StayiNatHome NZ's Journal

If you've been closely following this long weekend's City Nature Challenge (in NZ or globally), you'll know that New Zealand's official entries into the global City Nature Challenge this year are Dunedin, Christchurch, and Auckland. We're also running our #StayiNatHome project throughout NZ's Level 4 lockdown for all of Aoetearoa-New Zealand.

How, you might ask, are NZ's City Nature Challenge cities performing in comparison to the rest of #StayiNatHome?

Here's the answer to that question, and how you'd get it.

These numbers are going up all the time so this is just a Sunday morning snapshot of where things are at half way through the City Nature Challenge. Clicking on any of those links above will give you the latest numbers.

NZ's City Nature Challenge cities

As of right now (10 AM Sunday morning), New Zealand's three City Nature Challenge cities are at a total of 3,585 observations of 1,110 species observed by 247 people and identified by 180 people. It's a great start!

Ōtautahi/Christchurch is currently leading the charge with 1,599 observations of 608 species observed by 86 people.

Ōtepoti/Dunedin is close behind Christchurch with 1,290 observations of 551 species observed by 59 people.

The Auckland region has more people out observing but doesn't yet have as many keen super users as Christchurch or Dunedin. Auckland is currently at 704 observations of 402 species observed by 102 people.

The most observed species are so far the cabbage tree and the house sparrow, which seems like a pretty accurate assessment of New Zealand's cities.

Seven users in these cities have made uploaded than 100 observations, including @meurkc, @hedgehog111, and @ginakahikatea in Christchurch, and @ruth103, @daturademon, @david_lyttle, and @john_barkla in Dunedin. @jack4 is the top Auckland observer so far with 74 observations.

Eight iNaturalist NZ users have made more than 100 identifications NZ's City Nature Challenge cities: @lloyd_esler, @dave_holland, @tripleaxel, @cooperj, @hedgehog111, @wild_wind, @skipperdogman, @davidorlovich. Lloyd Esler is in Invercargill too. It's been a fantastic effort by all identifiers and we're all very grateful.

The rest of NZ on #StayiNatHome

The rest of New Zealand on #StayiNatHome, during the same time period (Friday to Sunday morning), have made a total of 882 observations of 514 species observed by 209 people and identified by 93 people. So, of all the observations made in NZ so far over the City Nature Challenge weekend, 80% have been made in Dunedin, Christchurch, and Auckland.

There's lots of action still to come

The City Nature Challenge cities are putting in a fantastic effort so far, adding New Zealand's contribution to the global stocktake of species in the global City Nature Challenge.

Dunedin, Christchurch, and Auckland together make up about 42% of the NZ population, so it's great to see the buzz around the City Nature Challenge getting people in these cities out observing above and beyond #StayiNatHome.

We're still only just over half way through the City Nature Challenge so there's a lot more that's about to happen, and it's still important to spread the word and get more people involved. If you want some tips on what to look for in your garden, check out our 20 minute garden challenges.

---

Extra: Tips on searching on iNat NZ

I mentioned that I'd both tell you the answer to the question "how are NZ's City Nature Challenge cities performing compared with #StayiNatHome?", and also show you how to get that answer. Here's the "how" part.

This is for the keenest iNat users out there. If you only interact with iNaturalist NZ via the free iNaturalist app, you might want to stop here.

It involves the Explore page of the iNaturalist NZ website (not the app). That's where you can go to search for (and download) iNat observations.

When you first load the Explore page, you'll see a box for Species and a box for Location. If you've used this before, you'll know that you can type in a Species and/or a Location and you'll be shown all the iNat observations of those species at those locations. Handy.

It gets better. Note that there's also a grey Filters box. Tap on that and you'll find more options for your searches. For example, you can search for just Captive (=cultivated) observations, or just Your Observations, or just observations made between a start and end date. Note that there's also a Download button in the Filters box to download the results of any search as a spreadsheet.

In the Filters box, there's a blue "More Filters" link. Tapping on that expands the Filters box to show even more options. For example, there's Photo Licensing so you can search for observations with photos that you would be able to use off iNat (with appropriate acknowledgement of the photographer). There's also Person, Project, and Place.

So, to find all of the observations from our StayiNatHome project made during the City Nature Challenge (24–27 April), I can use the Filters box to search for observations in the Project "StayiNatHome NZ" with a start date "2020-04-24" (there's a calendar to choose from) and an end date "2020-04-27".

The website address (URL) in my browser for that search is "https://inaturalist.nz/observations?d1=2020-04-24&d2=2020-04-27&place_id=any&project_id=stayinathome-nz&subview=grid".

But wait! There's more! There's a lot more to iNaturalist than you see at first glance. It's one of the great things about iNaturalist. It keeps its user interface elegant and simple but you can dig deeper and access a lot of power. For example, there are a lot more ways you can filter your iNaturalist searches than are displayed on the Filters box. To access these, you need to directly add text to the website address and reload.

There's a wiki page on the iNaturalist Forum listing all of the additions to the iNat Explore website address URLs. The trick I used to answer our question is the "&not_in_place" option. Adding that, along with the IDs for the places in iNaturalist NZ for Dunedin, Christchurch, and Auckland, lets me refine my StayiNatHome search to only display the observations on StayiNatHome that have not been made in Dunedin, Christchurch, and Auckland.

I added "&not_in_place=129542,40501,8345" to my StayiNatHome search, after going to the iNaturalist NZ Places page and looking up the place IDs for Dunedin (ID 40501), Christchurch (ID 129542), and Auckland (ID 8345). You can see a place ID, for example, by clicking on the "Embed place widget" link and looking at the place ID in its web address.

So website address (URL) for my new search is "https://inaturalist.nz/observations?d1=2020-04-24&d2=2020-04-27&place_id=any&project_id=stayinathome-nz&subview=grid&not_in_place=129542,40501,8345". It displays all the observations from the StayiNatHome project made bewteen 24–27 April that were not made in Dunedin, Christchurch, or Auckland.

There you go! Now, back outside with us all to find more garden critters.

Now that you've got the hang of iNaturalist and got started with the City Nature Challenge weekend, what's next? To better explore your garden over this City Nature Challenge weekend, here are some prompts to get you outside exploring. Let's call them challenges. None should take you more than 20 minutes.

By doing one or more of these six 20 minute challenges, you'll be contributing a more detailed snapshot of one aspect of nature in your garden.

Take your pick of the options. Pick as many as you like. Can you do them all?

For each one you do, add the right hashtag to your observations' notes so we can pull all of these observations together at the end.

---

What's flowering and fruiting

Hashtag #fruitflowers

Have a hunt through your garden for any plants in flower or fruit. Photograph any that you find. Some flowers and fruit are quite small so look carefully.

On the iNat NZ website, people will annotate your photos with your plants' "phenology" (flowering, fruiting, flower budding).

If you don't find anything in fruit or flower, just take a photo of any plant in your garden and add the hashtag #20minfruitflowers to that so we know that you looked.

Why? Flowering and fruiting times of plants are often driven by the climate and the climate is changing. Animal species, like many insects and birds, rely on these flowers and fruit for food. The key step for understanding how flowering and fruiting times are changing is getting lots of observations of when plants are reproductive.

More? The NZ Plant Phenology project on iNaturalist NZ is accumulating observations of which plants are fruit and flowering when and where across New Zealand. If you join the NZ Plant Phenology project and add your observations there, you will be asked to fill in a few more details about your plants that make your observations even more useful.

---

20-minute bird count

Hashtag #20minbirds

Take 20 minutes in your garden to see how many bird species you can see and hear from your garden. For your first observation, please also type in the time you started your survey (eg #20minbirds start:1:10 pm).

The bird experts on iNaturalist NZ will be quick to ID any bird you can photograph or record singing. If you're new to bird ID, the good folks over at the garden bird count have a handy guide to common garden birds.

To keep things simple, we're just wanting to know which bird species you can see or hear in 20 minutes in your garden, not how many individual birds there are of each species.

(If you like, you can mention your counts of each species in your notes on the iNaturalist app, or if you're on the iNaturalist NZ website, you can add our "Count" observation field to your observations.)

Why? New Zealand under lockdown is a strange, unplanned experiment for our urban birds. How are they reacting to the lack of cars and cafes and noise? Your garden bird counts can help us find out.

More? If you're keen on birds, note that the New Zealand Bird Atlas project is running throughout New Zealand.

---

Garden Invertebrate Hunt

Hashtag #gardeninverts

The Garden Invertebrate Hunt project on iNaturalist has eight simple methods you can try to survey invertebrates in our gardens. These are described, with instructional videos, in this Garden Invertebrate Hunt article.

The eight Garden Invertebrate Hunt methods are as follows. They're all simple and designed to be easy to do from home without any special equipment: visual search, searching plants for damage, beating big plants, flower visitors, under things on ground, at night light, pitfall trap, and pan trap. You can find instructions of each of these here.

Why? It's the little things that run the world's ecosystems, but they're so often overlooked as we focus on the more obvious bird versus mammal story in NZ. There's growing concern around the world about the health of our invertebrates, especially pollinators. By surveying the invertebrates in your garden, you contribute to a dataset that researchers can use to uncover trends. Invertebrates are also still the wild west of discovery and there's a good chance that you'll find a species that's never been recorded in your neighbourhood before.

More? If you're keen, you can join the Garden Invertebrate Hunt project and add your observations to that project.

---

Lichens

Hashtag #gardenlichens

Lichens are these amazing, tight mutualisms between species from 2–3 kingdoms of life. They're a house built by fungus containing algae and sometimes cyanobacteria. The species work together to become one hardy, successful life form.

How many different lichens can you find in your garden? What are each growing on? Look on rocks, tree trunks, walls, and other old structures.

You can check out all of the 637 lichen species found so far on iNaturalist NZ here.

Why? Lichens are cool, but largely overlooked. We know very little about which lichens are growing where in NZ's towns and cities. Your observations will be a big help.

More? The Lichens of NZ project on iNaturalist NZ is the go-to place to meet New Zealand's lichen enthuiasts.

---

Wild seedlings

Hashtag #gardenseedlings

What wild woody plants are regenerating in your garden? Look for and photograph seedlings of wild woody plants (anything < 50 cm tall). The plant experts on iNat NZ will do their best to identify every seedling you find.

It's also interesting to know whether the parents of each seedling are in your garden. Have a look around for the nearest adult plant of the same species, and photograph that too if you find it.

Why? As our towns and cities get older and woodier, there's more natural regeneration happening. It's great to know about this because it tells us both which native trees and shrubs are naturally regenerating in our neighbourhoods, and also gives us an early warning sign for what the new woody weeds of the future might be.

More? The Woody Seedlings in a Square Metre project gathers together a standardised dataset of which woody seedlings, and how many, are found in random square metres placed in habitats throughout New Zealand. If you'd like to contribute, measure out one square metre in your garden, in a habitat suitable for woody seedlings, and add your observations to the Woody Seedlings in a Square Metre project.

---

Lawn plants

Hashtag #lawnplants

If you get down on your hands and knees, you'll find that a garden lawn is much more than just grass. There can be 50 plants species all growing together in an old garden lawn. How many species can you find? Photograph each different plant species you can find in your lawn.

Let's see who has the most diverse lawn in NZ!

Why? Lawns are a microcosm of plant ecology, like a rainforest in miniature down at your feet. Different species are competing for dominance and which lawn species dominate where under what conditions is giving plant ecologists insights into how all plant communities function.

---

A word about habitats

There's a surprising diversity of habitats to be found in a typical home garden, especially from the perspective of something small like an insect or lichen or seedling. Think about where in your garden you're finding different species, and why those habitats are the best places for those species.

One way to work through your garden looking for species is to focus on one type of habitat at a time. Here's a helpful list of common garden habtiats from @meurkc that you might like to use to structure your exploring.

• Parkland/Woodland (open forest, scattered trees > 3m tall)
• Orchards
• Shrubbery (scattered shrubs up to 3 m tall)
• Herbaceous Border/flower bed (large flowering herbs, tussocks, NZ flaxes)
• Vegetable Garden
• Rock gardens and green roofs
• Walls/fences (brick, rock, stone, concrete, wood, letter boxes)
• Lawns/meadows
• Paths/drives/gutters (cracks and edges)
• Wetlands/Streams (seepages, creeks, rivers, drains, floodplains, ponds)
• Inside the house (pot plants, spiders and moths)

You can add in the notes of your observations which habitat a species was found in.

Happy exploring!

All across the world, for four days from Friday 24 April to Monday 27 April, people in cities around the world will be (carefully) getting outside to do a stock take of the world's urban biodiversity. It's the global City Nature Challenge with iNaturalist.

This year it's (sadly) a big opportunity for us all to contribute to a vision of what urban nature is like when our cities are not filled with the hustle and bustle of cars and people. This year's City Nature Challenge is about working together to document the nature in our cities while we keep our communities safe by staying in our bubbles.

In last year's City Nature Challenge observers around the world came within a whisker of making a million observations in just four days, and found over 32,000 species. Yes, wow!

This year we'll all be focusing closer to home than our big city parks and wild areas. That's not a problem though as you'll find a surprising number of species living in and around your home and garden. (My family is up to 439 species now in our home and garden.)

New Zealand has been #StayiNatHome for over four weeks now, and together we've documented an astounding amount of nature in New Zealand's homes and gardens and neighbourhoods. Over this City Nature Challenge long weekend, it's your chance to fill in all the gaps.

How many species can you find in your home and garden in just four days?

How many of your friends and neighbours can you get outside to spend some quality time with nature using the iNaturalist app?

Revisit your favourite species and hunt for new species you've not observed before. There are lots of things to try, and we'll highlight some over the long weekend.

You can look under pot plant pots and bricks, or look on plants for distinctive damage from herbivorous insects. Get a flat tray (eg oven tray) and see what invertebrates you can shake out of branches. You can turn on your outside light after dark and see what moths and other insects come in. You can look for wild seedlings in your garden, or take time to photograph your garden's lichens. Or take 20 minutes to see how many bird species you can see and hear from your garden. There are lots of species to find and lots of ways to find them.

We'll be posting more over the City Nature Challenge weekend. For now, spread the word and let us see (and hear) what's in your home and garden.

It's Easter time, and that means eggs. In the Northern hemisphere, where Easter celebrations began, this obsession with eggs makes a lot of sense: it's Spring time there and lots of species are coming out of winter and getting to work making babies. However, here down under, we're watching the sun get lower in the sky each day as winter approaches. You might conclude that including eggs in our Easter celebrations is a bit odd.

That's not necessarily true. There are still plenty of species in New Zealand that are making the most of the last of the good weather to make more babies. With some hunting, you can still find eggs out there in your garden right now (and not just chocolate ones).

Easter's also a good excuse for us to take a moment to explore all of the eggs that have been observed so far on iNaturalist NZ–Mātaki Taiao. If we look across all years and months, 327 iNat NZ users have made, and appropriately annotated, 1,235 observations of the eggs of 176 species. Impressive!

Which eggs have been most observed? You might think they'd be bird eggs, but no.

The first birds come in a #14 and #15 (blackbird and thrush eggs). The most observed eggs are of NZ praying manitis and the South African praying mantis. That's perhaps not surprising as they make obvious and durable egg cases in our gardens. After that there's the elephant fish, which makes distinctive egg cases that commonly wash up on NZ beaches. Next most popular are the eggs of four spider species, then the distinctive eggs of speckled welks that show up on beaches. Check out the current top 15 most observed eggs below.

Rank	Species	Observations
1	New Zealand Mantis (Orthodera novaezealandiae)	184
2	South African Mantis (Miomantis caffra)	79
3	Elephant fish (Callorhinchus milii)	67
4	Katipo spider (Latrodectus katipo)	39
5	False Katipo spider (Steatoda capensis)	36
6	Trapezoid Crab Spider (Sidymella trapezia)	30
7	the spider Steatoda lepida	23
8	Speckled Whelk (Cominella adspersa)	21
9	Monarch (Danaus plexippus)	19
10	Cart-Rut Shell (Dicathais orbita)	19
11	the shellfish Poirieria zelandica	18
12	Red-mouthed Whelk (Cominella virgata)	18
13	the limpet Siphonaria obliquata	18
14	Blackbird (Turdus merula)	16
15	Song Thrush (Turdus philomelos)	15

If we just zoom in to look at March and April, iNat NZ users have still found the eggs of 54 species. NZ's two praying mantis species still top the list, but we've also got three butterflies in the top 15, the cabbage whites, coppers, and monarchs, that are still laying eggs in Autumn. Also found in gardens now are the distinctive egg masses of green planthoppers and green vegetable bugs.

There are still a lot more eggs of NZ species to photograph and share on iNaturalist NZ–Mātaki Taiao. Getting lots of observations of eggs of any one species also fills in gaps in our knowledge of when in the year the species is egg-laying. They also reveal how that timing changes across New Zealand and might be shifting over time. Egg observations are hepful.

You can easily annotate observations with life stage on the iNaturalist NZ–Mātaki Taiao website. On any observation page, you'll find an Annotations section where you can annotate the observation with life stage, alive or dead, and sex. Annotations are also available from the Identify page when you're identifying others' observations. Even if you're not sure of a species identification, it's still helpful to add annotations to an observation.

You can see the results of everyone's hard work annotating life stages when you go to any species page on iNat NZ:

So Happy Easter everyone. I hope you manage to have as relaxing a break as you can while isolating in your bubbles. If you're out in the garden doing an Easter egg hunt, why not pull out the iNaturalist app and look for some real eggs too.

Guest post by Steve Kerr (@steve_kerr), Honorary Curator of Entomology (Diptera), Otago Museum.

Have you ever noticed those large dark flies with bright metallic blue abdomens? Have you ever noticed how there seem to be many flies that look like this and wondered what they are? Well, so have I and I feel your pain!

In NZ there are approximately 2,500 species of fly that have been formally described and named. In addition, it is estimated there may be as many as 2,000 more awaiting description. That’s a lot of flies.

Flies (order Diptera, meaning ‘two wings’) are grouped into families, and then further grouped into genus and species. These groupings are generally based on gross and microscopic differences, and many of them can be differentiated at a glance. But many others are not so easy to distinguish and the differences can be quite subtle. Which brings us back to the topic here. Why so many blue flies and how can they be distinguished?

The three groups that contain the majority of large blue flies are the families Calliphoridae (the Blow Flies), Tachinidae (the Bristle Flies) and Muscidae (the House Flies). Others can be seen in a few other families and we’ll get to those shortly.

The purpose of this short piece is to introduce the NZ Blue Flies and to give a handy guide as to how to tell them apart with the naked eye. Photos of these species are included to facilitate comparisons, but a quick search on the iNaturalist NZ–Mātakai Taiao website will bring up many more. So, let’s get cracking.

European blue bottlefly (family Calliphoridae)

The family Calliphoridae holds the majority of large, dark, blue-tailed flies (see Dear, 1985). By far the most common is the European blue bottlefly, Calliphora vicina. It’s a cosmopolitan species (that is, found worldwide) and is readily seen on a daily basis in any urban garden here in NZ, almost year round. C. vicina is relatively large (about 1–1.3 cm) with a medium gray thorax (mid-section) with thin black stripes, and a bright metallic blue abdomen (tail section) which is said to have a ‘tessellated’ appearance. Tessellated means having a ‘tile-like’ appearance, and in shifting light or from different angles the abdomen looks as if it is covered with many small overlapping silver, black and blue tiles; this in fact is the one feature which will ID this fly at a glance.

The adult fly when viewed from above is still quite distinctive (see below).

NZ Blue Blowfly (family Calliphoridae)

Another common NZ blue fly is the magnificent New Zealand Blue Blowfly (Calliphora quadrimaculata). I say magnificent because it is large … sometimes really large (approaching 2 cm) … and its abdomen is a shiny dark metallic royal blue. It is fairly common in forests and glades, often seen resting in the sun on tree trunks and on the leaves of trailside shrubs.

In addition to the distinctive solid metallic blue abdomen, C. quadrimaculata has a pair of distinctive bright orange-yellow spiracles (breathing pores) on the side of its thorax. For a better look at this stunning fly have a look at some close-up images on iNat NZ.

---

Xenocalliphora (family Calliphoridae)

Now things get a bit tricky. The family Calliphoridae has two other flies that look similar to both C. vicina and C. quadrimaculata. The differences are subtle and difficult to establish with the naked eye or in the field.

The first of these look-alikes is a small group of flies in the genus Xenocalliphora (see Dear, 1985). Several of these have bright blue abdomens (either glossy or tessellated with a silvery dusting) and they all have large, bright yellow-orange spiracles. In addition, the genus Xenocalliphora can be distinguished from all other New Zealand Calliphoridae by their yellow palpi (small antenna-like mouth parts or ‘feelers’) and the presence of numerous long glossy black bristles on the top of the head.

The eleven recognized species in the genus Xenocalliphora are not uncommon, but seldom noticed. They tend to be small to medium in size (7–9 mm) and are seen in a wide variety of locations including coastal forests and glades, on beaches and among stands of flax along lake margins (if you're in Dunedin, have a look around Tomahawk Lagoon).

Ptilonesia (family Calliphoridae)

The second Blue Fly look-alike in the family Calliphoridae is the genus Ptilonesia (see Dear, 1985). There is but a single species in this genus, Ptilonesia auronotata, and it is closely related to Xenocalliphora (Ptilonesia was once considered a sub-genus of Xenocalliphora). It is abundant on beaches and large numbers can be seen on the seashore intertidal zone between Brighton and Taieri Mouth south of Dunedin. Ptilonesia auronotata can be distinguished from all Xenocalliphora by the densely haired eyes, and black palpi. You may also notice that the hairs on the top of the head are short and sparse.

---

Blue tachinid flies

This brings us to a new family: Tachinidae, the Bristle Flies. The Bristle Flies, as their name suggests, sport long spiky erect bristles on their abdomens. In addition, they often have long, sometimes striking antennae. There are almost 200 described species in the family Tachinidae here in New Zealand. Observations on iNaturalist NZ–Mātakai Taiao show the extraordinary range and diversity of the tachinids.

As you may have guessed by now, some of the tachinids are blue! And as is often the case, they follow the same basic pattern seen in the calliphorids; they exhibit grey and sometimes delicately striped thoraxes and metallic blue abdomens.

A couple of good examples are shown below. They are quite similar in overall appearance to Calliphora vicina, rather uncommon, and often overlooked in the field. The best ways to distinguish them requires a close examination of the antennae and wing veins.

One of the commonest and most striking of the blue Tachinids is Pales marginata. It was first described by the eminent Otago entomologist (and former Otago Museum curator) Capt. F.W. Hutton. Pales marginata (originally Phorocera marginata) can be found throughout NZ in a range of habitats (Hutton, 1900).

The thorax is often a bright blue-green with several narrow black stripes anteriorly and a blue-green ‘scutellum’ (the shield-shaped structure at the base of the thorax). The scutellum generally exhibits a brown margin (see above). Another reliable distinguishing feature for all species in the genus Pales is the presence of very long antennae which, in the field, often stick straight out (see below).

---

Blue house flies

Not to be outdone, the family Muscidae (House flies) boasts a few Blue Flies as well. Here in NZ seventeen genera containing 145 species have been recognized in the family Muscidae. A small number are blue or at least bluish in colour and deserve mention here.

One of the most striking of these is Calliphoroides antennatis, so named because when first described in 1881, Hutton wrongly assigned it to the family Calliphoridae. By 1930 Malloch had recognized and moved the species into the family Muscidae.

Although Hutton listed it as rare, it is actually fairly common around Dunedin (they can be seen in reasonable numbers at Fraser’s Gully and along the trail from Bethune’s Gully up to Mt. Cargill). The fly can be easily distinguished, even by naked eye in the field, by its bright orange antennae and smoky dark wings. In addition, close inspection reveals consistently orange ‘knees’ and a yellow spot at the wing base (see below).

Another blue muscid is quite common on the beaches around Dunedin (Tomahawk Beach is ideal). It is fairly large and a bluish-grey in colour. Microscopic examination confirms it belongs in the genus Spilogona, but it has yet to be formally described and is nameless (although I like to call it the Blue Beach Muscid). The fly can be observed resting on piles of kelp on the foreshore and can be easily confused with Calliphora vicina.

One final blue Muscid is Australophyra rostrata (the black carrion fly; formerly known as Hydrotea rostrata). The fly is found throughout Australia and first appeared in NZ at least 100 years ago. Apparently it is still rather uncommon, although Otago Museum does have several specimens, collected in the Invercargill area in 1990. Pont (1973) noted that the fly is generally glossy black with a blue abdomen, although the Otago Museum specimens are a brighter blue all over—perhaps a bit of genetic drift over the many years that it has been here.

---

Blue flies in other families

Two last groups are shown below: one in the family Polleniidae and the other in Syrphidae.

The family Polleniidae is interesting because until just this year, all of the flies in this family (genus Pollenia, 35 species total) were considered to be part of the family Calliphoridae (Dear, 1985). After decades of debate, a recent phylogenetic analysis by Cerretti et al. (2019) resolved the issue, and a whole new family was erected.

Several of the NZ flies in the genus Pollenia have grey striped thoraxes and metallic blue abdomens, and look very much like small versions of C. vicina. The distinguishing features for Pollenia generally require microscopic examination, and I refer the interested readers here to Dear (1985) for a good treatment of the subject.

In contrast, the one blue fly in the family Syrphidae (Helophilus hochstetteri, shown below) is quite easy to spot and distinguish in the field, even from a fair distance. Like all flies in Syrphidae (the ‘Hover Flies’), Helophilus hochstetteri can hover over flowers and hold perfectly motionless like a humming bird. Its glaringly brilliant metallic blue abdomen shines like a jewel in the sun. It is quite common around Dunedin and can be seen visiting flowers in most any urban garden or field.

Concluding remarks

One has to wonder why so many flies in so many different families exhibit these seemingly constant colour patterns. The obvious assumption is that grey and black striped thoraxes and metallic blue abdomens impart some evolutionary advantage to the species. Perhaps at some time in the ancient past, a fly with these colours proved to be utterly unpalatable to other animals that might feed on it, and then over the eons other flies ‘adopted’ these same patterns as a means of protection. Such a thing has been proposed for the Viceroy butterfly in North America, which perfectly mimics the bitter tasting (or so I’ve heard) Monarch butterfly.

Of course, all of this is conjecture. It may be that we’ll never know. But there’s no denying that some of these flies are quite beautiful and special in their own ways, and the ‘wardrobe’ they’ve chosen is certainly popular!

---

Further reading

Cerretti, P. et al., (2019) Reclustering the cluster flies (Diptera: Oestroidea, Polleniidae). Systematic Entomology 44(4): 957–972.

Dear, J.P. (1985) Calliphoridae (Insecta: Diptera). Fauna of New Zealand 8: 1-88.

Hutton, F.W. (1900) Synopsis of the Diptera brachycera of New Zealand. Transactions and Proceedings of the Royal Society of New Zealand 1868-1961 (originally Transactions of the New Zealand Institute 1900); vol. 33, pp. 1-95.

Macfarlane, R.P., et al. (2010) Phylum Arthropoda, Subphylum Hexapoda. 2,500 speciesNew Zealand Inventory of Biodiversity; vol. 2, chapt. 9, pp. 233-467. Canterbury University Press.

Malloch, J.R. (1930) The calyptrate Diptera of New Zealand. Part I. Rec. Canterbury Mus. 3: 289-306.

Pont, A.C. (1973) Studies on Australian Muscidae (Diptera). IV. A revision of the subfamilies Muscinae and Stomoxyinae. Aust. J. Zool. Suppl. Ser. 21: 129-296.

---

---

When the cat's away, the mice will play, as the old saying goes. The equivalent for today is: when the people are away, how does nature play?

New Zealand, and much of the world, is in an unprecedented state with most people isolating indoors or making limited local movements. Our roads and centre cities are largely empty, keeping us safe, while brave medical professionals work hard to stamp out the Covid19 virus (if that's you, THANKS!!).

While we're self-isolating, how is nature reacting to our absence?

The short answer is that we don't know. This is a first for everyone, including researchers and the wild species living around us. You can help find out by keeping a watch on the nature in your neighbourhood, and sharing with you find on iNaturalist NZ–Mātaki Taiao.

It's also well worth putting our thinking caps on now: what species are most likely to change as a result of our self-isolation? This thinking can inform what species we focus our efforts on observing now, as well as after the Covid19 crisis has past.

I'm going to list a few things I've thought of below, while chatting with colleagues and other iNat NZ users. There will be undoubtedly be things we've not considered yet so please add your thoughts in the comments below.

Roadkill

Let's start with the obvious one. Few cars mean fewer dead animals on our roads. Roughly a million birds get killed on NZ's roads each year (that's extrapolating out per km roadkill rates based on my 17 years of road kill observations in and around Christchurch, which are consistent with roadkill rates in similar countries overseas). New Zealand's traffic volumes have plummeted during lockdown, and initial indications are that roadkill has too.

That's a good thing if you're a species likely to get hit by cars. It's a bad thing if you're a harrier hawk or black-backed gull supplementing your food supply with roadkill. It will also be interesting to see if car-wary species gradually start to spend more time foraging along the road edge.

Cafe lovers

New Zealand's city centres are largely dominated by smart exotic birds that scavenge our scraps, like house sparrows, starlings, and sea gulls. With all of the cafes and fast food joints closed, and all the shoppers gone, there's going to be a lot less easy people food about for our city's savy scavengers.

How are they reacting? I'm not sure yet. It looks like there's been a drop in gulls in central Christchurch, and there are no longer big groups of house sparrows around the city's cafes. Where have they gone? Have many of the gulls left the city for the farmland and estuaries? Have the house sparrows spread out through the suburbs?

Have you noticed any increases, or decreases, in these birds in your neighbourhood? As I write this, we've only had 14 observations of house sparrows and 26 gull observations made during #StayiNatHome. Don't forget to keep an eye out for what's going on with the house sparrows and gulls in your neighbourhood.

Predator un-control

As far as I've been able to learn, the mammalian predator control done by council staff in city parks and reserves has not been considered essential and has largely stopped. This means that if you've got your own backyard traps, now is an important time to keep them active. It also means that the lockdown might benefit mammalian predators.

Are you seeing more wild mammals about? Thankfully, we're out of breeding season for these species, so their populations won't boom after a month of no trapping. Still, the longer lockdown continues, the more they'll benefit.

Less mowing, more to see

With council lawn mowing and weed whacking reduced, it's going to be a good opportunity for weeds, and wild native plants, to increase. A month is not a long time for plant spread. Still, there may be more unmown and wild places in your neighbourhood where interesting plants can establish. Some of these might not have been documented in the wild in your neighbourhood (or in NZ) before. It is worth watching out for new wild things in previously mown places.

We're also coming into mushroom season and less lawn mowing will keep these mushrooms undamaged and obvious for longer across our cities. We've had 855 observations of 173 species of fungi so far during #StayiNatHome, which is phenomenal.

This could be an excellent time to document the mushrooms living in your neighbourhood. I'd wager that, with a little effort, you'll find fungi species that haven't been documented in your neighbourhood before. Maybe they'll be able to spread more spores this year too.

Domino effects

The trickier things to predict are the consequences of the obvious changes. If sea gulls and house sparrows largely abandon our city centres, what will take their place?

Josie Galbraith, at the University of Auckland, did some neat garden bird research, showing that the gardens that fed bread to house sparrows had fewer native birds like grey warblers (riroiro). Apparently, riroiro prefer to stay away from rowdy groups of bossy house sparrows.

If house sparrows scatter, will natives like grey warblers move in? We don't know, but it sure would be interesting to know if that's happening.

Now's the time to make regular counts of birds in your neighbourhood, and keep it going to see how those counts change after the end of lockdown when New Zealand tries to get back to normal.

Expect the unexpected

We can make some informed predictions of what's likely to happen, and focus on those species. It's also worth casting our attention wider for surprises. Nature has a habit of surprising us.

If you notice something new happening in the nature of your neighbourhood, please post observations of it to iNaturalist NZ–Mātaki Taiao. That could be wild species you've not noticed before. It could be species that were common getting harder to find. It could be species interacting in ways you've not noticed before, or behaving in novel ways.

While we're #StayiNatHome, keep your focus squarely on supporting your whanau. In your spare moments, consider casting your eye about for the other species living in your neighbourhood, and think about how they're reacting to this strange time that we're all living through.

(And, seriously, I'd love to hear your ideas in the comments about other ways that NZ nature might be reacting to our country-wide self-isolation.)

I'm often asked why people should share their nature observations on iNaturalist NZ–Mātaki Taiao, when we've already got lots of observations. We're approaching the milestones of a million observations, 20,000 species, and 20,000 observers across NZ. Most of those observations have been in NZ's cities and towns where most of us live.

So why bother sharing what's in your garden? There are lots of good reasons.

It's fun!

Humans are built for exploring. Our ancestors were extraordinary explorers. Fine-tuning all your senses to get out in nature and find new things is fun. iNaturalist supercharges that experience by making it quick to identify any species. It also makes it easy to find out what has been, and hasn't been, found in your neighbourhood.

What can you find that hasn't been found in your neighbourhood before, or hasn't been found in a long time?

The more species you learn to recognise, the more changes and dramas you'll notice happening around you. Your neighbourhood becomes filled with stories.

There are LOTS of new things to find

There are a lot of species in New Zealand, and we know very little about where (and when) most of them live, and about the species they interact with. There's a lot of this basic natural history still to uncover in Aotearoa. In fact, most of it is still waiting to be uncovered. This is not just in remote national parks—it's right at home in your garden.

So, while 20,000 species and a million observations might seem like a lot, it's not, at all. The New Zealand Organisms Register, which lists named species in NZ, has over 80,000 species listed (and less than 3,000 of those are bacteria, viruses, and protozoans). There's lots still to find, and new species are being added to iNat NZ all the time. Also, most species on iNaturalist have only been observed a small handful of times, so every new observation of these tells us more about them.

In just the last ten days of #StayiNatHome, nine species have been observed in our neighbourhoods that had never before been recorded in NZ on iNaturalist.

In Auckland, @heymilly found a weevil, @stephen_thorpe found a scale insect, and @marleyii found a lichen. Near Paraparaumu, @mattward made the first iNat NZ record of a native Pimelea herb. In Nelson, @obblue made the first iNat NZ record of a centipede species. In Christchurch, @jabba found a wild anise-scented salvia and @cooperj found a mushroom species. In Dunedin, @johnsteel found a wild succulent creeper. All of these are firsts for iNat NZ that were found in people's neighbourhoods.

That's just the new species for iNat NZ nationally. There are lots of first records for NZ suburbs and towns that have been made in the last ten days.

iNat NZ is your ticket to the age of discovery. Welcome aboard.

What's changing?

There's interest in NZ and around in the world in how nature is responding to this unprecedented global lock down. How will we know how nature is changing? Through lots of your observations from before, during, and after this crisis.

Observations of common species, like house sparrows and seagulls, are just as important to make as observations of rare things. It's the common species that are likely to change the most, since they were the ones that thrived in our towns and cities the way they were.

We'll write more in other article about what's likely to be changing. For now, keep in mind that your observations of common wild species are more important now than ever.

What's eating what, and when?

We need more observations of what species are eating what other species. We also need more observations on the timing of things. What is flowering and fruiting when? What's breeding or mating at the moment? Can you find juveniles at the moment or is everything an adult?

These details are important for understanding how nature is responding to changes in land use, invading pests, and, especially, to climate change.

You might have two commonly observed species in your garden, but you might be the first person to document one eating the other. Or, you might make a rare observation of a male and female mating (like @agoranomos did this week for mating earwigs in their Christchurch garden).

There are lots of new interactions to discover and document.

Learn what's common so you notice what's new

There's also a big picture here for New Zealand's biosecurity. New pests and weeds continue to slip through the official biosecurity net, despite us having some of the best biosecurity processes and staff in the world. Those pests that slip though are often first detected by members of the public.

The earlier these are noticed, the better are the chance that authorities can eradicate them from the country. Eradication means removing them all before they can establish and start damaging our primary industries and natural environment.

The more common species you recognise in your neighbourhood, the more likely you'll notice a new species when it first arrives. If you know about iNat NZ, you're also likely to whip out our iNat app and share a photo. Our experts will then promptly realise that its new and a potential threat. Biosecurity NZ and local council biosecurity staff will get alerted, alarm bells will ring, and another potential pest will get stopped in its tracks.

It all starts with you, and your human neighbours, getting to know more of your other neighbours (the other animals, plants, and fungi you live with).

If you do think you've found a new pest, photograph it, catch it if it's safe to do so, and call Biosecurity NZ on their free hotline at 0800 80 99 66.

All observations are useful

As long as your photos are good enough for iNat NZ users to identify the species, and as long as you let your smart phone share the date, time, and location of the photo, then you've made a useful observation. While some observations will be more important than others, they're all good. And, the more you observe, the more likely you'll make a super-exciting or super-important discovery.

iNat NZ does geoprivacy

Wait a tick, you might say. What if I don't want to tell the world exactly where I live? We've got you covered there too. Just select to obscure your observation, and you'll only show the world what town or city you're in, not exactly where you live. (When you set the geoprivacy to Obscured on the iNat app or iNat NZ website, you're fuzzing your coordinates to the size of a 10 mile square grid.)

So, what's in your garden?

There you have it. There are lots of reasons why it's useful to use iNaturalist NZ to observe the species in your garden, and inside your house. The more observations people make about New Zealand, and more we understand about New Zealand nature. And, the more fun we have!

So, stop reading this, grab the iNat app, and get yourself outside.

A common find in Kiwi gardens is the bumblebee. If you've got some pretty flowers in your garden, and it's a nice sunny day, or even an overcast mild day, there's a good chance you'll see a visiting bumblebee or three. Look again though, as there's more to bumblebees than fluffy neighbourhood pollinators.

Bumblebee 1, bumblebee 2, bumblebee 3, bumblebee 4

For a start, New Zealand has more than just one bumblebee species. There are four! Telling them apart takes a closer look at the colour bands. Check our the below illustrations by iNat NZ user @tony_wills.

Remember that you don't need to do the identifying yourself. Just take a good photo of a bumblebee showing the colour bands and upload it with the free iNaturalist app. The insect experts there will do the rest.

Which bumblebee is the most common?

By far the most abundant of the bumbled four is the buff-tailed bumblebee, Bombus terrestris. It's the only species with a black back at the back of its thorax. This band is yellow on the others. Currently on iNaturalist NZ–Mātaki Taiao, there are 2,111 observations of bumblebees in NZ and 73% of those are buff-tailed bumblebees. The buff-tail is so abundant that it's even managed to spread across the Tasman from New Zealand to Tasmania.

The two big fluffy bumblebees with a yellow band at the back of the thorax are Bombus ruderatus and Bombus hortorum. These have longer tongues than the buff-tailed bumblebee and are better at pollinating deeper flowers. The two species are pretty tricky to tell apart. Luckily, they're in their own subgenus from the other bumblebees and that subgenus is called Megabombus (which is a pretty spectactular name). You'll often find that your bumblebees will get identified by iNat NZ's insect experts to Megabombus, but they cannot confirm which Megabombus species from your photo.

(If you've got kids in your bubble with you during the Covid19 lockdown, see if they can invent some stories or drawings of Buff-tail and Megabombus the Bumblebees. Make sure that they remember that most bumblebees they'll see are females.)

There are no native bumblebees

Like the honeybee, all of NZ's bumblebees are northern hemisphere native species, introduced into New Zealand to provide pollination for our crop plants. Many of our fruit trees and vegetables depend on honeybees and bumblebees for pollination.

Despite New Zealanders' affection for honeybees and bumblebees, it's worth remembering that native plants don't need bumblebees and they don't need honeybees. Also, many of our weeds are also dependent on honeybees and bumblebees to set seed (for example, gorse and Scotch broom, two of our worst woody weeds). A bumblebee in your garden can be a great thing for your fruit trees and vege garden but it's not necessarily a good thing in a national park. (The answer to most questions in ecology is "it depends".)

Which bumblebees are in your garden?

There's still a lot we don't know about bumblebees in NZ, including why some species are more abundant than others, and how this differs through the country. For example, so far on iNaturalist NZ 84% of the 541 bumblebee observations in Wellington are buff-tailed bumblees, but only 61% of the 684 bumblebee observations in Canterbury are buff-tails. Why? We don't know.

Also, there's a great deal of alarm overseas about the decline of pollinators like honeybees and bumblebees, especially in Europe and North America. As far as we can tell, there's no equivalent decline happening in New Zealand. Having said that, there's also not a lot of good data here.

You can help, by spending a little time in your garden watching the bumblebees.

Praying mantises are fantastic sit-and-wait ambush predators. Their forelegs are massive and reach out to grab unsuspecting prey. In doing so, mantises help to keep other insect populations in check. There could well be some living out in your garden right now. Next time you're outside, have a look and let us know what you find with the iNaturalist app.

A tale of two mantises

It gets more interesting than that though. Did you know that there are now two praying mantis species wild in New Zealand? There's our home grown native, Orthodera novaezealandiae, and a larger South African species, Miomantis caffra. Miomantis caffra, was first found in NZ in 1978 by Auckland school boy, Richard Cuthbert, at his home. That's citizen science and StayiNatHome long before either were a thing.

Below are a couple of observations from #StayiNatHome over the past week.

Our native mantis is in decline

If you are living in the north of New Zealand, there is growing concern that our native mantis is now getting hard to find. Miomantis is most likely the mantis you now have in your garden. The perception is that Miomantis has replaced Orthodera in open areas like urban gardens. Because of this, the Department of Conservation now lists our native Orthodera as “At Risk-Declining”.

How the two species interact, and how and where Miomantis caffra is spreading, are still areas of active research. Your observations from your garden can help scientists to better understand what is going on.

University of Auckland Masters student Murray Fea did his thesis research on these two species in 2011. His climate modelling indicated that the South African should do just fine throughout much of the South Island, as well as the northern areas where it now thrives. It's worth watching out for in the south.

Murray also found that our male native mantises find the female South African mantises even more attractive than female native mantises. Unfortunately, the female South African mantises have a habit of eating their Kiwi amorous sutors. Murray has speculated that this might be the main reason why Orthodera novaezealandiae has been declining in the parts of NZ where Miomantis caffra is abundant. (Watch who you try to mate with.)

Mantises in our regions

We've just had a look at all of the praying mantis observations on iNaturalist NZ–Mātaki Taiao to look at how the percentage of mantises that are our native species changes throughout the country. Here's what we found:

Region	Orthodera (NZ)	Miomantis (SA)	%NZ
Northland	18	57	24
Auckland	87	267	25
Waikato	32	44	42
Bay of Plenty	19	54	26
Gisborne	6	25	19
Hawke’s Bay	19	34	36
Taranaki	24	44	35
Manawatū-Whanganui	36	93	28
Wellington	191	24	89
Tasman-Nelson	4	49	8
Marlborough	12	59	17
Canterbury	290	8	97
West Coast	0	2	0
Otago	20	0	100
Southland	0	0	-
TOTAL	779	801	49

There are some surprises in there. Apart from Wellington, the South African mantis now dominates all of the North Island's regions. In Tasman-Nelson, we've had very few native mantises reported. Alarmingly, of our 53 observations from that area, only 4 were of our native mantis. Gulp. The West Coast and Southland look to be terrible places for all mantises. If you find any there, please share them on iNaturalist NZ.

In better news, despite the modelling projections, our native mantis continues to dominate in Canterbury and Otago. That may change though, as the South African mantis hasn't been in Canterbury for long (our earliest observation is 2004, and the only one until 2016), and it's yet to be observed on iNaturalist NZ in Otago.

Also, what's going on in the Waikato? There's a much higher proportion of native mantises in the Waikato than any of the adjacent regions. Could it be an unexpected upper North Island stronghold? If you're in the Waikato, please let us know what praying mantises are living in your gardens.

We need your observations

We need more observations of mantises from Kiwi gardens, from everywhere, but especially those regions with few observations. If you want a break from your bubbles, why not pop out into your garden for a mantis hunt. The nymphs and adults can be pretty cryptic. They're good at lurking secretively. However, the egg cases are often easy to find, on warm walls, tree trunks, and other flat vertical surfaces.

Thankfully, the two species are easy to tell apart, as eggs, nymphs, and adults. If you find a mantis, you can just photograph it and share it with the iNaturalist app and our insect experts will ID it for you. Or, if you want to try it yourself, check out the table of features below.

Orthodera (NZ)	Miomantis (SA)
Green body with bright blue and yellow markings under forelegs	All yellow-green, sometimes dark orange to pale straw coloured
Wide shield-like back (thorax)	Narrow “waste” at thorax
Adults a little smaller than Miomantis and female abdomen not nearly as swollen.	Adult female with massive egg-filled abdomen
Egg case narrow, tall, and without a protruding pointed tip	Egg case broad and rounded with a protruding pointed tip

Finally, since we're now on the slow slide towards winter, there's another interesting aspect of mantis biology worth sharing. In my garden in Christchurch, I've watched the female NZ praying mantises lay her eggs and stay near them guarding them for as long as she is able, before finally succumbing to the winter cold.

If you find mantises at home, please photograph them and share them with the iNat app, but also be sure to take the time to watch them and soak in the insect dramas going on every day in your garden. If you're lucky like @jacqui-nz, you might even see one get eaten by a kingfisher!

Read more

Ramsay, G. W. 1984. Miomantis caffra, a new mantid record (Mantodea: Mantidae) for New Zealand. New Zealand Entomologist, 8:102–104.

Kiwi's have been self-isolating in our bubbles since Wednesday, and been busy supporting our families and friends online and putting teddy bears in our windows. Through it all we've kept on connecting with nature, and with each other, on iNaturalist NZ–Mātaki Taiao.

iNat NZ usages has increased this week

We've just had a first look at the numbers of observations and identifications made on iNat NZ since Aotearoa went into self-isolation. To our big surprise, the numbers are up. In the six days between the start of our bubbles on Wednesday morning to right now (10 pm on Monday), 431 observers have made 2,485 observations of 1,057 species in their homes across New Zealand. Those observations have been identified by 206 identifiers.

Those are amazing numbers, considering this strange and stressful time. In the week before we went into our bubbles, 347 observers made and uploaded 1,921 observations of 1,030 species, supported by 205 identifiers. That means in our six days in bubbles there's been a 24% increase in observers and a 29% increase in observations. Kiwis are getting out into their gardens and finding nature.

We're also 50% up in observers and 40% up in observations since this time last year, when 286 observers made and uploaded 1,784 observations of 968 species. That's less surprising as the iNat NZ community has continued to grow.

Check out some of the amazing finds from NZ homes

Below are some of our highlights of the finds this past week. You can explore them all, and more, on the stats page of our StayiNatHome project.

@faye444 found an odd spiky-leaved holly that got the plant people in Christchurch talking. @reinderw figured out that it was the holly cultivar, Ilex aquifolium 'Ferox Aurea'. Check out Faye's observation for her photo of the crazy leaves.

@skinkysam in Taranaki photographed a colossal wasp on her window. It's longer than her finger! The species is Norton's giant ichneumonid wasp (Megarhyssa nortoni), an introduced parasitoid of wood borers. This giant wasp was introduced on purpose to New Zealand in 1964 to control the pest borer Sirex noctilio in Pinus radiata plantations. It does its job well, only attacking this pest.

@karutahi photographed a gloriously purple flowered glory bush (Tibouchina urvilleana), wild on the edge of west Auckland. As pretty as it is, New Zealand doesn't need another escaped wody garden plant becoming a weed. It's one to look out for in wild Auckland.

@jovirens found an elegant, velvety purple fungus on a tree in Dunedin, called silverleaf fungus (Chondrostereum purpureum).

Up in Whangarei, @tutukiwi has "decided that to assist with sanity during the lockdown, I'll record everything that I can around my home". He's found some amazing things so far, from a kereru perched in the sun to an impressive looking adult tiger beetle.

Over in Okato, Taranaki, @emily_r photographed a crazy spiked larva on a leaf in a garden. It was identified as a larva of the steelblue ladybird (Halmus chalybeus). The larva and the adult of this species are both amazingly looking but completely different.

@aalbertrebergen photographed a partly albino grey warbler/riroriro in a garden in Waikouaiti. Riroriro are one of New Zealand's smallest birds and are hard to photograph, yet @aalbertrebergen managed to get a whole series of impressive photos of this rare colour morph.

Perhaps the most impressive find of the week so far has been a white-banded house jumping spider (Hypoblemum griseum), photographed by @christopherstephens. We've had a string of photographs of this species this week, from houses throughout New Zealand. What makes the photo by @christopherstephens so extraordinary is that this tiny little spider has taken down an adult porina moth that must be at least five times its size. Check it out!

Finally, you should admire this cute litte moth fly that @ryvesie photographed in north Auckland. We're still not sure what species it is but it sure is fluffy.

Let us know what you can find living in your home and garden.

Stay safe, stay home, & keep exploring.

#StayiNatHome