Birdwatch News Archive


It seems all pesticides have some kind of ecological 'knock-on' effect, as American Kestrels are now finding out. Photo: Steve Hillebrand (commons.wikimedia.org)
It seems all pesticides have some kind of ecological 'knock-on' effect, as American Kestrels are now finding out. Photo: Steve Hillebrand (commons.wikimedia.org)Enlarge image

American raptor poison fears


Posted on: 14 Mar 2011

An unrestricted new pesticide has been shown to kill birds of prey in America, reviving bad memories of the DDT crisis in the 1960s.

New research on American Kestrels has shown that the rodenticide diphacinone - widely used as a substitute for rodenticides now banned or restricted by state law - shows significant build-up in the birds of prey at the top of the food chain, resulting in rapid fatalities.

American Kestrels that ingested more than 300 mg per kg of body weight died within 23 hours; others consuming a dose of 118 mg per kg also died, lasting no more than 47 hours. Lower doses resulted in survival. It is not known if the rodenticide affects breeding success like DDT, but any dose greater than 79 mg/kg appears to be eventually lethal for the small raptors.

The poison is developed to be tasteless and have a delayed action, which means that the live-prey eating kestrels are highly likely to eat contaminated mice and rats, as they will still be active after eating poisoned bait. Diphacinone is an anticoagulant which causes profuse unstoppable bleeding. Recovered kestrel corpses showed evidence of internal bleeding, though haemorrhaging was present even at non-lethal doses.

Using American Kestrel as surrogates for less common raptors, the study showed that protection limits for birds of prey need to be lower than the gamebirds previously used a surrogates. Rodenticides have also been found to be present in French, British and Canadian birds of prey, with possibly derogatory effects on populations exposed to the chemicals.

Reference: Rattner, B, Horak, K, Warner, S, Day, D, Meteyer, C, Volker, S, Eisemann, J, and Johnston, J. 2011. Acute Toxicity, Histopathology, and Coagulopathy in American Kestrels (Falco sparverius) Following Administration of the Rodenticide Diphacinone. Environmental Toxicology and Chemistry DOI:10.1002/etc.490

 




Your Comments

Tell us what you think...

You must be logged in to leave a comment. You can log in here.
If you don't have a user account please register.

Other News

Bird Atlas team scoops RSPB's most prestigious award

Posted: 01 Nov 2014
At the annual RSPB Members’ Day in Birmingham, the RSPB Medal was awarded to the team behind the Bird Atlas 2007–11 project in a special presentation.

Read more…


Twite saved by concrete company

Posted: 31 Oct 2014
Working in partnership with the RSPB, cement and concrete company CEMEX is helping the scarce finch to make a comeback in Derbyshire.

Read more…


Stop the killing, says the RSPB

Posted: 30 Oct 2014
Leading wildlife charity is challenging the shooting community to take action to stop the illegal persecution of birds of prey.

Read more…


Act for nature

Posted: 29 Oct 2014
Two leading wildlife charities are calling on the government to enact new laws to support nature and improve the wellbeing of the British population.

Read more…


Bewick's Swan numbers plummet

Posted: 28 Oct 2014
New figures from the WWT reveal that Britain's smallest and rarest swan species has suffered an alarming crash in numbers.

Read more…


  2 3 4 >