Earth is a restless place. 地球是一个动荡不安的地方.
Its seasons driven by the orbit around our sun. 季节变化是由围绕太阳的公转决定的.
An epic journey that sets the rhythms of all life. 一段史诗般的旅程决定了所有生命的节奏.
Humans honour this passage through ritual and celebration. 人类通过仪式和庆祝来纪念这一时刻.
Nature marks the cycle with its own patterns. 大自然用自己的模式来记录这一循环.
Over the course of a year, 在一年的时间里,
the planet's most spectacular events of migration, 地球上最壮观的迁徙行动,
rebirth and transformation unfold. 开始了重生与蜕变.
Moment by moment, 每时每刻,
month by month, 月复一月,
throughout a wild year on Earth. 在地球上狂野的一年里.
狂 野 地 球
七月 – 八月
迁徙季节
Early July sees the sun's abundant energy focused on the northern hemisphere. 7月初,太阳充沛的能量集中在北半球.
Intense light and heat act as catalysts on the ice caps of the Arctic, 强烈的光和热在北极的冰盖上起着催化剂的作用,
as they start to shift and thaw. 当它们开始移动和融化.
Water carves vertical rivers that plummet deep into the frozen abyss. 水雕刻出垂直的河流,这些河流深深地坠入冰冻的深渊.
The icy landscape accelerates its flow towards the sea. 冰冷的景色加速了它流向大海的速度.
Huge fault lines appear. 巨大的断层线出现了.
Something has got to give. 总得给点什么.
This is iceberg calving season. 这是冰山崩解的季节.
The ice sheets in Greenland 格陵兰的冰原
shed billions of tons of ice a year during the melt. 在融化过程中,每年有数十亿吨的冰脱落.
In recent years, 近年来,
the melt season has started earlier and is lasting longer. 融化季节开始得更早,持续时间更长.
Now,more ice melts in the summer than gets replenished over winter. 现在,夏季融化的冰比冬季补充的冰还要多.
The overall loss of ice has become catastrophic. 冰的总体损失已成为灾难性的.
30 years ago, 30年前,
Greenland's ice sheets would melt 25 billion tons of ice each summer. 格陵兰岛的冰原每年夏天会融化250亿吨的冰.
Last season, 上一季,
more than 600 billion tons of ice was lost in the melt. 在融化过程中损失了6000亿吨冰.
The climate is truly changing. 气候确实在变化.
The glacial melt 冰川融化
adds to some of the world's most nutrient-rich waters in the Svalbard archipelago. 在斯瓦尔巴特群岛的一些世界上营养最丰富的水域.
By July, 到七月,
millions of seabirds have migrated from the south to feed around the clock in 24-hour daylight. 数以百万计的海鸟从南方迁徙,24小时不间断地觅食.
It's an ideal place for birds to breed and raise their young. 这是鸟类繁殖和养育后代的理想场所.
Auks have chosen to nest in the scree slopes at the base of the island's cliffs. 海雀已经选择在岛上悬崖底部的碎石坡筑巢.
For Arctic foxes that have spent the winter scavenging, 对于那些在冬季觅食的北极狐来说,
it's a perfect time to hunt. 这是狩猎的最佳时机.
The eggs are well protected, 卵保护得很好,
but the adult birds still have to venture out. 但成年鸟还是要冒险出去.
Though,attacking them head-on rarely works. 不过,正面攻击他们很少奏效.
The auks are just too quick off the mark. 海雀太快了.
What's required is some of that famous fox cunning. 我们需要的是一些著名的狡猾的狐狸.
And a lucky break wouldn't hurt. 幸运的休息不会有什么坏处.
A gull is also on the hunt. 一只海鸥也在捕猎中.
The threat from above distracts the auks for a split second. 来自上面的威胁在一瞬间分散了海雀的注意力.
And a split second is all the fox needs. 狐狸只需要一瞬间.
He has outfoxed the auks. 他打败了海雀.
Many auk species avoid predation by nesting on the precarious cliffs. 许多海雀物种通过在不稳定的悬崖上筑巢来避免被捕食.
The more perilous their perch,the better off they are. 他们的栖居地越危险,他们就越富裕.
Each pair only have one precious offspring. 每一对都只有一个珍贵的后代.
It's only three weeks since the chick has hatched. 小鸡孵出才三周.
But already,it's eager to leave the nest. 但它已经迫不及待地想离开巢穴了.
It's quite the maiden flight. 这是首航.
Hundreds of metres to the safety of the ocean. 几百米到了安全的海洋.
And every summer, 每年夏天,
one brave chick is the first to take the leap. 一只勇敢的小鸡是第一个跳起来的.
It's more like falling than flying as their tiny wings act as a parachute. 这更像是坠落而不是飞行,因为它们小小的翅膀就像降落伞.
But their fathers follow them down. 但他们的父亲却跟着他们.
Helping to steer them towards a water landing. 帮助他们向水上登陆.
Soon,the sky begins to fill with jumpers. 很快,天空开始布满了跳伞者.
And their chaperones. 还有他们的陪护.
In just a few days, 几天之内,
100,000 chicks will take the leap. 10万只小鸡要跳了.
None do it alone. 没有人能独自完成.
But not all make it. 但并非所有人都能成功.
Some fall short on a dangerous landing strip filled with hungry predators. 有些人在充满饥饿的食肉动物的危险着陆地带落空.
Luckily,Dad is about. 幸运的是,爸爸就要来了.
And from here,it's a quick dash to the sea. 从这里,快速冲向大海.
The chicks that make it to the water have no time to rest. 到了水里的小鸡没有时间休息.
Not strong enough to take to the air again, 没有足够的力量再次升空,
the chicks now commence a heroic migration, 小鸡们开始了英勇的迁徙,
swimming to waters off Iceland. 游到冰岛附近海域.
Even as far as North America. 甚至远在北美.
Over 1,000 kilometres away. 1000多公里外.
In Alaska, 在阿拉斯加,
the land is also shedding its icy cloak, 大地也在褪去它冰冷的外衣,
as streams splash towards the sea. 当溪水奔向大海时.
These changes trigger the arrival of another great traveller. 这些变化引发了另一位伟大旅行者的到来.
Sockeye salmon are returning to Bristol Bay, 大马哈鱼正返回布里斯托尔湾,
the place they were born. 他们出生的地方.
They have migrated thousands of kilometres from the deep ocean, 他们从深海迁徙了几千公里,
using the earth's magnetic field like a compass. 像指南针一样利用地球磁场.
The smell of their home stream has been imprinted in their memory since birth. 他们家乡的味道从出生起就深深地印在他们的记忆里.
Their arrival is keenly anticipated by brown bears, 棕熊热切地期待着它们的到来,
who start gathering along the banks of the bay as the salmon return. 当鲑鱼回来的时候,他们开始聚集在海湾的岸边.
They've come for the ultimate teddy bears' picnic. 他们是来参加泰迪熊终极野餐的.
As the salmon exhaust the last of their energy to spawn, 当鲑鱼耗尽最后的能量产卵时,
they reach the end of their life cycle. 他们到达了生命周期的尽头.
What seems like a river of death is actually a vital regenesis. 似乎死亡之河实际上是一个至关重要的再生.
Rivers usually take nutrients out to sea. 河流通常把营养物质带到海里.
But here, 但在这里,
the annual spawning returns nutrients to the rivers. 每年的产卵都会将营养物质返回河流.
Feeding not just the bears, 不仅喂熊,
but also,the trees for kilometres around. 还有,周围数公里的树木.
It's a cycle that is reset every year, 这是一个每年都会重置的循环,
where nothing goes to waste. 什么都不会浪费的地方.
Across North America, 横跨北美,
summer warms the land. 夏天温暖大地.
California's valleys are iridescent with growth. 加利福尼亚的山谷因生长而绚丽夺目.
Its beaches bustle. 海滩熙熙攘攘.
Inland,its deserts sizzle. 内陆沙漠沙沙作响.
In the rolling sands of the Sonoran Desert, 在索诺兰沙漠滚滚的沙滩上,
there's no relief under the cloudless skies. 万里无云的天空下一点也不轻松.
The sidewinder snake must change her behaviour in summer. 响尾蛇在夏天必须改变她的行为.
To avoid the blistering heat, 为了避免起泡的热量,
she limits her time searching for prey, 她限制了寻找猎物的时间,
venturing out only in the early morning and dusk. 只在清晨和黄昏时冒险外出.
Shunning the hot sand, 避开热沙,
she restricts her contact to two body parts at a time. 她一次只能接触两个身体部位.
The peculiar mode of locomotion 特殊的运动方式
helps make her the fastest rattlesnake on sand. 使她成为沙滩上最快的响尾蛇.
Leaving a J-shaped signature as she hunts. 在她打猎时留下一个J形的签名.
Dunes like mountains become a Sisyphean task. 像山一样的沙丘成了西西菲亚人的任务.
Persistence is the only option for this hungry snake. 坚持是这条饥饿的蛇唯一的选择.
But with little moisture to carry scent, 但由于水分太少,无法散发香味,
sniffing out prey is hard. 嗅出猎物很难.
Using special temperature pits on the side of her head, 在她头的侧面使用特殊的体温计,
she scans the environment for life's heat signal. 她扫描环境寻找生命的热量信号.
Able to pick out the slightest variation between the hot sand 能分辨出热沙粒之间的细微差别
and a hot lunch. 一顿热腾腾的午餐.
A gecko is cold-blooded, 壁虎是冷血动物,
making it virtually invisible to the snake's thermal sensors. 使蛇的热传感器几乎看不见它.
But that only works if it stands still. 但这只有在它静止不动的情况下才有效.
One false movement,and it's game over. 一个错误的动作,游戏就结束了.
Fortunately,the sidewinder can survive an entire month without food. 幸运的是,响尾蛇可以在没有食物的情况下存活整整一个月.
Enough time to catch a meal. 有足够的时间吃饭.
Deserts cover almost one quarter of the Earth's surface. 沙漠几乎覆盖了地球表面的四分之一.
But not all deserts are scorching sand dunes. 但并非所有的沙漠都是灼热的沙丘.
The arid steppes of Central Asia 中亚干旱的草原
are an empty,windswept place. 是一个空荡荡的地方.
But as high summer draws close, 但随着盛夏的临近,
scattered rains bring the promise of greener pastures. 零星的雨水带来了更绿牧场的希望.
Drifting with the season, 随风飘荡,
the nomads of Mongolia are always on the move. 蒙古的游牧民族总是在迁徙.
When grazing is scarce, 当放牧稀少时,
they must travel longer distances. 他们必须走更远的距离.
Over hundreds of kilometres to find pasture. 在几百公里外寻找牧场.
Their lives are inextricably tied to their horses. 他们的生活与马密不可分.
It's been part of their existence for over 3,000 years. 这是他们存在了3000多年的一部分.
Children learn to ride almost as soon as they are able to walk. 孩子们几乎一学会走路就学会骑马.
And summer is the time for gathering and racing across country. 夏天是在全国各地聚会和比赛的时候.
The nomads believe to be without a horse, 游牧民族认为没有马,
is like a bird without wings. 就像一只没有翅膀的鸟.
The nomads depend on their livestock 游牧民族以牲畜为生
for all of life's essentials. 所有的生活必需品.
So they will stay here as long as there is enough grass. 所以只要有足够的草,他们就会留在这里.
Using the sun and stars, 利用太阳和星星,
the hills and mountains to find their way. 山峦起伏,寻找自己的路.
For these people, 对这些人来说,
life is in perpetual motion. 生命是永动机.
Further westwards, 再往西走,
summer is also transforming the mighty Himalayas. 夏天也在改变雄伟的喜马拉雅山.
The rooftop of the world reaches over 7 kilometres into the sky. 世界的屋顶高达7公里.
Known as the Third Pole, 被称为第三极,
the Himalayas are home to the largest body of ice outside the Arctic and Antarctica. 喜马拉雅山是北极和南极洲以外最大的冰体所在地.
The heat of the summer causes meltwater from the mountains to spill into ravines and fill rivers running towards the lowlands. 夏天的酷热使山上的融水流入沟壑,填满了流向低地的河流.
By July, 到七月,
the migration of water from mountaintops to valleys reaches a crescendo. 水从山顶向山谷的迁移达到高潮.
In the Terai region of Nepal, 在尼泊尔的特莱地区,
floodplains receive rich deposits of Himalayan silt, 漫滩上沉积着丰富的喜马拉雅粉土,
providing nutrition for some of the tallest grasses in the world. 为世界上一些最高的草提供营养.
July's lush growing season also cultivates another of nature's seasonal flourishes. 七月郁郁葱葱的生长季节也培育了另一个大自然的季节性繁荣.
Insects. 昆虫.
One particular insect stirs from its hibernation state. 一种特殊的昆虫从冬眠状态中苏醒过来.
Hatching from water-borne wriggler into its winged form. 从水栖蠕动动物孵化成有翼的形态.
The warm,wet conditions are perfect for mosquitoes. 温暖潮湿的环境非常适合蚊子.
Females make a higher pitched buzz than males, 雌性的嗡嗡声比雄性高,
and it's the females that cause vexation. 是雌性引起了烦恼.
Because only they seek a blood meal. 因为只有他们才会寻求血餐.
It's not just mosquitoes. 不仅仅是蚊子.
Ticks,gnats,flies 虱子、蚊虫、苍蝇
all boom at this time of year as well. 每年的这个时候都会繁荣起来.
It's impossible to keep up with the endless swatting of pesky freeloaders. 你不可能跟得上那些没完没了的讨厌鬼.
The greater one-horned rhino may appear to have impenetrable armour. 更大的单角犀牛似乎有着难以穿透的盔甲.
However,its plates are nothing but big folds of skin. 然而,它的盘子不过是皮肤的大褶皱.
And it's the folds the flies love best. 那是苍蝇最喜欢的褶皱.
For these cracks 对于这些裂缝
are the sweatiest parts of the rhino's body, 是犀牛身上出汗最多的部位,
full of bacteria and dead skin cells. 充满细菌和死皮细胞.
Delicious. 好吃.
Living with a blanket of bugs is a constant summer time irritation 和一堆虫子生活在一起是夏天的常事
for the rhino. 为了犀牛.
But help is at hand. 但援助就在眼前.
Mynah birds love to forage on creepy crawlies. 八哥鸟喜欢在爬行动物身上觅食.
Even the baby rhino becomes a walking dinner table. 就连小犀牛也变成了一张能走路的餐桌.
Despite the irritation of insects, 尽管有昆虫的刺激,
for the mynah bird, 为了八哥鸟,
they provide a veritable feast. 他们提供了一场名副其实的盛宴.
July and August 七月和八月
are monsoon months across South East Asia. 是东南亚的季风季节.
The rains reach into Cambodia, 雨水进入柬埔寨,
causing the mighty Mekong River to flood. 导致湄公河泛滥.
Swollen with so much water, 被这么多水弄肿了,
the river starts to flow backward, 河水开始倒流,
away from the sea. 远离大海.
The inflow of water is so immense that it triggers the largest freshwater lake in South East Asia to balloon. 流入的水是如此巨大,它触发了东南亚最大的淡水湖气球.
Lake Tonle Sap grows an astonishing six times its former size, 洞里萨湖的面积是原来的六倍,
becoming a vast inland sea that swallows a fifth of Cambodia. 成为吞噬柬埔寨五分之一国土的辽阔内海.
It's one of the biggest seasonal variations faced by any people on the planet. 这是地球上所有人面临的最大的季节变化之一.
Roads become rivers. 道路变成河流.
Houses built on stilts can now only be reached by boat. 建在高跷上的房子现在只能乘船到达.
The water teems with the largest gathering of freshwater fish in the world, 这里盛产着世界上最大的淡水鱼,
filling both the lake and the surrounding flooded forests. 填满了湖泊和周围被洪水淹没的森林.
As the lake grows, 随着湖水的增长,
millions of birds migrate here to feed on the seasonal feast. 数以百万计的鸟迁徙到这里来吃这个季节性的盛宴.
They'll stay here till the life-giving waters start to recede. 他们会待在这里直到生命之水开始退去.
But for now, 但是现在,
it's a fisherman's paradise. 这是渔民的天堂.
While the natural world is on the move,humans are too. 当自然界在移动时,人类也在移动.
It's the last lunar month of the Islamic calendar. 这是伊斯兰历的最后一个农历月.
Millions of pilgrims travel to the Holy City of Mecca in Saudi Arabia, 数百万朝圣者前往沙特阿拉伯的圣城麦加,
the spiritual centre of Islam. 伊斯兰教的精神中心.
All Muslims strive to make The Hajj 所有穆斯林都努力朝觐
at least once in their lives. 他们一生中至少有一次.
Circling the Kaaba seven times,all sins are dispelled. 绕着喀巴七圈,所有的罪恶都被驱散了.
Each year, 每年,
more than two million pilgrims gather to join the sacred sea of people. 200多万朝圣者聚集在一起,加入神圣的人海.
The Islamic calendar follows the motion of the moon,not the sun. 伊斯兰历法遵循的是月亮的运动,而不是太阳.
It's one of many calendars across cultures recording the passing of time since antiquity. 它是许多不同文化的历法之一,记录了远古以来时间的流逝.
For the natural world, 对于自然界来说,
the calendar is unwritten. 日历是不成文的.
Length of day. 一天的长度.
Falling temperature. 温度下降.
A change in current announces,"It's time." 电流的变化宣布,“是时候了.”
Southern right whales 南露脊鲸
rely on these natural timekeepers 依靠这些天生的计时器
to know when to move. 知道什么时候搬家.
Each year, 每年,
as winter takes its grip on the South Pole and the days become shorter, 随着冬天来到南极,白天越来越短,
whales migrate from the waters around Antarctica to the safe harbour of Australia. 鲸鱼从南极洲周围的水域迁徙到澳大利亚的安全港.
In the warm shallows,protected from predators, 在温暖的浅滩上,为了躲避掠食者,
a young calf takes a vital breath. 一只幼崽犊需要呼吸.
Here in the calm winter waters, 在这平静的冬天,
the calf fattens up on mother's rich milk. 幼崽犊靠母亲的浓牛奶发胖.
In a few months when the days are longer and the calf is stronger, 再过几个月,白天长了,幼崽也强壮了,
they'll embark together on the long return journey to the feeding grounds of Antarctica. 他们将一起踏上返回南极觅食地的漫长旅程.
Further south, 再往南,
in a bay of island Tasmania, 在塔斯马尼亚岛的一个海湾里,
the churning surface of the sea cloaks what stirs below. 翻腾的海面掩盖了下面搅动的东西.
A spindly army of spider crabs march to the beat of their primordial drum. 一群细长的蜘蛛蟹随着它们原始的鼓声前进.
Winter sea temperatures have triggered their advance. 冬季的海水温度引发了它们的提前.
In places, 在某些地方,
they are ten bodies thick, 他们有十具尸体厚,
forming a mountain of crustaceans. 形成甲壳类动物的山脉.
Hundreds of thousands of crabs migrating to the shallows to transform. 成千上万的螃蟹迁移到浅滩进行转化.
An itch here. 这里有点痒.
A scratch there. 那里有划痕.
A sign that the old coat is ready to come off. 这件旧外套即将脱掉的迹象.
One of the first to moult, 第一批蜕皮的动物之一,
this male secretes enzymes to lift and separate his old shell. 这只雄性会分泌酶来提升和分离它的旧壳.
He cracks through to reveal his new coat, 他破门而入露出他的新外套,
bright orange and soft. 明亮的橙色和柔软.
His shell offers no protection until it hardens. 他的壳在变硬之前无法提供保护.
Now,at the most vulnerable moment in his life, 现在,在他生命中最脆弱的时刻,
the very crowd he sought for protection turn against him. 他寻求保护的人群转而反对他.
All around,newly moulted crabs are hunted and ripped apart. 四周,新蜕皮的螃蟹被猎杀并撕开.
This mutilated crab limps desperately searching for cover. 这只残缺的螃蟹一瘸一拐地拼命寻找掩护.
But he's an easy target. 但他很容易成为目标.
Even with four missing limbs, 即使失去了四肢,
he fights back. 他反击.
Perhaps these angels will give him sanctuary. 也许这些天使会给他庇护.
Safe at last. 终于安全了.
In time,he'll eventually regenerate. 最终,他会再生的.
His attackers may not be so lucky. 袭击他的人可能没那么幸运.
Smooth stingrays arrive for this all-you-can-eat buffet. 光滑的黄貂鱼到达这一切你可以吃自助餐.
It's hard to know where to start. 很难知道从哪里开始.
Entree. 主菜.
Main. 主要的.
Dessert. 甜点.
And with a flick of his tail, 他的尾巴一甩,
he is back for seconds. 他一会儿就回来了.
The crabs' only defence is in their sheer numbers. 螃蟹唯一的防御措施就是数量庞大.
By dawn, 黎明前,
hundreds have been hoovered up. 数以百计的人被搜捕.
Finally satiated, 终于满足了,
the rays slink into the murk. 光线偷偷地射进阴暗处.
The surviving spider crabs march solemnly towards the depths, 幸存的蜘蛛蟹庄严地向深处行进,
stepping over fallen comrades. 跨过倒下的同志.
Or is it leftover lunch? 还是吃剩的午餐？
This mob will meet again next year for the same gruesome event 这群暴徒明年将再次为同样可怕的事件开会
in Tasmania's winter waters. 在塔斯马尼亚的冬季水域.
On the continent of Africa, 在非洲大陆,
it's the movement of rain that sets the pulse for life. 是雨水的运动为生命设定了脉搏.
By August, 到八月,
one of the natural world's greatest migrationsis now underway. 自然界最伟大的迁徙之一正在进行中.
On the border of Kenya and Tanzania, 在肯尼亚和坦桑尼亚边境,
wildebeest are on the move. 角马在移动.
Having left the Serengeti, 离开塞伦盖蒂后,
they have travelled over 500 kilometres north. 他们向北行驶了500多公里.
Towards the savannah grasslands of the Masai Mara, 走向马赛马拉的大草原,
storms on the horizon are their beacon. 地平线上的暴风雨是他们的灯塔.
They know instinctively that where there's rain. 他们本能地知道哪里下雨.
there's greener pastures. 那里有更绿的牧场.
As the living tributaries converge, 随着活支流的汇合,
the wildebeest grow in numbers. 角马越来越多.
Soon the herd is over one million strong. 很快牛群就超过一百万只了.
By August, 到八月,
the herd reaches the Mara River. 牛群到达马拉河.
The crocodiles have been expecting them. 鳄鱼一直在等着它们.
For some, 对一些人来说,
this is the first time 这是第一次
they've encountered such an obstacle. 他们遇到了这样的障碍.
Others know all too well what's to come. 其他人都很清楚会发生什么.
Herd leaders assess the danger, 牧群首领评估危险,
searching for a crossing point where the odds seem just a little bit better. 寻找一个可能会好一点的交叉点.
They pause at the water's edge, 它们停在水边,
waiting for someone to break rank. 等着有人打破军衔.
Somehow, 不知怎么的,
he makes it past the waiting jaws. 他越过了等待的下巴.
Then,the dam breaks. 然后,大坝决口了.
In an hour, 一小时后,
thousands will cross at this one point. 成千上万的人会在这一刻穿越.
Most will make it. 大多数人会成功的.
Some will not. 有些人不会.
The river takes its sacrifice. 这条河牺牲了自己.
As the rain clouds move on, 随着雨云的移动,
so too do the wildebeests. 牛羚也是.
To the lust pastures of Kenya. 去肯尼亚的野性牧场.
Further south,in Zambia, 再往南,在赞比亚,
the lack of rain and relentless sunshine sucks the life from the earth. 缺少雨水和无情的阳光将地球上的生命吸走.
The clear blue skies are welcomed by Carmine bee-eaters. 晴朗的蓝天受到胭脂红食蜂人的欢迎.
Every year, 每年,
they migrate hundreds of kilometres southward to converge here, 它们向南迁移数百公里,汇聚在这里,
on Zambia's Luangwa River. 在赞比亚的卢安瓜河上.
As the water level drops,it exposes the riverbank. 当水位下降时,它暴露了河岸.
This is what the birds are seeking. 这就是鸟儿们所追求的.
For it's where they nest. 因为那是它们筑巢的地方.
Each bird rushes to secure a spot. 每只鸟都争先恐后地寻找一个地方.
But they won't necessarily get their first choice. 但他们不一定会得到他们的第一选择.
Resident white-fronted bee-eaters are already here. 白额食蜂人已经在这里了.
They live year-round in the region. 他们常年生活在这个地区.
And recently moved to the riverbank to breed. 最近搬到河边繁殖.
They've had a head start making burrows. 他们开始挖地洞了.
And won't be evicted without a fight. 不打架就不会被驱逐.
But the migrants haven't travelled this far for nothing. 但这些移民并没有白跑这么远.
A prime patch of real estate is worth every flying feather. 一块黄金地段的房地产抵得上每一根羽毛.
Both bird species dig into the riverbank to lay their eggs. 这两种鸟都在河岸边挖洞产卵.
The location of the burrow is key. 洞穴的位置是关键.
Too close to the bottom and reptiles can barge through the door. 太接近底部,爬行动物会从门中突入.
Too close to the top, 太接近顶端了,
and they're in easy reach for other egg thieves. 其他偷蛋贼也很容易找到.
The middle of the bank is optimum. 河岸中间是最佳位置.
Passers-by can do just that. 路人可以做到这一点.
Thankfully, 谢天谢地,
all neighbourhoods have access to food. 所有的街区都有食物供应.
Even mid-dry season, 即使是在旱季,
permanent waterholes of the Luangwa River harbour aquatic insects. Luangwa河的永久性水洞孕育着水生昆虫.
And the birds are nimble hunters. 鸟儿是敏捷的猎人.
But their favourite food is along the riverbank. 但是他们最喜欢的食物是沿着河岸.
In August, 八月,
the sausage tree is in bloom. 香肠树开花了.
That's a boom for bees. 这是蜜蜂的繁荣.
And bee-eaters. 还有吃蜜蜂的.
The only problem with this diet is the sting in the tail. 这种饮食的唯一问题是尾巴上的刺.
But that's quickly disabled. 但这很快就失效了.
Like all halcyon days, 像所有宁静的日子一样,
they'll soon be over. 他们很快就会结束.
The bee-eaters must hatch and fledge their chicks before the rains return and the river rises. 吃蜜蜂的人必须在雨过天晴和河水上涨之前孵化雏鸟.
When this happens, 当这种情况发生时,
the riverbank nests will vanish underwater. 河岸的巢穴将消失在水下.
And the birds will once again,take to the wing. 鸟儿会再次振翅飞翔.
The great animal migrations on the African continent are rivalled by similar migrations in the African seas. 非洲大陆上的大型动物迁徙与非洲海中的类似迁徙不相上下.
Along the KwaZulu-Natal coastline in South Africa, 沿着南非夸祖鲁-纳塔尔海岸线,
the arrival of a cold-water current sweeps up the coast, 一股冷水流席卷海岸,
carrying with it a bloom of plankton. 携带着大量浮游生物.
This cool,northwards flow helps propel billions of sardines in search of food. 这股凉爽的北流帮助数十亿沙丁鱼寻找食物.
At their peak, 在他们的巅峰时期,
shoals can span over seven kilometres, 浅滩可以跨越7公里,
providing an irresistible lure for predators. 为掠食者提供不可抗拒的诱惑.
Army of common dolphins,15,000 or more, 普通海豚大军,15000或更多,
arrive ready to strike in a coordinated assault. 准备发动协同攻击.
They separate the school of sardines, 他们把沙丁鱼群分开,
corralling the fish by blowing a barricade of bubbles. 用吹泡泡的方法把鱼围起来.
Weaving them into tighter and tighter balls. 把它们编织成越来越紧的球.
As they push the sardines to the surface, 当他们把沙丁鱼推到水面时,
the tiny fish have nowhere to escape. 小鱼无处可逃.
The oily scent of the battle attracts more hungry predators. 战斗中油腻的气味吸引了更多饥饿的食肉动物.
Dusky sharks move in to take advantage of the dolphins' hard work. 灰暗的鲨鱼为了利用海豚的辛勤劳动而搬进来.
Jaws slash through the bait balls with precision. 下颚精确地划过饵球.
The churn on the surface signals to the aerial attack force. 地面的震动向空中攻击部队发出信号.
Gannets hover. 塘鹅在盘旋.
Then they too,join the fury. 然后他们也加入了狂怒.
Diving at 100 kilometres an hour, 以每小时100公里的速度潜水,
they strike the water and torpedo to depth. 他们把水和鱼雷打到深处.
But the feast is worth it. 但这场盛宴是值得的.
The predators along this coastline cannot always rely on the sardines passing their way. 沿着海岸线的食肉动物不可能总是依赖沙丁鱼.
Warming oceans means the cool currents which trigger the sardine run have been happening later and later. 海洋变暖意味着触发沙丁鱼运动的冷洋流发生得越来越晚.
Some years, 有些年,
the run has failed completely. 运行完全失败.
For many species across our planet, 对于地球上的许多物种来说,
the timing of natural events is changing because of rising global temperatures. 由于全球气温上升,自然事件发生的时间正在改变.
For the creatures adapted so precisely to nature's biological clock, 因为这些生物如此精确地适应了大自然的生物钟,
climate change presents a new rhythm they must shift to. 气候变化提出了一个新的节奏,他们必须转向.
If they can. 如果可以的话.
If they cannot, 如果他们不能,
many of the great migration events on our planet 我们星球上的许多大迁徙事件
may diminish, 可能会减少,
or simply disappear. 或者干脆消失.