[BCNnet] results of chickadee survey

[Judy Pollock]

The results of the Audubon-BCN Census study of chickadees were released
today.   The gist of it is that we found three large holes in our map of the
data where no chickadees at all were sighted, and in other areas numbers of
chickadees were low or low to normal.  I have pasted in a lengthy press
release
below with the thought that you may find some of it interesting.  Some of the
information may be new to you, and you can take a look at the quotes we put in
to get a sense of our take on this story - and let me know how you think we
did!  Watch the Trib and Sun-Times tomorrow for our story.

We had a great many participants, including those who responded to an
announcement on BCNnet.  This allows us to see and describe things at a level
of accuracy that no one else is able to.  After researching this press release
and finding out how little people really know about the impacts of this
disease
on wild birds, it is clear to me that the information we are generating is
very
useful and much needed.  If you would like to be involved in organizing the
next steps of this study, please let me know.

Study Finds Chickadees Gone in Large Areas
West Nile Threats to People and Wildlife

A study of results gathered by 74 trained monitors throughout the 6-county
Chicago region found that the black-capped chickadee, a common bird of our
woods and towns, appears to have been completely extirpated in large areas. 
This is the first study that focuses attention on the effect of West Nile
disease on songbirds, and it raises questions about the effects of chemicals
used to control mosquitoes. Previous reports have focused on crows, blue jays,
hawks and owls.  Experts fear that there could be many other bird species
whose
populations are also suffering. 

The map of the survey results tells a dramatic story.  In three areas of our
region - parts of eastern Lake County, some south suburbs, and a large area of
northern Chicago and nearby suburbs - chickadees were almost completely gone.
Thirty trained volunteer monitors spent 101 hours searching 31 sites with good
chickadee habitat and found only two chickadees. Judging from previous October
data, more than 120 chickadee sightings would be expected for this level of
effort at these sites.  The findings in these three areas are in marked
contrast to the rest of our region.  In all other areas surveyed, chickadee
numbers were reported as low or average (ranging between one and 23 per
survey); in these areas very few observers found no chickadees.

The mosquito season is now waning. West Nile concerns will not be in the
forefront until spring 2003. Audubon recommends carefully weighing the
needs of
birds in developing next year’s pest control strategies.  “The populations of
many bird species are already suffering. We should plan so that next year we
don’t add further stress by unwise or excessive spraying of pesticides. The
spray kills fish and many species of insects, disrupting the chain of life
that
birds and we ourselves depend on,” says Stephen Packard, Audubon director for
the Chicago region. 

The map of the area where chickadees are missing in the north suburbs
coincides
with the map of the highest incidence of human West Nile Virus cases. 
Twenty-two chickadee searches totaling 81 hours turned up only two birds in an
area of approximately 120 square miles  extending from northwest Chicago
through Des Plaines to Northbrook, and east to the lakefront from Winnetka
south to the northernmost neighborhoods in Chicago.  Bird Conservation Network
(BCN) Census coordinator Lee Ramsey pointed out: “These are impressive and
troubling results.  We are encouraging trained monitors to check their areas
frequently and report data on all bird species.” Many observers reported
having
seen dead or ill chickadees in early August, when thousands of dead crows were
being picked up by municipalities in this area. Early August was also the date
many gave of their last sightings of chickadees in the area.

A second area where no chickadees were found is in the south suburbs,
encompassing Calumet City, Park Forest and Crete. Finally, no chickadees were
found in five surveys in Zion and Lake Forest.  For the rest of the region,
chickadees were reduced in numbers but present; only three of 42 surveys
outside these areas failed to turn up chickadees. Numbers were low at the
points surveyed in DuPage and Northwestern Cook County, and average to low in
points in southwest Cook, western Will, Kane, McHenry and western and southern
Lake County.

The chickadee is a common year-round resident of our area, frequently seen in
woods and neighborhoods.  Normally this bird is highly visible in the fall, as
it travels in large family groups searching for food in trees and shrubs, and
at bird feeders.  The chickadee can have up to 12 young in a nest and may have
two broods in a summer, so our area normally sees great numbers of these birds
in fall. When birds are affected by a disease such as this one, it is expected
that resistant birds will in time replace the ones killed by the disease.
Chickadees that survived and reproduced in other areas will likely disperse
back into most areas in the coming months or years.

Study participants commented on low numbers of many other bird species. One
hundred and twenty four species of native birds are known to have been
affected
by the virus.  Judy Pollock, Audubon’s Project Manager, commented, “We still
don’t know the fate of many of the birds that breed here in summer and which
were preparing to migrate when the disease hit. For example, one observer
commented on the disappearance of red-headed woodpeckers from her property. 
Another threat to this declining species really concerns me. Illinois is at
the
population center for this bird, and its numbers are plummeting due to habitat
loss.”  

According to Scott Wright, Branch Chief, Disease Investigations, USGS National
Wildlife Health Center, “This type of study is exactly what is needed to
advance our understanding of the workings of this disease, and it is admirable
that the BCN Census is undertaking it.  From this study, it appears that we
should take a close look at the survival rate of chickadees and some of our
other songbirds. We have much more to learn about the impact of this
disease on
wild birds.”

Both West Nile disease and some mosquito control methods are threats to humans
and many other mammal and bird species. Audubon supports wise mosquito-control
and encourages that the planning for 2003 start now. 

Trained and experienced bird monitors of the Bird Conservation Network Census
conducted the study.  A tradition exists among birders to collect data that
will help with bird conservation, and the results of this type of a study are
highly regarded.  Audubon and the Bird Conservation Network operate a
year-round bird census in our area.  This is the second study of the impact of
West Nile Virus by this group. The first study documented that crows had
entirely disappeared from the north suburban area, and found reduced
numbers in
some other areas. 

Material from various sources
about the study  and West Nile virus

"Communities can greatly enhance their ability to eliminate the threat of
disease-carrying mosquitoes by replacing chemical larvicides with
bacteria-based products, which kill mosquitoes, but not beneficial insects,
such as dragonflies; amphibians; and fish that prey upon mosquitoes. By
eliminating pools of stagnant water in parks and at dumps, and by allowing
some
drainage of dammed areas, communities also decrease the available breeding
ponds for mosquitoes. Homeowners can help; cleaning out gutters and removing
tarps, tires, and other objects where water can collect also prevents
mosquitoes from reproducing. Aerial spraying of pesticides has been shown
to be
less effective than targeted, localized spraying. If pesticides are to be
employed, a focused, limited, and timely response works best." 
Frank Gill, Senior Vice President for Science
Audubon (National Audubon Society)

“Several species of Culex mosquitoes are suspected as the main vectors of this
disease.  One, Culex restuans, feeds only on birds.  Another, Culex pipiens,
feeds primarily on birds but may also bite mammals.  This mosquito is very
adaptable, breeding in catch-basins, gutters, and other urban stagnant water
all around the world. You might wonder how mosquitoes get to birds through all
those feathers - they bite birds around the eyes and feet.”
Robert Novak
Professional Scientist
Center for Economic Entomology, Illinois Natural History Survey

“West Nile Virus has patchy distribution in its effects humans and wildlife.
Within those patches, bird mortality can be extremely high.”
Scott Wright
Branch Chief, Disease Investigations
USGS National Wildlife Health Center

“Thanks to dedicated volunteers, this region has many years of data to use to
analyze the current troubling situation. The upcoming Christmas counts, spring
counts and nesting bird censuses will be valuable in trying to make sense of
what’s going on.”
Alan Anderson
Cook County Coordinator, Breeding Bird Surveys
Chicago Audubon Society

Phone numbers of study participants who can talk about the lack of birds in
their yards and neighborhoods of various communities are available on request.

Additional information:

Observers were asked to look for chickadees on October 10, 11, 12 and 13 in
their yards or in woods where they would expect to find them, and to record
the
number of chickadees they found and the amount of time spent looking.  They
were also asked send data from the same spot in previous Octobers, if
available, and if not, to estimate whether the number of chickadees they found
was high, average or low.  Finally, respondents who found no chickadees in a
location were asked when they last saw them.

The study results cannot be ascribed to habitat differences: the older, wooded
neighborhoods, forest preserves, and parks of these areas are optimal
chickadee
habitat.  Nor can they be ascribed to time of year: comparisons were made to
previous years’ October data to determine expected numbers.

ps - Another fact I uncovered in my conversations about this is that research
is being done now which suggests that no crows that are exposed to this
disease
survive it. 

Judy Pollock
bobolnk@ix.netcom.com