Biology Reference
In-Depth Information
and relative rarity. The noisy birds live for decades and feed on a variety of nuts and seeds.
Before George's large-predator project took off, macaws had been one of his main study
subjects, along with quetzals and bellbirds, enigmatic bird species of Central America that
present urgent conservation challenges. These birds all range widely, and so—in a biologic-
al sense—they are surprisingly similar to the big cats. They are “area sensitive,” meaning
that they need huge expanses of habitat to survive. What can we learn about rarity from their
study?
“We've found that macaws can fly hundreds, maybe thousands, of kilometers in search of
an available nest cavity,” George said, gesturing toward the flock. They seem to know when
and where to move to find food, no matter how far away. It is a triumph of avian memory in
this vast forested region and possibly a trait under strong selection pressure. Individual birds
that could time their food-searching forays accurately enough to find bonanzas of ripening
nuts most likely survived to produce more offspring than those that could not.
On the habitat-use continuum from fruit flies to macaws, individuals of most species lean
toward the fruit fly end and live out their lives in relatively small areas. Individuals that range
over large distances often belong to the very species that networks of protected areas strive
but often fail to conserve. So George had begun to focus on another important question: How
were the rovings of macaws, jaguars, and peccaries related to specific features of their habit-
ats? He was particularly interested in the distribution of forest tree species that might affect
all three species and, of particular interest for the macaws, the spacing of the bonanza nut
trees in their range and critical places to nest.
Like the sakis, macaws love to eat the unripe seeds of large forest trees. In fact, they are
seen as pests by Brazil nut harvesters, though research has shown they have little impact
on yield. With their preferred food supplies dispersed throughout the region and seasonal in
abundance, there is no other way for the macaws to live.
