birds or butterflies?

[Barb Beck]

Don,
I am sure it depends on the bird and butterfly but we had one case where
birds did a number on leps.  During the last big forest tent caterpillar
(Malacosoma disstria) outbreak it looked like the trees around our cabin had
been sprayed... ours maintained their leaves.  All of the trees 100 feet or
more from our place were stripped.  We have two large bird feeders, lots of
suet out,  and a pack or hungry Chickadees and other feeder birds who did a
very thorough job of rooting out the cocoons for these leps.  Of course
later the caterpillars moved to our trees too but at least they were not hit
as badly as were those of our neighbours.  Likewise in town our bird feeders
seemed to have protected our trees from the caterpillar some of  those of my
neighbours were infested.

BTW the outbreak was quite bad - I have a lot of bird recordings I made that
summer that sound like they were recorded in a pretty good rain.  It was
raining but not drops of water.

Anytime you muck with things there are winners and losers.  We put out bird
food - the birds win and the leps lost.  Are other species of leps impacted
by the birds during the winter - probably but it was not as obvious.

Barb Beck
Edmonton, Alberta, Canada


-----Original Message-----
From: owner-leps-l at lists.yale.edu [mailto:owner-leps-l at lists.yale.edu]On
Behalf Of Rudy Benavides
Sent: January 21, 2002 7:51 PM
To: don.benson at attcanada.net
Cc: leps-l at lists.yale.edu
Subject: Re: birds or butterflies?


Don,

I monitor a few nestboxes at a location that has a 70 box trail and is
approx. 13,000 acres in size.  As Norbert pointed out, the biologist
responsible there has also deemed the place to be at capacity for nest
boxes. The main competition for nesting boxes here has always been between
bluebirds and tree swallows, but with a smattering of a few other sp. of
cavity nesters for occupants.  After a brood fledges from the nestbox we
remove the old nest left behind.  Since we record information on broods, we
also check the nest contents for things like unhatched eggs, dead birds,
etc. which may remain buried at the bottom of the nest.  I usually find the
debris of stuff left behind to be interesting as well.  This year I had a
combination of tree swallows and bluebirds occupying the boxes that I looked
after.

In addition to all the feathers that tree swallows use to line their nests,
I found small insect parts (legs and other appendages),eg., from
grasshoppers and other inverts (such as cranefly and midge remains).  But in
the bluebird nests there were the usual insect bits and pieces of hard
leftover material, including the head and thorax (or a part thereof)of a
caterpillar or two....in each bb nest box.  I can't provide an id, but the
boxes are generally located in meadows not too far from the edge of forests.
  And I suspect these lep. larvae came from forest/edge species, but that's
just a guess based on observing the bbirds repeatedly flying from the boxes
to the forest during the nesting period.  Anyway, I think you have to be
pretty good to id the cat. remains that have been drying inside a hot
nestbox as long as possibly 4 weeks.  If anyone has any suggestions along
these lines (testbook, methodology, etc), I would certainly appreciate
hearing from you as the upcoming season is right around the corner.

I guess my point is, don't just count on tree swallows occupying the boxes.
There are other cavity nesters that will use them as well and they also
enjoy the juicier tidbits that are available out there, so consider
placements, my suggestion, if possible.

Rudy

Maryland
-----------------------------------------------------
>From: "Don Benson" <don.benson at attcanada.net>
>Reply-To: don.benson at attcanada.net
>To: leps-l at lists.yale.edu
>Subject: birds or butterflies?
>Date: Mon, 21 Jan 2002 15:28:14 -0800
>
>A group of us are trying to enhance a 14 hectare site in Richmond, British
>Columbia. The birders are putting up bird boxes for tree swallows.  The
>butterfly people are trying to attract butterflies by planting larval
>foodplants and nectar plants. Eventually we hope to introduce anise
>swallowtails and purplish coppers to the site.
>
>Will the tree swallows eat the butterflies?  Are we working at cross
>purposes by putting up bird boxes in an area where we are trying to create
>habitat for butterflies?
>
>Don Benson
>
>
>



>Don Benson wrote:
>
> > A group of us are trying to enhance a 14 hectare site in Richmond,
>British
> > Columbia. The birders are putting up bird boxes for tree swallows.  The
> > butterfly people are trying to attract butterflies by planting larval
> > foodplants and nectar plants. Eventually we hope to introduce anise
> > swallowtails and purplish coppers to the site.
> >
> > Will the tree swallows eat the butterflies?  Are we working at cross
> > purposes by putting up bird boxes in an area where we are trying to
>create
> > habitat for butterflies?
> >
> > Don Benson
> >
> >
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