Charles Anderson discovers dragonflies that cross oceans

譯者: Marie Wu 審譯者: Adrienne Lin

Actually, I come from Britain,

我其實是英國人，

but I've been living in Maldives for 26 years now.

但是我已經在馬爾地夫住了26年了，

So, that's home really.

馬爾地夫才算是我真正的家。

The Maldives, as I'm sure you're aware, are a chain of islands

大家應該都知道，馬爾地夫是由一連串小島組成，

off the southwest coast of India here.

位於印度西南海岸外緣，

Capital, Malé, where I live.

首都是馬累，我就住在那裡。

Actually, sitting here today in Mysore,

其實，今天會場的所在地邁索爾，

we're closer to Malé than we are to Delhi, for example.

就離馬累比較近，去德里反而遠一點。

If you're in IT, India, obviously, is the place to be at the moment.

如果你從事資訊產業，印度很顯然是最好的選擇；

But if you're a marine biologist, Maldives is not such a bad place to be.

但如果你是個海洋生物學家，馬爾地夫也算是個不錯的選擇。

And it has been my home these years.

正因為這樣，我才在馬爾地夫住了這麼多年。

For those of you who've been there, fantastic coral reefs,

如果各位曾經去過那裡，就知道那裡有超棒的珊瑚礁、

fantastic diving, fantastic snorkeling.

超棒的潛水、超棒的浮潛。

I spend as much of my time as possible

我把所有時間都用來

investigating the marine life.

研究海洋生物，

I study fish,

我研究魚類，

also the bigger things, whales and dolphins.

也研究更大的動物，像鯨和海豚。

This is a blue whale. We have blue whales

這是一隻藍鯨，藍鯨出現在

in the waters around here, off Maldives,

這附近的海域，就在馬爾地夫

around the waters of India. You can see them off Kerala.

和印度之間，你可以在卡瑞拉附近看到他們。

And, in fact, we're very lucky in this region.

我們很幸運能住在這個地區，

One of the best places in the world to see blue whales

因為這個地區就是全球觀賞藍鯨

is here in this region.

最佳地點的其中之一。

In Sri Lanka, if you go down to the south coast of Sri Lanka,

在斯里蘭卡，如果你在東北季風季節

during the northeast monsoon season,

來到斯里蘭卡南部海岸的話，

you can see blue whales very, very easily.

你可以很輕易地就看到藍鯨，

It's probably the best place in the world to see them.

那裡可能是世界上觀賞藍鯨的最佳地點。

Now, when I talk about the northeast monsoon season,

好，當我說到東北季風的時候，

I'm sure many of you here know exactly what I mean,

我相信大部分的人都知道我指的是什麼，

but perhaps some of you are not quite so sure.

但有些人可能還不太清楚，

I need to explain a little bit about monsoons.

我來稍微解釋一下季風是怎麼回事。

Now, monsoon, the root of the word "monsoon"

好，「季風」這個詞，

comes from the word "season."

很明顯和「季節」有關，

So, it's just a season. And there are two seasons in most of South Asia.

所以可以把季風看成是一個季節。而在大部分南亞地區，有兩個季節。

And in the summer India heats up, gets very hot.

夏天時，印度會漸漸變熱，而且會變得很熱；

Hot air rises, and air is drawn in off the sea to replace it.

當熱空氣上升，海洋上空的空氣就會被拉扯過來取而代之，

And the way it works is, it comes from the southwest.

這股氣流會從西南方向來，

It comes off the ocean here and is drawn up towards India.

從這裡的海洋表面，被拉扯到印度陸地；

So it comes from the southwest. It's a southwest monsoon.

由於氣流是從西南方向來，所以被稱為西南季風。

Picks up moisture as it crosses the ocean.

在季風通過海洋表面時，夾帶了大量的水氣，

That's what brings the monsoon rain.

就帶來了季風雨。

And then in the winter things cool down.

然後到冬天時，氣候變冷，

High pressure builds over India.

高氣壓在印度上空盤旋，

And the whole system goes into reverse.

使整個系統便反轉過來，

So, the wind is now coming from the northeast

於是，風就從東北方向吹過來，

out of India, across the Indian Ocean,

從印度大陸吹到印度洋，

this way towards Africa.

再一路吹向非洲。

Keep that in mind.

請各位記住這一點。

Now, I'm a marine biologist, but I'm actually

好，我是海洋生物學家，可是我覺得

a bit of an old fashioned naturalist, I suppose.

自己比較像老派的自然學家。

I'm interested in all sorts of things, almost everything that moves,

我對各式各樣的事情都感興趣，包括所有會動的東西，

including dragonflies. And I'm actually

也包括蜻蜓。

going to talk, this afternoon, about dragonflies.

我今天下午就是要跟你們談談蜻蜓。

This is a very beautiful species, it's called the Oriental Scarlet.

這是一個非常美麗的蜻蜓品種，叫做東方猩紅蜻蜓。

And one thing you need to know about dragonflies,

有一件關於蜻蜓事是很重要的，

one important thing,

你們必須瞭解，

is that they lay their eggs in fresh water.

蜻蜓會在淡水中產卵，

They need fresh water to breed.

他們需要淡水才能繁殖。

They lay the eggs into fresh water.

蜻蜓把卵產在淡水中，

Little larvae hatch out in fresh water.

小小的幼蟲就在淡水中孵化出來，

They feed on other little things. They feed on mosquito larvae.

他們捕食其他小生物，包括蚊子的幼蟲，

So, they're very important.

所以他們非常重要，

They control mosquito larvae, among other things.

他們可以控制蚊子幼蟲的數量。

And they grow and grow by stages. And they climb out

在經過幾個生長階段之後，他們會從水裡爬出來，

of the water, burst out, as the adult which we see.

蛻變成為我們看到的成蟲。

And typically, there is a lot of variation,

當然，不同種類間的會有不同的差異，

but if you have a dragonfly with, say, a one year life cycle,

如果持續觀察，你會看到蜻蜓的生命週期通常是一年，

which is quite typical, the larva, living in the fresh water,

他的幼蟲通常會在淡水中生活

lives for 10 or 11 months.

10或11個月，

And then the adult, which comes after, lives for one or two months.

而他蛻變為成蟲之後，會再活一或兩個月。

So it's essentially a freshwater animal.

因此，蜻蜓本質上是一種淡水動物，

It really does need fresh water.

他們需要依靠淡水才能生存。

Now, the particular species of dragonfly

好了，我要講到的一種很特別的蜻蜓

I want to talk about is this one,

就是這種，

because most dragonflies, like the one we've just seen,

因為大多數的蜻蜓，像我們剛剛看到的那種，

when the adult is there for its brief one or two months of life,

在他短暫的一兩個月的成蟲期內，

it doesn't go very far. It can't travel very far.

不會飛得很遠，不能長途旅行，

A few kilometers, maybe, is quite typical.

頂多就是幾公里而已。

They are very good fliers, but they don't go too far.

蜻蜓非常善於飛行，但是他們不會飛很遠。

But this guy is an exception.

但這個傢伙是個例外，

And this is called the Globe Skimmer,

他的名字叫做黃蜻，

or Wandering Glider.

又稱薄翅蜻蜓，

And, as the name might suggest, it is found pretty much around the world.

在世界各地都能找到他，

It lives throughout the tropics, the Americas,

分佈遍及熱帶、美洲、

Africa, Asia, Australia, into the Pacific.

非洲、亞洲、澳洲以及太平洋地區。

And it wanders far and wide. We know that much about it.

活動範圍非常廣泛，我們對他的瞭解也僅止於此，

But it really hasn't been studied very much.

從來沒有人好好地研究過這種蜻蜓，

It's a rather mediocre looking dragonfly.

因為他的長相真的是太平凡了。

If you're going to study dragonflies, you want to study those really bright beautiful ones,

如果你要研究蜻蜓的話，你會想去研究那些美艷的品種，

like that red one. Or the really rare ones, the endemic endangered ones.

像那隻紅的，或是稀有品種、某地瀕臨絕種的品種。

This is, it seems a bit dull you know.

這個嘛，看起來真的很不起眼，

It's sort of dull-colored. And it's fairly common.

他的顏色有點暗淡，而且相當常見，

And it occurs everywhere -- you know, why bother?

任何地方都可以看到。你會想，何苦浪費時間？

But if you take that attitude, you're actually missing something rather special.

但如果你真的這樣想的話，你就會錯失發現特殊現象的機會，

Because this dragonfly has a rather amazing story to tell.

因為這種蜻蜓具有非常不平凡的經歷，

And I feel very privileged to have stumbled across it

是我居住在馬爾地夫時，

living in the Maldives.

偶然有幸發現的。

When I first went to the Maldives,

我剛到馬爾地夫的時候，

dead keen on diving, spent as much of my time

非常熱衷潛水，我把所有的時間

as I could in and under the water.

都花在潛水，

Didn't notice any dragonflies; maybe they were there, maybe they weren't.

我根本沒注意到任何蜻蜓，他們可能就在附近，也可能不在，

Didn't notice them.

我完全沒有注意到。

But after some time, after some months, one day

但是過了一段時間，可能有幾個月之後，

as I was going out and about,

有一天我在外面走的時候，

suddenly I noticed hundreds of dragonflies, hundreds of dragonflies.

我突然注意到有上百隻的蜻蜓，

Something like this, these are all this species Globe Skimmer.

就是這個品種，全都是黃蜻，

I didn't know at the time, but I know now,

當時並不知道什麼品種，但我現在知道了，

they're Globe Skimmers, hundreds of them.

他們是黃蜻，有好幾百隻，

And they were there for some time. And then they were gone.

他們在那裡待了一段時間，然後就不見了。

And I didn't think anything more of it until

我也沒去多想，

the following year, when it happened again,

直到第二年，同樣的事又發生了，

and then the year after that, and then the year after that.

然後又一年也是這樣，再下來的一年也一樣。

And I was a bit slow, I didn't really take too much notice.

我反應比較慢，沒有真正放在心上，

But I asked some Maldivian friends and colleagues, and yes they come every year.

但是我問過一些馬爾地夫的朋友和同事，他們都說這些蜻蜓每年都來，

And I asked people about them and yes,

我問其他人，答案也是一樣，

they knew, but they didn't know anything,

他們都知道蜻蜓每年來訪，但是其他什麼都不清楚，

where they came from, or anything.

他們不知道蜻蜓從哪裡來，什麼都不知道。

And again I didn't think too much of it.

我還是一樣沒有多想。

But slowly it began to dawn on me that something

但是慢慢地我發覺到，

rather special was happening.

應該是有什麼特別的地方才對，

Because dragonflies need fresh water to breed.

因為蜻蜓需要淡水來繁殖，

And the Maldives, and I'm sure some of you have been there --

而馬爾地夫--我相信你們一定有人去過--

so here is home.

好，這裡就是我的家鄉，

So, Maldives, beautiful place.

馬爾地夫，美麗的地方。

(Laughter)

（笑聲）

It's built entirely of coral reefs.

馬爾地夫全部都是珊瑚礁，

And on top of the coral reefs are sand banks.

珊瑚礁上面是沙洲，

Average height, about that much above sea level.

平均高度只高過海平面一點點。

So, global warming, sea level rise, it's a real serious issue.

因此，全球暖化、海平面上升，是馬爾地夫面臨的嚴重問題。

But I'm not going to talk about that.

但我今天不是要談這個話題。

Another important point of these sand banks

沙洲有一個特點，

is that when it rains,

就是下雨的時候，

the rainwater soaks down into the soil. So, it's gone.

雨水會滲透到下面的土壤，你看不見的地方。

So, it stays under the soil.

所以，雨水留在土壤下面，

The trees can put their roots into it.

樹本就利用樹根來吸水，

Humans can dig holes and make a well.

人類則挖坑鑿井，

But dragonflies -- a bit tricky.

可是蜻蜓，就不好辦了。

There is no surface fresh water.

沒有地表的淡水，

There are no ponds, streams, rivers, lakes,

沒有池塘、小溪、河流、湖泊，

nothing like that.

什麼都沒有，

So, why is it that every year

那麼為什麼每年

millions of dragonflies, millions,

還有幾百萬隻的蜻蜓，

millions of dragonflies turn up?

會出現在這裡呢？

I got a little bit curious. In fact I'll stop here,

我覺得很好奇。在這裡我想先暫停一下，

because I want to ask, and there is a lot of people who,

因為我想問你們問題，你們一定有很多人

from India of course, people who grew up spending your childhood here.

是從印度來的、在印度長大、或在印度度過童年，

Those of you who are Indian or spent your childhood here,

如果你是印度人，或者在印度這裡長大，

let me have a show of hands, who of you --

請舉一下手，有誰 -

not yet, not yet!

還沒開始，還沒哦！

You're too keen. You're too keen. No. Hang on. Hang on.

你們太急了，太急了。不，稍等，

Wait for the go. I'll say go.

等我喊開始。

Those of you who grew up in India,

你們如果在印度長大，

do you remember in your childhood, dragonflies,

記不記得小時候曾經看見蜻蜓，

swarms of dragonflies? Maybe at school,

一大群的蜻蜓？學生可能會

maybe tying little bits of string onto them?

在他們身上綁上一節細繩？

Maybe pulling bits off? I'm not asking about that.

然後把他們扯碎？我不是要問你們那個。

You've only got to say, do you remember seeing lots of dragonflies.

你只要告訴我，是不是記得曾經看見過很多的蜻蜓，

Any hands? Any hands? Yes. Thank you. Thank you.

請舉手。好，謝謝。

It's a widespread phenomenon

那是在整個南亞，包括馬爾地夫

throughout South Asia, including the Maldives.

都隨處可見的現象。

And I got a bit curious about it.

我還是很好奇。

In the Maldives -- now, in India there is plenty of water,

在馬爾地夫--當然在印度有很多水，

so, dragonflies, yeah, of course. Why not?

自然就會有很多蜻蜓，對吧？

But in Maldives, no fresh water. So, what on Earth is going on?

但是在馬爾地夫，並沒有淡水。那，到底是怎麼回事？

And the first thing I did was started recording

於是我做的第一件事，就是開始記錄

when they turned up in the Maldives.

他們在馬爾地夫出現的時間。

And there is the answer, 21st of October.

答案是10月21日。

Not every year, that's the average date.

不是每年都在同一天，但就在那幾天，

So, I've been writing it down for 15 years now.

因為我已經記錄了15年了。

You'd think they're coming from India. It's the closest place.

你會想他們是從印度來，因為那是最近的地方。

But in October, remember, we're still in southwest monsoon,

但在十月份的時候，是吹西南季風，

Maldives is still in the southwest monsoon.

馬爾地夫仍受西南季風影響，

But wind is, invariably, every time, is from the west.

風每回都是從西邊吹來，

It's going towards India, not from India.

是吹向印度，不是從印度吹來。

So, are these things, how are these things getting here?

那麼，這些傢伙是怎樣來到這裡的呢？

Are they coming from India against the wind?

他們是逆風從印度飛過來的嗎？

Seemed a bit unlikely.

有點不太可能。

So, next thing I did is I got on the phone.

所以，我接下來開始打電話。

Maldives is a long archipelago.

馬爾地夫是由一串很長的群島組成，

It stretches about 500 miles, of course it's India here.

延伸大約500英哩(800公里)，一直到印度這裡。

I got on the phone and emailed to friends and colleagues.

我打電話和發電子郵件給我的朋友和同事，

When do you see the dragonflies appear?

問他們什麼時候看到蜻蜓出現？

And pretty soon, a picture started emerging.

很快地，我大概瞭解狀況了。

In Bangalore, a colleague there sent me

班加羅爾的一個同事，

information for three years, average,

連續三年提供我蜻蜓出現的日期，

24th of September, so late September.

大約在9月24日前後，也就是九月下旬。

Down in Trivandrum, a bit later.

往下的曲凡德郎，就晚一點。

Far north of Maldives, a bit later.

而馬爾地夫的最北端，又更晚一點。

Then Malé, then further south.

再來是馬累，然後更往南，

And then the southernmost Maldives.

最後是馬爾地夫的最南端。

It's pretty obvious, they're coming from India.

很明顯，它們是從印度來。

But they are coming 400 miles across the ocean, against the wind.

他們逆風飛行，從400英哩(650公里)外漂洋過海來到這裡，

How on Earth are they doing that?

他們是怎麼辦到的呢？

I didn't know.

我當時並不知道。

The next thing I did was I started counting dragonflies.

我做的第二件事情，就是開始計算蜻蜓的數目。

I wanted to know about their seasonality,

我想知道他們的季節性，

what time of year, this is when they first arrive,

我知道他們每年開始出現的時間，

but how long are they around for? Does that give any clues?

但是他們會待多久？能否從他們的數目找到一點線索？

So, I started a very rigorous scientific process.

於是，我開始了一個很嚴謹的科學研究，

I had a rigorous scientific transect.

我用嚴謹的科學研究交通工具，

I got on my bicycle,

也就是我的自行車，

and I cycled around the island of Malé.

沿著馬累島轉，

It's about five kilometers around,

一圈大概有五公里，

counting the dragonflies as I go,

一邊騎，一邊數蜻蜓，

trying not to bump into people as I'm looking in the trees.

在我數樹上的蜻蜓時，還得小心路人。

And they're here for a very short time,

我發現他們在這裡只待一段很短的時間，

October, November, December. That's it.

十月、十一月、十二月，就走了。

And then they tail off, there's a few, but that's it.

他們的數量會減少，只剩下一些，其他都走了。

October, November, December. That is not the northeast monsoon season.

十月、十一月、十二月，那不是東北季風季節，

That's not the southwest season.

也不是西南季風季節，

That's the inter-monsoon,

那是介於二個季風之間的時期，

the time when the monsoon changes.

也就是季風變換的時期。

Now, what I said was, you get the southwest monsoon going one way,

好了，我剛才說的是，這裡西南季風往這個方向吹，

and then it changes and you get the northeast monsoon going the other way.

緊接著，變成東北季風往相反方向吹。

And that sort of gives the impression you've got one air mass

你會以為是有一個氣團

going up and down, up and down. It doesn't work like that.

在這附近上上下下，實際上並不是如此。

What happens, actually, is there is two air masses.

實際上，那裡有兩個氣團，

And there is a front between them, and the front moves.

氣團之間有個鋒面，是鋒面在移動。

So, if you've got India here,

所以，如果這裡是印度，

when the front is up above India you're into the southwest monsoon.

當鋒面在印度上空時，就吹西南季風；

Then the front moves into the northeast monsoon.

當鋒面移走，就吹東北季風。

And that front in the middle is not vertical,

而且氣團中間的鋒面並不是垂直的，

it's at an angle.

他呈一個角度。

So, as it comes over towards Malé

所以，當鋒面向馬累這邊移動過來的時候，

I'm standing in Malé underneath the front.

我站在馬累的鋒面之下，

I can be in the southwest monsoon.

就處於西南季風裡，

But the wind above is from the northeast monsoon.

但是這上面的風卻是從東北季風吹過來的。

So, the dragonflies are actually coming from India on the northeast monsoon,

所以，這些蜻蜓其實是跟著東北季風從印度來的，

but at an altitude at 1,000 to 2,000 meters up in the air. Incredible.

而且是在海拔一千到二千米的空中，真不可思議。

These little insects, it's the same ones we see out here [in India],

這些小小的昆蟲，就和我們在印度這裡看到的一樣，

two inches long, five centimeters long,

兩英寸長，或五公分長，

flying in their millions, 400 miles across the ocean,

跟著其他百萬隻蜻蜓一起飛行，在二千米的高空上，

at 2,000 meters up. Quite incredible.

飛越400英哩(640公里)的海洋。真是太不可思議了！

So, I was quite pleased with myself. I thought wow, I've tracked this one,

為此，我對自己相當滿意。我想，哇，我追蹤到了這個，

I know how they come here. Then I scratched my head a bit,

我知道他們是怎樣到這裡的。然後我抓了抓我的頭，

and that's okay,

是很不錯，

I know how they come here, but why do they come here?

我知道他們怎樣到達這裡，但是為什麼他們要來這裡呢？

What are millions of dragonflies doing, flying out over the ocean every year

這幾百萬隻蜻蜓在做什麼？每年飛越海洋上空，

to their apparent doom?

就是為了來送死嗎？

It doesn't make sense. There is nothing for them in Maldives.

沒有道理嘛。馬爾地夫沒有任何他們需要的東西，

What on Earth are they doing?

他們到底在做什麼？

Well, to cut a long story short,

好吧，長話短說，

they're actually flying right across the ocean.

他們其實是要飛到海洋對岸，

They're making it all the way across to East Africa.

橫跨整個海洋，一直飛到東非去。

I know that because I have friends who work on fisheries' research vessels

我會知道，是因為我有朋友在漁場考察船上工作，

who have sent to me reports from boats out in the ocean.

他們從船上傳送報告給我，

I know because we have reports from Seychelles,

還有人從塞席爾傳送報告給我，

which fit in as well, down here.

也很吻合，在這裡。

And I know because

而且如果把雨量

when you look at the rainfall,

也考量進去，你就會知道，

these particular insects, these Globe Skimmers

這些特別的昆蟲，這些黃蜻，

breed in temporary rain water pools.

是在臨時的雨水積水池裡繁殖的。

Okay, they lay their eggs where the seasonal rains are,

他們會在雨季來臨的地方產卵，

the monsoon rains.

雨季就是季風雨。

The larvae have to develop very quickly.

黃蜻的幼蟲必須很快地發育，

They only take six weeks. Instead of 11 months, they're six weeks.

他們只需六星期，而不是11個月。六個星期後，

They're up, and they're off.

他們就蛻變為蜻蜓，飛走了。

Now, here we have, in case you can't read at the back,

好，我們來看看，如果你坐在後排看不清楚的話，

the top is rainfall for India.

這上面是印度的降雨分佈。

And we're starting in June. So this is the monsoon rain.

這些是季風雨，從六月開始，

By September, October, it's drying out.

到九月、十月的時候，就乾掉了，

Nothing for these dragonflies. There is no more seasonal rain.

這些蜻蜓就沒有雨了，沒有季節性雨水了，

They've got to go hunting for seasonal rain.

他們需要去尋找季節性的雨水。

And they fly south. As the monsoon withdraws to the south

所以他們向南飛，跟著向南移動的季風，

they come down through Karnataka, into Kerala.

他們向南飛，經過卡南塔卡，再到卡拉拉，

And then they run out of land.

然後就到了陸地的盡頭。

But they are incredibly good fliers. This particular species,

但是他們非常善於飛行，這種特別的品種，

it can fly for thousands of kilometers.

可以飛行上千公里。

And it just keeps going. And the wind, the northeast wind

所以他們就一直飛，而東北風

swooshes it around and carries it off across the ocean to Africa,

把他們托起來，帶著他們飄洋過海，

where it's raining.

來到正在下雨的非洲，

And they are breeding in the rains of Africa.

讓他們在非洲的雨水中繁殖。

Now, this is southeast Africa. It makes it look like there are sort of

好，這是東南非洲，你會以為好像有

two breeding periods here. It's slightly more complicated than that.

兩個繁殖季節，實際上要稍微複雜一點。

What's happening is they are breeding in the monsoon rains here.

他們其實是在這裡的季風雨中繁殖，

And the dragonflies you can see today

而你們現在在外面校園裡

outside here, on the campus,

所看到的蜻蜓，

are the young of this generation.

就是他們的後代，

They hatched out in India.

也就是在印度這裡孵出來的。

They're looking for somewhere to breed. If it rains here they'll breed.

這些蜻蜓其實在找適當的產卵地點，哪裡有雨就在哪裡產卵，

But most of them are going to carry on. And next stop,

但大部分的蜻蜓會繼續長途旅行，他們的下一站，

perhaps only four or five days away is going to be East Africa.

還要飛四、五天才會到達，也就是東非，

The wind will swoosh them out across here.

季風會把他們帶到那兒去；

If they pass the Maldives they might go and have a look,

在他們經過馬爾地夫的時候，或許會停下來看看，

nothing there, they'll carry on.

如果什麼都沒有，就繼續旅行，

Here, here, Kenya, East Africa,

來到這裡，東非的肯亞，

they've actually just come out of a long drought.

那裡才剛結束一段長期的乾旱，

Just last week the rains broke. The short rains broke

上星期才開始下雨，雨季開始了，

and it's raining there now.

現在雨下個不停。

And the dragonflies are there. I have reports from my various contacts.

有人告訴我蜻蜓現在停留在那裡，

The dragonflies are here now. They're breeding there.

交配季節到了，

When those guys, they'll lay their eggs now.

他們在那裡產卵，

They'll hatch out in six weeks. By that time

卵會在六個星期內孵化，

the seasonal rains have moved on. It's not there, it's down here.

到那時，季風雨已經又移動了，不在那裡，會移到這裡，

They'll fly down here. And the clever thing is

蜻蜓也會跟著移動下來，最神奇的事是，

the wind is always converging to where the rain is.

季風永遠都會伴隨著季風雨出現。

The rain occurs, these are summer rains.

雨季來臨的時候，是在夏天，

This is a summer monsoon.

這是夏季季風，

The sun is overhead there. Summer rains in southern Africa.

太陽高高在上，而夏季的雨水則在南非，

The sun is overhead, maximum heating,

溫度很熱，

maximum evaporation, maximum clouds,

水氣都蒸發了，雲量很多，

maximum rainfall,

雨量也很大，

maximum opportunities for reproduction.

是繁殖的最佳季節。

Not only that, because you have this convection,

不只這樣，由於對流的關係，

you have this rising of the air

熱空氣上升，

where it's hot, air is drawn in.

就牽引進冷空氣，

There's a convergence. So, wherever the rain is falling,

來彌補上升的熱空氣。所以，只要有下雨的地方，

the air is drawn towards it to replace the air that's rising.

冷空氣就會被牽引過來取代上升的空氣。

So, the little fellow that hatches out here,

這些產過卵的蜻蜓，

he gets up into the air, he is automatically carried

就被上升的空氣托到空中，自動被

to where the rain is falling.

帶到會下雨的地點。

Lay their eggs, next generation, they come up,

產卵、孵化、蛻變成蜻蜓，

automatically carried to where the rain is falling.

再自動被帶到會下雨的地點。

It's now back there. They come out, it's time to come back.

他們現在回來了，蛻變成蜻蜓後又回來了。

So, in four generations, one, two, three,

所以，在經過四代之後，

four and then back.

他們又回來了，

A complete circuit of the Indian Ocean.

環繞了印度洋一周，

This is a circuit of about 16,000 kilometers.

全長約一萬六千公里，

16,000 kilometers, four generations, mind you,

一萬六千公里，四個世代，

for a two inch long insect. It's quite incredible.

是這種二吋長的昆蟲辦到的壯舉，真是令人不敢相信！

Those of you from North America

如果有人是從北美來的，

will be familiar with the Monarch butterfly.

就比較熟悉帝王斑蝶(大樺斑蝶)，

Which, up until now has had the longest known insect migration.

那是目前所知遷移路線最長的昆蟲，

It's only half the length of this one.

但他們的路程只有這些蜻蜓的一半而已，

And this crossing here, of the ocean,

這些蜻蜓還會橫跨海洋，

is the only truly regular transoceanic crossing

是目前所知能夠定期橫跨海洋

of any insect.

的昆蟲。

A quite incredible feat.

很不可思議吧！

And I only stumbled on this because I was living in Malé,

因為我在馬爾地夫的馬累住得夠久，

in Maldives for long enough

我才會注意到這件事，

for it to percolate into my brain

我的腦袋也才會發現

that something rather special was going on.

這件特別的事情。

But dragonflies are not the only creatures that make the crossing.

但是蜻蜓並不是唯一會飄洋過海的生物，

There is more to the story.

我還研究了其他物種，

I'm also interested in birds. And I'm familiar

我對鳥類特別有興趣，我所熟知的這種鳥，

with this fellow. This is a rather special bird.

是很特別的一種鳥，

It's a falcon. It's called the eastern red-footed falcon, obviously.

是鷹的一種，人們叫它東方紅腳隼，

But it's also called the Amur Falcon.

或有人稱之為黑龍江隼，

And it's called the Amur Falcon

因為這種鷹是在

because it breeds in Amurland.

黑龍江地區繁殖的，

Which is an area along the Amur River, which is up here.

也就是沿著黑龍江一帶，在這上面，

It's the border, much of it is the border

靠近邊界一帶，也就是

between China and Russia, up here in the far east.

中俄邊界，在遠東這上面，

So, Siberia, Manchuria.

在西伯利亞、中國東北這一帶，

And that's where it breeds.

他們會繁殖下一代。

And if you're a falcon it's quite a nice place to be in the summer.

如果你是一隻鷹，你會覺得這個地方的夏天很棒，

But it's a pretty miserable place to be in the winter.

但是冬天就很糟了，

It's, well, you can imagine.

所以試著想一想，

So, as any sensible bird would do,

任何有頭腦的鳥，

he moves south. They move south. The whole population moves south.

都會飛到南邊，所以整群鷹都飛向南邊，

But then the being sensible stopped.

直到他們覺得適合的地方才會停下來。

So, now they don't stop here, or even down here.

他們不會停在這裡，也不會停在這裡，

No, they turn across here.

他們還會橫跨這裡，

They have a little refueling stop in northeastern India.

在印度東北部會稍做停留，補充體力，

They come to the latitude of about Mumbai or Goa.

他們會停在孟買或果亞一帶，

And then they strike out across the ocean, down to Kenya.

然後再出發橫跨海洋，往南到肯亞，

And down here, and they winter down here [in southern Africa].

來到非洲南部過冬。

Incredible. This is the most extraordinary migration

真了不起！這是掠食性鳥類最奇特

of any bird of prey. A quite incredible migration.

的遷徙旅程，很了不起的遷徙！

And they are not the only one that makes the crossing.

而他們也不是唯一橫跨海洋的鳥類，

They have the most incredible journey, but several make the crossing from India

他們的旅程是最了不起的沒錯，但是還有其他鳥類

to Africa. Includes this one, the hobby.

像這種隼一樣從印度飛到非洲，

This fellow is a very nice bird, this is the Pied cuckoo.

這種鳥很美，叫做斑翅鳳頭鵑，

Those of you from northern India will be familiar with this.

住在印度北部的人就很熟悉這種鳥，

It comes with the monsoons.

他們會跟著季風遷徙，

This time of year they cross back to Africa.

今年他們隨著季風回到非洲去了。

And this guy, the roller, a rather beautiful bird.

這隻佛法僧鳥很美，

It's known as the Eurasian Roller. In India it occurs in the northwest,

人們稱它為藍胸佛法僧，它會出現在印度西北部，

so it's known as the Kashmir Roller.

所以又稱為喀什米亞佛法僧。

And these birds, what I've done is I've complied all the records,

為了研究這些鳥，我把手邊的資料都拿出來，

all the available records of these birds,

所以有關這些鳥的資料全都蒐集起來，

put them together, and found out they migrate at exactly the same time

放在一起，我發現他們遷徙的時間，

as the dragonflies.

都和黃蜻一樣，

They make use of exactly the same winds.

他們都運用同樣的季風，

They travel at exactly the same time with the same winds

在同樣的時間，乘著同一股季風，

to make the crossing. I know they travel at the same altitude.

橫越海洋。我發現他們的旅程都差不多，

It's known about the Amur Falcon. This guy, unfortunately,

最有名的是這隻黑龍江隼。但這個傢伙不怎麼幸運，

one of these met an unfortunate end.

下場不是很好。

He was flying off the coast of Goa,

那時它在果亞的外海飛行，

21 years ago, 1988. October, 1988.

那是1988年十月，也就是21年以前，

An Indian Navy jet was flying off Goa,

有架印度海軍的噴射機也在果亞附近飛行，

bang! In the middle of the night. Fortunately, a two engine jet

碰！就在半夜，擊中了有二架引擎的噴射機，

got back to base, and they pulled the remains of one of these [Eurasian Rollers] out.

飛機返回基地後，他們拿出來的是藍胸佛法僧的殘骸。

Flying at night over the Indian Ocean 2,424 meters.

大半夜的，在印度洋上空2,424公尺高度飛行，

Same height as the dragonflies go.

和黃蜻飛行的高度相同，

So, they are using the same winds.

所以是同一股風。

And the other thing, the other important factor

還有另外一件值得一提的事，

for all these birds, all medium sized fellows,

就是這些鳥全都是中型鳥，

and this includes the next slide as well, which is a bee-eater.

也包括下一張投影片裡的鳥，那是一隻蜂虎，

Bee-eaters eat bees. This one has a nice blue cheek.

蜂虎會吃蜜蜂，這隻蜂虎的臉頰是藍色的，

It's a Blue-cheeked Bee-eater.

所以叫做藍頰蜂虎。

And every one of these birds that makes the crossing

每一種從印度飄洋過海

from India to East Africa

來到東非的鳥類，

eats insects, large insects,

都會吃昆蟲，大型的昆蟲，

the size of dragonflies. Thank you very much.

就像蜻蜓這種大小。謝謝各位！

(Applause)

(掌聲)