Tuesday, October 29, 2013

Nicotine in the Nest

Cigarette Butts incorporated in nest- Blue Channel 24
Some birds have a nicotine habit. It has long been known that some species of urban birds like house sparrows line their nests with used cigarette filters as well as many other types of human litter, picking up anything that fits their structural purpose.  A report from the National Autonomous University of Mexico investigated the phenomenon in house finch and sparrow nests.  They found that nests with used cigarette filter material had 60% fewer mites than those with unused filters.  Whether the birds selected filters for protection or just insulation is under study now.

Over 2500 species of mites from 40 families are associated with birds.  They can be roughly divided into those living on birds' bodies and others living in their nests.  Nest mites that feed on blood are associated with decreased reproductive success, slowing chick's development or even killing them.  Whether this is a cause or simply reflects larger populations of mites in nests with weakened birds is still being studied.*

Birds such as starlings are known to incorporate fresh aromatic plants into their nests and actually refresh them from time to time.  Theories to explain this behavior range from building up immunity of their chicks to serving as a repellent against harmful parasites.

So have birds figured out that filters reduce parasites or have they just found a ready source of "commercial" insulation with a high R value?  Do the birds benefit from the parasite reduction or is their health affected by the nicotine?  Stay tuned for the next chapter from future studies.

*Much more detailed information on bird nests at this Eastern Kentucky University site.

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