No loon music?

In one of his essays the naturalist Aldo Leopold wrote, “And when the dawn wind stirs through the ancient cottonwoods, and the gray light steals down from the hills over the old river sliding softly past its wide brown sand bars – what if there be no more goose music?” Given recent findings in the field, researcher Walter Piper might well ask us here in the north to ponder: What if, someday, there be no more loon music?

Piper is the lead scientist on The Loon Project (https://loonproject.org) that has studied loons in Oneida County for many years. In a recent post he sounded an alarm about three environmental conditions threatening loons’ prosperity, and all relate directly to climate change. He observes, “No rational person who has seen these data and is capable of looking at the world with an objective eye can doubt that climate change is harming loon populations.” So, what are these threats?

One is swarms of blood-sucking black flies that prey specifically on loons and have been shown to drive them off their nests. The flies emerge in May and June, just when loons are making nests and laying and incubating eggs. The flies drive loons off their nests, leaving the eggs at the mercy of predators and the elements. Anyone who has experienced a pestilence of the more generic black flies while fishing or paddling on a lake can attest to the viciousness of their attack. Humans can fight back with head nets or repellents. Loons have no such protections.

Then there are rainstorms, increasingly frequent and intense as the climate warms. Piper cites a study in Northeast showing that flooding there is now a common cause of loon nest failures. (The same is not true, so far, here in the Midwest). And finally there’s water clarity. Piper’s research indicates that clarity during July – the time when loon chicks need to eat voraciously – has been in decline, owing to increases in heavy rains that send silt-laden runoff into the lakes.

Water clarity matters because loons feed by sight. Lower visibility means the adult loons are less efficient in locating and catching fish to feed their young. The study’s data showed that chicks’ body mass tracks with water clarity in July, a critical growth period. In other words, lower water clarity leads to lower growth, leads to higher mortality.

Other research suggests that as the climate gets warmer, loons’ breeding territory is shifting toward the north. A 2019 report from the Audubon Society suggests that changing climate could eventually force loons out of some or all of their Upper Midwest breeding territory. Under some future climate scenarios, that territory’s southern boundary would shift toward and possibly into Canada, which even today is where the most loons nest.

Piper asks rhetorically, “Do we sit down with our children and grandchildren and explain to them that they will have to go to Canada to see the birds whose charismatic presence near our summer homes has so enriched our lives?” It’s a sobering possibility to ponder.