”Fossils reveal that loons have been on earth about 70 million years, making them one of the most ancient bird families.“
This sentence, from the National Park Service’s web page describing the Common Loon, is in error. Loons — even by a loose definition — have not been on Earth anywhere near 70 million years. Moreover, this faulty information from a reputable source has spawned additional spurious pronouncements scattered across websites and social media.
On its face, the Park Service’s statement seems plausible. It feels as though loons have always inhabited northern lakes. Perhaps we feel this way because of the self-assuredness with which loons slither beneath the water’s surface to initiate a fishing bout. Perhaps it is loons’ alertness to all sights and sounds in their aquatic environment or the ease and confidence with which they move about their territories and confront intruders. On the other hand, maybe loons simply look primitive — and hence, ancient — to us when we observe their ungainly movements on land. But I suspect that — more than any other aspect of their biology — the ethereal echoing of loons’ wails and tremolos across the surfaces of northern lakes hints at an ancient origin.
Humans’ view of loons as primitive creatures emblematic of northern climes dates back to native people of North America. The Ojibwe, who have looked upon loons as harbingers of death and bearers of magic, have also shared northern lakes with them for thousands of years. Thus, from a strictly human standpoint, loons are old. That is to say, loons have been integral to northern ecosystems for as long as humans can remember.
But we humans are a very recent evolutionary arrival. Whereas mammals as a whole evolved some 200,000,000 years ago, Homo sapiens, by most measures, is no more than 200,000 years old. Human residency in North America began very recently indeed — about 16,000 years ago by common reckoning.* Humans’ recent evolutionary appearance makes our historical and cultural records worthless for charting the comings and goings of most other species.
Enough about humans. What about loons? To get a sense of how old loons are, we need to look at the entire avian lineage.
It was 145 million years ago (mya) when Archaeopteryx’ feeble wingbeats were first heard faintly overhead by the theropod dinosaurs from which they evolved. Following Archaeopteryx, the first known bird, many avian lineages evolved that were dead ends (i.e. they left no living descendants). These included the ternlike Ichthyornis (95 to 85 mya) and the massive diver Hesperornis that lived 85 to 75 mya. But early members of the chicken/duck lineage roamed Earth at around this time too, as did the flightless Paleognatheae, a group that includes ostriches and kiwis.
For their part, loons are members of a rather recent avian branch, the Neoaves (“new birds”). As the name suggests, this massive group burst onto the scene after the early avian lineages — some 60 to 50 mya.
Loons fall within a group of Neoaves termed “water birds” that includes gulls, sandpipers, herons, albatrosses, cormorants, and pelicans. Loons’ closest living relatives are neither grebes nor ducks, which they seem to resemble closely, but penguins and tropicbirds, from which they diverged around 50 mya. However, the first bird species that experts agree might be called a loon (Colymboides minutus) appeared 35 mya.** (This species was less than half the size of the common loon and less well adapted to diving.) Loon species assignable to the common loon’s genus (Gavia) do not turn up in the fossil record until about 16 to 18 mya. And the common loon itself (Gavia immer) made its debut not more than about 3 million years ago.
In short, we cannot accurately describe loons as “ancient”. If you wish to point to a member of an ancient avian lineage, you will have to settle instead for a duck, a turkey, or an ostrich. True, common loons have been plying the waters of freshwater lakes — and calling hauntingly across them — for as long as humans can remember. But that says less about the duration of loons’ residency in the north country than about our own fleeting existence there.***
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References
Brodkorb, P., 1953. A review of the Pliocene loons. The Condor, 55(4), pp.211-214.
Carroll, S.B., 2016. Genetics and the making of Homo sapiens. Human Evolution Source Book, pp.646-656.
Gingerich, P.D., 1976. Evolutionary significance of the Mesozoic toothed birds. Smithsonian Contributions to Paleobiology, 27, pp.23-33.
Lovette, I.J. and Fitzpatrick, J.W. eds., 2016. Handbook of bird biology. John Wiley & Sons.
Mayr, G., 2004. A partial skeleton of a new fossil loon (Aves, Gaviiformes) from the early Oligocene of Germany with preserved stomach content. Journal of Ornithology, 145, pp.281-286.
Mayr, G. and Kitchener, A.C., 2022. Oldest fossil loon documents a pronounced ecomorphological shift in the evolution of gaviiform birds. Zoological Journal of the Linnean Society, 196(4), pp.1431-1450.
McIntyre, J.W., 1988. The common loon. Spirit of northern lakes. UNIVERSITY OF MINNESOTA PRESS, MINNEAPOLIS, MN(USA). 1988.
Prum, R.O., Berv, J.S., Dornburg, A., Field, D.J., Townsend, J.P., Lemmon, E.M. and Lemmon, A.R., 2015. A comprehensive phylogeny of birds (Aves) using targeted next-generation DNA sequencing. Nature, 526(7574), pp.569-573.
Shook, B., Nelson, K., Aguilera, K. and Braff, L., 2019. Modern Homo sapiens. Explorations. https://pressbooks-dev.oer.hawaii.edu/explorationsbioanth/chapter/unknown-14/
* Recent stone tools suggest that humans might have arrived in many parts of North American 35,000 to 40,000 years ago. Even if this is so, we are very recent arrivals on the continent.
** Mayr and Kitchener recently reported a primitive “loon” fossil from about 54 mya. But this species (Nasidytes ypresianus) was a very different beast from the loons alive today. It possessed a wide and short beak like a modern coot, had limited diving ability, and likely fed by browsing on invertebrates, not pursuing fishes. Whether and how it might have vocalized is, of course, unknown.
*** Thanks to Linda Grenzer, for this wonderful photo of the former territorial male on her lake, Clune.