Sharon L. Moore
Order: Gaviformes
Family: Gavidae
Common Loons (Gavia immer) are historically beloved birds in North America and Canada. Admired for their stunning fishing abilities and complex repertoire of calls, they have long been considered iconic symbols of pristine wilderness. In fact, the Common Loon has been designated the provincial bird of Ontario and the state bird of Minnesota. Since ancient times they have featured prominently in Native American mythology. They are also found in English literature and poetry and, in the modern era, they have enjoyed “walk-on” roles in many Hollywood films.
From September to mid May you may see and hear Common Loons locally as they feed in our Pacific coastal waters and the inland saltwater of the five inlets of the south Salish Sea. We have seen them fishing at the Brown Point jetty at Ocean Shores. Closer to Olympia, when kayaking we’ve spotted them in Squaxin Passage near Hope Island and also in the Nisqually Reach waters near Tolmie State Park. Hood Canal, particularly close to Seabeck, is also a good possibility for spotting these large water birds.
Loons are relatively quiet during fall, winter and early spring as they fish the open waters. However, when you’re birding or kayaking in these environs, if you should hear a prolonged, mournful, unmodulated call sounding like a wail, you’ll know there is Common Loon nearby. While they generally feed alone, at night they often gather in small flocks on protected waters.
An ancient bird, the Common Loon carries a lineage dating back at least 70 million years. Their closest modern surviving relatives, according to recent biochemical studies, are frigate birds and penguins. Common Loons are the largest of the five North American loon species that also includes Pacific, Red-throated, Arctic and Yellow-billed.
With a 32-inch body and a 46-inch wingspan, they are powerful flyers, strong swimmers and formidable divers. Highly skilled flyers, they are capable of reaching speeds of 70 miles per hour. Their legs are set far back on the body allowing them strong take-offs from the water and smooth landings as well. But this somewhat awkward leg placement has a disadvantage as well in that they are virtually unable to walk on land and therefore must nest and breed close to the water.
During winter the loon’s coloring is nondescript with a white throat, white around the eye, a thick black bill and steep forehead. The back is black with a lighter grey mottling and a dark collar extends forward to the neck. By spring the Common Loon finally begins to display its regal summer breeding coloration that includes a black, iridescent head and neck and prominent black and white checkered back. Both sexes carry the same coloring in winter and summer with the male only distinguishable by his larger size.
As to diet, these loons exclusively prefer small fish up to 10 inches long such as sculpin, gunnel, perch, rock cod, suckers and minnows. Feeding only during daylight assures them of seeing their prey. While fishing, they have a fascinating way of swimming barely on the surface of the water with their heads mostly submerged as their red eyes search under the water for fish to catch.
Extremely agile in the water, the Common Loon is capable of executing a 180-degree turn in a fraction of a second while chasing prey. Though they can remain under water for up to fifteen minutes, they generally stay below the surface for only five minutes or less. Should the water be murky or the fish scarce, they will also eat snails, leeches, crustaceans and mollusks. These birds need large fish supplies, particularly when a mated pair is feeding two hungry chicks. As estimated by biologists, a family of four will require a half-ton of fish during a 15-week period.
The mating and nesting season, beginning in May or early June, is a busy time for Common Loons. They will have migrated north by then to the boreal forests of Canada and Alaska and large, pristine lakes. Monogamous pairs may return to their annual breeding grounds. Newly sexually mature males, between ages two to four, will be searching for a lifetime mate. Courtship between males and females includes chasing, diving, swimming together and lowering their bills into the water in synchronous display.
The male chooses the nest site. It may be on the shore of the lake where he was born. It may also be a previously used and abandoned site at the waters’ edge on another lakeshore or a small island. This location allows the pair some safety with clear visibility of the surrounding landscape and enough expanse of water for them to escape predators if necessary.
The loon pair builds the nest with grasses, reeds and twigs that they both glean and press into a mound with a shallow depression for the one to three eggs the female lays. While they’re finishing the 22 inch-wide nest, the male often becomes intensely territorial and will frequently signal that he is occupying his chosen territory with loud yodeling calls reverberating for miles. If challenged by an interloper, he will display threatening, circling behaviors and, in rare circumstances, will fight to injure or actually kill the encroacher.
Both parents incubate the eggs for 24 to 31 days. With their heavy down coats and wide-open eyes, the hatchlings emerge with a high degree of ability to survive. After the parents keep them warm for a few hours, the chicks are ready to leave the nest and ride on their parents’ backs to the water. Amazingly, they begin to swim immediately as the parents fish for them. In these early days of the chicks’ lives, the female does much of the hunting for food while the male guards the young. At only a few days old the chicks are capable of diving underwater, searching for food and observing their parents fish.
During this family time, in the evenings the loon pair often calls to each other or call in unison in a lovely tremolo duet signaling that all is well. Though the juveniles fledge at 49-days-old, the parents may continue to feed them until they succeed at catching enough fish to feed themselves adequately. Finally, at summer’s end, the young will migrate for the first time, possibly with their mothers, to their winter-feeding waters along the Pacific Coast as far south as Mexico. The males are the last to head south. The result of this Common Loon intense parenting is that the survival rate of their fledglings may be as high as 95%.
As to the loon life span, field biologists originally estimated that the species lived about ten years. Then an Arctic Loon surprised everyone with a leg band documenting that she was 28 years old. Quite recently an article in Audubon Magazine described even older Common Loons nesting at Seney National Wildlife Refuge in Michigan. As a long-time breeding pair, ABJ, the male, is 34-years-old and his mate, Fe, is at least 35. Together they migrate every year up to 3,000 miles and return in spring to ABJ’s original lake birthplace. Over 25 years these remarkable parents have successfully raised 29 chicks.
As to the species’ survival status of the North American Common Loon, data published in a 2015 bird survey considered the overall population to be stable and healthy. Yet these now out-of-date figures do not verify that these birds are currently thriving. In truth, they are facing a variety of deadly environmental threats. One of the most obvious is ongoing destruction of lakeshore habitat by over-building. A second serious concern is widespread mercury in the atmosphere from coal-burning ash that has been building up in lakes through acid rainfall. This has led over past decades to drastic reductions of wild fish stocks that loons depend on. Mercury poisons fish, depleting fish stock and causing mass starvation of bird populations. This ongoing catastrophe has led to a drastic reduction in loon reproductive success in Canada, New England, Wisconsin, Illinois, Indiana, Iowa and Ohio. Responding to this dire situation, the U.S. Forest Service has designated the Common Loon a species of special status due to the threats from habitat loss and toxic metal poisoning in its U.S. range.
Other environmental dangers confront loons. The spread of avian botulism, caused by Clostridium botulinum, is killing thousands of water fowl and shore birds. It is proving nearly impossible to eradicate. Another threat is from lead sinkers, used by fishermen, which kill loons when they ingest them. Yet another extreme challenge to loons’ survival, particularly in coastal waters, is oil spills such as occurred recently in southern California. Another oil spill has just been reported (January, 2022) on the Peruvian coast, this one the result of a tsunami. Not only do oil spills kill the fish stocks that loons depend on, but in the U.S. and worldwide many thousands of loons die each year in oil spills that saturate their plumage leaving them unable to dive, swim, fly or keep warm.
Finally, a severe threat to all birds’ survival is global warming. Along with obvious, growing environmental damage, evidence is building that rising temperatures are causing spring heat waves to endanger young loons’ survival in the nest. Given this significant devastation to the Common Loon’s feeding and breeding grounds, it is not surprising that the species is projected by the National Audubon Society to abandon the lower 48 states in coming decades and move north into the boreal forests where there may still be cool, pristine lakes providing enough fish for them to survive. Should humanity reduce and stabilize the earth’s temperature, perhaps those regions will remain habitable for the loons and countless other species that will have fled there. Can they and all other life forms be saved from extinction given advancing climate change? That is the persisting existential question of our time.
Photo credit: Common Loon, Minocqua, Wisconsin. John Picken. Wikimedia
