From their event page: 

Join Fairmount Park Conservancy and Troy Bynum of TB Wildlife Photography LLC on Sunday, April 27 from 1 1 AM–1:30 PM for an introduction to the City Nature Challenge and the iNaturalist app followed by a guided bird hike in West Fairmount Park.

The City Nature Challenge (CNC) is an annual event where cities around the world compete to see who can record the most wildlife observations (plants and animals) on the iNaturalist app. While there is a friendly competition component of the CNC (click here to see how Philadelphia ranked last year), the observations made are also really important in helping scientists to track changes in wildlife populations over time.

We’ll start inside with a brief intro on how to use the iNaturalist app. Troy, a skilled wildlife photographer and owner of TB Wildlife Photography LLC, will also go over some helpful tips and tricks for using your phone’s camera outside. From there, we’ll head out on a hike where Troy will guide us as we look and listen for birds in both open fields and more forested areas. As we hike, participants are encouraged (but definitely not required) to use the iNaturalist app to take pictures of plants and animals to add to Philadelphia’s City Nature Challenge totals.

After the hike, we’ll return to Ohio House where staff will be available to assist with uploading any observations to iNaturalist. We’ll also have a monitor setup so we can see in real time all of the observations made throughout the park and city.