Birds de-fouling their own nests

Birds in Mexico City are keeping their nests warm and pest-free by lining them with cigarette butts, according to a BBC Online story quoting a study by researchers at St Andrews University.

The nicotine and other chemicals in discarded filters are said to act as ‘a natural pesticide’ that repels parasitic mites.

At the same time, the cellulose butts provide useful nest insulation.

St Andrews University scientists studied the nests of house sparrows and house finches that contained from none to 48 stubbed-out cigarettes, and that averaged about 10.

In respect of both species, nests with larger numbers of butts were significantly less infested by mites.

Wild birds are known to protect their nests from mite invasion by importing certain chemical-emitting plants.

The full story is at: http://www.bbc.co.uk/news/uk-scotland-edinburgh-east-fife-20607413.

There is a downside to all of this. Stories in the past have told how building fires have been started by birds incorporating into their nests butts that have not been fully extinguished.