Posted on 04/07/2008 2:49:22 PM PDT by blam
Birdfeeders Can Both Help And Harm Bird Populations
Attractive feeders can become ecological traps, encouraging birds to settle in an area that cannot support them once supplemental feeding has stopped. (Credit: iStockphoto/Andrew Howe)
ScienceDaily (Apr. 7, 2008) — Millions of people tend bird feeders in their backyards each year, often out of a desire to help the animals. But a new survey of research on the topic finds that feeding may not always bring a positive outcome for the birds.
In many cases, bird feeding was shown to have immediate positive outcomes. A number of studies indicated, for example, that chicks which were given supplemental food were far more likely to fledge than those that were not given extra food.
But feeding is a complex business and can lead birds to make poor decisions later in life. Attractive feeders can become ecological traps, encouraging birds to settle in an area that cannot support them once supplemental feeding has stopped. In those cases, feeders create a population level that cannot be sustained by natural levels of food.
There are also times when feeding can affect the timing of a bird's life in unexpected ways. One study, for example, showed that Florida scrub jays breeding in suburban habitats with access to supplementary food breed earlier, but find themselves out of sync with natural food items which are important when rearing nestlings. This means the extra food can lead to a decrease in breeding success rather than an increase.
Surprisingly, the research team also found evidence in several studies which indicated that the flurry of activity caused by bird feeding does not increase the birds' risk of predation. Counter-intuitively, the presence of feeders has been associated with lower levels of predation by domestic cats.
Robb and Bearhop say that the wide variety of outcomes they discovered in their work point to a real need for more comprehensive research on the topic. Although bird feeding itself may seem somewhat marginal, an incredible number of people do it. Surveys conducted in the US in 2003 revealed that more than 43 percent of those asked give birds some kind of food. In the UK, surveys indicate that as much as 75 percent of the general public feeds the birds.
"Changing the natural dynamics of food supply at such a large scale represents a major intervention in the ecology of birds," says Robb. "But we have a remarkably limited understanding of the impacts of bird feeding."
There have been relatively few studies conducted which incorporate urban and suburban yards, for example, and very few studies have run for more than one or two years or considered more than one species. Robb and Bearhop plan to continue their investigations at field sites in Northern Ireland and Cornwall.
"It seems highly likely that natural selection is being disrupted," Robb says.
Published as a Frontiers in Ecology and the Environment e-View paper the meta-analysis led by Gillian Robb (Queen's University Belfast, UK) and by Stuart Bearhop (University of Exeter, UK) reviewed results from more than 50 pieces of research conducted over the last decade.
Adapted from materials provided by Ecological Society of America, via EurekAlert!, a service of AAAS.
Thanks for the article, blam.
I just took down my bird feeders. I don’t know how I could have been so insensitive to these creatures of the wing.
I’m just going to shoot them so they don’t have to suffer anymore.
[An allegory for Welfare]
Aw hell. My guns, my birdfeeders, my two-cycle outboard.....can I do one friggin’ thing right?
Add to list of world's problems that are meowmeow's fault:
Bad bird judgment
My feeders attract rats. So, recently I put a laser on my .22 air rifle because in dark conditions, my scope was not good enough.
I love to paint a laser on a rat, almost as much as I love killing them.
"Whack the birds
Tuppence a round..."
Beautiful birds - like beautiful flowers - trick us into taking care of them. It’s a good thing.
I keep a little patch of weeds to draw mourning doves. They eat the seeds.
The neighbors hate me.
Good thing. The world never seems to run out of rats, does it?
Only the small birds, finch, orioles, wren. The jays can’t deal with the finch feeder. Neither can the squirrels and woodpeckers. Win-win
LOL, it’s amazing those poor little birds have survived this long!
Just another article to put “man” in a bad light. Take it with a grain of salt.
I see a host of city ordinances coming on. Birdfeeders must be regulated.
I'd like to see that study. We enjoy watching the birds, but took our feeders down because the neighbor's cats were spending too much time underneath them.
***Attractive feeders can become ecological traps, encouraging birds to settle in an area that cannot support them once supplemental feeding has stopped.***
Oh, dear, an ecological trap. If only the birds could fly away! Poor birds, stuck in a vortex of free seed and suet, that, if it were to disappear, would cause widespread death and calamity. Oh why won’t they fly away and be FREE???
I don’t have to worry about that.I can’t keep the damn squirrels out of my feeders.They always figure out a way to get to them no matter what I do.One day I did get a payback.One of them had tried to scurry up a pole I just set up and it had fire ants crawling on it.All of a sudden it was a squealing and flipping around as he was getting bitten by the ants.It was so funny,I wish I had my video camera handy.
Could you plant a bigger patch next year? The doves here are eating all my sunflower seeds. And I've got a whole yard full of weeds they won't touch.
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