We assessed the feasibility of marking ruby-throated hummingbirds (Archilochus colubris) with radio frequency identification (RFID) tags. We trapped 27 hummingbirds at feeding stations on a 2.0-ha study site. We subcutaneously implanted each hummingbird with a 0.067-g RFID tag and released it at the capture site. We deployed RFID transceiver systems at 5 feeding stations and electronically monitored tagged hummingbird activity continuously on the study site through 3 summers. Post-release relocation rate exceeded expectations based on previous leg band recovery data, and bird activity data acquisition was consistent and reliable and required minimum labor.