Page 100 - BBC Wildlife Volume 36 #05

Q&A

Q SPECIES BIODIVERSITY
WHAT

IS IT? How many species
go extinct each day?

A This is impossible to answer precisely. take the natural rate as one per million
New species appear all the time and and that brings current rates to between
can go extinct before they’ve even been 0.01 and 0.1 per cent per year.
described, and estimates as to the rates of There are said to be 1.6 million
extinction very enormously. described species on our planet, but some
One approach to working it out experts believe there could be as many
would be to first take the yearly ‘natural as 100 million. So, work out the worse-
A‘magical’
metallic ball extinction rate’ – the rate at which species case scenario maths and the daily rate of
of beauty. would go extinct if we humans weren’t extinction comes in at 273 species per day.
around. This is often stated as one per We are said to be in the midst of a sixth
million (or 0.00001 per cent) per year – extinction. Unlike previous mass extinction
It’s the sort of other-worldly spherical
but again, opinion on this varies. events, which were the result of climatic
Orchid bee: Konrad Wothe/naturepl.com; deforestation: Ulet Ifansasti/Getty; owl: Paul Miguel/FLPA
flying object that you might expect to
Experts now believe that current rates of shifts, geological activity and a very large
see being chased around the Quidditch
extinction have soared to between 1,000 asteroid, responsibility for the current
field at Hogwarts School of Witchcraft
and 10,000 times this natural rate. So, losses is down to us. Sarah McPherson
and Wizardry by a bespectacled boy
on a broomstick. But this is no Snitch.
This beautifully iridescent airborne
creature is one of many species of
orchid bee (Euglossa spp), which
specialise in pollinating tropical
American orchids. They also happen to
be skilled concoctors of magic potions.
Males go to great lengths to collect
fragrant substances from flowers,
plant sap and rotting wood, which they
store in bristly pockets on their hind Deforestation
legs ready to waft at females during to clear land for
farming is a huge
the courtship season. Catch one if
extinction driver.
you can. Stuart Blackman

Q BIRDS
Why do tawny owls

sometimes cut their

calls short?

A If you hear a tawny call that from August into November. The
seems to be missing the final species breeds early in the year,
component, it’s probably coming with March 23 the average ‘first
from a youngster that has left its egg date’ here in the UK, and the
nest and is seeking a territory of timing of the breeding season
its own. Tawny calls take time means that territory establishment
to develop fully, and juvenile and calling activity peak from
calls also differ in pitch from October onwards.
those of the adults. Interestingly, it has been
Autumn nights are
punctuated by the Tawny chicks become discovered that the pitch of the
tawny male’s classic independent and move male call is related to body mass.
hoot, along with the away from their natal The larger the male, the longer the
female’s ‘keewik’ call. territories roughly three final vibrato section of the call.
months after fledging, Mike Toms