1. The coast - the frontier
between land and seaCopy !req
2. This is the most dynamic
of all the ocean habitatsCopy !req
3. The challenge here is
to survive changeCopy !req
4. Extreme changeCopy !req
5. Cape Douglas, on the most
westerly of the Galapagos islands,Copy !req
6. totally unprotected from the massive
rollers of the Pacific OceanCopy !req
7. and one of the roughest
coastlines in the worldCopy !req
8. The marine iguanas of the Galapagos
are the world's only sea-going lizardsCopy !req
9. Seaweed is all they eat,
but doing so is a dangerous businessCopy !req
10. The local crabs have
become specially flattened,Copy !req
11. minimising the effect
of the pounding wavesCopy !req
12. And the iguanas have huge
claws to grip the rocksCopy !req
13. This seaweed really is fast foodCopy !req
14. There are only a few seconds
in which to grab a few mouthfulsCopy !req
15. before the next breaker
comes pounding inCopy !req
16. Female iguanas feed
only on the exposed rocks,Copy !req
17. but the males which are larger swim and
dive beneath the surface to reach the weedCopy !req
18. They go as deep as ten metres,Copy !req
19. for there beyond the destructive reach
of the waves, they find the best frondsCopy !req
20. Being cold-blooded they
have to return to landCopy !req
21. after about ten minutes or
so to warm up again in the sunCopy !req
22. Finding food is not the only
challenge for coastal residentsCopy !req
23. These rocky shores are hardly
a safe place to lay their eggsCopy !req
24. and each year the marine iguanas
have to journey inlandCopy !req
25. to find a more suitable oneCopy !req
26. The females lay their eggs in burrows
and leave them there to hatch,Copy !req
27. and to do that they
need nice soft sandCopy !req
28. Down at the water edge, it was easy
to escape danger in rocky crevices,Copy !req
29. but up here the females
are dangerously exposedCopy !req
30. A Galapagos hawkCopy !req
31. The lizards don't give up
without a struggleCopy !req
32. These hawks stay on the coast all year
But they are exceptionalCopy !req
33. The majority of the birds
that frequent this frontierCopy !req
34. spend most of their time elsewhere
- in or above the open oceanCopy !req
35. However all seabirds have to come
to land in order to lay their eggsCopy !req
36. And after spending many lonely
months searching the ocean for food,Copy !req
37. they have to re-establish
their social relationshipsCopy !req
38. Frigate birds display and
exchange nesting materialCopy !req
39. Waved albatross danceCopy !req
40. The need to lay their egg on firm ground
ties the albatross to the coastCopy !req
41. but parental responsibilities
are sharedCopy !req
42. While one looks after the egg,
the other can go off to feedCopy !req
43. The need to breed brings
many different animalsCopy !req
44. to the coast each year
for a few weeksCopy !req
45. Male sea turtles spend all
their lives at sea, but the females,Copy !req
46. like birds, must come to
land to lay their eggsCopy !req
47. To do that green turtles that live
and feed off the coast of BrazilCopy !req
48. swim fifteen hundred miles to the
tiny island of AscensionCopy !req
49. that lies bang in the middle
of the Atlantic OceanCopy !req
50. Exactly how they manage to
navigate with such accuracyCopy !req
51. and find this tiny lump of rock,
just seven miles wide is a mysteryCopy !req
52. But each year up to five thousand
turtles manage to do so and then,Copy !req
53. close to the coast of Ascension,
they mateCopy !req
54. Travelling to and from Ascension and
nesting here can take up to six monthsCopy !req
55. and throughout that entire time,
none of them feed at allCopy !req
56. After mating a female has to
leave her natural elementCopy !req
57. and haul herself up onto landCopy !req
58. She does so at night,
laying about three or four timesCopy !req
59. at around fifteen day intervalsCopy !req
60. After that she then swims all the way
back to the seas off BrazilCopy !req
61. She returns to this very same
island throughout her lifeCopy !req
62. Remarkably, all the world's sea turtles
return year after yearCopy !req
63. to just a few traditional
breeding sitesCopy !req
64. Crab Island, in Australia,
is one of themCopy !req
65. This tiny two-mile long crescent of sand,Copy !req
66. lying a few miles off
Queensland's northerly tip,Copy !req
67. provides nesting sites
for half the entire populationCopy !req
68. of one of the world's
rarest sea turtlesCopy !req
69. Flat-backed turtles are large,
over a metre longCopy !req
70. - but they have to be carefulCopy !req
71. There are other giant
reptiles here tooCopy !req
72. Salt-water crocodilesCopy !req
73. Every night throughout the yearCopy !req
74. there are flat-backs burying their eggs
all along this lonely stretch of sandCopy !req
75. Nine weeks later and things
are about to happenCopy !req
76. These eyes shining in the darkness
belong to night heronsCopy !req
77. As if from nowhere, hundreds of birds
suddenly appear on the sand dunesCopy !req
78. Pelicans wait patientlyCopy !req
79. Jabiru storks pace up and downCopy !req
80. Before long they see what
they've been waiting for.Copy !req
81. Because these turtles lay
their eggs throughout the year,Copy !req
82. the hatchlings emerge night after night
in a steady trickle of beak sized mealsCopy !req
83. Pelican's broad beaks allow
them to dig out the hatchlingsCopy !req
84. before the herons can spear
them on the surfaceCopy !req
85. The surf may be hundreds of metres awayCopy !req
86. and at least a third of the tiny turtles
do not survive the journeyCopy !req
87. And its not just the birds
that take themCopy !req
88. Crocodiles, sharks and hungry fish
are all waiting in the shallowsCopy !req
89. In fact only one in every hundred
hatchlings will survive to adulthoodCopy !req
90. Another beach, another continent,
and a very special nightCopy !req
91. Here in Costa Rica there is a turtle which
has found a way of reducing these dangersCopy !req
92. When Ridley's turtles arrive
to lay their eggsCopy !req
93. they don't come in tens or hundreds...
but in thousandsCopy !req
94. Over the next six days around four hundred
thousand females will visit this beachCopy !req
95. At the peak time, five thousand
are coming and going each hourCopy !req
96. The beach gets so crowded that
they have to clamber over one anotherCopy !req
97. to find a bare patch of sand
where they can dig a nest holeCopy !req
98. Forty million eggs are laid
in these few daysCopy !req
99. So these turtles ensure
that six weeks laterCopy !req
100. when their hatchlings emerge
it's not just a trickleCopy !req
101. It's a floodCopy !req
102. On some nights, over two million
hatchlings race down to the sea togetherCopy !req
103. With so many appearing simultaneously,Copy !req
104. the predators are overwhelmed and most
of the young turtles reach the sea safelyCopy !req
105. Leaving the sea and emerging onto
land is hard enough for turtlesCopy !req
106. It'd even harder for fishCopy !req
107. Each year for hundreds of miles
along the Newfoundland coast,Copy !req
108. capelin throw themselves
onto the beachesCopy !req
109. At least a million tonnes of
fish floundering out of the waterCopy !req
110. - a real gift for scavenging
eagles and gullsCopy !req
111. Odd though it may seem for a fish,
these capelin,Copy !req
112. like the turtles, have also
come out of the sea to breedCopy !req
113. The males are trying to
fertilise the eggsCopy !req
114. that the females are
depositing in the sandCopy !req
115. Like the Ridley's turtles,Copy !req
116. they have synchronised their mass
laying with the tideCopy !req
117. In a few days it will be overCopy !req
118. Most of the capelin die but only after
they've left their eggs in the sandCopy !req
119. Other capelin populations
lay their eggsCopy !req
120. in the ocean so why do the
Newfoundland fish spawn on landCopy !req
121. It seems that eggs deposited in
the beach may be saferCopy !req
122. from predators and develop faster
than in colder waters out to seaCopy !req
123. But wherever they do so,
the huge spawning shoalsCopy !req
124. provide the concentration of food that
seabirds need when they assemble to breedCopy !req
125. Ninety five percent of the
world's seabirds nest together,Copy !req
126. mostly in large spectacular coloniesCopy !req
127. This is Funk Island forty miles
off the coast of NewfoundlandCopy !req
128. - an isolated rock crammed
with breeding sea-birdsCopy !req
129. This was the last breeding ground for the
flightless Great Auk, sadly now extinctCopy !req
130. Today it's still the world's
largest Guillemot colonyCopy !req
131. Over a million of them share the
crowded island with 250,000 gannetsCopy !req
132. It's not the lack of suitable sitesCopy !req
133. that causes the seabirds
to breed in such densitiesCopy !req
134. Here in the North Atlantic,
there's a wide choice ofCopy !req
135. empty coastline that
the birds could useCopy !req
136. The key factor limiting the size
and location of seabird coloniesCopy !req
137. seems to be the availability of food
in the surrounding oceanCopy !req
138. There are lots of hungry mouths to feed
and a constant demand for fishCopy !req
139. Throughout the long summer days
at colonies like funk,Copy !req
140. There's a continual stream of birds,
heading out to the ocean to find foodCopy !req
141. and returning with full crops
to feed their youngCopy !req
142. Gannets will travel up
to two hundred milesCopy !req
143. from the colony on
a single foraging tripCopy !req
144. They are not fussy eaters
and will take everythingCopy !req
145. - from tiny sand eels to herringCopy !req
146. Puffins, on the other hand,
are very particular aboutCopy !req
147. what they eat and because they can
only fly short distances,Copy !req
148. they only nest where there's a good
supply of suitable food close byCopy !req
149. One such place is the sea of Okhotsk
in far eastern RussiaCopy !req
150. This is the island of TalanCopy !req
151. Throughout the long arctic winter,
it is encircled by iceCopy !req
152. But as spring approaches,
that begins to break upCopy !req
153. and seabirds that have spent
the winter feeding outCopy !req
154. on the open ocean far to
the south begin to returnCopy !req
155. Its isolated position and steep cliffs
make Talan a perfect nesting siteCopy !req
156. The Tufted Puffins arrive firstCopy !req
157. These are the Pacific cousins of
our less spectacular Atlantic speciesCopy !req
158. Horned puffins soon followCopy !req
159. In all, fourteen different species
return to Talan each springCopy !req
160. and in just a few weeks
the once silent cliffsCopy !req
161. come alive to the calls of
4 million breeding seabirdsCopy !req
162. This is a multi-storey avian cityCopy !req
163. Assembling in these dense colonies after
having spent a largely solitary lifeCopy !req
164. at sea provides the birds with
the social stimulationCopy !req
165. that is the key to co-ordinating
their breedingCopy !req
166. By nesting and laying together
they ensure thatCopy !req
167. most of their chicks will leave
the nest at exactly the same timeCopy !req
168. Just like the turtles this is the way
they spread the impact of predatorsCopy !req
169. The world's largest eagle
- Steller's sea eagleCopy !req
170. A third as big again as a goldenCopy !req
171. Throughout the summer, the eagles
hunt in Talan's crowded coloniesCopy !req
172. Riding on the updrafts,
they patrol the top of the cliffs,Copy !req
173. Iooking out for any Kittiwake
that ventures too far from the rock faceCopy !req
174. Suddenly the huge eagle stoops
with the aerial agility of a falconCopy !req
175. Co-ordinated panic among the kittiwakes
confuses their attackerCopy !req
176. But the eagle doesn't give upCopy !req
177. And it has got oneCopy !req
178. Another kind of seabird on Talan
has a particularly effective wayCopy !req
179. of defending itself against predatorsCopy !req
180. - but it doesn't appear until
an hour before sunsetCopy !req
181. As if from nowhere, dense swarms of
seabirds suddenly arrive off-shoreCopy !req
182. They're spent the day feeding far away,
where the sea ice has already broken upCopy !req
183. They are crested auklets,
hardly bigger than starlingsCopy !req
184. A million of them return to Talan each
year to nest in its fields of bouldersCopy !req
185. For an hour before sunset,
the hillsides comes aliveCopy !req
186. with huge flocks of circling auklets
They're nervousCopy !req
187. No one wants to be the first to landCopy !req
188. Auklets are very social when
they are back together at the coastCopy !req
189. One of the advantages of nesting
in such densitiesCopy !req
190. may be the chance to share
information on good feeding sitesCopy !req
191. It also gives them the
opportunity to courtCopy !req
192. But perhaps most importantly,
there is safety in numbersCopy !req
193. Ravens and peregrines circle above
the scree slope every eveningCopy !req
194. By taking off together,
the auklets hope to confuse the predatorsCopy !req
195. Eventually their persistence
pays offCopy !req
196. The birds that face the
greatest challenge in comingCopy !req
197. to the coast to nest are
surely the penguinsCopy !req
198. Unable to fly, they have no alternative
but to brave the immense wavesCopy !req
199. Most penguins live in the southern oceanCopy !req
200. and they have to accept being
hurled about by the surfCopy !req
201. Whatever the weather, the penguin parents
have to come back to feed their chicksCopy !req
202. A southern sea lion bullCopy !req
203. - he knows the penguins always use
the same traditional landing beachCopy !req
204. Having braved the thundering surf,Copy !req
205. the penguins have to make a mad dash
across open rock to get to their nestsCopy !req
206. Despite his massive size and
a body adapted for swimming,Copy !req
207. the bull chases the penguins for forty
or fifty metres across the rocksCopy !req
208. Having caught his penguin, the sea lion
carries it out into deeper water where,Copy !req
209. by violently thrashing the little body,
he skins his mealCopy !req
210. The seas around the Falklands are some
of the roughest in the worldCopy !req
211. In spite of that, the southern ocean
is home to millions of tiny seabirdsCopy !req
212. hardly bigger than swallows-petrelsCopy !req
213. Being so small they are very
vulnerable to the bad weatherCopy !req
214. A severe storm can blow
them miles off courseCopy !req
215. and keep them away from
their nests for daysCopy !req
216. But these birds have developed a very
effective solution to that problemCopy !req
217. They lay a rather special eggCopy !req
218. Most bird's eggs, left exposed for even
a few hours, will chill and never hatchCopy !req
219. But these eggs are differentCopy !req
220. They can be left for several days
without incubation and remain undamaged...Copy !req
221. while the parents struggle
home through the stormCopy !req
222. Prions have also come up with
a good way to avoid most predatorsCopy !req
223. They never come back to the
coast until after darkCopy !req
224. These are Thin-billed PrionsCopy !req
225. Their burrows honeycomb this
hillside in the FalklandsCopy !req
226. It'd deserted throughout
the daylight hours...Copy !req
227. but as soon as it's darkCopy !req
228. and difficult for airborne
predators to hunt...Copy !req
229. the prions returnCopy !req
230. As soon as they land, they callCopy !req
231. The problem, of course...Copy !req
232. is finding your burrow
among all the othersCopy !req
233. He's listening out for
his mate's call...Copy !req
234. and down he goes.Copy !req
235. The Alaskan coastCopy !req
236. It's spring and the last of
the winter storms is subsidingCopy !req
237. The plankton in this sea is in
bloom again and just off shore,Copy !req
238. humpback whales have
returned to feedCopy !req
239. For these huge animals, there is a real
risk in coming into such shallow waterCopy !req
240. and each year a good number
of them pay the priceCopy !req
241. It is an ignominious ending
for an ageing whaleCopy !req
242. But so much flesh will not go to wasteCopy !req
243. A black bear emerges
cautiously from the woodsCopy !req
244. Visitors to the coast that don't come to
breed, have usually come to scavengeCopy !req
245. A whole range of different animals
have learnt to exploitCopy !req
246. the enormous quantity of food...Copy !req
247. .. that washes up everyday on
coastlines around the worldCopy !req
248. But like so much at the coast
the quantity of flotsamCopy !req
249. and jetsam is unpredictableCopy !req
250. Nobody can rely on it aloneCopy !req
251. This carcass even attracted
a shy pack of wolves only too happyCopy !req
252. to anoint themselves with the...Copy !req
253. scent of rotting whaleCopy !req
254. It was months before the
scavengers finallyCopy !req
255. cleaned up all the meat
on this huge and...Copy !req
256. unpredictable gift from the seaCopy !req
257. Whales give birth to their young at sea
and so can spend their entire lives thereCopy !req
258. Other marine mammals - one of that are
in fact distant cousins of bearsCopy !req
259. - have to return... each year to
their ancestral home on landCopy !req
260. The high arctic
Here lives one of them... the walrusCopy !req
261. Walruses spend nearly
all their lives at sea,Copy !req
262. but each year for just a few weeks...Copy !req
263. they have to return to the coast.Copy !req
264. They seek out isolated beaches
like this one on Round Island in the...Copy !req
265. far northern PacificCopy !req
266. Suitable sites like this,
free from bears, are so scarce...Copy !req
267. that at times as many as
fourteen thousand animalsCopy !req
268. will cram themselves on to this...Copy !req
269. one beachCopy !req
270. When they first emerge from
the sea the walrus are whiteCopy !req
271. That's because being warm-blooded
animals living in very cold ocean,Copy !req
272. they conserve heat by...Copy !req
273. keeping their blood concentrated
in the core of their bodiesCopy !req
274. On land it's warm enough for them
to allow their...Copy !req
275. outer blood vessels to dilate and
that turns their skin from white to pinkCopy !req
276. Now they can moult the outer
layers of their skin,Copy !req
277. rubbing themselves up
against the rocksCopy !req
278. But more than anything
else coming to landCopy !req
279. brings the walrus relief
from having to spend energyCopy !req
280. maintaining their body temperature
in an icy-cold oceanCopy !req
281. Heat conservation, in fact, may well
be the primary reason so many...Copy !req
282. sea mammals are forced to
return to the land each yearCopy !req
283. The world's coldest seas
are in AntarcticaCopy !req
284. Each spring, half the world's
Southern Elephant sealsCopy !req
285. return to the island
of South GeorgiaCopy !req
286. Elephant seals have particularly thick
insulation of blubber that keeps them warmCopy !req
287. For them breeding is the only
reason to leave the seaCopy !req
288. With temperatures down
to minus 20...Copy !req
289. and hundred mile an hour winds,
it can't be comfortable out on the beach,Copy !req
290. but heat dissipates more
rapidly through water...Copy !req
291. than through air so even
in these conditions...Copy !req
292. their young which at first
don't have a thick coatCopy !req
293. of blubber will be far
warmer on the landCopy !req
294. Once the males are established on the
beach the females soon followCopy !req
295. Within just ten days the empty beach
fills up with six thousand elephant sealsCopy !req
296. Almost immediately the females give
birth to pups sired the previous yearCopy !req
297. Their milk is very rich and the pups
grow astonishingly quicklyCopy !req
298. In just three weeks they turn form thin
bags of skin to fat balls of blubberCopy !req
299. As soon as they've given birth,Copy !req
300. the females become sexually
receptive again...Copy !req
301. and it's now that the
advantages of breedingCopy !req
302. in such dense colonies become clearCopy !req
303. Females can make their
choice from many males,Copy !req
304. while successful males can
have access to lots of femalesCopy !req
305. But to gain that access and
control a harem of females,Copy !req
306. the bull must be prepared to fightCopy !req
307. The larger the male, the louder the roar
and the more likely he is to winCopy !req
308. When males are well matched these bloody
battles will last twenty minutes or moreCopy !req
309. Eventually, the loser retreats into
a stream already pink with his own bloodCopy !req
310. These battles certainly help females
select the strongest bulls...Copy !req
311. but they bring great
dangers for the pups.Copy !req
312. Each year, in the denser
parts of the colony,Copy !req
313. a fifth of the pups are
crushed to deathCopy !req
314. This is why it may
be better to mateCopy !req
315. at the edge of the beach
close to the seaCopy !req
316. Less dominant males hide
in the surfCopy !req
317. They are waiting to try
and steal an illicit mating...Copy !req
318. with females as
they come and goCopy !req
319. This male knows he has been
spotted by the big bullCopy !req
320. who claims all the females
on this part of the beachCopy !req
321. Breeding in groups can bring advantages
to pups as well as to adultsCopy !req
322. Along the coast of Patagonia southern sea
lions breed together each yearCopy !req
323. in groups several hundred strongCopy !req
324. For the growing pups these colonies
act rather like a schoolCopy !req
325. The bonds and relationships
developed here on the beachCopy !req
326. may be vital for the
rest of their livesCopy !req
327. Sea lions are very social animals
and as adults and young forage together,Copy !req
328. they probably share...Copy !req
329. information about the location
of good feeding sitesCopy !req
330. Conditions here could hardly be better
for the growing youngstersCopy !req
331. As the tide goes out it leaves behind
a selection of sheltered poolsCopy !req
332. Perfect places for
learning to swimCopy !req
333. At high tide...Copy !req
334. it is easy for the pups to take their
first experimental dips in the surfCopy !req
335. A killer whaleCopy !req
336. These young pups have never seen
anything like it beforeCopy !req
337. The Whales though are
very experiencedCopy !req
338. Each year this same group turns
up along the coastCopy !req
339. at precisely the same time
as the pups are starting to swimCopy !req
340. The whales need to surprise the pups,Copy !req
341. so they have stopped calling
to one another and keep silentCopy !req
342. Speed is everythingCopy !req
343. The whales do not take pups
that are out of the water,Copy !req
344. but sometimes their momentum
drives them right up the beachCopy !req
345. and then there's real danger
of getting stuckCopy !req
346. The whale has to thrash in this
frenzied way to get off the beachCopy !req
347. Most of the pups are taken into deep
water while they're still aliveCopy !req
348. And there the whales - apparently
- play with themCopy !req
349. Often an adult whale is joined
in the game by a youngsterCopy !req
350. It may be learning how to grab a seal pup
before it risks a drive up the beachCopy !req
351. Whatever the reason the seal pup
- still aliveCopy !req
352. - is tossed back and forth
for over half an hourCopy !req
353. Even when the pup is dead, the whales'
sport is not completely overCopy !req
354. We can only speculate at the real reasons
behind this extraordinary behaviourCopy !req
355. But for the whales, the hunting
season is a short oneCopy !req
356. Before long the pups learn to
stay well clear of the waterCopy !req
357. and the whales become less
and less successfulCopy !req
358. After just two weeks, they move onCopy !req
359. The killing season is overCopy !req
360. That's how it often happens
along the coastCopy !req
361. Things are always changingCopy !req
362. They're never the same
for long in this,Copy !req
363. the most dynamic of all
the ocean's habitatsCopy !req