SUMMARY:
Rosenberg et al (2019)
“Decline of the North
American Avifauna”,
is reporting a decline in
57% of the bird species
in North America.
They estimated
a net loss of nearly
2.9 billion birds
in North America
since 1970.
They urge us
to remedy
all the threats,
claiming all were
“exacerbated by
climate change”,
and we must
stave off the
“potential collapse
of the continental
avifauna.”
The New York Times
piled on with:
“Birds Are Vanishing
From North America” .
Scientific
American
added:
“Silent Skies: Billions of North
American Birds Have Vanished.”
But when you examine
the study methodology,
the bird count is grossly
inaccurate.
At best 1% of birds
are counted and the
remaining 99% are
estimated !
Bird "counts"
are only done
at roadside stops,
for only three minutes,
based mainly on hearing
bird calls, rather than
actually seeing the
birds that are counted !
That methodology is
ridiculously inaccurate,
even though the name
sounds very scientific:
The US Geological
Breeding Bird Surveys
( BBS ).
This was just another
fake study intending
to blame fossil fuels,
CO2 emissions and
climate change for
something bad
that may, or may not
be happening.
A "bird apocalypse"
based on haphazard
data collection
is an imaginary "crisis".
Blaming climate change
makes even less sense !
DETAILS:
Population estimates
for most land birds
are based on data
from the US Geological
Breeding Bird Surveys
( BBS ).
Each survey route
consists of 50
roadside stops,
each a half‑mile
apart.
At each stop,
observed birds
are recorded for
only three minutes
-- with the
overwhelming
majority of birds
being heard,
and not seen.
Many birds
can be missed
in such a short
period of time.
And only at
roadside
locations.
Each year,
on about
the same date,
the BBS survey
is repeated.
BBS "models"
assume that
each stop
will only count
birds within a
400‑meter radius.
And that assumes
exceptional hearing
abilities of the
observers !
Each BBS route
surveys perhaps
1% the region’s
landscape.
Starting with 1%,
based on not very
accurate observations
( mainly bird sounds )
means that the
remaining 99%
has to be guessed !
What could possibly
go wrong with that
methodology ?
That would be like
measuring the
temperature of 1%
of the world's oceans,
and then guessing the
temperatures for the
remaining 99% !
The "models"
that are used
for the guesses
include several
assumptions
and adjustments.
For example,
in 2004,
researchers
estimated there
were 6,500,000
Rufous
Hummingbirds.
In 2017, the
estimate was
21,690,000 !
That tripling
of the "count"
was mostly due
to changes in data
"adjustments" !
Hummingbirds
are very difficult
to detect.
We've got two
hummingbird
feeders hanging
from the house
just outside our
bedroom window
-- the birds
are hard to see,
except when
they are feeding
less than ten
feet away
from our eyes
( when hovering,
near their food,
and not moving ).
For the
BBS survey,
each actual
hummingbird
observation
used to be
multiplied
by 25x.
See one
hummingbird
in three minutes,
then the "model"
assumes there were
24 others not seen !
Recent surveys
are even worse,
multiplying by 64x.
See one
hummingbird
in three minutes,
then the "model"
assumes there were
63 others you did not see !
63 "virtual hummingbirds" !
If no hummingbirds
are seen the next year,
then 64 hummingbirds
from the prior year
are assumed to
have died.
The one real bird
and the 63 imaginary
hummingbirds
are assumed dead !
That is not real science !
The greatest population
losses were claimed for
warblers and sparrows,
where actual observations
are multiplied by 4x to 10x.
These data collection
methods are inaccurate,
and not repeatable, with far
more "virtual birds" than
actual birds heard, or seen.
Rosenberg et al
summarized
their study with
one sentence:
“Cumulative loss of nearly
three billion birds since 1970,
across most North
American biomes,
signals a pervasive
and ongoing
avifaunal crisis.”
I've got a better summary:
These are dishonest
leftist "scientists"
using junk science
( science fraud ),
who began their "study"
knowing they were
going to demonize CO2
and climate change.
There's also
good news from
recent studies
in National Parks
that use a much
greater density of
observation points,
and not only
three minute
roadside counts.
For the 50 species
they observed,
all but 3 populations
were stable.