Thanks, Bill, for keeping us up to date on this.
Cheers,
Bill Hull
Cincinnati

On Tue, Jun 24, 2008 at 5:03 PM, Bill Whan <[log in to unmask]> wrote:
>       For readers who have been concerned with birds feeding on other birds,
> as nature has demanded for millenia, here is news that our species has
> been killing birds in a misguided attempt to thwart nature. The folks at
> USDA have provided final numbers of cormorants killed during 2007 in an
> effort to control damage alleged to other bird species and vegetation in
> Ohio.
>       The cumulative take for 2007 was 3,689 double-crested cormorants in
> Ohio, during 13 "damage control activities," eleven conducted by our
> Division of Wildlife, with two others conducted cooperatively by ODOW,
> the USF&WS (Ottawa NWR), and the USDA's Wildlife Services. This compares
> with 5,868 taken in 2006.
>       The report mentions the culling's effects on other species. We are
> invited to rejoice that 41% of other waterbirds stayed on their nests
> while cormorants were being shot. The DOW estimated that disturbed birds
> were absent from nests for approximately 7.4 +/- 0.7 minutes on average
> during these absences. A number I'd like to see documented.
>       Authorities estimated that decreases in nest numbers for cormorants,
> great egrets, and great blue herons decreased ~25% this year because of
> severe thunderstorms with high winds, not because of cormorants;
> black-crowned night-herons, which nest later, were less affected, and
> suffered deficits of only 4%. Still, the numbers of great egret and
> great blue heron nests counted in 2007 were said to be within 10% of the
> mean estimates for the previous five years. Great egret nest numbers
> remained stable at Turning Point Island in Sandusky, where BCNH nests,
> after increasing 50% in 2006, decreased by 40% in 2007, "perhaps
> demonstrating the variability of Night-heron nest numers at that
> location." GBH numbers at Green Island fell by 30% in 2006, but
> increased by 50% in 2007.
>       The report is said to demonstrate that the cumulative impact of
> cormorant culling is "biologically insignificant to nonexistent" on
> non-target species. It does not mention that culling has not
> benefited co-nesters' populations, either; i.e., the numbers of great
> blue herons, great egrets, black-crowned night-herons, and the small
> numbers of other allied species has not increased with culling of DCCO,
> but has rather remained more or less stable for many years. In other
> words, our wildlife professionals have killed thousands of cormorants
> over the past three years, but have nothing to show for it in terms of
> increased populations of co-nesters. In fact, in spite of growing
> cormorant numbers, no diminution of co-nesters has been demonstrated
> over the past 12 years, except for the storm-related numbers of both
> cormorants and their co-nesters last year.
>       You may draw your own conclusions by asking for the "Monitoring Report
> for Environmental Assessment for Reducing Double-crested Cormorant
> Damage in Ohio" from USDA/APHIS, 6929 American Parkway, Reynoldsburg, OH
> 43068.
> Bill Whan
> Columbus

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