Dead birds were intoxicated, an investigation finds

Blackbird eating a rowan berry

Related Stories

Young blackbirds found dead at a primary school in Cumbria suffered from alcohol poisoning, according to an investigation.

Animal health specialists were called to examine a dozen birds found in the playground, many with trauma injuries.

Post-mortem analysis revealed that one of the birds had a large amount of pure alcohol in its liver.

Scientists suggest the birds sustained their injuries in flight because they were intoxicated by fermented berries.

Staff from the Animal Health and Veterinary Laboratories Agency (AHVLA) published their results in the Veterinary Record.

A local wildlife sanctuary cared for a further bird found in the area, which they described as unsteady on its feet, using its wings to support itself and leaning on the walls of its enclosure.

Under the influence

The bird made a full recovery and was released after two weeks of care.

Trouble brewing

When AHVLA researchers analysed the dead blackbirds they found all the birds had eaten berries from a nearby rowan tree.

Tim Harrison, development officer of the British Trust for Ornithology's (BTO) Garden BirdWatch explained: "Generally speaking, birds that have a lot of fruit in their diet are more efficient at metabolising alcohol and are better adapted at eating fruit that has higher alcohol concentrations."

He continued: "There are anecdotal reports of birds acting 'drunk' but these tend to be very rare".

But damaged berries were also recorded on the ground where the birds were discovered.

Blackbird in pyracantha Birds with a diet rich in fruit have a greater tolerance to alcohol

Scientists explained that the berries on the ground were damaged and would have been vulnerable to yeast infestation. This would have precipitated fermentation and subsequent alcohol production.

According to Paul Duff and colleagues at the AHVLA, who carried out the post-mortem analysis on the dead blackbirds, the berries found in the birds' guts smelled of fermentation - the chemical process of sugars breaking down into alcohol.

Tissue samples sent for analysis partially confirmed the scientists' suspicions when one revealed high concentrations of ethanol, pure alcohol, in the liver of an affected bird.

However, alcohol was not identified in the toxicology tests of two other samples.

A similar diagnosis was made in 1999 for a group of redwings, which had been feeding on holly berries that were fermenting following a frost.

Join BBC Nature on Facebook and Twitter @BBCNature.

More on This Story

Related Stories

The BBC is not responsible for the content of external Internet sites

More from nature

  • Cardinal fish and ostracodFish filmed spitting 'fireworks'

    Film crew captures ostracods' spectacular defensive lightshow that makes predatory fish spit them out.

  • Arapaima'Locally extinct'

    A giant fish which used to dominate the Amazon river is now absent in many areas


  • DragonflyRapid reactions

    Dragonfly's super quick reactions recorded in slow motion by BBC film-makers


  • Wingless adult male of the midge Belgica antarcticaExtreme survivor

    Antarctic midge's small genome may be an adaptation to its extreme environment


  • Myotis midastactus specimen (previously identified as Myotis simus)Golden discovery

    A bat from Bolivia is described as a new species by scientists


  • Dinosaurs 'shrank' to become birds

    Huge meat-eating, land-living dinosaurs evolved into birds by constantly shrinking for over 50 million years, new research shows.

  • Would we starve without bees?

    Honey bees are under threat, and as pollination significantly contributes to the food we eat, what would we do without them?

  • Eggshells may act like 'sunblock'

    Birds' eggs show adaptations in pigment concentration and thickness to allow the right amount of sun for embryos, scientists say.

  • Female shrimps are more aggressive

    Female snapping shrimps are more aggressive than males when defending their territories despite their smaller claw size, a study shows.

BBC iWonder

  • Honey bee close-upInsect intelligence

    Are honey bees as smart as your sat nav?

  • Tyrannosaurus rex skull (c) Mark Williamson / Science Photo LibraryDinosaur dynasty

    One group of dinosaurs survived and their descendants can be seen all around us today


  • Brown rat cluse upRise of the rodent

    Reports of giant, 'super rats' are filling the headlines. But why are we being overrun by rats?


  • Cuckoo portraitHoliday hotspot

    What makes the UK such an attractive destination for visiting wildlife?


Awesome! And there's nothing common about such beauty.

Elaine Bernon on Facebook comments on the trio of common blue butterflies in our Photo of the Day.

Things To Do

RUN BY THE BBC AND PARTNERS

More Nature Activities >

BBC © 2014 The BBC is not responsible for the content of external sites. Read more.

This page is best viewed in an up-to-date web browser with style sheets (CSS) enabled. While you will be able to view the content of this page in your current browser, you will not be able to get the full visual experience. Please consider upgrading your browser software or enabling style sheets (CSS) if you are able to do so.