New Zealand Fairy Tern Sleep Facts

Endangered and elusive, the New Zealand fairy tern is a tiny shorebird whose main hobbies include nesting in inconvenient places and not reproducing enough. It’s hard to worry about insomnia when you’re worrying about bird extinction. A perfect bedtime story for lovers of relaxation, rare species, and bureaucratically-managed conservation plans.

Thanks to Guy for sponsoring this episode!

Transcript

Welcome to the I Can't Sleep podcast,

Where I help you learn a little and sleep a lot.

I'm your host,

Benjamin Boster,

And tonight's episode is about the New Zealand fairy tern.

This sponsored episode is dedicated to Katie,

From Guy.

The New Zealand fairy tern,

Or Taraiti,

Is a subspecies of the fairy tern,

Endemic to New Zealand.

It is New Zealand's rarest native breeding bird,

With about 40 individuals left in the wild.

It nests at about four coastal locations between Whangarei and Auckland,

And in the North Island.

It is threatened by introduced predators,

Extreme storms and tides,

Beach activity,

And waterfront development.

The New Zealand fairy tern is currently considered a subspecies of the fairy tern.

Two other subspecies exist,

Which breeds in Western and Southern Australia,

And another which breeds in New Caledonia.

Fairy terns were first described from the Bass Strait in Australia,

In 1843.

The New Zealand species was first identified by the Dunedin naturalist,

Thomas Potts,

In the Rakaia Riverbed in Canterbury.

It was breeding in the Rakaia Gorge.

He noted there were already two specimens in the collections of the Canterbury Museum of Natural History.

The New Zealand fairy tern is distinguishable from the other two species on the basis of its morphology and behavior,

And has a distinct genetic haplotype.

Genetic studies found there was almost no gene flow or migration between the New Zealand and Australian populations.

The New Zealand fairy tern was noticed as being common in the late 19th century.

However,

These records have been suggested as inaccurate,

As the birds can be difficult to distinguish from little terns.

From 1940 to 1983,

The New Zealand fairy tern was known to have bred at several sites along the northern coastline of the North Island.

Their breeding range extended from Ruakaka in Northland to Tauranga in the Bay of Plenty.

New Zealand fairy terns were also reportedly found in Canterbury in the South Island.

However,

From the mid-1970s,

The population declined rapidly.

By 1984,

New Zealand fairy tern breeding was restricted to three sites,

In Northland,

The Papakanui Sandpits in Kaipara Harbor,

The Waipu Sandpit,

And the Mangafai Sandspit.

Currently,

New Zealand fairy terns still occupy these breeding sites,

With the addition of a new breeding site in 2012 at the Te Arai Stream mouth,

South of Mangafai.

Forest and Bird is working to establish an alternative breeding site on the Kaipara Harbor.

In August 2018,

The Department of Conservation and the New Zealand Defence Force worked to build a nest site ahead of the breeding season of Papakanui.

Unlike other species of terns,

Which forage in the open ocean,

The New Zealand fairy tern is not a plunge diver,

But instead feeds in the top five to eight centimeters of the water.

It can capture prey in extremely shallow water,

Such as estuaries and tidal pools.

Adult birds have been observed feeding gobies and flounders to their chicks,

And adult diet may include a substantial number of shrimps.

Birds were observed foraging in Te Arai Stream,

The mouth of which is a popular flocking for post-breeding fairy terns,

But appear to be getting most of their food from elsewhere.

Courtship begins in September,

With egg laying occurring between late October and early January.

Birds typically lay one to two eggs per nest.

Nests are small,

Unlined scrapes in the sand,

And are roped off and monitored by the Department of Conservation.

The nests are constructed near white,

Gray,

And orange shell debris to help disguise the eggs and chicks,

And are found at least one kilometer away.

The eggs are laid in a way from getting too close or too far apart from each other.

Guthrie Smith describes a nest as follows.

On such a strip,

Sparsely sprinkled with little heaps of pebbles and surface shells,

And twos and threes,

Lay the couple of eggs.

The surface seashells had been allowed to remain as camouflage,

Untampered with,

But from elsewhere had been also collected 20 or 30 other halves and holes,

Showing deep lateral widths of purple and pink.

Not a brilliantly-tinted shell had been missed over the couple of acres I searched.

The hen-tern had then laid eggs to match the bivalves,

The shells' bright pink.

Females spend more time incubating eggs than males,

While males provide the majority of food to the chicks.

The chicks are mobile from hatching,

And ready to fully fledge from 30 days old.

They are vulnerable to environmental events,

Such as storms and high tides,

And predation.

The encroachment of human activity on their nesting grounds,

Often popular beaches,

Is a major threat to these birds.

Beach narrowing,

Mainly due to housing developments and weed invasion,

Forces the terns to nest closer to the sea,

Putting their eggs at risk during storms.

Introduced predators and human disturbance also threaten nesting sites.

The wintering range of the birds extends over the Kaipara Harbor.

Outside the breeding season,

Fairy terns form flocks on the harbor,

Often around Tapora.

The number of birds had plummeted to three breeding pairs and 11 individuals by 1983.

But intensive conservation efforts were put in place by the New Zealand Wildlife Service.

Mangafai and Papakanui spit nest sites became protected in 1983,

And a site at Waipu in 1994.

Numbers increased so that in 1998,

The population totaled some 25 to 30 birds,

With eight to 10 breeding pairs spread over three breeding sites.

Numbers continued to increase due to the Department of Conservation's recovery plan.

And by 2006,

Had reached 30 to 40 individuals,

Including 12 breeding pairs.

Five years later,

Numbers were stabilized at 40 to 45 individuals,

And around 10 breeding pairs.

In 2019,

There are 45 individuals and approximately 12 breeding pairs.

A fairy tern recovery plan was created in 2005 and aimed to cover strategy over 10 years.

But the recovery group was dissolved before the end of that term.

During the 2008 breeding season,

At least 11 chicks were fledged,

Although no more than six chicks were fledged per season in the decade following.

During the 2018-2019 breeding season,

It was estimated that numbers had dropped to only five breeding pairs,

And only three chicks hatched,

Making it the worst breeding season for 27 years.

The Department of Conservation suspected this worsening was partially due to high winds,

As well as the appearance of a mysterious blue substance on the beach at Waipu.

A 2017 review recommended the establishment of a fairy tern recovery group to formulate a strategy for management of the species.

This group aims to be in force by 2019,

And research has begun to determine the reasons for the fairy tern's decline.

In the 2006 birthday honors,

Gwenda Pullum was awarded a Queen's Service Medal for her work to protect fairy terns.

The New Zealand Fairy Tern Trust,

Established in 2008,

Contributes to the conservation effort by donating up to $40,

000 annually for predator trapping.

With a total population at the time of fewer than 50 individuals,

Including just 10 breeding pairs,

The IUCN rated this species as critically endangered.

A New Zealand government source considers that this bird is probably New Zealand's most endangered indigenous breeding bird.

It nests on sand and shell banks just above high tide marks and nesting is highly vulnerable to human development,

Introduced predators,

Domestic animals,

Storms,

Very high tides,

And disturbance by humans on foot and in vehicles on the beach.

The New Zealand fairy tern's habitat is now limited to the Lower Northland Peninsula.

The Te Arai North Limited-Owned Araiti Golf Club was built near the fairy tern's nesting area.

The bird is further threatened by a proposed residential subdivision at Te Arai,

Next to one of its prime breeding sites.

As part of its treaty settlement,

Te Uru Ohau purchased land in the Mangawhai River and Mangahaiai Forest and signed a co-governance agreement with developer Te Arai North.

2,

000 homes were originally proposed for the development.

However,

After opposition from the Te Arai Beach Preservation Society,

Fairy Tern Charitable Trust,

And others,

This was scaled back to 46 homes and a 196-hectare public park.

Disagreement stems from the damming of the Te Arai Stream,

Interfering with the life cycle of fish said to be key to the diet of fairy terns.

In 2019,

Scientists who have been studying fairy terns at Mangahaiai on Northland's East Coast now suspect the bird's decline may be linked to the removal of mangroves from the harbor.

Now let's learn about Sandager's wrasse.

The wrasses live in small shoals consisting of one male and several attendant females and juveniles.

In the presence of the male,

All juveniles will grow into females.

But when the male dies or is removed from the shoal,

The group's dominant female then undergoes physiological changes to convert itself into a male.

The male fish has a deeper body and differs significantly in coloration.

For example,

The male has very distinctive bands,

Whereas the female is paler in color and only has two dark spots.

The fish was named after Andreas Fleming Steward Sandager,

A lighthouse keeper in New Zealand who collected the first specimen.

As the scientific name has Sandary as the specific epithet,

A proposal was made in 1927 to change it to Sandagerie on the theory that the original description constituted a misspelling.

However,

In 2011,

It was shown that Sandager was also spelled Sandager.

Sandager at that time,

And thus the original spelling of the scientific name should stand.

The animals of New Zealand,

Part of its biota,

Have an unusual history because before the arrival of humans less than 900 years ago,

The country was mostly free of mammals,

Except those that could swim there,

Like seals.

Sea lions and offshore whales and dolphins or fly there like bats.

However,

As recently as the Miocene,

It was home to the terrestrial St.

Bathan's mammal,

Implying that mammals had been present since the island had broken away from other landmasses.

The absence of mammals meant that all of the ecological niches occupied by mammals elsewhere were occupied instead by either insects or birds,

Leading to an unusually large number of flightless birds,

Including the kiwi,

The takahē,

And the kakopau.

Because of the lack of predators,

Even bats spent most of their time on the ground.

There are also about 60 species of lizard,

Four species of frog,

All rare and endangered,

And the tuatara,

Reptiles resembling lizards,

But with a distinct lineage.

Some butterflies of New Zealand are endemic,

While many species have been introduced and some species of butterflies,

Periodically migrate to New Zealand.

The Australian Painted Lady has been known to migrate from Australia to New Zealand in times of strong migration in Australia.

Humans first arrived via the Pacific Islands in several waves at some time before 1300 AD,

Bringing with them the Polynesian rat and the domesticated dog.

Europeans later brought pigs,

Ferrets,

Stoats,

Mice,

Rats,

Dogs,

Cats,

Sheep,

Cattle,

And many other mammals.

Of these,

The rats,

Ferrets,

Cats,

Stoats,

And dogs have all seriously impacted the New Zealand fauna,

Driving some species to extinction.

Brush-tail possums were introduced from Australia for a fur industry,

And deer from Europe as game animals,

But seriously damaging the forest habitat of many birds.

In recent years,

Successful efforts have been made to remove possums,

Rats,

Ferrets,

And other mammals from many large and small offshore islands in an effort to return these places to something more closely resembling their pre-human state.

Similarly,

Efforts are being made to control such species in selected locations on the mainland.

Now let's turn to the kiwi.

Kiwi are flightless birds endemic to New Zealand.

Approximately the size of a domestic chicken,

Kiwi are the smallest ratites,

Which also include ostriches,

Emus,

Rayas,

Cassowaries,

And the extinct elephant birds and moa.

DNA sequence comparisons have yielded the conclusion that kiwi are much more closely related to the extinct Malagasy elephant birds than to the moa,

With which they shared New Zealand.

There are five recognized species,

Four of which are currently listed as vulnerable,

And one of which is near threatened.

All species have been negatively affected by historic deforestation,

But their remaining habitat is well protected in large forest reserves and national parks.

At present,

The greatest threat to their survival is predation by invasive mammalian predators.

The vestigial wings are so small as to be invisible under their bristly,

Hair-like two-branched feathers.

Kiwi eggs are one of the largest in proportion to body size,

Up to 20% of the female's weight of any order of bird in the world.

Other unique adaptations of kiwi,

Such as short and stout legs,

And using their nostrils at the end of their long beak to detect prey before they see it,

Have helped the bird to become internationally recognized and internationally well-known.

The kiwi is recognized as an icon of New Zealand,

And the association is so strong that the term kiwi is used internationally as a colloquial demonym for New Zealanders.

The Maori word kiwi is generally accepted to be of imitative origin from its call.

Some linguists derive the word from proto-nuclear Polynesian kiwi,

Which refers to Numenius tahitiensis,

The bristle-thighed curlew,

A migratory bird that winters in the tropical Pacific Islands that kind of resembles with its long,

De-curved bill and brown body.

So when the first Polynesian settlers arrived,

They may have applied the word kiwi to the newfound bird.

Some linguists,

Like Robert Blust,

However,

Propose that kiwi originated from proto-oceanic name for the Pacific golden plover,

Kiwiwi.

The bird's name is usually spelled with a lowercase k.

It normally stays unchanged when pluralized in English,

Mirroring its usage in the Maori language itself.

The genus name Apteryx is derived from ancient Greek without wing,

A,

Without or not,

Pteryx,

Wing.

Although it was long presumed that the kiwi was closely related to the other New Zealand radides,

The moa,

Recent DNA studies have identified its closest relative as the extinct elephant bird of Madagascar.

And among extant radides,

The kiwi is more closely related to the emu and the cassowaries than to the moa.

Research published in 2013 on an extinct genus,

Proapteryx,

Known from Miocene deposits of the St.

Bathans fauna,

Found that it was smaller and probably capable of flight,

Supporting the hypothesis that the ancestor of the kiwi reached New Zealand independently from moas,

Which were already large and flightless,

By the time kiwi appeared.

The adaptation to a terrestrial life is extensive.

Like all other radides,

Ostrich,

Emu,

Moa and cassowary,

They have no keel on the sternum to anchor wing muscles.

The vestigial wings are so small that they are invisible under the bristly,

Hair-like two-branched feathers.

While most adult birds have bones with hollow insides to minimize weight and make flight practicable,

Kiwi have marrow,

Like mammals,

And the young of other birds.

Like most other radides,

They have no uropygial gland,

Preen gland.

Their bill is long,

Pliable and sensitive to touch,

And their eyes have a reduced pectin.

The feathers lack barbules and aftershafts,

And they have large vibrissae around the gape.

They have 13 flight feathers,

No tail,

And a small pygostyle.

Their gizzard is weak,

And their cecum is long and narrow.

The eye of the kiwi is the smallest relative to body mass in all avian species,

Resulting in the smallest visual field as well.

The eye has small specializations for a nocturnal lifestyle,

But kiwi rely more heavily on their other senses.

The side of the kiwi is so underdeveloped that blind specimens have been observed in nature,

Showing how little they rely on sight for survival and foraging.

In an experiment,

It was observed that one third of a population of A.

Raui in New Zealand,

Under no environmental stress,

Had ocular lesions in one or both eyes.

The same experiment examined three specific specimens that showed complete blindness and found them to be in good physical standing outside of ocular abnormalities.

A 2018 study revealed that the kiwi's closest relatives,

The extinct elephant birds,

Also shared this trait despite their great size.

Unlike virtually every other paleonath,

Which are generally small-brained by bird standards,

Kiwi have proportionally large encephalization quotients.

Hemisphere proportions are even similar to those of parrots and songbirds,

Though there is no evidence of similarly complex behavior.

Before the arrival of humans in the 13th century or earlier,

New Zealand's only endemic mammals were three species of bat,

And the ecological niches that in other parts of the world were filled by creatures as diverse as horses.

Wolves and mice were taken up by birds,

And,

To a lesser extent,

Reptiles,

Insects,

And gastropods.

The kiwi's most nocturnal habits may be a result of habitat intrusion by predators,

Including humans.

In areas of New Zealand where introduced predators have been removed,

Such as sanctuaries,

Kiwi are often seen in daylight.

They prefer subtropical and temperate potocarp and beech forests,

But they are being forced to adapt to different habitat,

Such as subalpine scrub,

Tussock grasslands,

And the mountains.

Kiwi have a highly developed sense of smell,

Unusual in a bird.

And are the only birds with nostrils at the end of their long beaks.

Kiwi eat small invertebrates,

Seeds,

Grubs,

And many varieties of worms.

They also may eat fruit,

Small crayfish,

Eels,

And amphibians.

Because their nostrils are located at the end of their long beaks,

Kiwi can locate insects and worms underground using their keen sense of smell,

Without actually seeing or feeling them.

This sense of smell is due to a highly developed olfactory chamber and surrounding regions.

It is a common belief that the kiwi relies solely on its sense of smell to catch prey,

But this is not scientifically observed.

Once bonded,

A male and female kiwi tend to live their entire lives as a monogamous couple.

These relationships may last for up to 20 years.

Usually,

Only one egg is laid per season.

The kiwi lays one of the largest eggs in proportion to its size of any bird in the world.

So,

Even though the kiwi is about the size of a domestic chicken,

It is able to lay eggs that are about six times the size of a chicken's egg.

Kiwi eggs can weigh up to one quarter of the weight of the female,

Helped by their inability to fly that could limit the extent by its body weight.

Brown kiwi females carry and lay a single egg that may weigh as much as 450 grams.

The eggs are smooth in texture and are ivory or greenish-white.

The male incubates the egg,

Except for the great-spotted kiwi,

In which both parents are involved.

The incubation period is 63 to 92 days.

Producing the huge egg places significant physiological stress on the female.

For the 30 days it takes to grow the fully developed egg,

The female must eat three times her normal amount of food.

Two to three days before the egg is laid,

There is little space left inside the female for her stomach,

And she is forced to fast.

It was believed that the large eggs were a trade of much larger moa-like ancestors and that kiwi retained large eggs as an evolutionary neutral trade as they became smaller.

However,

Research in the early 2010s suggested that kiwi were descended from smaller flighted birds that flew to New Zealand and Madagascar,

Where they gave rise to kiwi and elephant birds.

The large egg is,

Instead,

Thought to be an adaptation of prococity,

Enabling kiwi chicks to hatch mobile and with yolk to sustain them for two and a half weeks.

Reviews

Thank you Benjamin! Not your fault but I couldn’t fall asleep so I actually heard the entire thing. I would love to visit Australia and New Zealand! Never heard of the fairy tern! 😊

Glass is Clearly a good subject to put oneself to sleep! 🪟💤🪟💤🪟💤
Thanks, Ben!