Feathered Findings: Waiheke’s Bird Count Successes

In the wake of the most recent five-minute bird count results, we are excited to spotlight some of the native and endemic birds showing significant count increases since November 2020.

The five-minute bird counts are conducted in November each year, to indicate the impact of the stoat eradication and predator control projects as well as other conservation efforts. The counts involve twelve staff, volunteers, and contractors who are trained to identify birds by sight and sound. The counts are conducted at 70 spots around Waiheke with 3 counts taken at each, they encompass five habitat types (inland forest, regenerating shrubland, coastal forest, urban and coastal forest).

*Increase Waiheke 5-Minute Bird Counts November 2023 vs November 2020

Bird 01: Silvereye/Tauhou — Count Increase: 180%

One standout is the silvereye/tauhou, which has seen an amazing 180% increase. This surge indicates that local conservation efforts on Waiheke Island are having a real positive effect, from predator eradication and control projects to habitat restoration work.

Did you know silvereyes (tauhou) are known to undergo partial migrations within New Zealand, which is quite unusual for small birds? For example, a bird banded in Marlborough was later found in Wellington. It’s wonderful to see nature's resilience and the community's dedication to protecting our native wildlife.

Bird 02: Grey Warbler/Riroriro — Count Increase: 40%

The riroriro (grey warbler) is NZ’s second smallest bird. They are often heard rather than seen and have perhaps the most recognisable and commonly heard sound of our ngahere (bush).

Riroriro hide themselves well, weaving quickly through tree branches and then miraculously disappearing, which make them hard to spot. They are often mistaken for silvereyes (tauhou), but their call is sometimes assumed to be of the tūī. Many people go through their life hearing and seeing this bird without even realising it exists!

They have the conservation status ‘not threatened’, however like all of our endemic species, they thrive in the absence and/or control of introduced predators. Our five-minute bird count has revealed a 40% increase in recorded riroriro numbers on Waiheke compared to previous years, which is a fantastic result.

Bird 03: Shining cuckoo/Pīpīwharauroa— Count Increase: 172%

The pīpīwharauroa (shining cuckoo) is the smallest and one of the most iridescent members of the Cuckoo family. They are a summer visitor to NZ, and Māori welcomed pīpīwharauroa with the Whakataukī “Ka tangi te wharauroa, ko ngā karere a Mahuru,” which means "If the shining cuckoo cries, it is the messenger of spring."

Like all cuckoos, they have evolved to possess a particularly strange parenting strategy, dubbed as ‘brood parasitism’, in which they profit from other bird species by laying their eggs in the nests of other, often smaller birds. The shining cuckoo often arrives in NZ just in time to commandeer the riroriro’s (grey warbler) second clutch.

Pīpīwharauroa are partially susceptible to window strike, but one of their biggest threats are invasive predators. Our bird count indicates a massive increase of pīpīwharauroa on Waiheke!

Bird 04: Sacred kingfisher / Kōtare — Count Increase: +84%

The kōtare are one of our more recognizable native birds, known for their distinctive call, plumage, and large black beaks! These beaks are so aerodynamic that engineers used them as inspiration for the nose of Japanese bullet trains.

These magnificent beaks also give kōtare valuable excavating skills, allowing them to nest in a wide range of places such as hollow trees, banks, or cliffs to make their burrows.

Kōtare inhabit a large range of different habitats, from coastal areas and estuaries, to farmlands. You’ll also see kōtare perched on the tops of buildings or power lines, as they adapt and take advantage of any structure to provide a vantage point to spot prey.

Their adaptability in terms of diet and habitat is likely a factor in their conservation status of ‘not threatened’. However like most native birds, they are vulnerable to predation from introduced mammals and habitat degradation and thrive in pest-free and protected sanctuaries

Bird 05: Tūī Count Increase: 40%

The bird that needs no introduction. Yet another distinctive endemic icon, the Tūī. Acrobats of the sky, they are certainly attention grabbers. By sound and sight, they catch your attention. The Tūī actually have 2 voice boxes which enable their extraordinary range of calls, some of which are so high pitched they are inaudible to humans. They have been known to mimic bells, phones, other birds, and even humans.

Tui being one of the most prevalent honeyeater birds in NZ play a massive role in pollination of flowering native plants such as ōwhai, puriri, rewarewa, kahikatea, pohutukawa, rātā, and flax. If you want to support tui in your backyard, plant these species. The Tui population on Waiheke, as we all know, is doing rather well; you hear and see them everywhere, there is no escape! Tui do well in areas where introduced predators such as possums, rats, and mustelids like stoats are controlled or eradicated. It is thought that rats and stoats are their biggest nest predators, preying on their chicks and eggs.

Bird 06: Kererū Count Increase: 10%

Fab, fat, and feathered, the Kererū (New Zealand wood pigeon) is one of the two remaining endemic pigeons in NZ, the other being the closely related Parea, Chatham Island pigeon, which, believe it or not, is up to 20% bigger than your average Kererū!

Kererū are seed-spreading machines; without them, our ecosystem would face decline. Being the only remaining species which can eat whole fruit more than 10mm, they are responsible for eating and spreading fruit from at least 70 different species of native plants.

The Kererū also has the occasional drunken habit in which they take on a bit too much fruit than they can handle, and it begins to ferment in their crops...

The Kererū is not threatened, but numbers are still considerably low. With stoats and rats preying on their slightly flimsy-looking nests. They also fall victim to window strikes a lot on Waiheke, which is one of the suspected reasons we have only recorded a 10% increase in their numbers in our 5-minute bird count, much less than other species

Bird 07: Weka +236%

Weka are curious and cheeky by nature, and it's no secret that these chicken-sized rails can cause a bit of trouble. They are known opportunists, raiding gardens, getting into chicken coops, stealing food, and anything else that takes their fancy - including cutlery, watches, clothes, keys, and more. They will take the objects to the nearest cover to investigate them, so it’s best not to chase them but simply watch where they go and retrieve any objects later.

They have a vast diet and eat just about anything, including fruit, invertebrates, eggs, lizards, birds, and small mammals, they have even been recorded hunting and eating stoats.

Because of their scavenging habits, weka do cause a bit of a conservation conundrum, as they can pose a threat to many reptile, insect, and ground-nesting/burrowing bird species. However, as an endemic species, they are protected and play a role in New Zealand’s ecosystem.

The North Island weka was once widespread, but only a few thousand now remain on the mainland. Offshore islands, where predators are controlled, provide a refuge for weka, with a healthy population on Kawau Island, and populations on several other offshore islands now being established.

Weka have only recently appeared on Waiheke and seem to be very successful, with our bird counts recording a 236% increase in their numbers.

Bird 08: Kākā +311%

Noisy and playful, they can be seen high in the sky above the motu, raiding your fruit trees, gathering in for dawn and dusk socializing, or just hooning around in full menace mode.

The success of Kākā on Waiheke is a very special story.

Today, if you're outside for more than 5 minutes, it's likely that you will see, if not hear a Kākā. Not too long ago a Kākā sighting was unusual.

Previously, it was speculated that Kākā would fly over to Waiheke from places like Aotea (Great Barrier Island) and/or Te Hauturu-o-Toi (Little Barrier Island). The 2016 discovery of two nests in Onetangi was therefore massive, and now kākā have become such a normal part of island life - it is hard to think that North Island kākā remain ‘at risk’ and there are very few places in Aotearoa where they can be seen regularly.

Kākā have a varied diet: nectar, fruit, seeds, insects. They are one of the few ‘sap-feeding birds’ and use their strong beaks to tear away the bark of trees to get at the sap and insects. Along with this, they are also pollinators of plants such as kōwhai, rātā, and flax.

Kākā are highly affected by deforestation and introduced pests. Due to their nesting in hollow trees, stoats are one of their biggest threats, preying on the mothers, chicks, and eggs. There is no way for them to escape a hollow tree once a stoat enters!

The low stoat numbers on the island, as a result of island-wide eradication efforts, have been crucial in helping Kākā numbers soar - with a 311% increase in five-minute bird count numbers.

Bird 09: Pīwakawaka / New Zealand +179%

Arguably one of the most charismatic manu of the ngahere, the pīwakawaka (fantail), is a strategic insect hunter. Flushing out insects with their own movements, hawking—waiting from a perch then swooping down, or shadowing other species to catch the insects disturbed by their movement.

They are known to follow tauhou (silvereyes), parakeets, tīeke (saddleback), and humans! Their fan tail, which contributes to about half of their overall length, allows them to twist and turn in mid-flight with speed and ease to get to their prey. They are also known on occasion to forage on the ground.

Pīwakawaka are vulnerable to extreme weather events, rats, and other introduced predators (like stoats). Yet fortunately for them, they are excellent breeders, and they can nest up to 4-5 times per season, each nest containing 2-5 eggs! This has helped keep their population stable, and they are classified as ‘Not Threatened'.

Bird 10: Variable oystercatcher / Tōrea pango +67%

The Waiheke coastline echoes with the distinctive sounds of the Tōrea pango or Variable oystercatcher. Recognisable by its vivid, long orange beak, this bird thrives on a diet rich in invertebrates, especially bivalve molluscs like pipis and cockles. With its powerful beak, the oystercatcher can break through shells and dig into the mud to find its meals.

Ornithologist, John Dowding famously described the Tōrea pango as resembling 'grumpy old men,' often spotted mumbling and grouching along the beaches. Across New Zealand's coastlines, these birds are not just known for their unique sounds but also for their striking plumage variations—from solid black to pied or smudgy—which once led them to be thought of as multiple species.

With an estimated population of 5,000-6,000, the Variable oystercatcher is on a path to recovery. Their conservation status, now labeled as 'recovering,' benefits from shared protection measures with the dotterel, with whom they frequently breed. Despite challenges like predation and habitat loss, largely from human activities, adult oystercatchers are resilient, although their nests and chicks face significant threats.