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MORGAN: They're our planet's
first builders,
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nature's architects
and engineers,
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crafting homes
of spectacular design
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in every corner
of the globe.
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Some are elegantly simple,
others surprisingly complex.
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So it looks like a teenager's
bedroom from the outside,
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but if you were to cut this
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right down the middle
and look inside...
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Whether they were made
by beaks or paws,
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these homes have
a universal purpose --
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to keep their owners safe
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from a dangerous world
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as they give birth
and raise a family.
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It makes it
a perfect bear home.
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It's secure,
it's dry.
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And it turns out that the quest
for real estate in the wild
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is all about the same three
things we value most --
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location, location, location.
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A strategic location
in space...
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At a precise location in time...
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These are the essential
must-haves
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of just the right home.
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It looks like an ideal place
to live, doesn't it?
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The valley of
the Snake River --
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Jackson Hole, Wyoming.
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t features beautiful
Rocky Mountain views,
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plenty of running water,
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and a good mix
of trees and shrubbery.
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It's the perfect spot
to build your dream house
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and to commune with nature.
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The surprising thing is,
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much of what you see here
isn't exactly natural.
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It was shaped and crafted
by a rodent --
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the beaver.
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This is where a family of
beavers is making its home.
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The dad has been homesteading
here for nearly a decade,
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and he and his mate
have a couple of kits.
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Their ancestors have been
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working this area
for thousands of years.
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For this family,
like all homeowners,
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location is crucial.
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For once they chose this spot,
they set about
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giving it a complete makeover
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to meet their
exacting specifications.
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I'm Chris Morgan.
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I'm an ecologist
and I'm fascinated by
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how animals
construct their homes
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and why they decide to live
where they do.
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There he is.
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There's our inhabitant.
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Beavers are very choosy
about where they build.
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There's one thing
no beaver can do without.
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It's top of the list in their
real-estate requirements,
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and that's a stream.
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When beavers hear the sound
of running water,
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they feel compelled to build.
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But before they
start work on their house,
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they first build a dam.
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And check out this dam.
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It's amazing!
It's huge!
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Beavers are the only mammals
besides humans
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that construct dams
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to block water.
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[Laugh]
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And they build big ones.
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A beaver dam can be
hundreds of feet long,
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and it's strong enough
to support me.
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It is such
an impressive construction.
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I mean, look at this.
It's packed with
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big logs down to
these tiny twigs,
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and every single of of them --
look --
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has been chewed off
by a beaver.
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These are all different
building materials,
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and one of the most impressive
to me is the fact that
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these beavers will swim with
and push and hoist
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these giants rocks --
look at the size of that --
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right onto the top of the dam.
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And they use these
big rocks as anchors,
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along with the giant logs,
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and then they intersperse it
with mud and grass
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and other debris --
look at that, perfect --
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and create this
watertight system
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with one idea in mind,
and that is to
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bring the water level up
behind this dam.
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And the difference between
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this water level
and that water level
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is approaching,
I'd guess, three feet.
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It's quite something.
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These beavers are not only
designers and architects,
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but stonemasons,
woodworkers, builders.
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They do it all.
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The dam converts a stream
into a pond.
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Wow.
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That's just the place to live
if you're a water-loving,
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web-footed beaver
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who's much better at swimming
than walking.
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Now that the pond's
nice and deep,
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the beaver family
instinctively shift gears
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to start working
on their house -- the lodge.
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With all this construction work,
they need a lot of wood.
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Fortunately, their ancestors
evolved into lumberjacks,
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and they work
the night shift.
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Since the tender
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inner bark of trees is
a beaver's favorite food,
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they can harvest a crop
while they gather lumber.
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Watch out!
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But there is a limit
to how much they can drag,
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so our clever beavers
let the water do the work.
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When you think about it,
it's really not a stretch
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to call these guys
hydro-engineers.
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So they'll excavate
these channels.
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Look at this.
They've actually dug the mud
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out of this
with their front paws.
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They'll float these
big logs out,
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back to where the dam is
and where the lodge is,
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and it allows them
as an aquatic mammal
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to swim up these channels
and access the new trees.
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What an awesome system.
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By damming the stream
so it floods its banks
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and then digging
a network of canals,
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the beavers have devised a way
to swim right into the forest
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to reach more trees.
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It's a watery world.
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And through their efforts,
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they've also reshaped
the entire neighborhood,
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transforming a woodland
into a wetland.
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Of course, beavers don't work
from a blueprint,
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but they certainly seem
to have one in mind.
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And since this pair has built
dams and lodges before,
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their instincts
are bolstered by experience.
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This is the heart of it all,
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the heart of
the beaver neighborhood.
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Look at the size of this.
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This is the lodge.
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My goodness.
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It looks like a total
jumbled mess of logs,
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kind of like a volcano of logs.
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They've stripped off the bark
and eaten the inner bark.
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Look at those teeth marks.
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And then they use their food,
the food waste,
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as building material,
so it looks like
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a teenager's bedroom
from the outside,
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but if you were to cut this
right down the middle
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and look inside...
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You'd see just
how complex it is.
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This lodge is build up against
the pond's shore,
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but the entrances are underwater
for security.
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Above is a suite of rooms.
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Amazingly, the beavers actually
carve them from the inside,
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chewing and clawing
their way through
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that solid mound
of wood and earth.
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There's a kind of a mud room,
where they can dry off,
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and a family room,
where they eat and sleep.
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They left the domed roof
a little loose
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to vent out CO2
and to let in fresh air.
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And as a finishing touch,
they'll excavate the mud
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on the shore side
to create a moat
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so their home will be
completely surrounded by water.
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Beaver lodges are all built
around the same general lines,
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but each one is unique,
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a designer home that's perfectly
matched to its surroundings.
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The goal is to have a house
that's cozy and warm,
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safe and secure,
where they can raise
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their young ones --
in fact, the same things
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that motivate every
house-building animal.
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But finding just the right
location to build in,
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that's the challenge.
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Most animals can't do
what beavers do.
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They can't alter
their neighborhood
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to meet their needs.
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So they have to make
the best use of their habitat,
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taking advantage of
whatever nature offers.
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This red-faced warbler
has found a convenient spot
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to raise her family --
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right on the ground,
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tucked away
under a fallen branch.
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The warbler's neighbor,
a brown creeper,
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takes an entirely
different approach.
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It climbs straight up
a tree trunk
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to hide its nest
inside the bark.
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And these house finches
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make their home among the spines
of a cholla cactus.
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That's like putting up
a barbed-wire fence
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to keep out trespassers.
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Of course,
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the conditions where you live
help determine
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where you put your home.
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A great desert skink escapes
the searing heat
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of the Australian Outback
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by digging a network
of underground tunnels.
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Down here, it can be nearly
40 degrees cooler
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than up on the surface.
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A gopher tortoise makes its home
underground too
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because the pine forest
it lives in is prone to fire.
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No matter where
you make your home,
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your surroundings
are bound to present
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both challenges
and opportunities.
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A good homemaker
knows how to deal with both.
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The salt marsh sparrow
makes its nest,
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not surprisingly,
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in coastal salt marshes
from Maine to Virginia.
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A house near the shore
offers a lot of attractions,
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but it also harbors risks.
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This is a place where
ocean and land collide,
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a place of constant change
and powerful forces.
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As a home site,
it has its drawbacks.
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You see,
the female sparrow
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builds her nest on the ground,
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and the marsh floods
with the tide.
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Twice each day,
the pull of the moon
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draws the sea
into the marsh.
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And twice each month,
when the moon is full,
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and again when it's new,
the tides are especially high.
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Nesting here
is certainly risky.
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But on the other hand,
there's less competition
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for space and food,
so this is where the sparrow
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has carved out a niche.
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She's in a race against time
and the rising tide.
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The sparrow weaves her nest
under the top layer of grass
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so it's hidden from predators
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but high enough
so it should stay above water.
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It takes 24 to 26 days
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from the time she begins
laying her eggs
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until her last chicks fledge --
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almost the exact length
of the lunar cycle.
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There's no margin for error.
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For most of
the sparrow nests,
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flooding is inevitable.
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It can be a disaster.
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A female sparrow has no way
to get her eggs
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back into the nest
if they float away.
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That's why the nest
is constructed with
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an overhanging dome
to make sure the eggs stay put.
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As long as they remain
within the confines of the nest,
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they can bob around for an hour
or two until the tide recedes.
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When mom returns,
she'll warm them up,
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and they'll continue
to incubate.
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After the eggs hatch,
the chicks have
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no protective shell
to float around in,
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so they're more vulnerable
than ever.
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Young chicks can't swim.
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They're defenseless
against the rising water.
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But once they're about
five days old,
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they're strong enough
to climb up above
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a flooded nest
and wait out the tide.
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This chick has made it
through the night.
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She was just big enough
to reach safety.
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Her siblings weren't so lucky.
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A few inches can make
all the difference
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between a successful nest
and a catastrophic failure.
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But enough sparrows survive
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00:17:23,977 --> 00:17:26,811
to keep the little birds
coming back to these marshes
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00:17:26,813 --> 00:17:28,279
year after year.
254
00:17:42,395 --> 00:17:45,163
One creature that
lives on the water
255
00:17:45,165 --> 00:17:47,565
but avoids the problems
of a flooded nest
256
00:17:47,567 --> 00:17:48,933
is the hooded merganser.
257
00:17:48,935 --> 00:17:52,170
Mergansers are striking
little ducks,
258
00:17:52,172 --> 00:17:54,572
especially the males,
259
00:17:54,574 --> 00:17:57,775
with their black-and-white
crests.
260
00:17:57,777 --> 00:18:04,115
In the spring, they puff them up
to attract a mate.
261
00:18:09,589 --> 00:18:12,990
Once courtship is over,
262
00:18:12,992 --> 00:18:18,296
house-hunting and child-rearing
are left up to the female.
263
00:18:18,298 --> 00:18:23,334
Most water fowl build their
nests on the ground
264
00:18:23,336 --> 00:18:26,370
or on floating mats
of vegetation,
265
00:18:26,372 --> 00:18:31,943
but hooded mergansers
are rare ducks.
266
00:18:31,945 --> 00:18:35,480
They seek out the shelter
of a hollow tree.
267
00:18:35,482 --> 00:18:38,416
Out of the thousands of trees
in this forest,
268
00:18:38,418 --> 00:18:40,618
this one is perfect.
269
00:18:40,620 --> 00:18:44,922
Struck by lightning years ago,
it still stands tall,
270
00:18:44,924 --> 00:18:46,958
with a convenient entrance
271
00:18:46,960 --> 00:18:48,159
50 feet up.
272
00:18:48,161 --> 00:18:51,295
A woodpecker probably
drilled out that hole
273
00:18:51,297 --> 00:18:53,498
while it foraged for insects.
274
00:18:55,735 --> 00:18:59,871
Over time, the hole's been
widened and rubbed smooth,
275
00:18:59,873 --> 00:19:03,374
perhaps by squirrels
or raccoons...
276
00:19:05,245 --> 00:19:09,614
And by generations
of hooded merganser moms.
277
00:19:12,619 --> 00:19:14,585
At the bottom of the cavity,
278
00:19:14,587 --> 00:19:17,355
she lines her nest with
soft down features
279
00:19:17,357 --> 00:19:19,157
plucked from her own breast,
280
00:19:19,159 --> 00:19:23,861
and here she lays
a clutch of eggs,
281
00:19:23,863 --> 00:19:25,763
up to a dozen or so.
282
00:19:25,765 --> 00:19:29,000
Mergansers can afford
to lay so many eggs
283
00:19:29,002 --> 00:19:31,302
because they nest in a location
284
00:19:31,304 --> 00:19:35,072
that's safe from the elements
and from predators.
285
00:19:38,912 --> 00:19:41,946
After four or five weeks,
286
00:19:41,948 --> 00:19:44,048
the eggs begin to open.
287
00:19:48,955 --> 00:19:51,756
Once hatching is underway,
288
00:19:51,758 --> 00:19:54,091
the nest is a busy place,
289
00:19:54,093 --> 00:19:56,093
and noisy.
290
00:19:56,095 --> 00:19:57,728
[Chirping]
291
00:19:57,730 --> 00:19:59,730
All that vocalizing promotes
292
00:19:59,732 --> 00:20:02,800
a family bond,
as the ducklings get used to
293
00:20:02,802 --> 00:20:06,537
the sound of
their mother's voice.
294
00:20:06,539 --> 00:20:09,373
She won't stay in the nest
for long, though.
295
00:20:13,346 --> 00:20:15,213
Within hours of
the last egg hatching,
296
00:20:15,215 --> 00:20:18,282
the ducklings are home alone.
297
00:20:22,989 --> 00:20:25,056
Their mother's not far away,
298
00:20:25,058 --> 00:20:27,758
and her calls
299
00:20:27,760 --> 00:20:30,628
are the only thing
that could entice them
300
00:20:30,630 --> 00:20:32,463
to abandon their cozy nest.
301
00:20:32,465 --> 00:20:36,667
Barely a day old,
they can't
302
00:20:36,669 --> 00:20:39,503
fly up to the entrance,
so instead,
303
00:20:39,505 --> 00:20:42,573
they climb.
304
00:20:49,782 --> 00:20:52,883
They're equipped with strong
claws just for this purpose.
305
00:21:12,505 --> 00:21:14,705
When they reach the opening,
their first view
306
00:21:14,707 --> 00:21:17,942
of the outside world
must come as quite a shock.
307
00:21:20,079 --> 00:21:21,746
It's a five-story drop.
308
00:21:24,817 --> 00:21:27,885
But somewhere down below,
309
00:21:27,887 --> 00:21:29,820
their mom is urging them
310
00:21:29,822 --> 00:21:32,323
to leave
the only home they know
311
00:21:32,325 --> 00:21:36,627
so they can live the life
they were born for,
312
00:21:36,629 --> 00:21:39,897
and that persuades them
to do something
313
00:21:39,899 --> 00:21:43,267
that seems a little crazy.
314
00:22:08,594 --> 00:22:11,796
Some ducklings
aren't as bold as others...
315
00:22:15,668 --> 00:22:18,736
And he who hesitates
gets a push.
316
00:22:25,445 --> 00:22:27,445
Finally,
317
00:22:27,447 --> 00:22:29,213
driven by instinct and joined
318
00:22:29,215 --> 00:22:30,915
to one another by
an inseparable bond,
319
00:22:30,917 --> 00:22:34,685
they all take the plunge.
320
00:22:52,605 --> 00:22:55,740
Once they've assembled
on the ground,
321
00:22:55,742 --> 00:22:57,375
still following
their mother's voice,
322
00:22:57,377 --> 00:23:02,113
they will make their way
together through the woods
323
00:23:02,115 --> 00:23:07,451
to their new home
on the water.
324
00:23:07,453 --> 00:23:12,289
As for the tree,
it won't stand empty for long.
325
00:23:12,291 --> 00:23:17,495
Some other creature will
take over the lease soon,
326
00:23:17,497 --> 00:23:21,499
perhaps a squirrel
327
00:23:21,501 --> 00:23:24,135
or a wild turkey,
328
00:23:24,137 --> 00:23:29,306
and our hooded merganser will be
back in residence next year
329
00:23:29,308 --> 00:23:32,042
to bring another family
into the world.
330
00:23:42,522 --> 00:23:44,955
Few animal homes
could be simpler
331
00:23:44,957 --> 00:23:46,924
than the hooded merganser's.
332
00:23:49,662 --> 00:23:51,128
But here in this oak forest
333
00:23:51,130 --> 00:23:53,364
in the Ozark hills
of southern Illinois,
334
00:23:53,366 --> 00:24:00,004
you'll find homes that are
almost absurdly complicated.
335
00:24:00,006 --> 00:24:04,708
The builder uses
whatever is at hand,
336
00:24:04,710 --> 00:24:07,344
and his tower of sticks
and leaves is a reflection
337
00:24:07,346 --> 00:24:10,014
of the place where he lives.
338
00:24:15,188 --> 00:24:17,955
The architect behind this house
339
00:24:17,957 --> 00:24:21,926
is a little rodent
with a good reason to build big.
340
00:24:23,996 --> 00:24:27,431
He's an eastern woodrat.
341
00:24:30,136 --> 00:24:32,336
He works nights,
342
00:24:32,338 --> 00:24:35,139
gathering building materials
343
00:24:35,141 --> 00:24:38,309
and fitting them
into his grand edifice.
344
00:24:38,311 --> 00:24:40,311
It's a work in progress.
345
00:24:40,313 --> 00:24:43,347
As time goes on,
346
00:24:43,349 --> 00:24:47,218
it'll just keep getting
bigger and bigger.
347
00:24:47,220 --> 00:24:50,788
Over the course of a lifetime,
this woodrat's den
348
00:24:50,790 --> 00:24:53,891
will grow to an enormous size,
349
00:24:53,893 --> 00:24:58,496
with multiple chambers
and plenty of storage space.
350
00:25:00,199 --> 00:25:03,367
So why does he need
such a big house?
351
00:25:03,369 --> 00:25:04,602
Because the woodrat
352
00:25:04,604 --> 00:25:08,105
is an avid collector,
which is why he's
353
00:25:08,107 --> 00:25:10,608
also known as a pack rat.
354
00:25:10,610 --> 00:25:13,677
He collects food,
for instance --
355
00:25:13,679 --> 00:25:16,447
seeds and nuts,
356
00:25:16,449 --> 00:25:18,182
fruit and leaves.
357
00:25:20,720 --> 00:25:23,621
What he doesn't eat
358
00:25:23,623 --> 00:25:25,489
he stores for the winter
inside the den.
359
00:25:28,628 --> 00:25:34,231
But woodrats are looking for
more than just food.
360
00:25:34,233 --> 00:25:37,801
They have a natural inclination,
bordering on obsession,
361
00:25:37,803 --> 00:25:39,770
to scavenge their tiny territory
362
00:25:39,772 --> 00:25:41,906
for anything
they find interesting
363
00:25:41,908 --> 00:25:44,575
and cart it all home.
364
00:25:50,249 --> 00:25:55,619
They seem especially attracted
to the things we throw away --
365
00:25:55,621 --> 00:25:58,255
toys,
366
00:25:58,257 --> 00:26:01,158
used shotgun shells,
367
00:26:01,160 --> 00:26:03,627
and anything shiny.
368
00:26:03,629 --> 00:26:06,330
They just love metal.
369
00:26:06,332 --> 00:26:10,200
But here's the mystery --
370
00:26:10,202 --> 00:26:13,470
we have no idea why they're
drawn to all this stuff.
371
00:26:13,472 --> 00:26:17,241
Most of it is of
no practical use to them.
372
00:26:17,243 --> 00:26:19,610
It's not warm.
They can't eat it.
373
00:26:19,612 --> 00:26:22,680
No matter.
374
00:26:22,682 --> 00:26:25,716
They're inveterate hoarders.
375
00:26:25,718 --> 00:26:30,521
It all gets incorporated
into the walls of the house
376
00:26:30,523 --> 00:26:33,257
or socked away
in a storage chamber.
377
00:26:35,595 --> 00:26:38,028
All this is a far cry
378
00:26:38,030 --> 00:26:39,296
from the compact
379
00:26:39,298 --> 00:26:42,466
and purely functional homes
of most animals,
380
00:26:42,468 --> 00:26:44,702
but then,
most animals lack
381
00:26:44,704 --> 00:26:47,972
the woodrat's predilection
for junk.
382
00:26:52,244 --> 00:26:54,278
Sometimes,
living in the right location
383
00:26:54,280 --> 00:26:59,650
is really all about having
the right kind of neighbors.
384
00:27:03,255 --> 00:27:07,524
Here in the Chiricahua Mountains
of southeast Arizona,
385
00:27:07,526 --> 00:27:09,360
there lives a little hummingbird
386
00:27:09,362 --> 00:27:13,397
that's taken
that lesson to heart.
387
00:27:13,399 --> 00:27:16,367
I've come to learn more about it
from biologist Harold Greeney.
388
00:27:16,369 --> 00:27:18,969
GREENEY: God,
this is just beautiful. Wow.
389
00:27:18,971 --> 00:27:21,338
MORGAN: He's
a hummingbird expert,
390
00:27:21,340 --> 00:27:24,642
and he knows how to find them
by sight or by sound.
391
00:27:24,644 --> 00:27:28,946
GREENEY: One strategy is
to just walk fairly directly
392
00:27:28,948 --> 00:27:33,384
from one spot to another
and then just stop and listen.
393
00:27:33,386 --> 00:27:37,187
MORGAN: Harold has probably
found more hummingbird nests
394
00:27:37,189 --> 00:27:38,589
than anyone on the planet.
395
00:27:38,591 --> 00:27:40,557
GREENEY: I think
she kept on going.
396
00:27:40,559 --> 00:27:42,192
MORGAN: He has
a special interest
397
00:27:42,194 --> 00:27:44,161
in the hummingbird
that lives around here.
398
00:27:44,163 --> 00:27:45,696
It's called
the black-chinned.
399
00:27:45,698 --> 00:27:47,364
-She's coming in.
-Is she?
400
00:27:47,366 --> 00:27:48,766
GREENEY: She's gonna go.
401
00:27:48,768 --> 00:27:51,602
Now she's off to the right.
Here she goes.
402
00:27:51,604 --> 00:27:53,504
And she just sat on the nest.
403
00:27:53,506 --> 00:27:55,005
-Is she on the nest?
-She just went to the nest.
404
00:27:55,007 --> 00:27:56,573
MORGAN: Oh, no way.
You spotted it.
405
00:27:56,575 --> 00:27:57,675
GREENEY: Yeah. Oh, there,
406
00:27:57,677 --> 00:27:59,176
she just came off
the nest again.
407
00:27:59,178 --> 00:28:01,345
You don't even think
the nest could fit there --
408
00:28:01,347 --> 00:28:02,546
MORGAN: Oh, that's so cool.
409
00:28:02,548 --> 00:28:05,182
Wow, it's wrapped
right around the branch.
410
00:28:05,184 --> 00:28:07,151
You would walk
right past that.
411
00:28:07,153 --> 00:28:09,053
It's no bigger than a golf ball,
really.
412
00:28:09,055 --> 00:28:10,454
GREENEY: Yeah.
413
00:28:10,456 --> 00:28:15,459
MORGAN: A bird so small making
such a tiny, fragile home,
414
00:28:15,461 --> 00:28:18,529
it's easy to see
how vulnerable it can be.
415
00:28:18,531 --> 00:28:21,498
And in fact,
the black-chinned falls victim
416
00:28:21,500 --> 00:28:23,300
to an array of predators --
417
00:28:23,302 --> 00:28:29,640
squirrels, snakes,
and especially other birds.
418
00:28:29,642 --> 00:28:35,079
One of the worst offenders
is the Mexican jay,
419
00:28:35,081 --> 00:28:37,548
which makes its own nest
in these woods.
420
00:28:37,550 --> 00:28:40,718
Harold's good at
spotting them, too.
421
00:28:40,720 --> 00:28:42,886
Do you see the nest right there
in the fork of that tree?
422
00:28:42,888 --> 00:28:43,921
MORGAN: Oh, yes.
423
00:28:43,923 --> 00:28:47,024
GREENEY: She's on
the nest right now.
424
00:28:47,026 --> 00:28:48,992
MORGAN: Yeah. Very nice.
425
00:28:48,994 --> 00:28:52,329
I'm distracted 'cause there's
one there and there's one there,
426
00:28:52,331 --> 00:28:53,931
and they're both looking
right down here,
427
00:28:53,933 --> 00:28:55,232
seeing exactly
what's going on.
428
00:28:55,234 --> 00:28:57,234
GREENEY: Yeah, we're kind of
close to their nest here,
429
00:28:57,236 --> 00:28:59,403
and, you know, they're coming
to check us out and make sure
430
00:28:59,405 --> 00:29:01,105
we're not posing a threat.
431
00:29:01,107 --> 00:29:03,140
They're just like any other
bird, when you get down to it.
432
00:29:03,142 --> 00:29:04,308
MORGAN: Right, right,
433
00:29:04,310 --> 00:29:05,976
but they are the enemy
of the hummingbird.
434
00:29:05,978 --> 00:29:07,411
GREENEY: They are,
in this case,
435
00:29:07,413 --> 00:29:08,746
the enemy
of the hummingbird.
436
00:29:08,748 --> 00:29:11,548
MORGAN: And it's not hard
to understand why.
437
00:29:11,550 --> 00:29:14,017
The jays have
their own young to feed,
438
00:29:14,019 --> 00:29:18,822
and a hummingbird nest
is so convenient.
439
00:29:18,824 --> 00:29:22,326
Harold himself
shot this rare view
440
00:29:22,328 --> 00:29:26,396
of a jay feasting on
a black-chinned's eggs.
441
00:29:38,310 --> 00:29:42,112
But some hummingbird nests
are safer than others,
442
00:29:42,114 --> 00:29:46,216
and Harold has discovered why.
443
00:29:46,218 --> 00:29:51,555
GREENEY: Not too far away here
is the hawk nest.
444
00:29:51,557 --> 00:29:53,690
MORGAN: It turns out
the hummingbird
445
00:29:53,692 --> 00:29:55,893
doesn't build her nest
just anywhere.
446
00:29:55,895 --> 00:29:58,529
Way easier to spot
this one probably, eh?
447
00:29:58,531 --> 00:30:00,831
GREENEY: Yes,
it's slightly larger.
448
00:30:00,833 --> 00:30:03,534
MORGAN: She often chooses
a neighborhood where
449
00:30:03,536 --> 00:30:05,369
she can get help
from her neighbors.
450
00:30:05,371 --> 00:30:08,205
Either Cooper's hawks
451
00:30:08,207 --> 00:30:10,274
or their close cousins,
the goshawks,
452
00:30:10,276 --> 00:30:12,342
will serve the purpose.
453
00:30:12,344 --> 00:30:13,644
Oh, I see.
454
00:30:13,646 --> 00:30:15,679
This one's difficult to miss,
that one. Wow.
455
00:30:15,681 --> 00:30:17,147
GREENEY: You could probably fit
456
00:30:17,149 --> 00:30:19,149
a hundred hummingbird nests
inside there.
457
00:30:19,151 --> 00:30:20,951
And it's sort of,
you know,
458
00:30:20,953 --> 00:30:23,120
at the upper level
of this forest,
459
00:30:23,122 --> 00:30:24,888
watching over this whole area.
460
00:30:24,890 --> 00:30:28,559
MORGAN: Now, you'd think that
a big killer like a hawk
461
00:30:28,561 --> 00:30:31,595
would make short work
of a hummingbird.
462
00:30:31,597 --> 00:30:35,999
In fact, they don't bother
with such small prey.
463
00:30:36,001 --> 00:30:39,169
GREENEY: For a bird this size,
the morsel is so small.
464
00:30:39,171 --> 00:30:40,671
The challenge is so great.
465
00:30:40,673 --> 00:30:43,240
You burn more calories
chasing a hummingbird
466
00:30:43,242 --> 00:30:44,842
than you get from eating it.
467
00:30:44,844 --> 00:30:46,910
You know, if you had to
run up this hill
468
00:30:46,912 --> 00:30:48,712
to eat a Tic Tac
and then go down
469
00:30:48,714 --> 00:30:50,280
and come back up
to get a second one...
470
00:30:50,282 --> 00:30:52,282
MORGAN: I'd probably only do it
seven or eight times.
471
00:30:52,284 --> 00:30:53,317
[Laughter]
472
00:30:55,921 --> 00:30:58,121
MORGAN: Jays, on the other hand,
are perfect
473
00:30:58,123 --> 00:31:02,359
meal-sized prey for hawks,
who attack them from above.
474
00:31:04,063 --> 00:31:07,431
The jays have
only one defense --
475
00:31:07,433 --> 00:31:11,201
being annoying.
476
00:31:11,203 --> 00:31:15,005
When a jay finds a hawk,
it sounds the alarm.
477
00:31:16,575 --> 00:31:18,475
That alerts the other jays,
478
00:31:18,477 --> 00:31:21,245
and they all gather round
to give the hawk what for,
479
00:31:21,247 --> 00:31:23,847
trying to drive it away.
480
00:31:28,120 --> 00:31:30,120
And sometimes it works.
481
00:31:32,858 --> 00:31:35,325
Because the hawks are
such a big threat to jays,
482
00:31:35,327 --> 00:31:37,594
they've become
the hummingbird's protector.
483
00:31:37,596 --> 00:31:41,765
As the old saying goes,
484
00:31:41,767 --> 00:31:46,136
the enemy of my enemy
is my friend.
485
00:31:46,138 --> 00:31:50,140
Should we go up the hill
and get a closer look?
486
00:31:50,142 --> 00:31:52,042
GREENEY: Oh, yeah,
look at this.
487
00:31:52,044 --> 00:31:53,043
Spectacular.
488
00:31:53,045 --> 00:31:54,511
MORGAN: Whoa!
Beautiful.
489
00:31:54,513 --> 00:31:57,180
Oh, fantastic!
A great vantage point.
490
00:31:57,182 --> 00:31:58,849
GREENEY: And that's
the vantage point
491
00:31:58,851 --> 00:32:00,217
that instills fear in the jays.
492
00:32:00,219 --> 00:32:02,452
So they normally forage at
all levels in the forest --
493
00:32:02,454 --> 00:32:04,087
on the ground,
up into the canopy --
494
00:32:04,089 --> 00:32:05,756
but when they know
that hawk's there,
495
00:32:05,758 --> 00:32:08,692
they don't want to be underneath
her because the way she hunts
496
00:32:08,694 --> 00:32:11,228
is to swoop down upon them.
497
00:32:11,230 --> 00:32:13,964
MORGAN: So from the hawk's
position on high,
498
00:32:13,966 --> 00:32:16,833
you can imagine a kind of cone
stretching down,
499
00:32:16,835 --> 00:32:20,904
taking in everything
in the hawk's target area.
500
00:32:20,906 --> 00:32:25,108
For the jays,
it's a no-fly zone.
501
00:32:25,110 --> 00:32:28,779
But for the hummingbirds,
it's a safe haven,
502
00:32:28,781 --> 00:32:34,017
and their nests tend to be
clustered inside that zone.
503
00:32:34,019 --> 00:32:36,553
The question is,
504
00:32:36,555 --> 00:32:40,057
do the hummingbirds really
understand what's going on here?
505
00:32:40,059 --> 00:32:44,461
Do they seek out hawks when
they look for a place to nest?
506
00:32:46,332 --> 00:32:49,700
Well, probably not.
507
00:32:49,702 --> 00:32:51,535
GREENEY: We know that
the hummingbirds are
508
00:32:51,537 --> 00:32:53,503
very faithful
to successful nest sites,
509
00:32:53,505 --> 00:32:56,273
so they build a nest,
and if they are successful
510
00:32:56,275 --> 00:32:57,507
in fledging a brood,
511
00:32:57,509 --> 00:32:59,176
they'll come back
and re-use that same site.
512
00:32:59,178 --> 00:33:00,444
MORGAN: They may have no idea
513
00:33:00,446 --> 00:33:02,212
that they're under
the watchful eye of the hawks.
514
00:33:02,214 --> 00:33:05,182
GREENEY: That's actually
my guess, yeah.
515
00:33:05,184 --> 00:33:08,485
MORGAN: For
a black-chinned hummingbird,
516
00:33:08,487 --> 00:33:12,356
the trick is finding
just the right place to live
517
00:33:12,358 --> 00:33:15,492
and the right neighbors
to live near.
518
00:33:18,530 --> 00:33:22,032
But there's more to location
than being in the right place.
519
00:33:22,034 --> 00:33:24,901
You also have to be there
at the right time.
520
00:33:27,373 --> 00:33:30,507
Winter seems like
the worst possible season
521
00:33:30,509 --> 00:33:34,544
for a bird to build a nest,
522
00:33:34,546 --> 00:33:39,950
but the cold doesn't stop
these little songbirds.
523
00:33:39,952 --> 00:33:43,286
Gray jays maintain their
territories all year round
524
00:33:43,288 --> 00:33:48,191
in the northernmost forests
of North America
525
00:33:48,193 --> 00:33:49,459
and they breed
526
00:33:49,461 --> 00:33:51,995
in the dead of winter.
527
00:33:51,997 --> 00:33:54,398
Here in Canada's
Algonquin Provincial Park,
528
00:33:54,400 --> 00:34:00,037
a pair of jays is working
together on their nest.
529
00:34:00,039 --> 00:34:01,705
They've picked a spot
530
00:34:01,707 --> 00:34:04,908
that's exposed on the south side
to catch as much of
531
00:34:04,910 --> 00:34:07,277
the weak winter sunlight
as possible
532
00:34:07,279 --> 00:34:11,515
and is nestled under a branch
to offer at least
533
00:34:11,517 --> 00:34:15,385
some protection
against snowstorms.
534
00:34:39,378 --> 00:34:45,482
It's the female's job
to incubate the eggs.
535
00:34:45,484 --> 00:34:47,918
She sits in the nest
without a break
536
00:34:47,920 --> 00:34:49,786
for nearly three frigid weeks,
537
00:34:49,788 --> 00:34:55,158
doing her best to keep warm
in subzero temperatures.
538
00:34:59,965 --> 00:35:03,333
It's up to her mate
to keep her well-fed.
539
00:35:05,437 --> 00:35:11,308
There's precious little to eat
in this frozen landscape,
540
00:35:11,310 --> 00:35:13,443
unless you plan ahead.
541
00:35:20,686 --> 00:35:23,220
During the fall,
gray jays harvest
542
00:35:23,222 --> 00:35:26,556
the bounty of the forest
and store it away
543
00:35:26,558 --> 00:35:30,494
in caches hidden in trees
throughout their territory.
544
00:35:36,101 --> 00:35:39,102
Bugs and berries
and bits of meat
545
00:35:39,104 --> 00:35:42,038
are tucked under
flakes of bark.
546
00:35:42,040 --> 00:35:47,144
And not just
any tree will do.
547
00:35:47,146 --> 00:35:51,481
Gray jays prefer black spruce
for food storage.
548
00:35:51,483 --> 00:35:56,386
The bark is especially flaky,
and its resin seems to do
549
00:35:56,388 --> 00:36:00,390
a better job of
preserving perishable food.
550
00:36:00,392 --> 00:36:05,428
This pair of jays spend months
creating a network
551
00:36:05,430 --> 00:36:09,432
of perhaps
10,000 food caches.
552
00:36:09,434 --> 00:36:11,635
That meant they had to collect
553
00:36:11,637 --> 00:36:14,804
and stash food
hundreds of times every day
554
00:36:14,806 --> 00:36:17,974
and create a mental map
of their territory
555
00:36:17,976 --> 00:36:21,144
to record where
they put their groceries.
556
00:36:24,216 --> 00:36:26,616
Their memories are phenomenal.
557
00:36:26,618 --> 00:36:32,756
They manage to retrieve as much
as 80% of the food they hide.
558
00:36:35,894 --> 00:36:37,928
The eggs will hatch
in a few weeks,
559
00:36:37,930 --> 00:36:40,063
before spring has even begun.
560
00:36:40,065 --> 00:36:41,598
That will give the chicks
561
00:36:41,600 --> 00:36:45,936
a head start on growing up
and developing brainpower.
562
00:36:45,938 --> 00:36:48,738
They'll need it
when fall rolls around
563
00:36:48,740 --> 00:36:50,907
so they can find and store food
564
00:36:50,909 --> 00:36:55,378
and remember where
they put it all.
565
00:36:57,649 --> 00:37:00,884
The Green Mountains of Vermont
are home to
566
00:37:00,886 --> 00:37:03,587
the gray jay's
much larger cousin,
567
00:37:03,589 --> 00:37:06,056
the common raven.
568
00:37:09,061 --> 00:37:11,061
In late winter,
these granite cliffs
569
00:37:11,063 --> 00:37:15,432
echo with
their rasping calls.
570
00:37:19,404 --> 00:37:21,571
Now, while the rest
of the forest
571
00:37:21,573 --> 00:37:23,640
is still closed
for the season,
572
00:37:23,642 --> 00:37:28,245
the ravens are
starting a family.
573
00:37:28,247 --> 00:37:34,784
Ravens are big birds,
and they build a big nest,
574
00:37:34,786 --> 00:37:39,256
woven from sticks a yard long.
575
00:37:39,258 --> 00:37:44,194
Because ravens are
so secretive and cautious,
576
00:37:44,196 --> 00:37:46,429
their nests need to be hidden
out of the way,
577
00:37:46,431 --> 00:37:49,299
like this one,
578
00:37:49,301 --> 00:37:53,370
in a crevice on a cliff face,
579
00:37:53,372 --> 00:37:56,640
with a rock overhang
for protection.
580
00:37:56,642 --> 00:37:58,775
It's perfect for this family.
581
00:37:58,777 --> 00:38:01,478
In fact,
the layout is so perfect,
582
00:38:01,480 --> 00:38:03,546
it's been used
for thousands of years
583
00:38:03,548 --> 00:38:05,548
by countless generations
of ravens.
584
00:38:05,550 --> 00:38:10,854
Once the chicks hatch,
they grow fast.
585
00:38:10,856 --> 00:38:13,456
Within a few weeks,
586
00:38:13,458 --> 00:38:17,127
they're nearly as big
as their parents,
587
00:38:17,129 --> 00:38:19,996
and they're ravenous.
588
00:38:22,501 --> 00:38:25,935
Both adults work overtime
to keep food on the table
589
00:38:25,937 --> 00:38:27,704
for four hungry nestlings.
590
00:38:27,706 --> 00:38:31,141
Like jays,
591
00:38:31,143 --> 00:38:34,377
ravens store some food
in hidden caches,
592
00:38:34,379 --> 00:38:38,715
but mostly they let the winter
do their hunting for them,
593
00:38:38,717 --> 00:38:42,052
and winter is
a cold-blooded killer.
594
00:38:47,292 --> 00:38:50,493
A dead deer can feed
a lot of ravens.
595
00:38:50,495 --> 00:38:54,731
They're sociable birds,
596
00:38:54,733 --> 00:38:57,200
happy to share a big meal
with other ravens,
597
00:38:57,202 --> 00:39:00,403
as well as a few neighbors.
598
00:39:02,941 --> 00:39:05,342
Their calls also alert
less-welcome diners.
599
00:39:05,344 --> 00:39:08,345
Eagles are too big
600
00:39:08,347 --> 00:39:10,347
and too powerful
to disinvite.
601
00:39:16,688 --> 00:39:19,155
But ravens are patient.
602
00:39:22,794 --> 00:39:25,628
Once the eagle
has eaten its fill,
603
00:39:25,630 --> 00:39:27,731
there's still plenty left.
604
00:39:31,370 --> 00:39:35,739
Some of the meat
they'll eat on the spot.
605
00:39:35,741 --> 00:39:38,942
But for these working parents,
the main priority
606
00:39:38,944 --> 00:39:41,745
is to bring food
back to the nest.
607
00:39:41,747 --> 00:39:44,881
Their chicks are
in a hurry to grow up.
608
00:39:47,719 --> 00:39:50,587
Before long, it'll be their turn
to make their homes
609
00:39:50,589 --> 00:39:54,090
in these ancient
granite cliffs.
610
00:40:02,834 --> 00:40:05,969
Many mammals do what jays
and ravens do --
611
00:40:05,971 --> 00:40:08,838
start a family
during the winter.
612
00:40:08,840 --> 00:40:10,039
But to succeed,
613
00:40:10,041 --> 00:40:13,410
they need the right home
in the right place.
614
00:40:13,412 --> 00:40:18,415
I've been studying bears
for more than 20 years.
615
00:40:18,417 --> 00:40:20,850
My own work is based in
the Cascade Mountains
616
00:40:20,852 --> 00:40:23,520
of Washington State
and up in Alaska,
617
00:40:23,522 --> 00:40:27,557
but black bears
are making a comeback
618
00:40:27,559 --> 00:40:31,428
all over the eastern
United States,
619
00:40:31,430 --> 00:40:33,630
so I've come to Maryland's
Allegheny Mountains
620
00:40:33,632 --> 00:40:35,398
to learn more about
how these bears
621
00:40:35,400 --> 00:40:37,767
make their homes and where.
622
00:40:40,472 --> 00:40:43,840
A bear's home is really
a seasonal thing,
623
00:40:43,842 --> 00:40:45,442
a hideaway where
it can hibernate
624
00:40:45,444 --> 00:40:48,711
during the long winter months,
625
00:40:48,713 --> 00:40:52,115
and for a female,
it's much more than that.
626
00:40:52,117 --> 00:40:53,149
[Chuckling] Oh.
627
00:40:53,151 --> 00:40:54,451
Look at that.
628
00:40:54,453 --> 00:40:57,854
I love getting into
the mind of a bear
629
00:40:57,856 --> 00:40:59,956
and wondering what
they're thinking.
630
00:40:59,958 --> 00:41:02,058
So imagine a female bear
in November
631
00:41:02,060 --> 00:41:04,627
is looking for a place that
she's going to spend
632
00:41:04,629 --> 00:41:05,895
the next six months.
633
00:41:05,897 --> 00:41:08,898
So she's thinking about
it needs to be isolated
634
00:41:08,900 --> 00:41:10,366
and insulated and safe
635
00:41:10,368 --> 00:41:12,869
and maybe somewhere
that's near food and water.
636
00:41:12,871 --> 00:41:15,338
In the days just before
she goes into her den,
637
00:41:15,340 --> 00:41:17,340
she'll be drinking
gallons of water
638
00:41:17,342 --> 00:41:19,175
just to help her
process the fat
639
00:41:19,177 --> 00:41:21,144
so that she
can survive the winter.
640
00:41:21,146 --> 00:41:23,480
So she's got an awful lot
on her mind
641
00:41:23,482 --> 00:41:25,982
as she's trying to select
the best home,
642
00:41:25,984 --> 00:41:28,351
but this would be perfect.
643
00:41:28,353 --> 00:41:31,488
This den is empty now,
but last year,
644
00:41:31,490 --> 00:41:34,357
for one bear,
it was a very special place.
645
00:41:34,359 --> 00:41:37,560
Perfect.
646
00:41:37,562 --> 00:41:42,966
Completely dry
and sheltered in here.
647
00:41:42,968 --> 00:41:45,068
This is where it all happens.
648
00:41:50,509 --> 00:41:53,443
She comes into this den alone
649
00:41:53,445 --> 00:41:56,412
and she stops eating,
she stops drinking.
650
00:41:56,414 --> 00:41:58,882
Her heartbeats drop
to about eight per minute,
651
00:41:58,884 --> 00:42:02,085
her respiration, breathing,
down to about eight per minute,
652
00:42:02,087 --> 00:42:04,787
and she's alone.
653
00:42:04,789 --> 00:42:07,690
But then something even more
surprising happens.
654
00:42:07,692 --> 00:42:10,460
In February,
she gives birth inside this den,
655
00:42:10,462 --> 00:42:13,029
half asleep,
to maybe four or three cubs,
656
00:42:13,031 --> 00:42:16,666
and then two months later,
they follow the light
657
00:42:16,668 --> 00:42:20,603
at the end of the tunnel
and shadow mom as she leaves
658
00:42:20,605 --> 00:42:23,673
into this big,
wide world of adventure.
659
00:42:23,675 --> 00:42:27,010
What a way to start life.
660
00:42:33,952 --> 00:42:39,122
Black bears here in Maryland
are reproducing at a rapid rate.
661
00:42:39,124 --> 00:42:44,761
In some areas, their population
has doubled in the past decade.
662
00:42:44,763 --> 00:42:49,432
That means they often make their
homes near where people live,
663
00:42:49,434 --> 00:42:53,369
so the state has an interest
in keeping a close eye
664
00:42:53,371 --> 00:42:56,439
on the bears
and locating their dens.
665
00:43:02,314 --> 00:43:06,349
It's the end of March
in these snowy woods.
666
00:43:06,351 --> 00:43:09,052
I've met up with Harry Spiker
and his team
667
00:43:09,054 --> 00:43:12,188
from the Maryland Department
of Natural Resources.
668
00:43:12,190 --> 00:43:14,490
SPIKER: There you go.
669
00:43:14,492 --> 00:43:15,892
MORGAN: They're checking on
670
00:43:15,894 --> 00:43:18,094
the health and welfare
of the local bears.
671
00:43:18,096 --> 00:43:19,929
We've got a short walk in?
672
00:43:19,931 --> 00:43:21,764
SPIKER: About a half-mile.
673
00:43:21,766 --> 00:43:25,468
MORGAN: We're planning
our approach to another den,
674
00:43:25,470 --> 00:43:28,638
one where the residents
are still at home.
675
00:43:28,640 --> 00:43:31,674
She's right up there,
up pretty high on the rocks.
676
00:43:37,449 --> 00:43:39,349
MORGAN: [Whispering]
They're trying to figure out
677
00:43:39,351 --> 00:43:40,383
the best route to the cave,
678
00:43:40,385 --> 00:43:41,618
and we have to be very quiet
679
00:43:41,620 --> 00:43:43,620
because we don't want to
disturb this female.
680
00:43:43,622 --> 00:43:45,321
You'll hit rock wall.
681
00:43:45,323 --> 00:43:47,323
Skirt around.
682
00:43:47,325 --> 00:43:51,127
MORGAN: You can see why a bear
would be drawn to this area.
683
00:43:51,129 --> 00:43:53,463
We're surrounded by
these giant boulders,
684
00:43:53,465 --> 00:43:55,898
and there are these
dark holes between them
685
00:43:55,900 --> 00:43:57,667
that look perfect for denning.
686
00:43:57,669 --> 00:44:01,170
And you can also see Harry's
military background coming out.
687
00:44:03,975 --> 00:44:06,075
He's going in first,
688
00:44:06,077 --> 00:44:08,645
and if he can't dart the bear
and she decides to exit,
689
00:44:08,647 --> 00:44:10,146
then Georgia here is the backup.
690
00:44:10,148 --> 00:44:12,649
She can hopefully dart the bear
as it comes through.
691
00:44:29,501 --> 00:44:32,035
[Pop]
692
00:44:32,037 --> 00:44:35,972
With the bear safely
tranquilized,
693
00:44:35,974 --> 00:44:38,408
I can take a look
inside her den.
694
00:44:38,410 --> 00:44:42,045
Oh, it's a very tight space.
695
00:44:42,047 --> 00:44:46,349
The perfect home,
nice and secure.
696
00:44:49,688 --> 00:44:53,189
Oh, wow.
697
00:44:53,191 --> 00:44:54,824
Oh, four cubs.
698
00:44:54,826 --> 00:44:57,026
She has four.
699
00:44:57,028 --> 00:44:58,995
[Laugh]
700
00:44:58,997 --> 00:45:00,596
Look at that.
701
00:45:00,598 --> 00:45:02,999
There's four of them,
four cubs in here,
702
00:45:03,001 --> 00:45:04,200
and a big female.
703
00:45:04,202 --> 00:45:06,869
She looks huge, actually,
just squashed in here,
704
00:45:06,871 --> 00:45:08,104
a tiny little space,
705
00:45:08,106 --> 00:45:10,673
a really narrow little section
of the cave,
706
00:45:10,675 --> 00:45:12,842
but it makes it
a perfect bear home
707
00:45:12,844 --> 00:45:14,744
because it's secure,
it's dry.
708
00:45:14,746 --> 00:45:16,546
She's pulled in
all these leaves.
709
00:45:16,548 --> 00:45:18,481
Look at all these
rhododendron leaves
710
00:45:18,483 --> 00:45:20,016
that she's snipped from outside
711
00:45:20,018 --> 00:45:21,818
and pulled in here
to make a bed.
712
00:45:21,820 --> 00:45:23,319
A perfect place, though.
713
00:45:23,321 --> 00:45:25,354
Really healthy female
and with four cubs.
714
00:45:25,356 --> 00:45:26,622
That's a really good sign.
715
00:45:26,624 --> 00:45:29,592
Okay, we're just
pulling out the cubs
716
00:45:29,594 --> 00:45:32,962
so that we can weigh them
and measure them.
717
00:45:32,964 --> 00:45:35,798
It's okay, little guy.
718
00:45:35,800 --> 00:45:36,866
Okay, I got two here.
719
00:45:36,868 --> 00:45:38,167
SPIKER: Coming out
over my shoulder.
720
00:45:38,169 --> 00:45:40,036
MORGAN: Another one there.
721
00:45:40,038 --> 00:45:41,637
MAN: Yep, it's coming.
722
00:45:41,639 --> 00:45:43,306
MORGAN: There you go,
little guy.
723
00:45:45,410 --> 00:45:48,077
GEORGIA: Seven on the dot,
seven pounds.
724
00:45:48,079 --> 00:45:52,949
MORGAN: Outside the den,
their mom doesn't look so big.
725
00:45:52,951 --> 00:45:55,017
She's only about
a hundred pounds,
726
00:45:55,019 --> 00:45:56,152
but she's a beauty.
727
00:45:56,154 --> 00:45:57,587
She looks in
really good shape.
728
00:45:57,589 --> 00:45:59,155
SPIKER: Oh,
she is in great shape.
729
00:45:59,157 --> 00:46:02,291
Her teeth look great.
730
00:46:02,293 --> 00:46:06,996
MORGAN: Quite a young bear,
by the looks of it.
731
00:46:06,998 --> 00:46:09,298
Incredible to see this this
thick mat of wool under there.
732
00:46:09,300 --> 00:46:11,100
-Oh, absolutely.
-That's what it's all about.
733
00:46:11,102 --> 00:46:12,168
She'd be lost without it.
734
00:46:12,170 --> 00:46:14,203
You feeling good
about her and the cubs?
735
00:46:14,205 --> 00:46:16,005
SPIKER: Real good,
yeah, very good.
736
00:46:16,007 --> 00:46:19,776
MORGAN: While the team does
737
00:46:19,778 --> 00:46:21,244
a full work-up
on the female...
738
00:46:21,246 --> 00:46:22,378
Look at that.
739
00:46:22,380 --> 00:46:24,547
I get a chance
to enjoy a moment
740
00:46:24,549 --> 00:46:26,482
I've always dreamed off.
741
00:46:26,484 --> 00:46:29,118
[Sigh]
742
00:46:29,120 --> 00:46:31,120
Hey. Hey.
743
00:46:31,122 --> 00:46:34,357
You guys are perfect,
aren't you?
744
00:46:34,359 --> 00:46:36,459
Oh, this has got to be
745
00:46:36,461 --> 00:46:41,063
one of the most memorable
experiences of my life.
746
00:46:41,065 --> 00:46:44,934
Just look at those guys.
Four of them.
747
00:46:44,936 --> 00:46:47,036
And we've got
two of these guys here.
748
00:46:47,038 --> 00:46:48,771
As soon as you put them
in your coat,
749
00:46:48,773 --> 00:46:50,740
they just want to feel
comfortable and warm.
750
00:46:50,742 --> 00:46:54,410
They kind of chill out,
and I guess it must feel like
751
00:46:54,412 --> 00:46:58,181
they're close to their mom,
like they are in that cave.
752
00:46:58,183 --> 00:46:59,582
It's the first time
753
00:46:59,584 --> 00:47:02,185
these guys have seen daylight,
and I'm definitely
754
00:47:02,187 --> 00:47:04,387
the first human being
that they've seen.
755
00:47:04,389 --> 00:47:07,523
That's an incredible thought.
756
00:47:07,525 --> 00:47:10,893
It's just the biggest honor
757
00:47:10,895 --> 00:47:13,462
playing surrogate mom
for a few minutes.
758
00:47:19,771 --> 00:47:22,038
They're lucky little bears,
759
00:47:22,040 --> 00:47:25,074
with a healthy mom
and a comfy den
760
00:47:25,076 --> 00:47:27,910
in just the right location.
761
00:47:36,387 --> 00:47:40,456
Back on the pond,
winter has worked its magic,
762
00:47:40,458 --> 00:47:44,227
radically transforming
the beavers' world.
763
00:47:44,229 --> 00:47:48,731
Their pond is
nearly frozen over...
764
00:47:54,005 --> 00:48:00,543
And the lodge is camouflaged
under a mantle of white.
765
00:48:00,545 --> 00:48:02,578
[Howling wind]
766
00:48:02,580 --> 00:48:05,181
All around,
the landscape may be buffeted
767
00:48:05,183 --> 00:48:06,716
by 60-mile-an-hour winds
768
00:48:06,718 --> 00:48:11,454
and chilled to
minus-30 degrees.
769
00:48:11,456 --> 00:48:14,857
Many of these animals
are grazers,
770
00:48:14,859 --> 00:48:17,059
so they're homeless.
771
00:48:17,061 --> 00:48:21,931
They have to stay on the move,
regardless of the weather,
772
00:48:21,933 --> 00:48:27,603
scratching out their survival
from beneath the snow.
773
00:48:27,605 --> 00:48:30,039
As a result,
they're exposed to the worst
774
00:48:30,041 --> 00:48:32,441
that winter can dish out
775
00:48:32,443 --> 00:48:37,680
and they depend upon their coats
to keep out the cold.
776
00:48:37,682 --> 00:48:41,817
The snow can pile up
three or four feet
777
00:48:41,819 --> 00:48:45,488
and everything gets
a coating of ice --
778
00:48:45,490 --> 00:48:50,259
everything.
779
00:48:50,261 --> 00:48:53,462
For the beavers,
780
00:48:53,464 --> 00:48:56,933
life couldn't be
more different.
781
00:48:56,935 --> 00:49:01,704
With the mud and the lodge walls
frozen hard as concrete,
782
00:49:01,706 --> 00:49:05,641
their home is impervious
to wind and snow.
783
00:49:05,643 --> 00:49:10,780
The ice on their pond
may be a foot thick,
784
00:49:10,782 --> 00:49:13,482
but thanks to
the beavers' efforts,
785
00:49:13,484 --> 00:49:15,518
the water is deep enough
that it won't freeze
786
00:49:15,520 --> 00:49:19,522
all the way to the bottom,
787
00:49:19,524 --> 00:49:23,693
so there's plenty of room
to swim.
788
00:49:29,767 --> 00:49:34,236
In the lodge, winter is
five months of family time,
789
00:49:34,238 --> 00:49:37,039
and this family
has a full house,
790
00:49:37,041 --> 00:49:39,141
with two parents,
791
00:49:39,143 --> 00:49:41,510
a pair of adolescents
born last year,
792
00:49:41,512 --> 00:49:44,246
and by late winter,
793
00:49:44,248 --> 00:49:48,050
newborn kits.
794
00:49:48,052 --> 00:49:52,121
With all that shared body heat,
the temperature in here
795
00:49:52,123 --> 00:49:56,459
may be 60 degrees warmer
than outside.
796
00:49:56,461 --> 00:50:00,863
The beavers' larder is near
their underwater entrance,
797
00:50:00,865 --> 00:50:04,567
maybe a thousand pounds
of tree limbs and logs.
798
00:50:04,569 --> 00:50:08,371
They can just pop out
the front door,
799
00:50:08,373 --> 00:50:11,907
grab a meal,
and swim back in to feed.
800
00:50:11,909 --> 00:50:17,580
Here in the darkness,
in the safety of their lodge,
801
00:50:17,582 --> 00:50:20,182
they spend most of
their waking hours
802
00:50:20,184 --> 00:50:22,718
reinforcing family bonds
by grooming
803
00:50:22,720 --> 00:50:25,154
and eating together.
804
00:50:28,359 --> 00:50:31,627
For kits,
like human kids,
805
00:50:31,629 --> 00:50:34,196
mealtime can
turn into a game.
806
00:50:46,511 --> 00:50:49,111
Much of a winter's day
is passed
807
00:50:49,113 --> 00:50:50,913
just sleeping.
808
00:50:57,722 --> 00:51:00,656
They've earned a rest.
809
00:51:00,658 --> 00:51:04,693
After all,
they worked hard last summer,
810
00:51:04,695 --> 00:51:06,095
engineering a new habitat
811
00:51:06,097 --> 00:51:11,233
and winterizing
their lodge.
812
00:51:11,235 --> 00:51:16,272
Now they get to enjoy
all the creature comforts.
813
00:51:24,015 --> 00:51:27,683
The beavers have created
what every animal looks for
814
00:51:27,685 --> 00:51:30,052
in a home.
815
00:51:34,459 --> 00:51:36,525
Oh, wow.
816
00:51:36,527 --> 00:51:39,929
It's a safe haven,
a place that's warm and secure,
817
00:51:39,931 --> 00:51:43,199
a place where they can
give their young ones
818
00:51:43,201 --> 00:51:46,035
the very best start in life.
819
00:51:54,811 --> 00:51:57,079
MORGAN: Their nature's
architects and engineers,
820
00:51:57,081 --> 00:52:00,850
crafting homes
of spectacular design,
821
00:52:00,852 --> 00:52:04,153
and every one of these fantastic
creations tells a story.
822
00:52:04,155 --> 00:52:06,355
While many homeowners
seek privacy,
823
00:52:06,357 --> 00:52:08,524
others band together.
824
00:52:08,526 --> 00:52:12,995
Competition and cooperation
push and pull on village life,
825
00:52:12,997 --> 00:52:15,865
giving rise to complex societies
where millions of citizens
826
00:52:15,867 --> 00:52:19,101
build a metropolis
like nothing else on earth.
827
00:52:57,241 --> 00:53:00,442
To learn more about what you've
seen on this "Nature" program,
828
00:53:00,444 --> 00:53:00,442
visit pbs.org.