When most people imagine scientific research they think microscopes and lab coats. When thinking of conservation they picture park rangers and polar bears. If people even consider loon conservation, they might imagine artificial nest rafts or aluminum fishing boats. These assumptions play a role in loon work, but when we try to study and conserve the loons of the Greater Yellowstone Ecosystem (GYE) there’s more to consider. An ecosystem of nearly 20 million acres of land^[1] marbled with towering mountains and dramatic canyons, a whopping 12 feet of annual snowfall,^[2] and nearly 7 million annual human visitors in its national parks alone^[3,4], the GYE is flush with curveballs for the collaborative effort to monitor and protect its uniquely isolated Common Loon population.

Add in a late winter, and loon work really gets challenging. As spring blossoms and temperatures warm in April, loons make their way from comfortable southerly wintering locales along the Pacific coast to the loons’ breeding grounds in the GYE. In April of 2019, however, the GYE greeted the loons with heavily iced over lake territories and the RCF loon team with impassable roads and a solid 3 feet of snowpack. This might seem like terrible news, but thankfully, loons are proactive -- they make frequent reconnaissance flights from nearby open water to determine the ice conditions of their territories to ensure that they will be the first to (re)occupy and claim them for the breeding season. For our team, this meant incorporating snowshoes and snowmobiles into our daily hiking routines as we trudged around to monitor the breeding and nesting progress of the loons. As temperatures rose, it meant challenging half-frozen stream crossings, sometimes on snowmobiles, and frustrating guesswork with our nest disturbance camera monitoring.

What does this all mean for the loons? As an easily disturbed species, small changes to their breeding timeline can have cascading effects on nesting success and productivity. In the context of the late winter of 2019, this climatic fluctuation led to early-season congregations of loons on open areas of the larger GYE lakes. In one brief sitting that May, our crew counted nearly 40 loons on the north end of Jackson Lake, preening, resting, and feeding. Some were probably northward migrants en route to Montana, Alberta, or Saskatchewan, but there were very likely local GYE loons among them waiting for their lakes to thaw. By May 26th that year, we still had two territories completely iced over!

In 2019 the late thaw meant that loons delayed their nesting, leading to more visitors visiting lakes when loons were incubating their eggs and most vulnerable to disturbance. The late snowpack also delayed our placing signs before the loons began nesting letting people know which areas were closed to human activity. Human disturbance is frequently a suspected cause of nest failure among breeding pairs in the GYE. Because the vast majority of visitors don’t know loons are present, let alone that their recreation choices can disrupt the loons’ normal nesting patterns, it’s extremely important to have educational signs in place by May. While some nests did fail last year, the season still ended with a level of productivity that should lead to continued growth for this small population (see prior blog post “17 Is a Big Number”). Even more exciting, several territories with a history of nest failure had surviving chicks last year -- a sign that management and closures put in place by the National Park Service, United States Forest Service, and Wyoming Game and Fish Department, in collaboration with RCF, are working to conserve these charismatic birds!

While the snowfall added new challenges to the 2019 season, working in the GYE always presents obstacles -- navigating mountainous terrain, mercurial weather, unexpected delays caused by wayward bison, and last, but not least, the futile task of trying to set a schedule based on the whims of unpredictable birds. Late winter or not, in 2020 the team has entered the season prepared to run the sleds again. Here’s hoping for a hasty thaw.

1. Greater Yellowstone Ecosystem – TPL
2. Yellowstone Weather – NPS
3. NPS News on Visitation
4. Annual Park Recreation Visitation Report

RCF loon team snowshoeing to a loon territory. Photo by Charlie Southwick.

RCF staff member fording river on hike to a loon territory. Photo by Vincent Spagnuolo.

RCF loon crew using snowmobiles to access remote loon lakes. Photo by Vincent Spagnuolo.

RCF loon crew gearing up for a hike to a loon territory. Photo by Charlie Southwick.

Aerial view of lake occupied by loons in Yellowstone National Park. Photo by Vincent Spagnuolo.

The number 17 does not come to mind when you think of big numbers, but when you’re working with Common Loons in the Greater Yellowstone Ecosystem (GYE), an isolated population numbering only 22 territorial pairs, small numbers like 17 can be relatively massive. This “big” number was important to the Ricketts Conservation Foundation’s Loon Study team because it was the number of chicks surviving at the end of our field season in the GYE! To give some context, it is the third most chicks observed in a GYE loon breeding season since monitoring began in 1989 (21 in 1989 and 18 in 2014). When you’re trying to keep a small and isolated population of loons from blinking out of existence, productive years like the one we observed in 2019 are critically important and every single loon chick counts! This is why the Ricketts Conservation Foundation is working hard in collaboration with all our state and federal partners in the GYE to understand the population and mitigate threats to nesting and survival.

Photo Credit - Daniel Poleschook

One of the most critical threats to the GYE loon population is human disturbance of nesting loons which can cause loons to flush off their nests leading to abandonment, depredation of the eggs by predators, or egg inviability due to exposure to the elements. Many loon territories in the GYE have had difficulty hatching chicks in recent years, and even one human-caused nest failure has a serious negative impact when working with such a small population! This past season we assisted the Wyoming Game and Fish Department (WGFD) and the Caribou-Targhee National Forest (CTNF) in developing 2 new closures and improving 3 existing closures to protect nesting loons across five lakes in the forest. We relied upon years of observational data, nest site locations, and trail camera research to inform the design and duration of each closure. These closures are temporary and are only in place during the nesting period when loons are the most sensitive to human disturbance. Some closures involve just closing off a portion of the lake like a cove, island, or section of marsh, while others require closing off the entire lake to boating or shoreline activities. You may see some of these loon closures in the CTNF as well as other loon closures across the GYE in the early summer as they’re well marked with posted signs and buoys.

Similar to the success targeted closures have in other parts of the loon’s range where conservation efforts work to protect nesting loons, these five closures resulted in four of the territories successfully hatching a total of seven chicks! The one pair to not hatch, unfortunately abandoned their nest due to unknown reasons. We still feel that four out of five is great and 80% can be considered a big number! To add perspective on the effectiveness and importance of these closures, in 2018, a voluntary closure was enacted at Moose Lake in the CTNF which resulted in the first chicks at that territory since 2003! The pair went on to hatch two “big” chicks this year with the improved and non-voluntary closure. Not only is there the obvious benefit of successful nests producing chicks, but minimizing human-caused nest failures strengthens loon pair bonds thus improving territory stability in the region, an important aspect of encouraging natural productivity levels and population dynamics. While this early success is promising, it’s important to note that no two lakes are the same and similarly, closures can be very different in design and approach. We’ll continue to work with the agencies to evolve the closures to be effective for loons while also minimizing the impact on human access and recreation.

It’s well known that loons are threatened by human impacts across their breeding range, particularly along the southern edge where human populations are the densest. While the GYE loon population is fortunate that development-related issues are less of a concern due to the protections of the National Parks and National Forests, it still must share the landscape with the human residents of the GYE and the millions of visitors drawn to the area each year. Targeted and informed conservation actions like these closures help humans and loons share the lakes and preserve the natural integrity of the GYE. We’re proud of these successful efforts to protect loons and commend our agency partners for their work to ensure the persistence of this population. We’re hopeful that together we’ll create a conservation scenario that leads to more “big” numbers of loon chicks in the coming years!