The City Nature Challenge is an annual global citizen science BioBlitz event coordinated by the California Academy of Sciences and the Los Angeles County Natural History Museum. It was first run in 2016.

Participating cities “compete” to see who can make the most observations, find the most species, and engage the most observers in discovering the nature that lives in and around their city.

A 'BioBlitz' is a citizen science, data collection based event, where experts and members of the community work together to discover and document as many species as possible within a specific location and time period.

BioBlitz events help us create snapshot into the range of biodiversity within the city, and provide the community meaningful opportunities to help survey biodiversity and increase connection to nature.

BioBlitz events, including the City Nature Challenge, contributes to delivering City of Melbourne’s Nature in the City Strategy, to create and maintain healthy ecosystems and thriving biodiversity within the city.

Mammals

Mammals that live in the city include those you might see often like possums or rats, but there are also many mammals we rarely see, such as micro-bats and native rats. A good way to find animals like these is to look in places where they might eat or sleep; watch tree hollows at dusk, look for burrows or holes under your deck or in your garden, or look out for other signs that these mammals live in your area.

Tracks, scats and signs

Look for tracks in the mud or dirt. Notice the shape and arrangement of paw-prints or footprints, and follow their trail. Some key things to look for: Do you see two feet or four? Are the footsteps close together (maybe indicating a smaller animal) or far apart (a bigger animal)? How many toes are there? Where did the tracks come from and where do they lead? Can you see any other signs that animals have been around? Can you find any feathers, fur, nests or scats? Different animals leave scats of different shapes! For example, possum poo looks very different to bat, or bird poo.

Birds

Many birds start singing very early in the morning. Dawn is the best time to sit quietly somewhere and listen to the birds waking up. Grab a pair of binoculars and look in shrubs, in branches of trees, or in other sheltering sites. If you hear a bird, follow the sound and try to see who is making all of the noise. You might be lucky to find birds nesting in tree hollows, in nests they have built in trees, or in shrubs around your garden. A good way to attract birds to an area is to have a bird bath.

Reptiles

Different types of skinks, turtles, snakes and lizards might inhabit our city. Watch out for reptiles seeking shelter in leaf litter, under logs and rocks and in long grasses. A good way to find lizards is to look under piles of material in your backyard: look under tiles, bricks and wood to see if there are any lizards hiding there.

Frogs

We have ground frogs and tree frogs in Melbourne. Many of our frogs live in or near aquatic environments, such as dams, ponds, wetlands and creeks, and areas with native rushes and sedges. Look out for tadpoles in water in local parks and in your garden. Many frogs are heard before they are seen, and many of them spend the night calling to each other. The best time to look for frogs is after dusk, if you hear a frog follow the noise and see if you can see them on reeds or on the banks of wetlands.

Insects

Scientists have identified about a million species of insects so far, and estimate that there may be up to 30 million. Insects differ from other animals in that they have three pairs of legs. With or without your magnifying glass, scour the ground, under bark, in leaf litter, search among the flowers or even look in your compost bin for insects.

A good way to see which insects are using your yard is to place biscuits in a jar lying down in the garden on a sunny day, return in a few hours and see what has been attracted to the bait! Another good way to watch for bees and butterflies is to sit and watch flowers on a sunny day, as these insects need to visit flowers to get nectar for food. We don’t know a huge amount about the insects in our city, so you might even discover a new species.

Water

Life depends on water. Look around you. Do you see a waterway, pond, lake or the ocean? What varieties of plants and animals do you see in or near the water?

The first Melbourne BioBlitz was held in 2014. More than 700 people participated, helping us record more than 3000 sightings and photographs. We are thrilled that so many people were interested in connecting with biodiversity in the City of Melbourne. Thank you to all who participated.

Since then, we have held various BioBlitz events including the HollowBlitz, Waterbug Blitz and the Microbat BioBlitz.

In 2023 we were excited to be participating for the first time in the City Nature Challenge – a global bioblitz event.