[Tweeters] Barred Owl dead from rodenticide

J. Acker owler at sounddsl.com
Sun Dec 17 14:26:54 PST 2017

On July 1, 2016 I banded a recently fledged female barred owl (Strix varia).
She was one of two nestlings from a well-established pair near Port Madison,
on Bainbridge Island, WA and was part of my ongoing 20+ year study of barred
owls. I research their breeding success, mate fidelity, territory size,
diet, longevity, and dispersion. Young owls have a high mortality rate, so
after I band them, I rarely hear of them again, and if I do, it is because
one has been reported dead, usually from a vehicular collision. This bird
proved no exception, except that the cause of death was a new one for me:
Brodifacoum. Because the bird was banded, I was contacted by the USDA
Forest Service in Corvallis, OR where a necropsy had been performed at
Oregon State University. Exposure to the rodenticide Brodifacoum was
identified, and appeared to be the cause of death; hemorrhage was observed
in several major organs. The owl was otherwise in good condition, and there
were no significant injuries or trauma apparent that might have resulted in

Young barred owls typically disperse from their natal area in August, and
this bird was no different. However, what was unusual was the distance she
flew. Her body was discovered in Mapleton, Oregon, on November 9, 2017,
some 250+ miles from where I had banded her. She was 20 months old, and
would have nested this spring.

Brodifacoum (d-CON is an example) is highly lethal to mammals and birds, and
extremely lethal to fish. It is commonly sold and purchased by home owners,
businesses and farmers who are concerned with rodent problems. It is a
<https://en.wikipedia.org/wiki/Bioaccumulation> cumulative poison, due to
its high lipophilicity (stored in the fat cells). A poisoned animal will
suffer progressively worsening internal bleeding, leading to
<https://en.wikipedia.org/wiki/Shock_(circulatory)> shock, loss of
consciousness, and eventually <https://en.wikipedia.org/wiki/Death> death.
Because it is a second generation poison, the predators that prey on rodents
are at risk, as are pets such as dogs and cats.

Please, help put out the word that rodenticides, especially second
generation rodenticides, kill more than rodents. Safe alternatives include
single-and multiple-entrance snap traps and electrocuting traps. For more
information about safer alternatives to rodenticides google "Raptors Are the
Solution" and "The Hungry Owl Project." Also see Audubon's online magazine
article "Poisons Used to Kill Rodents Have Safer Alternatives, a second
generation of ultra-potent rodenticides creates a first-class crisis for
people, pets, and wildlife." (Jan-Feb 2013).

-Jamie Acker

J. Acker

owler at sounddsl.com <mailto:owler at sounddsl.com>

Bainbridge Island, WA

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