RE5 Unit 8 Video · CRANE MIGRATION (沙丘鹤的大迁徙)

🎬 视频双语精读对照表 (Subtitle Script)

0:26

This is, I think without doubt,

毫无疑问，我认为这是北美大陆上最为壮观的鸟类大迁徙之一，

0:28

one of the most spectacular migrations that you can witness in North America,

甚至可以说是地球上最宏伟壮丽的自然奇观。

0:32

if not the most spectacular.

亲眼目睹这一幕，内心会油然而生一种振奋与崇敬之情，

0:35

There's just something really uplifting and inspiring about them,

世界各地赶来驻足观赏的人们都会产生这种深切的共鸣。

0:38

and people all over the world have felt that way.

那种宏大的生命律动令人沉醉、无法抗拒。

0:43

They're kind of impossible to resist.

每当沙丘鹤成群飞抵，就标志着初春的脚步正式踏上这片平原。

0:52

When the cranes arrive, it's the first time the spring's coming.

不久之后，新生的小牛犊也将降生，嫩绿的牧草蓬勃生长，

0:55

And then soon after, the baby calves will be coming and then hitting the ground,

整片大地苏醒，一年中最美好的时光就此启幕。

1:00

and the grass greens up, it's the start of the best time of year for me.

沙丘鹤在地球上繁衍生息了数千万年，

1:05

Cranes have been in the world for tens of millions of years,

而沿着普拉特河谷展开的这场春季大迁徙，也至少延续了上万年之久。

1:09

and they've been doing this migration for at least 10,000 years.

根据科学观测，每只沙丘鹤通常会在河谷中停留大约三周时间，

1:29

From what we know, each individual crane will spend about three to four weeks here,

它们在此展现出许多群聚水鸟共同的停歇行为（staging）。

1:33

and they're doing a behavior that's common with many other water birds called staging.

它们在此大量进食增肥积蓄能量，为后续漫长的北迁长途飞行做足准备，

1:38

They're kind of fattening up for the rest of their journey,

同时在庞大的鸟群中重逢伙伴、结交新朋友，展开繁复的求偶互动。

1:41

and then they're also kind of meeting up with their friends, with their mates, with family.

它们在这处中继栖息地上，首次展现出丰富多样的群居社交行为。

1:47

They start doing certain social behaviors here for the first time.

清晨旭日初升，数十万只沙丘鹤从河滩上遮天蔽日、雷鸣般同时振翅腾空，

2:02

They get up and there's a gigantic lift off off the river, and it is actually definite.

飞往周围广袤的农田与草场展开一整天的寻食觅食。

2:08

So then they go out and then they go to their feeding areas in the corn fields.

通常在农夫开春播种玉米之前，沙丘鹤就已经启程离去，因此双方能够和谐共存。

2:12

They're usually gone before we put a seed in the ground, so we really code this pretty well.

对这些奔波万里的沙丘鹤而言，散落残留的玉米粒就像全天候免费享用的丰盛自助餐，

2:18

And for the cranes, it's a breakfast buffet all day.

终日尽情畅享大自然的馈赠。

2:22

All day, all you can eat buffet.

沙丘鹤已经高度适应了将农田散落谷物作为主要能量补充来源的生活方式。

2:24

The cranes have adapted to where the grain is very important to their diet now.

实际上，每英亩农田里大约只残留遗留250磅散碎玉米，其中部分还会被散养牲畜吃掉，

2:29

We're probably really only leaving about 250 pounds of corn that the combine isn't getting,

但沙丘鹤却凭借顽强的适应力，在这微薄的谷物残余中蓬勃生存。

2:33

and then the cows are cleaning up part of that.

就物种繁衍与演化而言，它们堪称世界上最成功的鸟类之一。

2:36

But the cranes are thriving on that little amount that we're leaving.

学会取食人类农田玉米，虽然在它们数千万年的演化长河中不过是短短一瞬，

2:41

There are some of the world's most successful birds in terms of how long they've been around on this planet,

但这正是它们极强抗逆力与敏锐生存机会主义的绝佳例证——充分利用一切新出现的食物资源。

2:46

and I think they're eating corn, even though it's only been around for 100 years,

如今在普拉特河谷，玉米为沙丘鹤提供了约95%的高热量卡路里补给，

2:50

which is a tiny portion of their evolution.

但这只能提供能量，却无法提供繁殖发育所需的全部微量营养素。

2:52

It's another measure of their resilience and their opportunism.

它们必须深入这片潮湿的草甸湿地中，捕食昆虫、蜗牛与水生植物来获取关键营养。

2:56

They're taking advantage of a new food source.

因此，即便目前沙丘鹤种群数量繁盛，它们依然时刻面临着严峻的生存挑战。

3:01

Today in the Platte River Valley, about 95% of their caloric intake is from corn.

对整个种群而言，当前最大的区域性威胁莫过于湿地生境与水资源的持续退化缩减。

3:09

It provides them calories, but it does not provide them nutrients or protein and some essential minerals.

我们迫切需要守护这些湿地草甸，保护普拉特河主河道及其周边残存的脆弱生态系。

3:17

They get that from these wet meadows.

我们正全力推进草原生态修复，并与众多农场主协同合作，改善水鸟栖息环境。

3:19

So even though Santel cranes are doing well, they of course face threats, just like every other species.

沙丘鹤的生存繁衍完全依附于这条生命之河，它们无法脱离普拉特河水系而独存。

3:25

The number one threat region-wide for them is the loss of wetland habitat and loss of habitat in general.

它们高度适应湿地生境，而水资源丰沛程度直接受到气候变化的深远牵动。

3:32

We really need these meadows, and we're to a point where we have to preserve the last few percent

气候变化对沙丘鹤长远迁徙究竟会造成多大冲击，目前科学家尚无定论；

3:37

that remain along the big bed of the plant and elsewhere.

但不可忽视的是，它们如今春季飞抵河谷的时间比20年前提前了整整30天左右。

3:41

So we are working to restore these prairies, and also with multiple objectives in mind,

这种物候期的剧烈骤变极其罕见而迅猛。

3:46

to improve habitat for cranes, but also these other grassland and wetland birds.

它们虽然具备极强的生存耐受力，但无论如何，生命都不可或缺丰沛的水源滋养。

3:59

With the cranes, they can't really shift away from this river.

它们展现出的坚韧抗逆不仅关乎单个物种，更维系着整个大平原湿地水鸟生态系统，

4:03

They really need this river system.

若人类不立即采取坚决行动遏制生境破坏，整个生态网都将濒临崩溃。

4:05

These birds are adapted to water, and they need that, and water obviously is affected by climate.

因此，即便沙丘鹤此刻看似数量充裕，也绝不意味着它们不会面临脆弱灭绝危机。

4:10

The jury is kind of out on how climate change will affect Santel's, but we know that their migration has advanced.

回溯到20世纪30年代，沙丘鹤曾因人类过度猎杀与生境骤减而险遭灭顶之灾，

4:18

They were arriving about 30 days earlier than they did 20 years ago.

美国政府随后通过具有里程碑意义的立法，严格保护本土候鸟与野生鸟类，才扭转了濒危命运。

4:21

That's a very rapid shift.

如今沙丘鹤的生存奇迹，既归功于它们自身数千万年锤炼出的惊人抗逆力，

4:23

They can deal with all sorts of changes, but they need water and they need wetlands at the end of the day.

也彰显了人类积极介入立法保护、守护生态多样性的积极成效。

4:29

I think they're resilient, but I think that it's not really about them.

它们是自然界坚韧生命的希望象征，更是人与自然和谐共生的伟大见证。

4:34

It's about this whole Great Plains water bird ecosystem that is on the verge of something very dangerous

它们的繁荣成功，正是全人类守护地球生态的共同胜利。

4:40

if we don't really put our foot down and stop it.