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| Common Tern - One of Attenborough's Longest Distance Migrants |
With recent sightings of coastal waders such as curlew
sandpiper, black-tailed godwit and ruff on the Reserve, it is clear to see that
we are in the middle of that wonderful time of year that is the autumn migration.
This is the annual movement of birds from their northern breeding territories
to their southern over-wintering grounds and often involves journeys of
thousands of miles.
For most of Attenborough’s summer breeding birds including
nine warbler species, swallows, sand martins and the common tern this long
journey south would have started back in September. However, through early
October, birds that have bred further north can be seen as they move through the
county on passage.
The use of visual landmarks such as the River Trent is one
of the many ways in which birds navigate during their remarkable migration journey.
It is the proximity of the Nature Reserve to the river that makes Attenborough
a perfect ‘re-fuelling’ site for passage migrants (birds that appear for a short
duration between their origin and destination). During inclement weather,
species not normally found on the Reserve such as black tern are forced to land
or stop off and re-fuel before continuing on their migration. In extreme cases
North American or Continental European species that have been blown off their usual
migration course might even make an appearance. Because of this, October is one
of the most exciting months of the year to be out on the Reserve.
Bird migration has fascinated naturalists since the time of
Aristotle. Back then, although migration was obvious in large species such as cranes
and storks, it was inconceivable to think that smaller birds were capable of
making such incredible journeys. Until the early 1800’s, it was still widely believed
that swallows hibernated in the mud at the bottom of ponds. Bird ringing
studies have long since disproved traditional theories about migration and have
provided fascinating insights into the movements of birds.
Last year a ringed common tern (pictured) was regularly seen
feeding around the reedbed at the front of the Nature Centre. As it came to
perch on the fence posts and handrail, the ring number could be easily read. It
turned out that this bird was originally ringed as a chick in Oxford in 1997! We know from previous ringing
data that the common terns ringed at Attenborough migrate to Senegal in Africa
for the winter. That would mean that this bird has already flown over 90,000
miles in its lifetime!
As the common terns that have been with us for the summer
leave, it is not long before wintering ducks start to arrive. Over 1% of the
country’s population of shoveler reside at Attenborough for the winter. Male
and female shovelers stir up the water by swimming in a tight circular
formation. They then use their strange spatulate bills to filter insects from
the surface. By the end of October, goosander, goldeneye, wigeon, pochard, and teal
will have joined the resident mallards, gadwall and tufted ducks on the vast
water-filled gravel pits.
By November you might even get a chance to glimpse the rare
bittern skulking through the reeds. This scarce species of heron became extinct
in the UK
by the 1900’s. They returned as a breeding species some 15 years later however
even now they number fewer than 100 pairs. The bittern’s cryptic camouflage
enables it to blend in perfectly with its reedbed habitat as it hunts for fish.
Last year up to seven could be seen over-wintering in the reedbed on Clifton
Pond.
