[Birds singing]
For visitors who come here to look at birds this park offers an amazing diversity of birds.
There are currently 170 species of regularly occurring birds in the park.
And 255 species have been documented in this park alone.
[bird calling]
And that's incredible if you compare that
to the number of species that have been documented in North America which is 900 species.
So that's an incredible proportion.
Yosemite offers an incredible diversity of habitats for bird assemblages
all the way from 2,000 feet
all the way to the Alpine zone over 13,000 feet.
That's five distinct habitat zones that birds can inhabit.
Yosemite offers one of the most sought-after birds for birders.
A lot of people come to Yosemite to try to see the great grey owl.
75% of California's population of great grey owl is here in Yosemite National Park.
We're currently doing a research project on great grey owls.
We're in year three of a three-year study. We're doing a population census in the park.
We want to know how many individuals we have.
And also, we're doing a genetic study which is finishing up in the next couple of months
where we're determining if the great grey owl in the Yosemite region
is actually a distinct subpopulation.
So if that's the case
then the great grey owl in the Yosemite area would get its own subspecies status
which could elevate its conservation status.
One example of how science plays into management for birds
and how my job plays into that is with the willow flycatcher.
The willow flycatcher is a state endangered bird
and they used to be fairly common breeders in Yosemite National Park.
But over the last 20 years the species has been declining really rapidly.
So in 2006 and 2007 we -- with the Institute for Bird Populations --
conducted a two-year extensive park-wide census of this species
to understand what the current status was.
The results were profound. There were no breeding individuals left in the park.
That begs the question of what happened to this breeding population.
How could it disappear from a national park?
One leading hypothesis to try to explain this disappearance
has to do with climate change
and the gradual desiccation of meadows over time.
And the idea is that now that meadows are drying up
small mammals can access the nests of the willow flycatchers more easily
and predate the eggs and the nestlings.
And that these birds just aren't reproducing.
Birds are an incredible study subject because they have so much to teach us.
When I was going to graduate school and getting my degree
I never would have guessed that I would end up in such a remarkable place
with a job focus
that's understanding and learning as much about birds as possible
to protect and preserve and conserve them.
So, yeah -- it's a constant learning process and it will continue to be that way.
And every year there are new surveys that I'm doing or new walks or presentations
where I'm just learning more and more and more.
And that won't stop.