Pennsylvania Game News - September 2017 - 52

to scratch its
head while it
was perching.
American
crows can recognize human faces,
using the same
parts of their brains
to do this as we do,
according to research
by John Marzluff, a professor of wildlife
science at the University of Washington.
They also might leave a gift for a human who has been feeding them.
However, they might delay giftgiving if they think they will be offered
something better - usually food - at a
later time.
Research also has shed light on the
social adeptness of ravens. Ravens have
been shown to remember other ravens
with which they were friendly - even
after they'd been separated for three years.
The blue jay, another Corvid family member, can accurately select fertile
acorns 88 percent of the time and can
count to ﬁve.
It also mimics red-shouldered and redtailed hawks, presumably to trick other
blue jays into leaving the area, giving the
trickster time to harvest acorns without
competition.
Another scientist noticed that a blue jay
was smart enough to rub red ants on its
body, wiping away the ants' formic acid
secretions before eating them.
Because more than 80 percent of bird
species are socially monogamous, staying
with one partner for a season or, in some
cases, for life, they seemed to have developed an ability to understand and provide
52

what their partners want or need to successfully breed and raise their young.
But apparently 90 percent of both sexes
also sneak off to breed with others, resulting in more healthy offspring.
In autumn, birds such as blackcapped chickadees that store food for
the winter grow new cells in their brain
center - the hippocampus - allowing
them months later to remember where
they hid seeds.
Brood parasites such as the female
eastern cowbird have a large hippocampus, because they lay their eggs in other
species' nests they must remember and
revisit.
In general, invasive bird species, such
as house sparrows and European starlings,
have larger brains, are innovative, and
have more-flexible behavior, because
they often must adapt to highly developed
landscapes.
However, our brainiest birds might be
hummingbirds.
Among birds, the hummingbird has
the largest brain relative to its size. Their
brains account for a whopping 4.2 percent
of their total body weight.
The hummingbird's hippocampus is
ﬁve times larger than that of songbirds,
seabirds and woodpeckers. They can
remember every ﬂower in their territory
and how long it takes them to reﬁll with
nectar after they feed from them.
From year to year, at home and in migration, they also remember where every
feeder is, and which are more likely to be
full as opposed to empty.
Female hummers, which are on their
own once they have bred, seemingly
learn how to make nests by watching
older females work at it, and learn to
brood their eggs and feed their young
alone, as well.
Hummingbirds have the ability to
Pennsylvania Game News - September 2017

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