The City Nature Challenge has been running since 2016 when it was started as a competition between Los Angeles and San Francisco to record urban biodiversity using the iNaturalist platform. During a 7-day period, over 20,000 observations were made of 2500 species by over 1,000 participants. In 2017 the number of cities involved grew to 16, in 2018 it grew to 68 cities from various countries. In 2019 there were 159 participating cities where over 35,000 people uploaded just shy of 1 million observations over a 4 day period.
Although Australia has the 4th highest number of observations on iNaturalist, on iNaturalist, it only joined the City Nature Challenge in 2020. To become a participating city requires a significant investment of time and effort, with organizers beginning preparations from as early as September the previous year. In 2020 several groups stepped up., wth 4 Australian cities are participating in the challenge for the first time check out the projects from last year:
City Nature Challenge 2020: Greater Adelaide (SA)
City Nature Challenge 2020: Sydney (NSW)
City Nature Challenge 2020: Geelong (VIC)
City Nature Challenge 2020: Redlands City (QLD)
The event was a huge success with an increase in observations and users across Australia during the 4-day period of the event Friday, April 24th through to Monday, April 27th, well above previous records, see the full stats for 2020 here
This Year the challenge will again run for 4 days from Friday April 30th through to Monday, May 3rd inclusive, with many more areas within Australia taking part its a great time to join in. if you are not in an official area or an area using another platform you can join the "Global Project". Any observation taken during this time that is recorded within the area of a City Nature Challenge project will be included in the challenge results. Following this, through to May 10th is the identification period (observations can be uploaded during this time as well). This time is provided to allow participants to identify as many species as possible from the 4 day challenge period. The challenge is to see which cities can make the most observations, record the most species and engage the most people.
Of course, for South Australian residents, the City Nature Challenge 2021: Greater Adelaide is the project to join. This has been organised by the three amigos below Stephen Fricker (@stephen169 left), Seamus Doherty (@seamus-doherty center) and Larissa Braz Sousa (@larissabrazsousa right). you can keep up to date with the team on Twitter and Facebook @GAINbioblitz)
The Greater Adelaide organisers team. @stephen169 (left), @seamus-doherty (center) and @larissabrazsousa (right)
The area included (following local government area boundaries) extends from the Murray River mouth, across Lake Alexandrina, up the river, around Murray Bridge, across toward Mount Torrens, up past Kapunda, across to the north of Thompson Beach and along the coast back to the Murray River mouth (see map on the main page).
April has been a challenging month since the City Nature Challenge began as this coincides with the Northern Hemisphere Spring. Unfortunately for us, this means the challenge will occur in Autumn and we will miss out on recording the tremendous emergence of life in our Spring. However this shouldn't dissuade us, as in 2019 and 2020 Cape Town, South Africa recorded both the most observations and most species in the challenge, beating out many cities experiencing Springtime.
we all look forward to the challenge so in the meantime, sign up for the Greater Adelaide project and follow the Facebook page.
edited post by @cobaltducks,
City Nature Challenge: Background & First Australian Cities first published, January 14, 2020
Yellow-tailed Black-Cockatoo
Leafy Seadragon
Neophoca cinerea observed by David Muirhead 
Common White-faced Heron
#ownpic
