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Common Loon

(Gavia immer)

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Introduction

 

“Common Loon” - the official (and rather unflattering) name of our most popular seasonal visitors at Hotel Lake. When we have the good fortune to host a breeding pair, from their spring arrival onwards “our" loons are subjected to constant friendly scrutiny, and discussion of their successes or failures. The sharing of “Loon Sighting” details with friends and neighbours is a regular occurrence - we all want to know how “our” loons are faring, be it good news or bad. Unfortunately, in recent years the news appears to have been predominantly bad. We do have evidence of a successful breeding pair in 2013, shown in Theresa McNicholl’s beautiful photo immediately below, but we are unsure of the outcomes during the years that followed. More recently, in 2021 and in 2022, we did witness the Spring arrival of a single loon, who had the lake to itself for several months, made daily “I am here, where are you?” calls to no effect and eventually departed. During this time several groups of transient loons visited the lake but none filled the position of the missing pair member.

Why is this happening?   As you read on we hope to provide answers to this and many other questions - such as what makes loons such efficient fish killers, where their nests are likely to be sited, and what requirements shape their definition of an ideal lake. Also, why their daily summer routine on Hotel Lake is not as relaxed and carefree as you might think and why their takeoffs and landings are so wonderfully spectacular.

 

To answer these questions and more, we present a host of interesting details about loons in general and the Hotel Lake loons in particular.  We have gathered this information from the marvellous selection of sources which speak to our widespread fascination with the Common Loon. We begin with a quick look at the Common Loon’s basic characteristics, followed by a study of the Annual Cycle for a breeding pair of loons.  To get you in the mood, listen to this 16 second soundtrack from Cornell Lab of Ornithology.

Loon Call - "I am here, where are you?"
00:00 / 00:16

Loon Characteristics

The Common Loon (Gavia immer) is a bird superbly adapted to its aquatic environment - not much of a surprise when you realize that a loon spends almost its entire life afloat on a lake or an ocean. The loon hunts underwater and is capable of swimming submerged at speeds up to 20 km/h and to a depth of 60 m and can turn faster than most of the fish it encounters. The loon’s bones are solid rather than filled with air pockets, this adds weight which allows it to dive more easily. When a loon dives, its wings fold in tightly to minimize trapped air. The loon’s legs are set well aft and extend past the rear of the body, allowing highly effective propulsion in the water - especially while submerged - and also reducing drag in flight. Pigment in the loon’s eyes makes underwater vision particularly acute. Muscles that can absorb oxygen for long duration dives, a dense coat of waterproofed feathers and tail feathers that act as a rudder (for those tight turns) are additional  contributions to the loon’s fish killing ability.

                   

Not surprisingly, these  adaptations come at significant cost. The loon’s ability to manoeuvre on land is very limited. With the legs so far aft, the loon’s centre of gravity brings the bird’s chest to the ground and forward progress is made only with great difficulty, like a  wheelbarrow with a flat tire.  And the relatively  small wings make getting airborne and completing a landing quite violent procedures. Not for the loon is the “rear up and fly away” launch nor the pinpoint landing with a 2 metre post-landing roll (or ‘splash’).  More on this later. 

Western loons are slightly larger than those found in the prairie breeding area and slightly smaller than those tough eastern loons which have to put up with black flies, acidic lakes, botulism and jet skis. Loons weigh up to 5.9 kg or 13 lbs. The males are 20% heavier than the females. Wingspan is in the 127-147 cm range. Lifespan is 9 to 30 years and the adult survivability rate is 91%. A Minnesota pair are documented to have completed 20 years of breeding on the same lake. The photos ranged above show the black and white summer plumage of breeding loons. Juveniles and non-breeders are not as vivid and all loons look rather drab in their winter coats, shown below.                             

Photos: National Loon Center

North American Range of the Common Loon

Some 640,00 loons inhabit the northern hemisphere, with 95% of them residing in North America. In winter, loons live offshore on the coastal waters of the Pacific and Atlantic Oceans, the north shore of the Gulf of Mexico and the Gulf of California. In the summer the breeding population (birds 6 years of age and older) migrate to lakes in Canada, Alaska, New England and the states adjacent to Lakes Michigan, Superior and Huron. BC’s share is 25,000 breeding pairs.  In some years Hotel Lake has been known to host one pair. 

Annual Cycle

Let’s dive into the Annual Cycle at the point where the two loons that form our pair are preparing for their individual mid-March to early April return to the breeding grounds. The male and female have  wintered in separate locations. They do not mate for life, but once a breeding pair is together at a lake they will normally return to that same lake each year and resume their roles as a breeding pair. If one of the pair does not return to Hotel Lake, their place may be filled by a “floater”. Similarly, if neither of last year’s pair returns, in short order two “floaters” will assume their roles.

 

The male is normally the first to return and his immediate task is to select a nesting site. The female follows a few days later and a brief courtship (they could be in the 7th or 17th year as a “summer together but winter apart” couple), is followed by mating and the laying of 2 eggs - which are immediately at risk. While the parents share the 28 days of incubation duties, there may be brief intervals where the eggs are untended and in danger of becoming a meal for various predators, with racoons and  birds the leading culprits. The female normally takes the night shift on the nest while the male patrols their lake “turf”. The chicks hatch, the second some 24 to 36 hours after the first. After the second chick is dried off and catches its breath, the whole family takes to the water.

The chicks can swim and even dive (for a few seconds) soon after birth, but depend on their parents for food while they are fledglings (the period between birth and being capable of flight - about 11 weeks). Chicks are very vulnerable to predators in their first 4 weeks (turtles, eagles, gulls and “floater” loons just to name a few) and also to “death by chilling” - riding on a parent’s back frequently during the first two weeks considerably improves the odds. The younger chick is also at risk of “death by sibling” - in the first few days it is common for the older chick to try and injure and drive away the younger. Parental intervention doesn’t happen. 

 

Once the chicks resemble large balls of fluff and are too large to ride, they enter a particularly exciting phase (for them, their parents and for Hotel Lake residents) when they cannot submerge and often must be protected against eagle attacks. The loon parents are fierce defenders (eagles have died from loon beak stab wounds) but eagles are known to pair-up and attack using “cooperative or tandem tactics” - which often leads to the chick’s demise. At 8 weeks the chicks’ chances of survival improve dramatically when they are able to catch about half their food needs, are almost fully feathered and are exercising their wings in anticipation of their first flight. 

Once capable of flight the young loon is classified  as a Juvenile and rapidly becomes independent  of parental support. The parents initiate this phase by effectively ‘abandoning’ their chick or chicks - although they still keep in touch by calling. The parents seem to enjoy this relative freedom, regained after 3 months of  24/7 upbringing duties and find time to socialize with other adults prior to leaving the breeding grounds on their fall migration. The male departs first and a few days later the female takes to the air. They migrate separately and spend the winter in different locations. 

 

Juvenile loon(s) remain at the lake for as long as another two months, practicing fishing skills and takeoffs, flight and landings. They then depart on individual migrations to ocean waters they have never seen before. In the winter, on the ocean within a few miles of the shore, the loons may cooperate with others while hunting fish. At some point all the loons will moult, losing their flight feathers thus rendering them incapable of flight for several weeks. In March or April the cycle starts again with the spring migration to the breeding grounds. Except for the juveniles - they will stay on the ocean for 2 or 3 years before making their first ‘practice migration', not to breed, but to familiarize themselves with much of the cycle they will follow for the rest of their lives. They will be 6 or 7 years old before they breed.

Hunting and Feeding

The first meal for a newly hatched loon chick is often a minnow, and loons are superb fishers all their lives. It is estimated that a loon family of four will consume almost 400 kg of fish during the breeding season. The loon can consume a cutthroat trout with little difficulty, and it's diet includes frogs, sticklebacks, leeches, mussels, crayfish and aquatic insects. “Our” loons are no doubt delighted that Hotel Lake is stocked annually, at about mid-April —  with cutthroat trout. 

 

The following video  “Loons Hunting Fish Like Torpedoes..." captures the agility of the loon underwater. Note that the webbed feet of the loon are well aft of the rear of the body, and that the feathers on the loon’s back and wings are so tightly compressed that it looks more like a ceramic surface than feathers.                                                                                                

The Loon Nest

Given the loons’ lack of mobility ashore, their nests must be immediately adjacent to the water and present a minimal requirement for climbing skills. Nest preparation time ranges from 0 to 8 days;  zero days if a flat mud or rock surface has been chosen, 8 days if an elaborate platform is the parents’ choice.

A recent survey of 229 nests: 46% on grasses and rushes in the water, 17% on bare ground on an island or lakeshore, 5% on a partially submerged log, 3% on an Artificial Nesting Platform (ANP), and 0.3% on top of a stump in the lake.

The Flight of the Loon  

Much has already been made of the fact that the loon’s superlative skills as a swimmer and diver exist together with it's less than sterling capabilities in key areas of flight. Specifically, while this bird has an impressively high cruising speed (up to 120 kph) while migrating between ocean and lake, it's takeoffs and landings are arguably the most exciting of any waterfowl. 

 

The loon’s solid (thus heavy) wing bones help it dive, and a high aspect ratio wing (think ‘glider’) that folds tightly to its back and reduces underwater drag, result in a long and laboured takeoff run (and  “run” is definitely the right word here). The loon rears up out of the water with an “all feathers deployed” wing swipe, then proceeds to “run” across the water, wings flapping vigorously. The lift provided by the wings increases with speed, until the wings bear all the weight and the loon is flying. Remaining just above the water, as seen in the next photo, the loon then accelerates by taking advantage of a phenomena called "Ground Effect"(perhaps we could call it Water Effect in this case). There can be no climbing or turning until the speed has increased considerably.

We have two short videos for you. The first shows a pair of loons taking off. Note the Artificial Nesting Platform in the foreground.  The second video shows the takeoff in slow motion. Note the loon accelerating in Ground Effect after finally getting airborne.

The loon’s landing really is a thing of beauty. After a high speed, shallow gliding approach, a slight flare, the feet drag the surface, the chest impacts the water, and four seconds later, the loon is swimming normally.

The Loons’ Ideal Lake

It would appear that loons are looking for a lake at least the size of Hotel Lake, 25 ha (62 acres), with some small islands and an irregular, indented shoreline with pronounced bays. There must be areas of flat shore with vegetation that camouflages the nest and allows the nesting birds a minimally restricted field of view.

 

The lake water must be very clear, not choked with vegetation on or below the water. There should be an adequate food supply - fish not essential but a real plus. An adequate takeoff and acceleration run (you will note that even after getting airborne, the loon flies for some distance before it can gain “tree/hill clearing” altitude). Human activity must not exceed a reasonable level (some eastern loons have learned to live with power boats and Jet skis - while “our” loons get indignant when you bring your paddle board inside their Comfort Zone). The Nursery Area (used until the chicks are Juveniles) should be protected from weather and predators and be less than 2m deep.

The “Loon Worthiness” of Hotel Lake

Rating Hotel Lake’s ability to meet the various requirements of a breeding pair of loons seems at first to be an easy task. Adequate size - check. Water clarity - check. Lots of food including stickleback and cutthroat trout, frogs, mussels, leeches and aquatic insects check, check, check, check, check, check. Adequate areas for takeoff and landings - check. But wait a minute - how long has it been since we’ve seen a loon chick on our lake? Answer: Nine years as far as we can document. 

 

Many lakes in BC have, for a variety of reasons,  ceased to be hosts to loon breeding pairs. Is Hotel Lake destined to join the list? As noted in the Introduction to this article, the Hotel Lake Loon Chick Production Rate (HLLCPR) has been nothing if not meagre in recent years. It would seem to make sense to ponder whether the remaining requirements: 1. nesting sites, 2. nursery areas, and 3. a reasonable level of interaction with humans hold the answer to our lack of loons. Or is it something else?

Population Trend

Common Loons are not considered an endangered species - although the dangers they encounter are many and varied. Here’s one you might not have considered - loons migrating in rainy conditions can mistake a rain-soaked highway for the convenient strip of water they are hoping to see - with predictable results. But with respect to the survival of the breed, the minimum acceptable reproduction rate number has been calculated as 0.48 chicks per year per breeding pair. While the actual rate in North America varies between locales (the rate has fallen below 0.48 in some eastern locations where acid rain, heavy metal contamination and botulism take their toll) it presently averages 0.54 chicks per year per breeding pair.

Apparently we are not alone in wondering about declining loon reproductive success.  According to the Canadian Lakes Loon Fact Sheet (2019) “Loons are excellent indicators of broader lake health.  Loon reproductive success can tell us what impacts lake acidification and other conditions are having on fish stocks and aquatic life.” This fact sheet also acknowledges that “.....loon productivity has been consistently higher in western regions of Canada (British Columbia, Yukon, and the Prairies) than in the east (Ontario, Québec, and Atlantic Canada)." It identifies acid and mercury levels in lakes as well as  increased boating activity, water level fluctuations, contaminants, and habitat loss due to shoreline development as ongoing threats to loon chick production and survival.  

 the minimum acceptable reproduction rate number has been calculated as 0.48 chicks per year per breeding pair

Chart from Canadian Lakes Loon Survey:   Blue dashed line is the minimum acceptable reproduction rate of 0.48 chicks per year per breeding pair. The red line shows the declining numbers of six-week-olds per breeding pair.

 So What Can We Do? 

Here are some suggestions to help our loons:

Create or enhance the shoreline buffer (Riparian Area)….A strip of vegetation that borders the shoreline is critically important to the health of a lake. A natural  shoreline will not only create lots of safe nesting areas for loons but will help protect against erosion and reduce runoff.

 

Leave overhanging vegetation. Overhanging vegetation shades and cools the water and provides important habitat for wildlife, including fish. Fish often feed and spawn below overhanging vegetation and the leaves, twigs, fruit, flowers and even insects found on overhanging vegetation provide an important food source for many species. 

 

Dispose of garbage correctly. Making sure plastics, fishing line, and tackle are properly stored and disposed of prevents loons and other wildlife (e.g., turtles, waterbirds) from becoming seriously injured or entangled. Keeping food scraps contained avoids attracting nest scavengers that prey on eggs and chicks.

 

Give loons and other wildlife space. Giving loons and other wildlife a wide berth when you’re boating or boarding helps them remain focused on important behaviours like feeding and caring for their young. If you notice a loon rearing up, hear its “tremolo” cry (sounds like crazy laughter) , or watch it flatten its body, or come off the nest, these are signs that a loon is feeling alarmed and threatened. 

 

Eliminate the use of pesticides, herbicides and fertilizers and maintain regular septic cleaning to avoid chemicals and contaminants from entering the lake.

AND,

Take Immediate action and volunteer to join the Canada Lakes Loon Survey.  Become one of 4000 volunteers by signing up to help. Here is the link:  main.jsp

Hopefully we will listen to loon calls every morning, hear the long, slapping and whapping of their attempts to get airborne and thrill to their haunting cries this spring …. and for many years to come.       (Soundtracks below from Cornell Lab of Ornithology.)

The Wail
00:00 / 00:16

The wail is probably the most often-heard call to a missing mate or separated chicks. The meaning is believed to be: "I am here, where are you".

The Tremelo
00:00 / 00:20

The Tremolo is a wavering call to announce a loon's presence. It can also be an aggressive response when intruded upon by a predator or humans, and may also be a signal to other loons to move to safety.

The Yodel
00:00 / 00:11

The Yodel is a unique aggressive call given only by the male during confrontation or territorial disputes. The meaning is believed to be: "this is our territory".

The Hoot
00:00 / 00:21

The Hoot is repeated soft, short calls of curiosity or contentment between adults or adults and chicks which help to maintain contact with each other.

Loons: A Cry From the Mist (2022).  This newly-released 45 minute TV documentary features a couple of breeding loon pairs in a couple of locations in Ontario. Told by cottagers, citizen scientists and bird experts, it chronicles a year in the life of the loons. Beautiful cinematography and informative material presented by caring people.

https://tv.cottagelife.com/videos/?vid=6315963284112

Footnote:

The Canadian Lakes Loon Survey (CLLS) is one of the longest-running and most popular monitoring programs delivered by Birds Canada. Launched in Ontario in 1981, the CLLS expanded to include most of southern Canada in the early 1990s. In 40 years, over 4,000 volunteers have monitored Common Loons on 4,500 lakes. This impressive effort has generated massive amounts of information, which has been used to generate a new report (2021) which takes a small and large scale look across southern Canada to assess trends and patterns in the number of loon chicks being produced and also identifies factors that have an important influence on productivity. Clearly written, beautifully illustrated and so very worth reading the study can be found below in our reference section.

Similarly, we recommend the National Loon Center Foundation, in Minnestota. Here you will find some wonderful information and pictures.  https://www.nationallooncenter.org/about-loons/

References

(New-2021) Canadian Lakes Loon Survey: New Report Helps Explain Mysterious Declines. An analysis of the ways in which factors such as predators, contamination, global warming and acid rain influence the reproduction rate in different areas, showing that Common Loon productivity has significantly decreased across most of southern Canada over the past several decades.

https://www.birdscanada.org/canadian-lakes-loon-survey-new-report-helps-explain-mysterious-declines

 

Canadian Lakes Loon Survey.  View/download this highly detailed and informative 40 year study.

https://www.birdscanada.org/bird-science/canadian-lakes-loon-survey

 

Canadian lakes Loon Fact Sheet (2019) from “BirdsCanada”.

https://birdscanada.org/wp-content/uploads/2020/02/CLLSBackgroundFactsheet.pdf

Loons: A Cry From the Mist (2022).  This newly-released 45 minute TV documentary features a couple of breeding loon pairs in a couple of locations in Ontario. Told by cottagers, citizen scientists and bird experts, it chronicles a year in the life of the loons. Beautiful cinematography and informative material presented by caring people.

https://tv.cottagelife.com/videos/?vid=6315963284112

 

2008, Wildlife Data Centre - Common Loon. A comprehensive but dated overview of the Common Loon's characteristics and lifecycle.

https://e190b270-efec-40ee-bf4f-73e086a365cc.filesusr.com/ugd/caa3e3_8da8c23062654901866aeb2b674ee353.pdf

 

Hinterland, Who’s Who. An excellent resource on loons by the Canadian Wildlife Federation.

https://www.hww.ca/en/wildlife/birds/loon.html

 

The Common Loon: What Are They Saying?

https://naturecanada.ca/news/blog/the-common-loon-what-are-they-saying/

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