throat."

[chuckling] Here are these birds going over with this croaking sound.

But that was a phenological item, and from then on, of course, cranes increased and we see them regularly.

We record the first arrival of birds, the first blooming of plants.

We have compared our phenological data with my father's data.

We've been moving gradually toward climate change.

All of a sudden, we're seeing major changes.

I think keeping long-term records is graphic and shows you the changes.

All you need is some way of writing it down-- a pencil and paper.

Otherwise, if you didn't have it written down, you wouldn't be able to see it.

I think when the cranes arrive in the spring and you hear all of this calling from every direction and you watch it, it's drama; it's beautiful.

I'm 93 years old; I get just as excited as anybody.

[gentle music]