As part of Boston’s City Nature Challenge weekend, participants in the April 28 Bird Walk will have the option to use the iNaturalist phone app to record wildlife data in the field and submit observations. This event is open to guests of all ages, and you’ll need a smartphone with a camera to participate in the citizen science portion. All necessary iNaturalist training will be provided. Arnold Arboretum of Harvard University, 125 Arborway, Boston, MA 02130, USA Meet at the Arborway Gate.