The Danger of Blackflies

Many of the pairs I have observed on recent days have spent their time on the surface in a fruitless effort to shake or toss their heads to rid themselves of blackflies. Loons have their own dedicated species of blackfly, Simulium annulus, that depends on them for a blood meal prior to reproduction. Blackfly populations vary from year to year, and it seems pretty clear (though not scientifically proven) that the numbers of these nasty blood-suckers and their synchrony with nesting determines how many loon pairs abandon their nests in May. At this point, we have found seven loon pairs that have just initiated nests. I hope that this first wave of nests survives the blackfly infestation. In 1996, also an extraordinarily late year, abandonments occurred at a moderate rate (about 20%), but were not devastating, as in some years. So, I am optimistic that it could still be a good year for chicks, despite the lateness of ice-out.