From: Jay Mann <mannj@southern.co.nz>
Newsgroups: sci.bio.food-science
Subject: Re: Food Alert
Date: 2 Jun 1998 22:34:59 GMT

David Kendra <dkendra@mr.net> wrote:
: Brian Sandle wrote:
[snipped]

:> Travelling across the South Island of New Zealand near sunset is notable
:> for its near total lack of flights of birds in the farms. Probably the
:> herbicides have removed the weed seeds. And are the bugs gone?

: I am sorry to read about the lack of birds.  I love listening to birds during
: my early morning walks.  I guess the chemicals we use in Minnesota aren't as
: nasty as those in New Zealand.  Our bug population hasn't declined at all
: either!

And of course the recent major changes in introduced pests have no effect on
our New Zealand bird life?  The common wasp entered about ten years ago and
has spread without any natural constraints.  They really enjoy our southern
beech forests, where a bark-tapping aphid secretes a sugary solution in such
quantities that it pours down the trunks.  This secretion used to be a major
food source for other insects and presumably for some birds, but the wasps
have grabbed most of it.  In wasp-infected areas of "bush" (light forest),
the weight of the wasp population exceeds that of the weight of all other
animal species combined.  In a lot of our Canterbury areas, a mid-summer
walk is accompanied by the ominous drone of wasps from start to finish.

Then there are possums, which seem to keep adapting to still more native
trees as food sources.

Before we start worrying about the effects of herbicides used on, what, 10%
of NZ land?, we should consider the effects of massive wasp populations
competing for food supply with native birds and, for all I know, killing the
birds directly by stinging them.

Jay Mann <mannj@southern.co.nz>