This is a story about a time I caught 859 swans.
Along the south coast of England there is a rather unusual beach called Chesil Beach.
It's an 18 mile (29km) bank of pebbles running parallel to the shore trapping behind it a
long shallow lagoon of brackish water, so that's half salty, half fresh water. And that
water is called The Fleet. The Fleet is home to the largest colony of mute swans in Britain
and the only managed mute swan colony in the world; Abbotsbury Swannery, and that is managed
by warden Charlie Wheeler.
So why are there so many swans here at Abbotsbury? The main reason is The Fleet lagoon. In The
Fleet we have eel grass so there's acres and acres of eel grass beds that grow within The
Fleet. The Fleet is very shallow only being about a metre deep so it's basically the perfect
habitat for swans and we can have 1200-1300 swans in the winter time visiting the lagoon
itself. They congregate down this end in the lagoon where we are here because they nest
down this end and they nest down this end because the cygnets need fresh water when
they're very very young. So at Abbotsbury we have the only source of fresh water on
the lagoon. In the 11th century, King Cnut (of going for
a paddle in the sea fame) founded a monastery in the village of Abbotsbury and the monks
there managed the swans to eat. Then Henry VIII came along, destroyed the monastery and
bought up all the surrounding land and he later sold it off to a private family and
that included handing over the Crown's right to own any swans hatched at Abbotsbury.
The Queen does have crown prerogative, meaning she is able to claim any unclaimed swans.
Isn't that right?! There are only six species of swan in the
entire world and three of them - the mute swan, whooper swan and Bewick's swan - are
native to the UK. Although these are called mute swans, they
actually make a load of different vocalisations. They're just a lot quieter in comparison to
the other types of swans. Black swans are not actually black mute swans,
they're a completely different species. They come from Australia. Completely different.
Every two years in July, Abbotsbury Swannery catch all the swans on The Fleet. After building
their nests and rearing their cygnets in spring and early summer, all of the adult swans undergo
a moulting period where they replace all their tattered feathers with fresh new ones ready
for the year ahead. Now luckily for us, this means that there is a narrow window in which
all of the babies have grown up enough to be safely separated from the parents, but
none of the adults have their flight feathers yet so they can't fly away. And that is perfect
time to catch some swans. There is only one recorded death by swan.
This was a kayaker in Chicago. He managed to kayak through a breeding pair (the most
fighty and angry type of swans) and one of the swans capsized his kayak and then prevented
him from reaching the shore so he drowned. Swans cannot break your arm or leg. I mean,
when they do attack if they have to, if they're defending themselves, they'll attack with
this bit - essentially it's their wrist, the carpal joint. But because they've got to be
so light to fly, even though this one's probably about 11kg, their bones are hollow which means
that they can't actually put that much force into their attack. And look, you're quite
calm aren't you! Once all the swans are rounded up into the
holding pens, it's time for everyone to grab a swan and take it around each of the stations
to be counted, vaccinated and measured before release.
Got him? I've got him!
You're a noisy little fellow! First off let's check your rings. What have
we got here? Ok, white Victor Hotel Hotel
Ooh another Abbotsbury swan Is there a difference between white and yellow?
White ringed birds at Abbotsbury were hatched here, yellow ringed birds have come in from
elsewhere. Ok so this bird wasn't hatched here at the
swannery so it's an incoming bird from somewhere else.
A foreigner! A foreigner. And so it gets a yellow ring
and a BTO ring which is issued by the British Trust for Ornithology.
And what do the BTO do with all of this information about rings?
So yes, the British Trust for Ornithology, they coordinate bird ringing in the UK and
they sort of administer the rings and the database. So by putting these rings on the
birds, we get to learn about their movements, survival
(Can I have a white one?) (Sure)
We can learn lots about their movements, survival, mortality just by putting these rings on the
birds. So yeah, really useful data that can help conserve the species.
I'm gonna give you your vaccinations. What was it? Duck Viral Enteritis?
Yeah. No stomach bugs for you!
Can you talk me through what you're doing at this station?
Yeah, I'm vaccinating them against Duck Viral Enteritis. So we check their feet for a condition
called pododermatitis which is also known as bumble foot, and then we check their eyes
for corneal ulcerations and cataracts, and then we check they haven't got anything stuck
in their nostrils or their mouth and just their general condition.
I think my rings are all good. Yeah, go to the third one over there.
Up to the third one, ok, let's get you weighed and measured!
So what we're looking for in the age is are there any brown feathers on the back? If there
were any brown feathers it would indicate that it's not entirely moulted all its juvenile
feathers or plumage because as you know cygnets are brown and fluffy.
Another thing to be looking for is the colour of the beak as well, and this is a nice pinky-red
beak suggesting it's an older bird. Cool! And you've been calling out numbers
when you open up their wings as well. What's that?
So what we're looking for there is what's known as a moult score, so the birds at this
time of year, they moult all their flight feathers which is how we're able to catch
them and they're in the process of regrowing new feathers which will see them through to
next year. And essentially they start off coming through and you can't see any feathering
at all, that's a moult score of 0, then they have a tiny little bit of feather like a paintbrush,
that's a moult score of 1, and then that progresses up to a 5 where the new feathers are completely
formed. One way to tell the difference between a male
and a female swan is the size, so males are about 12-13kg and females are about 9-10kg.
Also at certain times of the year, this little bit here is called their bill knob (ooh it's
all soft!). That changes size and males usually have a bigger one but it does change at different
times of the year. The only really reliable way is to examine the cloaca which is lovely!
Andy, can you talk me through how you sex a swan?
Carefully! You have to evert the cloaca and see what
comes out. Oh there it is! So there is a phallus in there. Wild fowl have one unlike most birds
so you have to evert the cloaca until it pops out if there is one.
Right, time to release! Time for you to join your brothers and sisters.
*honk* Alright, no need to be like that! Honestly!
There you go. And fly my pretties! Even though you can't fly. Freedom!
Perfect! One down, another 500-600 to go! Easy!
How do you think today's catch went? Yeah, pretty good. So 859's a pretty good
count. Last year was just over 700. Our biggest count is something like 946 or something like
that so we haven't quite reached 1000 before but over 800 is still a pretty good number
today and yeah it all went smoothly. We didn't have really any flew away, probably a dozen
flew away so all in all a good day. And what have you noticed over the 30 years
of working here, has everything stayed pretty much the same or have things changed?
The overall population stays about the same but of course recently we've, you know, occasionally
get outbreaks of things like bird flu but it's been a really good learning curve. At
first we thought we were going to lose all the swans but it just didn't happen it only
targets certain age groups or you know, so it's never the devastating thing it used to
be. We've had lots of things come and go you know, there's been years when the nesting
populations are quite low, other years they're really high, survival rates can be low, survival
rates can be high. Ever since the oldest records go back, the number of swans on The Fleet
has roughly been the same. And what have you found out from doing this
over the years? Just as I say, yeah a general snapshot of
the numbers so you can see whether some years are lower than others and things like that.
It just depends. And also, just we know that that vaccination's been done and that they
are then covered for the next two years as wel.
They are somewhat understating the scientific importance of the swan roundup there. Having
such detailed information about a semi-wild species over such a long period of time is
both very rare and very useful. Based on data from the Abbotsbury swans, scientists have
been able to calculate year-on-year survival rates for swans, at what age they first breed,
what fraction of the population breeds in a year, that older birds are more likely to
be immune to bird flu suggesting that swans have a long-term immune memory, that there
is selection for breeding earlier in life even if that results in faster ageing, with
genetic evidence for that finding, the hormonal triggers for when swans moult their feathers
and direct evidence for evolution towards larger clutch sizes including how much of
that variance is due to the individual female just to name a few papers.
The round up is incredibly beneficial for both swans and swan scientists alike. But
perhaps, just perhaps, the real benefit was the feathery friends we made along the way.
How did you get into being a swan? *honk*
Oh very interesting! Did you just tell the swan to smile?
Yeah! Go on, smile! You're not a royal swan are you. Oh you are
gorgeous, you are! Oh you're my favourite. Don't tell the others but you are my favourite.
I want to say a huge thank you to Abbotsbury Swannery and Charlie Wheeler in particular
for letting me take part and film in their craziest day of the year. Although the round
up itself is a private event, the swannery is a tourist attraction and so you can go
visit, get up close to the colony and, you know, find out even more about swans!