Although he didn't realise it
at the time,
the most important specimens
Charles Darwin brought back
from the Galapagos were finches.
Initially he wasn't sure
how they were related
but when back in England,
they were examined by
the ornithologist John Gould
he reported that in fact
Darwin had brought back
13 different species of finch,
all of which were unique
to the Galapagos.
This realisation
played a significant role
in Darwin's formulation
of his theory of evolution.
The most important differences
between the finches
came in their beaks.
Some were large, some were small.
Each one was suited
to the availability
of particular foodstuffs.
Eventually Darwin theorised
that different species of finch
had evolved on different islands,
their distinctive beaks
being an adaptation
to distinct natural habitats
or environmental niches.
In the years since Darwin's visit,
many other scientists
and ornithologists
have come to the Galapagos
to study its finches.
In this experiment researchers are
observing the woodpecker finch,
using this wooden box
to stand in for a tree.
The woodpecker finch
is one of the only birds
to use tools to help it find food.
A stick or small twig enables it
to dig deeper into tree bark
for insect larvae.
This skill enables it to survive
in conditions which other birds
would find difficult.
In the dry season it can gather
up to 50% of its food in this way.
Woodpecker finches are hungry birds
which in the wild
need to eat every three hours,
so they never turn down the chance
of a free meal.
