Migration is one of the most fascinating
aspects of birds. As a bird ringer
I sometimes have the opportunity to handle a small bird like a Willow Warbler
who only weighs about 8 grams. I can then only sit back and wonder how is it
possible that this little organism can fly over 10 000km to Europe and a few
months later all the way back! Or what about an Arctic tern that will fly over
50 000km in one year! Amazing.
By carefully noting
when migrants arrive and leave your garden, you can build a record of migration
patterns. Your data might also indicate changes in migration
patterns. For example - with all the
talk about global warming there is a theory that migrants arrive and leave our
country earlier than in the past. By comparing the yearly arrival and departure times of
migrant birds like Barn
Swallows, Greater Striped Swallows and cuckoos, you will be able to check the accuracy
of this theory. All you need to do is
to carefully record in your notebook the date when you have first observed an
arriving migrant in your garden, and at the end of summer, when was the latest
date that they were observed.
There is also a tendency
for more and more migrants to overwinter here in South Africa. Recording these
sightings might provide valuable data as to why this is happening.
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