Black-topped Chickadee at bird feeder.
Oregon State University scientists have some excellent news for the well-meaning masses who position bird feeders in their lawns: The little songbirds who check out the feeders appear not likely to establish an unhealthy dependence on them.
“There’s still much we don’t know about how intentional feeding might induce changes in wild bird populations, but our study suggests that putting out food for small birds in winter will not lead to an increased dependence on human-provided food,” stated Jim Rivers, an animal ecologist with the OSU College of Forestry.
Findings from the research study, which took a look at black-capped chickadees equipped with radio frequency recognition tags, were released today (June 28, 2021) in the Journal of Avian Biology.
Around the world each year, numerous countless individuals put out food for wildlife, consisting of 50 million in the United States alone, driving a $4 billion market based upon food, feeders, and other devices. But the popular activity has actually long raised issues about making animals depending on human-provided food — specifically throughout winter and other parts of the yearly cycle that need animals to use up a great deal of energy.
“The extensive and widespread nature of people intentionally feeding wildlife can have unintended consequences for free-ranging animal populations, and those consequences are best documented in birds,” Rivers stated. “On the negative side, it can facilitate disease transmission, restructure local communities, and alter migration behavior, for example. There’s even evidence that it can lead to changes to birds’ bill structure. On the other hand, it can also have positive effects, such as enhanced body condition, wintertime survival, and reproductive output.”
RFID-chip-banded black-capped chickadee on chip-reader-equipped feeder. Credit: Photo supplied by Jim Rivers, OSU
Bird feeding is specifically popular in the northern latitudes, especially throughout winter season, when cold, rainy weather condition, and very little daytime minimize the time that birds have for finding health foods. But very little is understood, Rivers stated, about whether birds end up being reliant on the feed their human pals throw out for them.
“The only manipulative experiment to test that, also using the black-capped chickadee, was 30 years ago,” he stated. “It found no reductions in apparent survival after removal of bird feeders that had provided supplemental food in winter for 25 years, leading to the conclusion that bird feeding did not promote feeder dependency.”
Rivers and coworkers studied the feeder usage routines of 67 black-capped chickadees subjected to among 3 flight-feather-clipping treatments: heavy clipping, light clipping or, as the control, no clipping. Experimental elimination of main flight plumes is a recognized method for changing wing loading and increasing the energy expenses of flight, Rivers stated.
The birds were tagged with RFID chips, and 21 bird feeders along a 3.2-kilometer riparian zone were filled with sunflower seeds and geared up with chip readers to determine feeder sees by tagged birds.
Scientists picked the chickadee due to the fact that it is a little songbird (it weighs less than half an ounce) that often visits bird feeders throughout winter season throughout its variety; has high day-to-day energy requirements; and generally takes one seed at each feeder go to, permitting a clear procedure of feeder visitation rate.
“It’s an ideal species for evaluating how energetic challenges lead to behavioral changes in feeder use during winter,” Rivers stated. “Our study found that the experimentally handicapped chickadees, those experiencing elevated flight costs, did not increase their rates of visitation to the feeders.”
Instead, feather-clipped birds really reduced their feeder usage for a number of weeks — perhaps to minimize direct exposure to predation — however after that utilized the feeders at levels comparable to the unclipped control birds. The scientists took a look at variety of feeder sees, variety of feeders utilized and timing of feeder sees and discovered little distinction in between clipped and non-clipped chickadees.
“Feather-clipped chickadees reducing their use of feeders relative to control birds suggests that foods in the environment — like seeds, berries and small invertebrates — were sufficiently available to compensate for increased flight costs and allowed them to cut back on feeder use,” Rivers stated. “It’s clear that the chickadees in our study did not increase their visitation rates nor did they increase their reliance on supplemental feed during a period when they might have benefited from it the most.”
Reference: 28 June 2021, Journal of Avian Biology.
DOI: 10.1111/jav.02782
Janel Lajoie and Lisa Ganio teamed up with Rivers on the research study. Lajoie made a master’s degree from the OSU College of Forestry and Ganio leads the Department of Statistics in the OSU College of Science.
Funding the research study were the Department of Forest Ecosystems and Society and the College of Forestry at Oregon State University, with research study materials contributed by Global Harvest Foods, Kay Home Products and Perky-Pet, Inc.
