Pigeons ‘could be new canary in the coalmine’
Birds ‘can help to monitor pollution’
LONG derided as the rats of the sky, pigeons could soon be used to help monitor pollution, scientists have revealed.
The birds usually stay within a few areas in a city, making them ideal for measuring toxic chemicals in a particular area.
And their body tissue is surprisingly similar to that of humans, meaning tests on pigeons could also shine a light on the effect of pollutants on people.
Rebecca Calisi Rodriguez, of the University of California in Davis, said plans for this are already under way. Speaking at the American Association for the Advancement of Science’s annual conference in Austin, Texas, she explained: ‘Pigeons have existed for ages in close proximity to us, eating the same food, drinking and being exposed to the same water sources, soil, air, pollution.’
She said they could be more useful than machines as they process chemicals in their bodies, adding: ‘This offers up the opportunity to not only find toxin hot-spots in our environment, but to understand how these toxins affect biology.’ So far, scientists have tested pigeons only for levels of lead in their blood, which were found to be similar to children in the same area. They now plan to expand tests to other toxins such as pesticides.
Because pigeons are very territorial – typically staying within a few blocks of a city – they are ideally placed to monitor pollution and act as a ‘canary in the coalmine’.
Professor Rodriguez said: ‘Pigeons have a very small home range, spending the their life within a few neighbourhood blocks. And, because they are alive, they process these chemicals in their bodies. This offers up the opportunity to not only find toxin hot-spots in our environment, but to understand how these toxins affect biology.’ To test the effect of pollution on pigeons, a blood sample is taken from the birds. Tests on pigeon blood samples at an injured pigeon sanctuary in New York, the Wild Bird Fund, showed that levels of the pollutant lead in pigeon blood closely mirrored that of children in the same area.
Now Prof Rodriguez and colleagues are widening their tests to see how a wide range of pollutants affect the pigeon’s DNA. She said: ‘Birds, like us, are vertebrates. We share a lot of the same evolutionary history, and our bodies have many similarities in terms of tissue form and function. For example, like humans, pigeons lactate.
‘They produce crop milk in their crop sacs to feed their chicks when they first hatch. The process is controlled by the same hormones that control human milk production, and both types of milk have essential nutrients the babies need to survive. So as you see, what we learn in birds can have far-reaching implications.’
Miners used canaries in coalmines to detect build-ups of poisonous gases. The canaries were more sensitive to the gas, so when they collapsed, it would indicate the gas levels were too high.
‘Many similarities with humans’