- 10 minutes ago
Explores the elaborate mating rituals and ingenious nest-building habits of unique Australian birds, such as the Victoria's riflebird and the cassowary, as well as rainforest architects like the golden bowerbird...
澳大利亚多样化且高度适应环境的生态系统，造就了同样丰富多样的“筑巢衬垫”与筑巢技艺
澳大利亚多样化且高度适应环境的生态系统，造就了同样丰富多样的“筑巢衬垫”与筑巢技艺
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00:05Australia, a land of diverse and often extreme habitats, with vast expanses of wetlands,
00:16dense forests and arid plains. It's populated by an immense array of bird life and many species found nowhere else
00:33in the world.
00:34Among them, some of the most flamboyant, ear-splitting and bizarre birds imaginable.
00:52Successful breeding is critical to the survival of their species.
00:57They need to go to exceptional lengths to find mates and raise their young, giving the next generation the best
01:08chance of life.
01:10This is the story of breeding season.
01:26For avian life, Australia is a paradise.
01:35There are more than 800 species of birds here.
01:43And over 370 of these are only found in Australia.
01:51But birds of a different feather don't always flock together.
01:56Some prefer to live in the rainforest, like the golden bowerbird, who builds his U-shaped nest from twigs in
02:02the hope of attracting a female.
02:05The galar is part of the cockatoo family and can be found in open country across mainland Australia.
02:16Some, like the Cape barren goose, thrive by the seaside and can drink salt water.
02:23And many share their environment with humans.
02:30But wherever they live, these birds have got their work cut out.
02:34Holding their territory against invaders.
02:38Attracting and winning partners.
02:39Shhh, shhh.
02:42And safeguarding their chicks.
02:45Shhh.
02:56Shhh.
03:03Far north Queensland is famed for its beautiful beaches.
03:13And one stretch is named the cassowary coast, because it's home to one of the planet's most
03:24extraordinary looking birds, the cassowary.
03:32This is a mature female.
03:48Queensland becomes steamier and more tropical as you head further north towards the equator.
03:55And its lush rainforests are ideal habitat for the cassowary, which thrives on forest
04:01fruits.
04:09Like the Australian emu and African ostrich, she's a ratite, or flightless bird.
04:14Her flat breastbone has no keel attachment for wing muscles.
04:21It's thought that ratites evolved around 60 million years ago, in the Cretaceous period.
04:28And she certainly looks prehistoric.
04:31She's solitary and usually wary of humans, and can be hard to find in the forest.
04:43And she's huge.
04:48Over six feet tall and weighing more than a hundred pounds, like all female cassowaries,
04:54she's bigger and heavier than a male, as well as more brightly coloured.
05:04In the dark, dense foliage of the jungle, the shock of electric blue on her throat, vivid
05:10turquoise around her head and eyes, and dramatic red wattle all clearly identify her as a mature,
05:16breeding female.
05:23Comparatively little is known about this species.
05:27There are several theories about the purpose of the curious crest on her head, called a cask.
05:34Although it looks hard and horn-like, it's actually leathery and pliable, formed by a keratin shell
05:41growing over spongy cranial bones, and enclosing a mysterious empty chamber.
05:50Cassowaries are omnivores, and feed on fruit, beetles, insects, snails, and even carrion.
05:58One theory is that the cask helps them forage, and serves as a helmet as they dig through dense
06:03undergrowth.
06:12It may also protect the head from falling fruit, be used as a sound amplifier, or even
06:17a weapon in disputes.
06:24The cask continues to grow for life, and could also advertise a bird's status and age.
06:34Like the cassowary herself, the cask remains steeped in mystery.
06:44This female has a home range that overlaps and passes through that of several males, who will
06:50each have their own territory of almost three square miles.
07:01It's August, breeding season for this big bird, but she's already parted from her mate.
07:09She recently paired up with this male, and laid his eggs.
07:12But that's the end of their time together.
07:18Female cassowaries don't raise their young.
07:21Instead, they leave it up to the male to incubate the eggs, and later on, care for the chicks.
07:27She can have several partners over a four-month breeding season, and she's already on the lookout
07:33for another mate.
07:46The cassowary isn't the only Australian bird to have parenting arrangements like this.
08:15This is a male, brushed turkey.
08:22He's part of the megapode family, literally meaning large foot.
08:28He also lives in the rainforest in Cairns, far north Queensland.
08:35Brushed turkeys are very adaptable, and can be found all along the eastern coast of Australia.
08:42By September, springtime in Australia, the brushed turkey is hard at work preparing a nest.
08:52He'll spend all day, every day, scratching around in one spot on the forest floor.
09:01He may stop for a quick feed on insects, but then it's back to work.
09:10He piles up leaf litter, twigs and earth into a mound.
09:15This will play a vital part in his breeding strategy.
09:23He rakes up the layer of debris on the forest floor with his strong legs and large feet,
09:28and adds it to his little hillock.
09:34Then he turns over the existing pile again and again, breaking it down into a fine compost.
09:44If all goes to plan, this will become a warm nest.
09:58He's an average size for a brushed turkey, around 26 inches long.
10:03But the mound he's obsessively working on will end up being a whopping 13 feet wide,
10:09and between 3 and 6 feet high.
10:23And it's got to be good.
10:26Females roam around selecting multiple partners,
10:28and won't mate with him if his mound isn't up to their standards.
10:35So a lot's riding on its meticulous construction.
10:40The brushed turkey is a relatively common bird,
10:44and there are already several females in the vicinity who have smaller, paler wattles.
10:49They're regularly checking out his progress,
10:52and will wait until the mound is complete before deciding whether to mate with him.
10:57But right now, this brushed turkey is only interested in one thing.
11:04His mound.
11:09While he's still working on his masterpiece,
11:12he doesn't want anyone near it, male or female,
11:15and sends out a warning to any other brushed turkeys in the vicinity.
11:22Stay away.
11:36In the elevated Atherton Tablelands of northern Queensland,
11:41higher and cooler than their often sweltering surroundings.
11:46It's October, and breeding time for a very exotic bird.
11:53This is the Victoria's Rifle Bird, named after the British Queen,
11:57but is known as the Doo-Woo-Doo-Woo to the Aboriginal tribespeople.
12:03He's a bird of paradise.
12:09A fairly small bird, at around 10 inches long,
12:12he has an iridescent sheen to his feathers.
12:20His breeding season can last up to six months,
12:23so he's got to keep his strength up by eating fruits and insects
12:27he digs out of the bark of trees.
12:41Snack over, it's time to get back to business, attracting a mate.
12:49He's got a core area of between two to seven acres
12:53where he spends most of his time.
12:55Within that space, he selects a conspicuous vantage point,
12:59like a tree stump, as his display area.
13:10Having a good location to display in
13:13is all part of his strategy to get the females interested,
13:16so he's territorial over his posing post.
13:22Usually, his stage will be under a gap in the canopy cover,
13:25so that the sunlight can stream a spotlight
13:28to reveal his glowing feathers to their best advantage.
13:32And then...
13:36He blasts out his mating call.
13:40It's loud and unmistakable.
13:43This raspy cry is just to make sure
13:46he gets the attention of any female that might be nearby.
13:48Shhh!
13:51Before launching into his pièce de résistance.
14:06It's a dramatic, full, wingspread display
14:10that shows as much of his plumage as possible.
14:14Erecting his feathers before throwing out his wings is part of the act.
14:20And so is opening his beak wide to show the bright yellow interior.
14:28He keeps going, hoping to pique the interest of a female.
14:37And finally, he's graced with an audience.
14:47Unlike the male with his glorious plumage,
14:50female rifle birds are a dull brown.
15:01But after just a few seconds, she loses interest and flies off.
15:11It's thought the females may base their mating choices on quality of display.
15:16So perhaps this male needs to brush up his skills.
15:33While his display is impressive, this is Australia, home of the fantastic.
15:38So there's another bird that can win a showing-off contest with the rifle bird, hands down.
15:50The lyrebird.
15:59Lyrebirds live in temperate, often wet, woodland in the coastal southeast of Australia.
16:08This one has made his home in a forest outside Melbourne, in the southern state of Victoria.
16:15They're clumsy fliers and spend most of their time on the ground.
16:21Both the males and the females are a reddish brown and have powerful legs with long toes,
16:27ideal for raking over the leaf litter and soil looking for food,
16:31such as cockroaches, spiders and worms.
16:38A male lyrebird will also use leaf litter and earth to build a display mound to dance on.
16:45He may have over a dozen of these in his territory.
16:50At first glance, he may seem unremarkable.
16:54But as mating season approaches during the winter months,
16:58the male reveals his amazing talents.
17:1228-inch-long feathers fan out from his tail, which he drapes over his head in a waterfall formation.
17:28A male will start getting his display feathers when he's around three years old,
17:33and these get gradually longer every year until he hits sexual maturity at around seven.
17:39The more mature the male, the longer his tail feathers.
17:5112 silvery fluffy feathers, bookended by two thick banded feathers called lyrates,
17:57and two long slender median feathers make for a show-stopping performance.
18:15And if that isn't enough to thrill the ladies,
18:18his song is one of the most extraordinary of any creature on the planet.
18:34The lyrebird can imitate almost any sound it hears, including other birds and animals.
18:52Captive birds have even copied man-made sounds like trains, camera shutters and car alarms.
19:05As this male lives deep in the forest, he rarely hears artificial noises,
19:10and instead, he's woven the calls of the other birds that he hears into his own song.
19:40In all, he's included the calls of 12 other species.
19:49The purpose of having such an amazing talent for impersonation is unknown,
19:54but it's thought that the more complex a song the male can produce,
19:58the more attractive he is to females.
20:04His phenomenal ability comes from a special voice box.
20:10A bird's vocal organ is called a syrinx.
20:13The lyrebird is more complex than that of other songbirds,
20:17which gives him extraordinary flexibility.
20:36He sings for 20 minutes at a time, for several hours a day, until a female is attracted to him
20:43and allows him to mate.
20:51After copulation, he'll return to displaying to attract the next one.
20:59There's a female nearby, but she isn't showing signs of being impressed by his performance.
21:11And now, a rival male has barged into his territory and is displaying to the same female.
21:24Both female and male lyrebirds are fiercely territorial, with an average territory of three to six acres.
21:39The competition is on.
21:46The resident male tries to chase the interloper out, but he doesn't succeed in pushing him far away.
21:59And they end up displaying within a few feet of each other.
22:10It turns into a real talent show.
22:37Finally, the resident bird manages to chase the invader out of his territory.
22:44But the female has seen and heard enough.
22:48Today, she's not interested in either of them.
22:52She puts on a show of her own, with no mimicry, just her own beautiful song.
23:22Meanwhile, in the forest near Cairns, the brushed turkey has managed to breed.
23:27And now has a clutch of up to 24 eggs buried in the depths of his mound.
23:35His little hillock is now almost three feet high, but he's still hard at work.
23:47He's the sole custodian of these eggs.
23:55Because the females move around from partner to partner, it's impossible for him to know whether the eggs in his
24:02mound were actually fertilised by him or another turkey.
24:08Regardless of their paternity, he'll tend the mound for the seven weeks it takes to incubate the eggs.
24:17The heat caused by the composting action of the plant material will keep the eggs warm.
24:26Heat sensors in his beak enable him to determine the temperature of the mound.
24:31And he'll regulate it by adding or removing material.
24:37He's aiming for a temperature of between 91 and 95 degrees Fahrenheit.
24:43At 93 degrees, there will be an equal division between male and female chicks.
24:49If cooler, there will be more male chicks.
24:52If warmer, more female chicks.
24:57He'll guard the eggs until it's almost time for them to hatch.
25:01And then it's all up to the chicks.
25:03They must dig their way out of the mound and fend for themselves immediately.
25:13Brushed turkey eggs and chicks are a favourite food for carnivorous lizards, snakes and wild dogs.
25:35And it's not just animal predators who pose a threat to the brushed turkeys' successful breeding.
25:44Rural gardens frequently back onto brushed turkey habitat.
25:48And the turkeys' practice of making enormous breeding mounds in people's backyards
25:52can lead to these precious piles of compost being destroyed.
26:03A single egg only has a one in 200 chance of making it to adulthood.
26:08So the brushed turkeys' eggs have still got a long way to go.
26:41Just as the female brushed turkeys don't have any involvement in incubating or rearing their young,
26:47neither do the much larger cassowaries.
26:55And back on the cassowary coast, the female is far away from the eggs she laid this year.
27:05With parenting being the responsibility of the male, she's free to spend her time foraging.
27:13These giant birds are generally very shy,
27:16but this female lives close to a beach frequented by humans, which is far from ideal.
27:24But there are some good feeding opportunities here.
27:28These beach almonds provide a useful source of protein,
27:32along with the insects she eats in the jungle.
27:57Next to the beach is a campsite, and she's not afraid to make use of the amenities here.
28:22Cassowaries need to drink frequently.
28:28her legs have their ankle joint equivalent to where humans have their knees so she can
28:34bend easily to reach the water
28:55she has clearly become used to the humans here but this isn't a good thing
29:03beach goers are warned not to feed the cassowaries it can be dangerous for such a large animal to
29:12associate people with food becoming accustomed to humans can make the massive birds more aggressive
29:36not only is she one of the heaviest birds in the world
29:41she's equipped with a razor-sharp five-inch dagger on her dinosaur-like inner toe
29:47which she can use to vicious effect
29:54a high proportion of documented attacks have been perpetrated by birds who've been fed by people
30:06which may be what's worrying these picnickers
30:11and
30:18and
30:19I don't know.
31:09Whenever cassowaries come out of the jungle in search of human food, the greater the
31:14risk to their survival. They're more likely to cross roads and be hit by cars. The rate
31:25at which they're the victims of road accidents is of grave concern to conservationists. Cassowaries
31:34are classified as an endangered species. Luckily, she gets back to the jungle safely.
31:44To look for the more typical items in her diet, insects, and crucially, fruit.
31:53Cassowaries are called a keystone species because of their ecological importance. They're able
32:01to swallow fruits almost whole, and have what is known as a gentle digestive system, meaning
32:08that the fruits are excreted with the seeds still intact, and flesh still on them.
32:18Fruits stay in the gut for less than four hours. But in that time, the cassowary could move to
32:24a completely different area, distributing the fruit species more widely. So the survival
32:30of the cassowary is vital to the continuation of many other species.
32:54Fruits stay in the gut.
33:09In the mild climate of the woods around Melbourne, the male lyrebird is still going strong with
33:15his spectacular display.
33:41He'll spend four hours a day singing for another six weeks until the end of the breeding
33:47season, mating with as many females as he can.
33:58These birds have a division of labour that's found more frequently in the animal kingdom.
34:03Unlike the cassowary, it's the female of this species that will tend the egg and rear just
34:09one chick.
34:12Although he's busy trying to attract more partners, he's already had some success.
34:17He's mated with this female, who now has a very big job to do.
34:37She's in charge of building the nest.
34:46First on the list, gather some nesting material.
34:53She collects some moss, leaf litter, pieces of fern and twigs until she's got enough to
34:59create a cosy nest.
35:11She even uses the male's feathers to line it.
35:20It's a matter of personal preference as to where she sights her nest.
35:26Some females make their nests close to the ground, whilst others choose sights high up in the trees.
35:42Ten to fourteen days after mating, the female lays her egg.
35:47She just lays one a year, unless the egg or chick dies.
35:51If this happens and it's early enough in the season, the female can mate again and lay another
35:56egg.
36:08Six weeks later, up in the cosy but dark little nest in the tree, her chick hatches.
36:20Now it's mum's job to keep her hungry hatchling supplied with food until it can leave the nest.
36:27She must feed her chick every twenty minutes.
36:45She spends large parts of the day gathering up grubs and small insects which she carries
36:50in her throat, ready to feed to her young when she returns to the nest.
36:59Because of the rigorous feeding schedule, she will even venture out at night looking for
37:04food.
37:04A time when she's most at risk from predators like foxes and cats.
37:28Four weeks later, the lyrebird chick is fat, fluffy and healthy.
37:32With his nest being so high up in a tree, his wings need time to develop so he can fly
37:39safely
37:39out when he fletches.
37:41He'll spend ten weeks in the nest before leaving.
37:49Chicks in nests closer to the ground don't need to wait for their wings to develop as much,
37:54and will leave at around six weeks to go and live independently.
38:01While the female is tending to her hatchlings every need, the male is still putting on a performance,
38:08but with a different purpose.
38:14The males molt their tail feathers at the end of every breeding season, so he won't have
38:19his prized plumage for very much longer.
38:31At this time of year, these displays are all about defending his territory, rather than attracting
38:37a mate.
38:47Even when his tail feathers are gone, he'll still live in the same territory.
38:54He wants to keep exclusive rights to this area for the next breeding season.
39:00He'll attack anyone who dares to transgress his borders.
39:15The other male in the tree has come uncomfortably close to his patch.
39:19He may be challenging the resident male to see if he can take over his territory.
39:26The resident male responds by making his display even more robust.
39:38But it doesn't put off the intruder, who gets even closer.
39:56As things get more heated, they move further and end up down by the nearby creek.
40:04The resident male asserts his dominance by crowding and charging the trespasser, pushing
40:09him towards the edge of his territory.
40:25Finally, he gets the rival on the run.
40:35For now, his territory remains intact.
40:40For now, his territory remains intact.
41:16While the lyrebird is singing and dancing, the male cassowary has childcare duties to attend
41:23to.
41:25For now, his territory remains intact.
41:26Because in stark contrast to the lyrebird's arrangements, it's the male cassowaries who
41:31make the nest, incubate the eggs and look after the chicks.
41:40His four chicks are already around 11 weeks old.
41:44He'll stay with them for another six months, teaching them to look for food and water.
41:54They're striped for camouflage, but by six months, they'll lose their stripes and become a uniform,
42:00mousy brown.
42:06They won't begin to get their distinctive vivid colouring until they're around a year to 18 months
42:11old.
42:12Then the chicks will leave their dad's territory to establish their own.
42:22The male lives in a forest that adjoins a house and sometimes crosses the garden here,
42:27bringing his chicks with him.
42:31While three of them are robust, one of them seems to be weaker than the others.
42:38This little chick struggles to keep up.
42:42She may be sick.
42:44Infant mortality in cassowaries is very high.
42:49Predation, diseases, habitat destruction and road accidents all claim young cassowary lives.
42:57Out of these four chicks, it's likely that only one will survive to adulthood.
43:04For now, their dad takes care of their every need.
43:23It can be rainy and humid in this tropical part of the country, but today it's extremely hot.
43:3086 degrees Fahrenheit.
43:33Dad's brought his brood out here for the good foraging.
43:36But now he needs to get them out of the sun.
43:40dry voices.
43:40The wind pops off in the golden sun.
43:46Yeah, thank you.
43:57If there's no one can catch nature of the rain in an enigma,
43:58I won't do it anymore.
43:58Well, I'm just Bolick and I saw this as soon as well.
43:58But now I'm doing this wandering in an Fayette necessarily,
43:59And this hasresponding into the marshall.
44:00I'm only talking about the weather as soon as the stormy and before this time the pulse of all
44:00belangrijk stories happen,
44:00practice it gonna znajd say promising sounds that because the wind wavesLee
44:00let's go into theaky safe as soon as familias.
44:00That Hurray.
44:16When he decides to move on, the sickly little chick falls behind again.
44:30She may not make it to adulthood, but her father's attentive care will at least ensure she has
44:36the best chance of survival.
44:56The family crosses the road back into the forest.
45:09As they depart, the female cassowary appears from the forest.
45:13She may be the chick's mother, but she's free of parental obligation.
45:20She helps herself to a drink.
45:24Even though there's a chance she may run into her ex-partner and chicks, she won't take
45:29any interest in their welfare.
45:44From the tropical north to the temperate south, Australia's birds are some of the world's
45:53most singular and exotic.
45:59At every stage of the breeding season, they're hard at work.
46:10The strenuous job of attracting a mate.
46:17Defending a territory.
46:27Building a nest and tending to vulnerable chicks are all fraught with danger and difficulty.
46:41These vibrant, talented and eccentric birds all adopt their own breeding tactics to get the
46:54next generation safely on its way.
47:02And we can't help.
47:26We've been learning how to make a tree.
47:26We've been learning how to make a tree.
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