Island Life Magazine Ltd October/November 2017 | Page 85
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Migration is a wondrous natural
phenomenon, and true testament
to the extraordinary capabilities of
birds. 40% of all birds in the world
are migrants, the long distance
travellers amongst them being the
most well-known. So you may be
surprised to learn just how many
other birds make up this vast and
varied group – even the blackbirds
and robins that inhabit your local
park may be seasonal visitors from
Eastern Europe.
Just imagine having to find your
way from one country to another
with no map, satnav or compass
to guide you. Exactly how birds
are able to navigate so effectively
over such long distances remains
the greatest mystery of migration,
although we can be fairly sure of
the main contributing factors.
The sun
Understanding the position of
Hampshire & Isle of Wight Wildlife
Trust, working for a better future for
wildlife and wild places in Hampshire
and the Island.
Phone: 01489 774 400
E-mail: [email protected]
Website: www.hiwwt.org.uk
Hampshire and Isle of Wight Wildlife
Trust, Beechcroft House, Vicarage Lane,
Curdridge, Hampshire, SO32 2DP
the sun (or the stars and moon for
night-flying migrants) is a crucial
skill for any migrating bird. A bird
flying north knows to keep the
sun behind it, and understands
that in order to stay on course
the sun must be over its right
shoulder in the morning and over
its left shoulder in the evening.
Amazingly, birds also know that
the height of the midday sun gets
lower the further north they travel,
and they use this information to
help them determine when they
have reached their destination.
Even when the sun is hidden
by clouds in bad weather, birds
can detect its whereabouts using
polarised light, ultra-violet rays
invisible to the human eye.
An internal compass
It’s also possible that birds have
an internal ‘compass’. Scientists
have found tiny grains of
Country life
manganite in the brains of some
birds, a mineral that detects the
earth’s magnetic field. It may be
that this helps birds to navigate by
finding the position of true north.
Body fat
Knowing when you have reached
your destination is just as important
as finding it. Some small birds
use their body fat as an indicator
– before setting off, they gain just
enough body fat to last them the
journey. Once the fat is used up,
they know they have arrived.
As remarkable as they are,
birds are not perfect, and do
sometimes lose their way. But for
the most part, they arrive exactly
when and where they mean to.
So, if ever someone calls you a
birdbrain, take it as a well-earned
compliment.
Find out more at www.hiwwt.org.
uk/reserves
Photo: Brent Goose
Join us today and enjoy the benefits of being a member of
the Hampshire and Isle of Wight Wildlife Trust:
• Unlimited visits to 57 wildlife reserves in Hampshire and the Isle
of Wight and 2,500 reserves nationwide.
• A welcome pack when you join.
• Wildlife, Hampshire & Isle of Wight Wildlife Trust’s magazine,
delivered to you three times a year.
• The chance to take part in local group and community activities,
offering you a variety of opportunities to be involved in. More than
350 walks, talks and events throughout the two counties.
• Join by Direct Debit & receive your FREE full colour Local Wildlife
Reserve Guide.
www.visitilife.com
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