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Technology automatically tracking feeder visits

Small transmitters and RFID technology help us learn about bird feeding behaviors.

FeederWatch researchers and students at Cornell University are gaining an unprecedented amount of information about the feeding behaviors of our favorite backyard birds by fitting wild birds in the Ithaca, New York, area with small transmitters called PIT (passive integrated transponder) tags.
Watch a short video about the project.


The small transponders measure 2 mm by 12 mm and weigh less than 0.1 grams! Tags are attached to leg bands.

PIT tags and RFID technology

PIT tags are attached to leg bands--one tag per bird. These lightweight tags weigh less than 0.1 gram (for comparison, a Black-capped Chickadee averages approximately 11 grams). Each tag transmits a unique identification number to a reading device that is built into a specially "wired" bird feeder containing an RFID circuit board and antenna. Every time a bird with a tag visits the RFID feeder, the bird's identity is recorded along with the date and time of the visit.

Since initiating a pilot study of the technology in November of 2009, more than 120 Black-capped Chickadees, White-breasted Nuthatches, House Finches, and Tufted Titmice have been tagged and more than 2.5 Million visits to the wired feeders have been recorded!

What is RFID?


A tagged Black-capped Chickadee feeding at a bird feeder equipped with an RFID circuit board.

Radio Frequency Identification (RFID) is the technology used to read the PIT tags and automatically record the feeding behavior of the birds in our study.

RFID is a widespread technology that is used for a variety of commercial purposes. It is used to track boxes in warehouses and is even being integrated into passports! You may be most familiar with PIT tags as the "microchips" that veterinarians implant in pets so that lost animals may be identified and returned to their owners.

Dr. Eli Bridge of the University of Oklahoma is the engineering guru behind the development of the low-cost RFID readers. Learn more about Eli's inexpensive RFID readers on his web site.

What can we learn about bird behavior through the use of RFID?

RFID is providing incredibly detailed information about the behaviors of our tagged birds. We are using the technology to answer a variety of questions:
When do birds feed during the day?
How is feeding behavior affected by weather or competitors?
What influence does feeder location (edge vs. interior of a forest) have on feeding behavior?
How are feeding patterns influenced by gender and dominance status?
And over time, we can track survival in our study populations.

RFID Projects


Graduate student, Jon DeCoste, uses RFID feeders to study movements in sick and healthy House Finches.

Survival & Feeding Behavior. Many aspects of the daily lives of our common feeder birds remain a mystery. RFID technology is allowing us to better understand relationships among birds and between birds and their environment. David Bonter (Leader, Project FeederWatch) and Ben Zuckerberg (Assistant Professor, University of Wisconsin) initiated the RFID study of common feeder birds at several study sites in the Ithaca, New York, area to answer many of the questions outlined above.

David and Ben are quantifying feeder visitation rates by individual birds and studying how feeding behavior changes in relation to weather and land cover. The research involves numerous undergraduates from Cornell University, including Samantha Dean, Luke DeFisher, Sean Donegan, Sarah MacLean, and Carolyn Sedgwick.

The research focuses primarily on Black-capped Chickadees, Tufted Titmice, White-breasted Nuthatches, and various woodpeckers (Downy, Hairy, Red-bellied).

House Finch Disease. Jon DeCoste, a graduate student in Cornell's Ecology and Evolutionary Biology program, is examining various aspects of how the bacterium Mycoplasma gallisepticum infects wild finches, often leading to the "House Finch Eye Disease."

Jon is using a network of RFID feeders in the Ithaca, New York, area to study movements in both sick and healthy House Finches and to quantify where and how long birds feed. Jon predicts that sick birds will be less likely to move large distances and will spend more time at supplemental feeders than healthy birds.

Special thanks to Wild Birds Unlimited

The wonderful folks at Wild Birds Unlimited have provided tremendous support for this research by supplying free, high-quality bird seed. Please visit the WBU online store and say 'thanks'!

How can I help?

We designed and built our own RFID readers, which greatly reduced the financial barriers limiting this kind of research. But our projects still require funds to purchase PIT tags, batteries, and other equipment. To support this research, please donate to FeederWatch and type "RFID" in the Comments box under "Additional Information." Donations labeled "RFID" will only be used to support the RFID research.

RFID information, news & updates

The inexpensive RFID readers used in our research were detailed in the March 2011 issue of the Journal of Field Ornithology, along with a review article of how RFID can and has been used in ornithological research.

Visit Eli Bridge's RFID website for more details on the low-cost readers and RFID technology.

Read a list of scientific papers featuring RFID in ornithological research.

The RFID project is featured on All About Birds.

A short article on our research appeared in the 2010 issue of Winter Bird Highlights, an annual publication of Project FeederWatch that is mailed to all project participants in the fall.