Pekapeka | Billy Mclean

Every evening as the sun sets, our native songbirds and other familiar creatures settle into burrows, nests or roosts to seek safety and shelter for the night.

This is the time our native bat, the Pekapeka, wakes from its daytime sleep and begins checking light levels from its own roost, hidden within or upon these very same trees. Quietly, it waits for the right moment to emerge and fulfil their role in our delicate, yet enduring ecosystem. 

We have only two bat species remaining in New Zealand. Both are culturally significant as taonga species and scientifically important as indicator species. In many ways, they are the "canary in the coal mine" for our natural world, providing an early warning of ecological imbalance and ecosystem decline.

Although studies of these remarkable creatures have been limited in the past, several long-term research projects have now been gathering data for decades, while many new initiatives continue to emerge. The findings are alarming. In 2023, the long-tailed bat (Chalinolobustuberculatus) was found to have declined by more than 70 percent in just a decade and was consequently listed as Nationally Critical. For those who understand what this means, alarm bells should be ringing.

It was about twenty years ago, on a still, starry night, that I was heading home along a familiar route through farmland and fragmented ngahere after an evening of pest control with a pellet gun and spotlight. As I passed through a large natural archway in the bush, a sudden but distinctive silhouette cut sharply through the beam.

Approaching head-on like a silent miniature missile, it appeared from the darkness, swooped, dived, and strafed around me before vanishing back into the branches. It missed my head by less than an arm's length, leaving me blinking in bewilderment at what I had just seen.' Bat!' my mind screamed, still struggling to believe it. 

The unmistakable crescent-shaped wing remained burned into my memory. In that instant, a fascination was born with these chicken-nugget-sized, mysterious, and elusive creatures of the night. A new item had just been added to my bucket list.

Around that same time, I discovered arboriculture through a small but highly professional and caring local company. Several years later, I had qualified to Level 4 Advanced (back when that was a thing) and had been taught by my boss, trainers, and peers that our primary role as arborists is to manage and maintain our urban ngahere.

That responsibility is something I have always taken seriously. To do it well requires understanding, as best we can, what lives in, among, and upon the trees we work on every day. Over the years, my curiosity often returned to the dark staining and strange pungent smell I would encounter in large hollow trees on farms, roadsides, and rural properties. I often wondered what was responsible.

 It was in 2018 that this mystery was finally solved for me. Once again, I was out one evening with a pellet gun on a pest-control mission. It was summer, and the sunsets were late. As I leaned against an old taraire tree to take a shot at a rabbit, I noticed that familiar but distinctive odour coming from a huge open cavity in the trunk.

As I took my shot, I instantly heard scurrying, scratching, and commotion from inside the cavity. Expecting to see rats or possums, I looked up. Instead, to my surprise, amazement, and delight, I realised it was an entire colony of bats preparing to leave their roost for the night.

n that moment, the mystery was solved. The smell of this active and confirmed bat colony instantly connected with the smell I had encountered in so many trees I had thinned, lifted, reduced, felled, and chipped over the years.

The excitement of the discovery lasted only a moment. It was quickly replaced by shock and horror as memories flooded back of roost trees that may have been removed without anyone knowing what lived inside them. That moment changed my life.

With a knot tightening in my stomach and a lump in my throat the size of a grapefruit, I staggered away from what should have been one of the happiest and most fascinating discoveries of my life. Instead, I felt sick, confused, angry, disappointed, and ashamed. Ashamed of myself, my work, and my industry.

How could this happen? Why didn't I know? How many had we lost?

I've learned a great deal since then. It turns out bats are incredibly wily creatures, and I now understand the answers to those questions far better.

That opportunity for redemption came when I attended a public meeting hosted by Dr Natasha Bansal, Research Lead for Finding Franklin Bats from EcoQuest Centre for Indigeneity, Ecology and Creativity. When volunteers were sought for a community-based scientific research project investigating Franklin's pekapeka population, I jumped at the chance.

Natasha explained that this Department of Conservation-permitted project would involve five years of mark-and-recapture work to assess the size and health of our local bat population. Local volunteers were needed to help track, trap, and study bats. Funding came from Auckland Council and the Franklin Local Board, and Finding Franklin Bats was preparing for its first capture season.

At the time, I had no idea that only three years later I would be DOC-accredited, hold bat-handler certifications, have held more than a hundred bats in my hand, and seen many hundreds more. After twenty years on my bucket list, I had finally achieved what once seemed impossible.

To undertake mark-and-recapture work, Finding Franklin Bats first captures a small number of bats from natural flyways using harp traps. Healthy individuals are fitted with lightweight radio transmitters and tracked daily back to their roosts until the transmitters fall off. Once roost sites are identified, entire colonies can be captured using roost traps, fitted with individually numbered bands, measured, assessed, and then released with minimal stress or disturbance.

This process is repeated annually to monitor population size, survival, breeding success, and overall health. It requires an enormous contribution from trained specialists, community volunteers, funding partners, and specialised equipment.

After spending hundreds of hours alongside Natasha and other experts in the field, I have learned enough to move beyond the disappointment and bitterness I once felt. Instead, I would like to share some things every arborist should know so that we can avoid repeating past mistakes before another species is lost forever.

Long-tailed bats are insectivorous, tree-dwelling microbats. They spend their days roosting in trees and emerge at dusk to feed on insects throughout the night. Most feeding occurs on the wing, or "hawking", along forest edges, riparian margins, streams, wetlands, shelterbelts, and pasture.

Each bat consumes between 30 and 100 percent of its own body weight every night. For an animal weighing only 8–12 grams, that is an impressive number of insects, consisting largely of mosquitoes and small moths. They typically feed for most of the night, resting only briefly around midnight before continuing until dawn.

Just before sunrise, they return to their roosts. Selecting the right tree, with the right conditions, at the right time of year is critical to their survival. Different weather conditions require different roosting opportunities, meaning bats need a wide variety of suitable trees available within their home range.

Across much of New Zealand, native forests have been reduced to a fraction of their former extent. In many landscapes, remnant forests have been replaced with macrocarpa and poplar shelterbelts, while willows line streams, wetlands, and ponds.

As it turns out, those old shelterbelt trees, hollow willows, craggy macrocarpas, and invasive exotics growing along roadsides and waterways are often critical habitat for a taonga species teetering on the brink of extinction.

Would we be so casual about destroying feeding grounds, breeding sites, and shelter used by kākāpō? Probably not.

Bats, like most of our native fauna, do not distinguish between native and exotic trees. In some situations, they even prefer exotic trees over nearby fragments of native forest. We need to adapt our thinking to reflect that reality.

The Department of Conservation's national bat database records known bat detections, roosts, and sightings throughout the country. Any area within approximately 20 kilometres of a confirmed bat location should be considered potential bat habitat.

Long-tailed bats are protected under the Wildlife Act, meaning the destruction of active roosts and habitat associated with a critically endangered species may have significant legal implications.

So what is bat habitat?

Bat habitat includes far more than just the trees bats roost in. It also includes the foraging areas where they feed and the flyways and movement corridors they use to travel between sites. Riparian margins, wetlands, streams, shelterbelts, paddocks, and forest edges all form part of this habitat network.

Importantly, a lack of detections does not mean bats are absent.

Roost trees are typically mature trees containing hollows, cracks, cavities, or loose and flaking bark. They do not necessarily need to be exceptionally large.

Roost entrances can range from tiny cracks barely large enough to fit a thumb through, to large cavities extending several metres up a trunk. These features may occur in stems, limbs, dead spars, or under loose bark.

From December through to mid-February, female bats gather together in maternity roosts where they give birth and raise their young. Females produce only one pup each year. As a result, this is the period when colonies are most vulnerable to accidental destruction. These roosts generally consist of larger hollow cavities with restricted entrances that provide protection from predators. Because maternity roosts are often used repeatedly, they may contain visible guano deposits or produce a distinctive odour detectable at close range.

Unfortunately, signs of bat occupancy are often subtle and easy to miss. A faint ammonia smell, a small accumulation of guano, or the occasional quiet squeak may be the only evidence that bats are present when bats congregate in large numbers.

Even these signs can be difficult to detect when chainsaws are running, sawdust is flying, and machinery is operating. From a bucket truck or excavator cab, there is little chance of noticing them at all.

So what should you do if you discover an active bat roost?

Stop work immediately.

Notify the client, secure the site, and contact the Department of Conservation for advice. DOC has established protocols and guidance documents available through its bat resources programme. If in doubt, call DOC and seek guidance before proceeding.

Potential roost trees should be retained wherever possible. Just because bats are not present today does not mean they will not use that tree tomorrow. Bats require a diverse network of roost sites, and every suitable tree may have value.

Where practical, encourage clients to retain and manage habitat rather than remove it entirely. Often there are workable solutions that address safety concerns while preserving important habitat features.

How do you check for bats?

The most reliable method is to inspect potential roost features using an endoscope. This allows cavities, cracks, and hollows to be examined for guano deposits, staining, or bats themselves. Such work requires appropriate permits, training, and experience.

Alternatively, trained professionals can conduct roost inspections on your behalf.

Roost watches are the least invasive option but are generally less reliable. Bats may leave from unseen exits or simply choose not to emerge on a particularly cold night. Successful roost watches require patience, silence, darkness, thermal or infrared imaging equipment, and acoustic bat detectors capable of detecting ultrasonic echolocation calls.

Finally, what should you do if a tree has already been felled or dismantled and you suspect bats may be inside?

Leave it where it is.

At a minimum, leave the material undisturbed overnight. Unlike birds, bats do not usually burst from a roost when disturbed. Being heterothermic, they often need time to warm up before they can fly. They do this by shivering to elevate their body temperature and metabolism.

Depending on the time of day and ambient temperature, this process may take considerable time.

Their primary defence strategy is to remain hidden, silent, and undetected. After more than 30 million years of evolution, they have become masters of hide-and-seek. If disturbed, they are often more likely to crawl deeper into a cavity than to fly away.

Leaving the tree undisturbed overnight provides any surviving bats an opportunity to emerge naturally and relocate to another roost.

During winter, bats may enter torpor, a state of reduced metabolism that can last for days. In very cold conditions, they may require significantly longer periods before becoming active enough to move.

As mentioned earlier, bats have survived for more than 30 million years by becoming masters of hide-and-seek. They have evolved to exist unseen, unheard, and unnoticed. Ironically, it is that very adaptation that now places them at risk.

Most people will go their entire lives without seeing a pekapeka. Even those of us who work among trees every day can easily miss the signs that they are there. Yet every evening, as the light fades and the tūī, kererū, and pīwakawaka settle down for the night, these tiny mammals emerge from hollows, cracks, and loose bark to begin their shift.

I often think back to that first bat that streaked through my spotlight twenty years ago, and to the colony I discovered years later in the taraire tree. One encounter sparked a fascination. The other changed the way I look at every tree I work on.

As arborists, we are not simply managing trees. We are managing habitat. We are making decisions every day that affect the countless species that depend on those trees for shelter, food, breeding, and survival.

The good news is that awareness changes outcomes. Every retained hollow, every careful inspection, every conversation with a client, and every arborist who stops to ask, "Could bats be using this tree?" is a step in the right direction.

The future of New Zealand's pekapeka will not be decided solely by scientists, conservationists, or government agencies. It will also be shaped by landowners, contractors, farmers, and arborists making better decisions on the ground.

The next critically endangered species does not need another advocate after it is gone. It needs people paying attention while it is still here.

Our pekapeka are still here.

Let's make sure they stay that way.