Science of Spring: It's a bad season for hatching baby loons

By Tom Spears, Ottawa Citizen, June 5, 2020

Loons are back on their nests at this time of spring, but a leading loon scientist says we’re unlikely to see a lot of chicks this year.

The problem: Black flies, though not the kind that attack humans.

There is one type of black fly that targets loons, and only loons. It’s active in May, when the adult fly needs a meal of blood in order to reproduce. And clouds of the tiny flies (smaller than the kind that go for humans) swarm around each loon, just as they are sitting on eggs.

In years when fly numbers are low, the loons put up with it. But in years with many flies, loons can be driven off their nests and the eggs don’t hatch.

Connect with us