Editor´s choice - Automated tracking of wild hummingbird body mass

Submitted by Johan on 30 January 2015.

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A male ruby-throated hummingbird (Archilochus colubris) approaches an artificial feeder outfitted with a passive-integrated transponder reader and a precision electronic balance. As this bird, which is implanted with tag “384.199C8436E6”, perches to feed its ID is detected and its mass is automatically recorded. At the time of this photo (9:25 AM EST on June 6, 2014), the bird weighed 2.65 g. This individual was initially tagged as a juvenile (> 2 months of age) on August 11, 2012, making it almost 2 years old at the time the photo was taken.

This is a very interesting and valuable study evaluating the usefulness of automated RFID (radio frequency identification) technology for the recording of hummingbird mass over short (foraging bout), daily and seasonal time scales. In addition to providing a clear presentation of the methods, the study also gives impressive and exciting examples of results confirming that this technology is safe and potentially very powerful for obtaining repeated body mass data from the smallest birds. The detailed data showing mass changes of hummingbirds during foraging bouts (seconds), during the day (hours) and during the pre-migratory period (days) are indeed highly fascinating!

Thomas Alerstam, Editor in Chief


Below you can see a short video of a hummingbird feeding on one of the specially designed feeders.

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Editor´s Choice