[BCNnet] new WNV report

[Judy Pollock]

Here is some information from an Audubon press release about a report
analyzing
this year's Christmas bird count numbers.  This is a good time to think about
how to encourage local officials to plan an ecologically sound response to any
outbreak next summer.
------------------------------------------------
Comparisons of 2002 numbers with an 11-year average for eight Christmas count
areas show dramatic declines in the populations of three local bird species.  
Numbers of American crows were down by 81%, blue jays by 66%, and black-capped
chickadees by 35%. The counts were held in Cook, Will, Lake, DuPage, and Kane
counties in Illinois, and Lake County Indiana. The resulting data were
analyzed
for a report to Audubon by William Moskoff, Professor Emeritus of Economics
and
Biology at Lake Forest College, with review by Jeffrey Brawn of the University
of Illinois and Douglas Stotz of the Field Museum. Significant declines in
chickadee numbers were not recorded during previous outbreaks of West Nile
virus (WNV) in eastern states.

In the Barrington and Evanston-North Shore areas, numbers of both species were
down by 90% or more from the 10-year average. Crow and blue jay numbers are
down in every count. Chickadee numbers are lowest in the areas that had the
heaviest concentration of human cases of West Nile Virus: the north and south
suburbs.  The four counts that included parts of those areas with the high
concentration of human cases had an average 47% drop in chickadee populations,
while the other counts had a drop of 37%. 

Numbers were not down for all species. The study also examined other
year-round
resident landbirds: mourning doves, American goldfinches, downy woodpeckers,
Northern cardinals, and white-breasted nuthatches.  All of these species
showed
increases over the 11-year average on the 2002 Christmas Count.  Moskoff’s
analysis ruled out normal annual fluctuation in the numbers (due to such
things
as food supply, weather, and number of observers) as a cause of the
declines in
crows, blue jays and chickadees. 

An article that will provide additional details of Moskoff’s work will be
published in an upcoming issue of Meadowlark: a Journal of Illinois Birds. 

This study was not designed to test whether the decreases were due to disease,
to pesticide spraying, or to other factors. Moskoff was careful to point out
that there is no scientific proof that these bird declines were due to West
Nile virus. But three factors - the striking declines in some species, the
lack
of declines in other species with similar diets and habits, and the
concentrations of the declines in the areas where humans were hardest hit by
West Nile - strongly suggest that the disease is the cause.  

"Next summer will be a time of stress for recovering bird populations, and
Audubon urges municipalities to take the time now to carefully plan their
response to future virus outbreaks,” said Audubon’s director Stephen Packard.
Spraying for adult mosquitoes is one of the least effective methods of disease
prevention and the most disruptive to wildlife and ecosystems. Audubon urges
that other, safer, more effective measure be used first. “That will take some
planning and foresight,” Packard said. The most effective and least
ecologically detrimental measures include reducing standing water sources such
as uncleaned gutters through public 
education and applying bacterial larvicide to stagnant water with
“wrigglers” -
mosquito larvae that have not yet hatched into their adult stage. Spraying
with
the chemicals typically used by municipalities kills many fish and insect
species, disrupting the balance of nature by reducing natural predators of
mosquitoes such as dragonflies and eliminating the food sources of
insect-eating birds. 

Joel Greenberg, Duane Heaton, Ralph Herbst, Libby Hill, David Johnson, Dennis
Kania, Jim Kelly, Carolyn Marsh, Jeff Sanders, Joe Suchecki, and Geoff
Williamson kindly made thier Xmas count data avilable for this report, and
Eleanora DiLiscia and Marj Lundy also helped with the research.

Judy Pollock
Evanston (Cook)
bobolnk@ix.netcom.com