By Kathy Jones (Volunteer Manager, Ontario Programs & Canadian Lakes Loon Survey) and Dr. Doug Tozer (Director, Waterbirds and Wetlands), Birds Canada
Some of our Canadian Lakes Loon Survey participants were able to collect data this summer within the limits of COVID-19 restrictions. Thank you for taking part! Please send in your data by mail or submit it online – 2020 data entry will continue through the fall. If you were unable to survey in 2020, we hope you will join us again next year. Please help us plan for 2021 by registering early. You can visit birdscanada.org/loons to learn more about the survey and register via the Volunteer Portal.
One of the toughest changes brought on by the pandemic has been social distancing, which is especially difficult for us humans because we are highly social beings. We felt a closer look into the complex and often highly-social lives of Common Loons would help raise our spirits! Read on to discover a loon’s year-in-the-life, complete with sophisticated behaviours, complicated communications, and other fascinating life history traits.
Spring always starts with a stay-at-home order
Common Loons often return to the same lake year after year. Despite being conspicuous while out on open water, they tend to be secretive around their nests, which are located along the shore. It is the male rather than the female that chooses the nest site, for reasons that remain unclear. Both members of the pair put great effort into caring for and protecting eggs and young, although females incubate more than males. Both mates also aggressively defend against other loons, waterfowl, and other wildlife that compete for their main prey: fish.
Staying in touch
Communication is very important in the “family bubble,” with short, soft calls used during courtship and nest building, and hoots used during close-up “conversations.” Chicks will also use peeps and descending yelps while begging for food from their parents. Two calls used between members of the pair and with neighbours are the wail and tremolo. The wail is haunting, like a wolf howl, and is typically used by pair members to relocate each other, but can also be used to communicate with neighbours. The number of notes delivered within a wail (one to three) is thought to correspond with anxiety: the more notes, the more anxious the bird is. The tremolo sounds like laughter and is often used to express stress. Loon pairs occasionally perform a duet of tremolos, and the tremolo is the only call used in flight.
During spring, the loon “social bubble” is closed to unwanted guests. Males use a call referred to as the yodel to inform neighbours and aggressors that his territory is occupied and to stay out. The yodel consists of three introductory notes followed by repeated phrases of variable length. In subtle ways, each male’s yodel is unique, but individuals are known to alter their yodel structure between years, particularly if they switch territories. Evidence also suggests that males recognize and remember the yodels of neighbouring males from year to year. For a particular male, listening to neighbours might be like this: “Ah yes, there’s Tim to the west and Ben to east, just like last year. But wait: who’s this new guy on the block – I don’t recognize him!”
During the breeding season, loon pairs do “circle dances” when they meet with other loons. During the dance, three or more loons swim in a circle, dipping their heads under water while quickly looking back and forth at each other. Circle dances are often associated with a territorial invasion by a non-breeder. Here the invading loon calls with a tremolo to introduce themself. The territory-holding male often responds with a yodel. Dances typically change suddenly: a quick circle and the invader leaves, or it can turn spectacularly violent with the male fighting a male invader or the female fighting a female invader. If the fight is won by the territory-holder, life continues as before. If the fight is won by the invader, the other territory member accepts the new loon as their partner. Shockingly, territory takeovers often involve the intruder killing the chicks, and male-to-male fights often result in the death of the territorial male.
Photo: Nancy Barrett
Thank you to Noreen Dertinger for giving us permission to share a video of one of these encounterson Kennebec Lake, ON. Note that it shows (non-fatal) violence between loons that may not be suitable for all viewers.
As summer progresses, public gatherings increase
As the chicks get larger and the risk of being eaten by a predator decreases, loons start participating in “social gatherings.” These consist of 3 to 15 individuals swimming around peacefully peering at each other. Sometimes it’s in straight lines and they look like hockey players shaking hands after the game; sometimes it’s in big circles. There’s no diving or feeding. They’re just looking. The reasons for these mysterious gatherings are not well understood, but they may be a means for loons to meet and assess new potential mates. This is because social gatherings are more common on territories where there has been a recent “divorce” (i.e., switching of mates). Maybe it’s like a young couples’ bar; partners haven’t been together for very long, so maybe there’s still interest in switching up? Perhaps the territory-holders even solicit the gatherings somehow? During these gatherings, personal space is a must and loons will not tolerate other loons (except their own mate) within one body length.
After breeding, loons stop distancing and may join a fishing party
During migration in late summer, and on the wintering grounds, loons often gather in feeding groups of up to 250 individuals. This allows them to better pursue schools of fish, particularly those that can be found in the near-shore waters of the Pacific and Atlantic Ocean and the Gulf of Mexico where most loons overwinter. During fall and winter, loons will allow other loons to approach much closer than during the breeding season and the main vocalization used is the hoot.
In spring, adult breeding loons migrate back to their preferred nesting lakes and the cycle begins again!