Subject: [Tweeters] Fwd: Feeding Birds
Date: Feb 16 02:42:50 2012
From: Rob Sandelin - nwnature1 at gmail.com


Feeding birds changes the population dynamics and also territories. Feeding
increases the amount of surviving fledging species which utilize feeders
such as seed eaters like Chickadees. Does having higher levels than normally
sustainable populations of certain birds have affects on other birds or
organisms? Probably, but exactly what those are have not been studied.
Birds are both competitors, consumers and prey and local population booms
due to feeders contribute to all of the ecological equation. Studies show
Birds adjust their territories around a feeder. Does having a constant
easily attainable food resource cause competition and territory issues in
birds? Yes, but again these have been poorly studied. Bird feeders do
attract bird predators, they also attract and support non-target animals
such as rats, mice and squirrels. Does this food resource change non-target
animal populations? Are their more rats around because of feeders?

So bird feeders almost certainly change populations, behaviors and ecology.
We just don't know exactly the dimension of the change because such study is
very difficult to quantify. For example, (and these numbers are made up to
illustrate the idea) if the natural density of chickadees is 6 birds per
acre, and these birds eat 40 lbs of insects during a year in a natural
situation with no feeders, does having a feeder reduce their overall
consumption of insects? and does this reduction compensate for the increased
consumption by a larger artificially sustained population? If predation on
insects is changed, how does affect everything else?

Since territory size decreases with the number of local birds (more
birds=smaller territories for each bird) does a feeder compensate for this?
Is there a selection advantage in certain birds which allow them more
frequent access to the feeder resource and is this carried over in
generations? Are birds evolving to better exploit feeders? Do feeder birds
have certain competitive behaviors at feeders which carry over to non-feeder
situations? The questions are endless. And unanswered.

The density of feeders in a particular area (bird foraging territories can
encompass many yards in a suburban environment), is also a factor. There
may be 2, 3 even 6 or more feeders in the foraging territory of a
particular group of birds. How does this adjust over space and population?

The huge increase in bird feeding over the past 30 years has been a major
undocumented experiment in avian population ecology and one for which we
know very little about the affects.

Rob Sandelin
Naturalist, Writer, Teacher
Snohomish County

_____

From: tweeters-bounces at mailman1.u.washington.edu
[mailto:tweeters-bounces at mailman1.u.washington.edu] On Behalf Of Karen
McMains
Sent: Thursday, February 16, 2012 1:19 AM
To: tweeters
Subject: [Tweeters] Fwd: Feeding Birds


Are we helping or harming?
This is a response to someone who was feeding birds and found Pine Siskins
dead.

---------- Forwarded message ----------
From: Karen McMains <karen.mcmains at gmail.com>
Date: Thu, Feb 16, 2012 at 12:45 AM
Subject: Feeding Birds
To: WHATCOM BIRDERS <whatcombirds at lists.wwu.edu>



We are diligent feeders, and negligent feeder-cleaners, and have seen no
problems; we live next to Padden Creek, so perhaps the concentration of
birds and variety of habitat makes our laziness ok? We have seen no sick
birds. (Or perhaps we are feeding the raptors?)
P.S. we have tons of birds, and only one suet basket, and one seed feeder.
We would love advice if you all think we are doing something wrong. No dead
birds, lots of the usual suspects such as juncos, towhees, varied thrushes,
robins, finches, the once-daily flock of bushtits, now the grackles
(growl!), nuthatches, woodpeckers (can't tell hairy from the other kind),
the occasional flicker, and a Cooper's swoops through and gleans lunch every
once in a while. Tons of siskins these days. We leave our windows
deliberately dirty (Ha! nice excuse!) and have few collisions, like one
every couple of years and not fatal at that..
All advice welcome!
Karen

On Wed, Feb 15, 2012 at 9:01 PM, Adena Mooers <adenaf
<mailto:adenafiddler at gmail.com> coliiddler at gmail.com> wrote:


We found a dead PISI under our feeder this week and saw another one that
looked a bit sick sleeping in a strange place mid day. I think we will take
our feeders down. Ours are cleaned with bleach regularly but I still fear
that we concentrate feeding birds in one area so that they pass disease from
one to another.