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Oregon State University researchers have good news for the well-meaning masses who place bird feeders in their backyards: small songbirds that visit feeders seem unlikely to develop an unhealthy addiction to them.
“There’s still a lot we don’t know about how intentional feeding might induce changes in wild bird populations, but our study suggests that distributing food to small birds in winter will not increased reliance on human-supplied food,” Jim said. Rivers, wildlife ecologist at OSU College of Forestry.
The results of the research, involving black-capped chickadees fitted with radio frequency identification tags, were published in late June in the Avian Biology Journal.
Around the world each year, hundreds of millions of people produce food for wildlife, 50 million of them in the United States alone, resulting in a $4 billion industry based on food, feeders and other accessories. But this popular pastime has long raised concerns about making animals dependent on human-provided food, especially during winter and other parts of the annual cycle that require animals to spend a lot of money. ‘energy.
“The widespread 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 said. “On the negative side, it can facilitate disease transmission, restructure local communities and change migratory behavior, for example. There is even some evidence that it can lead to changes in the structure of birds’ beaks. On the other hand, it can also have positive effects, such as improved body condition, winter survival, and reproductive ability.
Bird feeding is especially popular in northern latitudes, especially in winter when cold, stormy weather and minimal daylight reduce the time birds have to locate natural foods. But not much is known, Rivers said, about whether the birds become addicted to the food their human friends throw at them.
“The only manipulation experiment to test this, also using the black-capped chickadee, was 30 years ago,” he said. “He found no reduction in apparent survival after the removal of bird feeders that had provided supplemental food in winter for 25 years, leading to the conclusion that bird feeding did not promote survival. addiction to feeders.”
A black-capped chickadee with an RFID chip visits a feeder equipped with a microchip reader. Photo courtesy of Jim Rivers/OSU
Rivers and colleagues studied the feeder use habits of 67 black-capped chickadees subjected to one of three flight feather trimming treatments: heavy trimming, light trimming, or, as a control, no trimming. Experimental removal of primary flight feathers is an established technique for altering wing loading and increasing the energy costs of flight, Rivers said.
Birds were tagged with RFID chips, and 21 bird feeders along a 3.2 kilometer riparian zone were filled with sunflower seeds and equipped with chip readers to measure feeder visits by tagged birds .
The scientists chose the chickadee because it is a small songbird (it weighs less than half an ounce) that frequents bird feeders during the winter throughout its range; has high daily energy needs; and typically takes a seed with each feeder visit, allowing for a clear measure of feeder visitation rate.
“It’s an ideal species to assess how energetic challenges lead to behavioral changes in feeder use during the winter,” Rivers said. “Our study found that experimentally handicapped chickadees, those experiencing high flight costs, did not increase their feeder visitation rate.”
Instead, the feathered birds actually decreased their feeder use for a few weeks – perhaps to reduce exposure to predation – but after that they used the feeders at levels similar to those of the birds. uncut control birds. The researchers looked at the number of feeder visits, the number of feeders used, and the timing of feeder visits and found little difference between cut and uncut chickadees.
“The reduced-feathered tits reducing their use of feeders compared to control birds suggests that foods in the environment – such as seeds, berries and small invertebrates – were sufficiently available to compensate for increased flight costs and their reduced feeder usage,” says Rivers. “It is clear that the chickadees in our study did not increase their visitation rates or increase their reliance on supplemental food during a period when they could have benefited most.”
Thanks to Oregon State University for providing this news.
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