Cigarette butts and birds

In another oddity,two types of city songbirds-the house finch and the house sparrow-pack their nests with scavenged cigarette butts(as many as 40 per nest) to protect their young from harmful mites.The birds seem to instinctively know that the chemicals in nicotine repel parasites.-SOURCE:Kerry Banks,CANADIAN GEOGRAPHIC MAGAZINE,May/June 2017 issue.