Border collies, seagulls, and beach bacteria

Public domain photo by Karen Arnold

Public domain photo by Karen Arnold

Using Border collies to chase seagulls may reduce bacterial contamination of Great Lakes beaches, according to a recent study.

Naturally, my first thought (as a scientifically-minded person) is:

Most fun job EVER (for a dog).

A group of researchers from Central Michigan University used Border collies to chase gulls from public beaches on Lake Michigan during the summers of 2012 and 2013. They counted the number of gulls present on the beaches each day, and they analyzed samples of beach water and sand for the presence of Escherichia coli. Their results showed that the dogs significantly reduced the number of gulls present on the beaches. When the dogs were used early in the summer, E. coli counts on test beaches were significantly reduced compared to counts on control beaches. However, if the Border collies were not brought in until later in the summer, E. coli counts were not significantly different. This means that fecal bacteria deposited by birds early in the summer stayed on the beach throughout the whole season.

What a lovely thought.

Great Lakes public beaches are routinely closed when elevated levels of E. coli are found. While most E. coli strains are not dangerous — the bacterium is, after all, part of the normal flora of the human intestinal tract — it can be used as a marker for the presence of fecal contamination. When the E. coli level is increased, the level of pathogenic bacteria is presumed to also be increased. Birds who feed at landfills and waste treatment facilities are one of the sources of fecal bacteria on freshwater beaches. According to another study presented at the same meeting as the Border collie study, markers for human fecal matter can be found in the cloacae of some seagulls that move between wastewater lagoons, landfills, and freshwater beaches. In other words, seagulls ingest human fecal matter and then transfer its bacteria to public beaches.

Dogs that are trained to chase but not harm birds have been used to reduce nuisance bird populations, particularly Canada geese, in parks and airports. A quick Internet search finds many companies that will bring in Border collies to harass geese where population reduction is needed. The goal is to keep the birds away, not to catch or kill them. I imagine this is quite popular with the public, since it’s much more fun to think about Border collies running around barking at birds than about landscape modification. (New landscaping was one of the methods used to reduce the Canada goose population, successfully I might add, at a park in my city.)

I don’t know if it’s economically feasible to bring in trained dogs and their handlers throughout a season to do bird abatement on public beaches, but it’s an appealing thought — especially compared to the idea of fecal bacteria where your children are digging. I would be interested to know if similar levels of contamination ever exist on saltwater beaches. I’ve never heard of a Carolina beach being closed because of bacteria. (It wouldn’t be because of E. coli in any case, because E. coli doesn’t survive well in saltwater. A different bacterial marker is used to test ocean water.)

And on that note — enjoy your summer vacation, if you are taking one!

© Laurie Anne Walden, 2014

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