Conservation and Management

Effects Of Human Activity

Many anthropogenic factors adversely impact survival, health and reproductive success. Because of its top trophic-level position, high visibility to people, limited dispersal ability and relatively slow replacement rate, this loon is widely used as an indicator species for aquatic integrity (Evers 2006).

Shooting And Trapping

Sport and game hunting were more common prior to the federal Migratory Bird Treaty Act of 1918. Historically, killed due to perceived threat to game fish (Bent 1919). Mortality from sport shooting was linked to local population declines (Forbush 1912, Brewster 1924), including New Hampshire (Hammond and Wood 1976) and the Pacific Northwest (Corkran 1988). Illegal take through recreational hunting in the U.S. and Canada is now rare, but still occurs (Franson and Cliplef 1993, Pokras et al. 1993, Miconi et al. 2000, Franson et al. 2003, Sidor et al. 2003).

Subsistence harvesting common and practiced across Alaska, n. Canada, and Greenland. Earnst (2004) documented the harvest of common loons in Alaska and found that in the decade 1987-1997, 567 were taken in the Yukon-Kuskokwim Delta and from 1995-1996, 195 were reportedly taken on St. Lawrence Island. In general, annual take in Alaska appears to be far less than in Canada. The Cree, Inuit, and Naskapis practice subsistence hunting in Quebec as allowed by subsistence agreements. A recent total annual loon harvest in Quebec was nearly 4,500 birds (primarily Common Loons) (J. Rodrigue, pers. com.). Harvest in Labrador is relatively rare (N. Burgess, pers. com.) and unknown in Greenland, but likely uncommon; a regular take and sale occurs in Greenland, but extent has not been determined (J. Nyeland, pers. com.).

Mercury, Lead And Other Contaminants

Species serves as a prominent biosentinel of persistent bioaccumulative contaminants, particularly mercury in the U.S. and Canada (Evers et al. 1998, Meyer et al. 1998, Scheuhammer et al. 1998, Scheuhammer et al. 2001, 2007, Evers et al. 2003, 2005, Fevold et al. 2003, Burgess et al. 2005, Champoux et al. 2006), lead (Pokras and Chafel 1992, Franson et al. 2003, Scheuhammer et al. 2003), and organochlorines (Sutcliffe 1978, Fox et al. 1980, Frank et al. 1983, Haseltine et al. 1983, McIntyre et al. 1993).

Mercury (Hg). Geographic patterns of Hg exposure are well-established. Mercury has adversely impacted reproduction in New England (Evers et al. 2008), the Canadian Maritimes and Wisconsin (Burgess and Meyer 2008), New York (BRI unpubl. data), and likely elsewhere at levels that can cause local negative impacts. Evers et al. (1998, 2003) found breeding individuals in New York and New England had the highest mean blood and egg Hg levels in the US, while juvenile blood Hg levels were four times those of an Alaskan reference site.

Mercury exposure affects behavior, physiology, and survivorship. These findings include behavior modifications in chicks (Nocera and Taylor 1998, Counard 2001) and increased lethargy in adults (Evers et al. 2008), measured in the field; in the lab, at dietary MeHg dosed levels relevant to known field conditions (Karasov et al. 2007, Kenow et al. 2007a), effects from Hg exposure include compromised immune system (Kenow et al. 2007b) and changes in blood biochemsitry (Kenow et al. 2008). High Hg individuals spend less time incubating eggs; pairs with blood Hg levels >4.0 ug/g incubated their eggs 85% of the time; compared to 99% of the time in the control group with Hg levels <1.0 ug/g (Evers et al. 2008). Juvenile loons are less impacted by environmental Hg loads while in molt than after molt is completed (Kenow et al. 2003b).

In addition to intensive long-term research and monitoring of Hg levels in the Rangeley Lakes, Maine and New Hampshire study (Evers et al. 2003, 2008), a parallel study is ongoing in Wisconsin. The goals are to conduct research to improve predictions of loon population dynamics in regions impacted by multiple stressors, to advance techniques for assessing the relative risk of Hg exposure and other stressors in the Upper Great Lakes, and to predict the population level benefits of reducing or controlling the impact of identified stressors (from Meyer 2006).

Lowest observed adverse effect levels (LOAELs) or thresholds are now known: 3.0 ug/g in blood and 40 ppm in feathers (Evers et al. 2008) and 1.3 ug/g (wet weight) in eggs (Evers et al. 2003). Adult loons foraging on prey averaging >0.16 ug/g (whole body, wet weight) exceed LOAELs. Strong agreement of LOAELs with an independent but similar field study in Wisconsin and Canadian Maritimes (Burgess and Meyer 2008) that found 50% fewer fledged young produced by adult loons with blood Hg levels of 3.45 ug/g (wet weight). Because of well-established spatiotemporal Hg exposure patterns and known LOAELs, used as primary indicator for identifying biological Hg hotspots (Evers et al. 2007) and national Hg monitoring programs in Canada and the United States (Wolfe et al. 2007; Negra 2009).

Lead (Pb). Lead poisoning through ingestion of Pb fishing sinkers, which loons apparently mistake as pebbles they use for grit, is an important cause of breeding adult mortality throughout eastern Canada and the US. Lead poisoning affects nerve impulse transmission with clinical signs such as head-shaking, gaping, wing and eye droop. Chronic toxicosis has been associated with immunosuppression, and decreased weight, body fat, and muscle mass (Sidor et al 2003, M. Pokras, pers. com.). Other in-field diagnostic symptoms include green feces, disorientation, and lethargy causing less frequent dives in depth and duration, increased occurrence in shallow waters and frequent bouts of beaching with progression of condition (K. Taylor, pers. com.). Lethargic behaviors may predispose lead-poisoned loons to boat collisions (Miconi et al. 2000).

Toxic effects well documented and confirm a direct link between ingestion of fishing tackle and mortality (McIntyre 1988, McNicholl 1988, Ensor et al. 1993, Pokras and Chafel 1992, Franson et al. 1993, Pokras et al. 1993, Poppenga et al. 1993, Scheuhammer and Norris 1996, Miconi et al. 2000, Franson et al. 2003, Sidor et al. 2003, Meyer 2006). In a nationwide waterbird study (based on live bird sampling) Franson et al. (2003) found loons to have the highest incidence of Pb ingestion (3.5%). In New England, a 14-year study diagnosing causes of mortality in 522 Common Loons documented that 44% of the breeding adults died from Pb toxicosis (Sidor et al. 2003). Substantial rates of Pb-related mortality are also known for Michigan (T. Cooley, pers. com.) and Minnesota (P. Perry, pers. com.).

Organic pollutants. Unlike Hg and Pb, organic pollutants are largely synthetic compounds and are recent additions to the landscape. A period of evolutionary acclimation is lacking, which makes synthetic compounds potentially dangerous to individual health. The impacts of organochlorine insecticides including DDT and its derivatives, such as DDE, are well known for thinning eggshells in raptors; loon eggshell thickness during the 1960s and 1970s also declined (Anderson and Hickey 1972) but apparently not at a level to cause local reproductive impacts (Vermeer 1973a, Gilbertson and Reynolds 1974, Ream 1976, Sutcliffe 1978, Fox et al. 1980, Frank et al. 1983, McIntyre et al. 1993).

Geographically comparable studies in Ontario (Frank et al. 1983) and New Hampshire (Haseltine et al. 1983, McIntyre et al. 1993) indicate overall declines in the 1980s and 1990s in DDE and polychlorinated biphenyls (PCBs). Few recent examinations of organic pollutants have been made. In the mid 1990s, organochlorine insecticide scans on eggs (including DDE, PCBs, dieldrin, heptachloradane, and other pollutants) found low levels in the Rangeley Lakes area of Maine (BRI, unpubl. data) and across other parts of New England (M. Pokras, pers. com.). Other organic pollutants such as polychlorinated dibenzodioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), organophosphorous insecticides (OPs), polycyclic aromatic hydrocarbons (PAHs), polybrominated diphenyl ethers (PBDE or flame retardants), and perflorinated chemicals (PFO or teflons) are now being measured in loon tissues. In Maine and New Hampshire, Goodale (2009) found 11 egg levels ranging 5-185 ppb (ww) for PBDEs and 24-326 ppb (ww) for PFOs (where 55% of the eggs exceeded avian effects thresholds).

Acid Rain

Acid rain impacts and the breeding range of loons overlap in large areas of eastern Canada, including southern Ontario and Quebec and the Canadian Maritimes, and smaller areas of the U.S., including north-central Wisconsin, the western Upper Peninsula of Michigan, and New York.

Yellow perch, a favored prey item (Barr 1996), are generally tolerant at lake pH levels >5 (although lower tolerances are known in lakes with high organic loads) (Burgess et al. 1998) and therefore provide prey for loons on mildly acidified lakes. However, highly acidic lakes in Ontario (total alkalinity < 40 micro-equivalents per liter) were significantly correlated with increased brood mortality (Alvo et al. 1988). A decline in breeding success on highly acidic lakes was also documented by Ashenden (1988). More rigorous efforts by Alvo (1996) documented the relationship of loon reproductive success and lake acidity and found (1) fledging success is highly unlikely at a lake pH of 4.0 to 4.3 (regardless of lake size), (2) high brood mortality is consistent on some lakes with a pH of 4.4 to 5.8 (particularly small ones), and (3) acidity-related brood mortality can occur on lakes with pH <6.3. On fishless lakes, adult loons will commonly forage on a neighboring lake while chicks are fed invertebrates (Alvo et al. 1988, Parker 1988). Invertebrate diets are generally considered energetically insufficient for successful fledging (Alvo et al. 1988), although loon pairs on fishless lakes with large leech populations can fledge young (Gingras and Paszkowski 2006). Exceptions of adaptive adult foraging behaviors are known (Parker 1985).

Several other investigators have documented lower loon productivity on acidic lakes (McNicol et al. 1987, 1995b; DesGranges 1989; Kerekes et al. 1994). In e. Canada, an estimated 150,000 lakes had a pH < 6.0 in the mid-1980s (Kelso et al. 1986). Although acid rain emissions have since declined and water chemistry has improved in one-third of Canada’s lakes (Clair et al. 1995), the remaining number of acidic lakes coupled with findings by Alvo (1996) indicates potential adverse effects persist. Doka et al. (2003) predict continued impacts to biota in lake ecosystems of se. Canada unless further reductions in sulfate deposition are achieved.

Acidic lakes also tend to have higher MeHg availability to the biota because acidification increases net MeHg production. Meyer et al. (1995) found chicks with blood Hg levels < 0.3 ppm (ww) had lower survival rates on lakes with a pH <6.3. Merrill et al. (2005) documented a decrease in food intake by loon chicks on these lakes as one potential cause, although disentangling behavioral or physiological impacts from the Hg versus disruptions in lake ecological processes requires further investigation. In Ontario, fish Hg levels had a negative correlation with lake pH and was linked with reproductive risks for loons on 30% of the study lakes (Scheuhammer and Blancher 1994).

Fishing Nets And Traps

Inadvertently caught in nets set by commercial and tribal fishing, which can cause substantial mortality. Commercial fishnet by-catch documented in freshwater areas in northern Lake Michigan and Lake Huron and the southern shore of Lake Superior (Carey 1993). In the 1960s and 1970s, Vermeer (1973) documented fishnet mortality in several lakes in the Northwest Territories and Manitoba. Approximately 50 migrant loons captured this way in one net over a one-week period on Lake Superior, Michigan (DCE).

In winter of 1998, Forsell (1999) documented 21% of dead birds caught in commercial gillnets from the Chesapeake Bay were Common Loons. Although bycatch in this region is highest for the Red-throated Loon, the Common Loon is a close second according to the waterbird vulnerability index (Forsell 1999). Since the mid-Atlantic coast supports high densities of Common Loons, annual takes in this region constitute a major conservation threat.

Reservoir Management

Water level fluctuations from both storage and peaking reservoirs have deleterious effects on loon nesting success. Increasing water levels inundate nests while lowering water levels strand nests, increasing the difficulty of incubation exchanges and enhancing predation (Fair 1979). In Voyageurs National Park’s Rainy, Namakan, and Kabetogoma lakes in Minnesota, an average of 60-70% of loon nests failed due to water level management between 1979 and 1986 (Reiser 1988). Since 2000, the International Joint Commission has instituted new hydrological regimes (Paruk et al. 2009). In reservoirs of the Rangeley Lakes (Maine and New Hampshire), significant negative impacts on nesting by water level fluctuations on Aziscohos Lake (Fair and Poirier 1993, DeSorbo and Evers 2002) and Richardson and Mooselookmeguntic lakes (Savoy and Evers 2001a, b) until settlement agreements established changes in water level management and institution of rafts. Recently, the Federal Energy Regulatory Commission (FERC) has encouraged hydrological management schemes that minimize impacts to nesting loons (see Management Strategies).

Annual and summer water level fluctuations are significantly correlated with adult female and juvenile loon blood Hg concentrations; thus reservoirs are also regularly investigated for their contribution toward methylmercury (MeHg) production and availability based on FERC relicensing requirements (Evers et al. 2007).

Oil

Marine oil spills are a major threat (White and Frink 1991). Since the early 1900s, multiple oil spills in Florida have accounted for loon mortality events numbering in the hundreds (Forrester et al. 1997). Several recent oil spills illustrate similar impacts in Alaska and New England.

In March 1989, the Exxon Valdez spilled 11 million gallons of oil across approximately 1,300 miles of Alaskan shoreline (Maki 1991); 216 Common Loon carcasses were recovered (Ford et al. 1996). According to the Exxon Valdez Oil Spill Trustee Council, pre-spill loon counts compared to annual post-spill March counts indicate that the Common Loon has recovered in this region.

In January 1996, the tank barge North Cape spilled 828,000 gallons of home heating oil off the Rhode Island coast, killing an estimated 400 loons (NOAA et al. 1999). Models based on the population dynamics of color-marked individuals indicate approximately 3,900 loon-years were lost in this event (Sperduto et al. 2003). On-site replacement of loons was deemed logistically impractical, so state and federal trustees made a precedent-setting decision that restoration would entail purchase of lake shoreline breeding habitat in Maine.

A subsequent ten-year project monitoring productivity quantified an assessment of post-injury mitigation of loon-years lost for three areas in Maine: the West Branch of the Penobscot River, the upper Allagash River, and the Downeast area of Maine (DCE). A similar approach may be used for assessing injury and compensating the loss of Common Loons killed during an oil spill in Buzzard’s Bay, Massachusetts on 27 April, 2003.

Human Intrusion On Breeding Lakes

Development and recreational pressures on lakes have been implicated in population declines and reduced breeding success (Vermeer 1973a, Ream 1976, Salt and Salt 1976, Alvo 1981, Titus and Van Druff 1981, Heimberger et al. 1983, Peck and James 1983, Dahmer 1986, Jung 1987, McIntyre 1988, Strong and Bissonette 1989, Semenchuk 1992, Kelly 1992, Kaplan 2003). Despite these declines, many studies report successful breeding on waterbodies with such disturbances (McIntyre 1979, Jung 1991, Taylor and Vogel 2003, Badzinski and Timmermans 2006) and that loons adopt adaptive strategies in response to human activity (Titus 1978, Sutcliffe 1980, Alvo 1981, Christenson 1981, Smith 1981, Titus and Van Druff 1981, Heimberger et al 1983, Jung 1987). The processes and limits of habituation are unknown and are best addressed by evaluating site-specific conditions. Evidence of ability to habituate suggests that properly designed management efforts can be successful.

Shoreline development. Habitat degradation and loss from shoreline development is commonly cited as a major contributor to declines in local breeding populations and reduced reproductive success (McIntyre 1988). Shoreline development adversely effects habitat quality by (1) modifying and/or removing vegetation and substrate material, (2) enhancing predator densities, and (3) increasing the overall presence of human activity.

Shoreline development is generally accompanied by increases in loon predators (McIntyre 1988). Raccoons are widely considered the most influential loon egg-predator (McCann et al. 2005, Meyer 2006) and their densities are generally correlated with increasing shoreline development (Sutcliffe 1980).

Breeding pairs historically unaccustomed to people are likely to relocate nest and nursery sites away from areas with high human presence (Smith 1981, Titus and Van Druff 1981, Kaplan 2003).

Recreational activity. The extent of boating impact depends on boater awareness and an individual loon’s ability to habituate. Ashenden (1988) showed recreational boating did not significantly impact productivity in Ontario. Recreational boating represents a greater disturbance and risk to loons in open water than those nesting and foraging in shallow water. Habituation to boating activity can dull response times, increasing susceptibility to collisions (K. Taylor, pers. com.). Thirty-nine percent of all loon mortality in New England was caused by trauma, with boat impacts contributing 36% to that total (Miconi et al. 2000). Christenson (1981) found that adults moved further distances with their young when boats were present. Energetic costs of such behavior are unknown, but it likely increases the likelihood of separation between chicks and adults, which may result in increased mortality.

Washouts of loon nests and blunt trauma mortality to loons from personal watercraft (Jet-skis) have been documented (Maine Audubon Society 1997, Jaruzel 1998, Miconi et al 2000). Disruption by personal watercraft is not limited to nest failure and direct mortality. Repeated travel in a localized area is a common mode of operation (Snow in Chin 1998), and the extended presence of personal watercraft near nest sites or families can disrupt incubation, expose eggs to predators, or impede parental care of young.

The impact of floatplanes on breeding lakes has not been quantified, however males regularly yodel in response to floatplanes flying over or into their territory. Other types of low-flying planes or even ultra-lights can elicit a response from a territorial loon pair. It is generally accepted that loons can acclimate to regular floatplane use and can even maintain a breeding territory and regularly fledge young in their presence (DCE).

Non-motorized watercrafts, such as canoes and kayaks, can access shallow water areas typical of nesting and brood sites. Additionally, canoeist and kayakers are more apt to use remote areas (Kaplan 2003). Disturbance from non-motorized sailboats and wind-surfing has not been documented, however anecdotal and behavioral evidence suggest a flapping sail can be perceived as a visual threat, and therefore has the potential to disrupt nesting and brooding activity, even in areas of high recreational use (LPC unpubl. data).

Non-motorized activity is most detrimental during nest initiation when egg investment is lowest and the likelihood of abandonment is highest. Kelly (1992) found flushing distances decreased as incubation progressed (week 1 = 129 m, week 2 = 121 m, week 3 = 91 m, and week 4 = 64 m). Though loons on lakes with high human use flush at shorter distances and less readily (Smith 1981, Titus and VanDruff 1981), any increase in activity near the nest may attract predators (McIntyre 1977a, 1988). Kelly (1992) found that the average time spent off the nest was eight minutes for flushes related to natural causes versus 24 minutes for those caused by human disturbance.

Excessive angler wading and boating in shallow vegetated areas disturb nesting and foraging activity (Zimmer 1979, Titus 1978, Titus and VanDruff 1981, Christenson 1981, Kelly 1992). Improperly disposed monofilament and fishing tackle pose mortality risks from entanglement and Pb poisoning (see Contaminants). Increased popularity of fishing tournaments can inadvertently encourage improper fishing practices during breeding season.

Global Climate Change

Impacts to the sustainability of Common Loon populations are unknown, but potential changes could include (1) warmer environments that could increase the methylation of Hg (Moore et al. 1998), (2) changes in marine near-shore fish availability (Klyashtorin 1998), and (3) hydrologic changes associated with abnormal summer weather events.

Botulism, Aspergillosus, And Other Diseases

Infections of Clostridium botulinum, common in the Great Lakes, and Clostridium perfrigens in marine environments (McIntyre 1988) can weaken and disorient individuals. While type C is relatively common and causes widespread disease in waterfowl, type E has been linked with multiple loon mortality events in Lake Michigan from 1963 to 1981 (Kaufmann and Fay 1964, Fay 1966, and Brand et al. 1983, Brand et al. 1988). An estimated 7,400 loons died during this time period (McIntyre 1988) and the deaths may be related to extreme, late-summer to fall lake level declines that facilitated the botulism outbreaks (Fuller and Shear 1995). Alewife (Alosa pseudoharengus) and American smelt (Osmerus mordax), both introduced species, are common forage fish that carry the botulism disease. Abundance of alewife, in particular, has been linked with botulism-related loon mortality events (Fay 1966, Brand et al. 1988). During the fall of 2006, an outbreak of botulism in northern Lake Michigan again occurred.

Recently, another suite of alien species have become established in Lake Erie and could lead to further loon die-offs (Roblee 2002). Complex links among (1) water level fluctuations, (2) introduced zebra mussel (Dreissena polymorpha) and quagga mussel (Dreissena bugensis), and (3) the introduced mollusk-feeding, round goby (Neogobius melanostomus) may be responsible for increased bioconcentration of botulism neurotoxins and greater availability to piscivorous birds in the fall. From 2000 through 2006, the New York State Department of Environmental Conservation estimated that over 12,000 Common Loons died from botulism type E in Lake Erie (K. Roblee, pers. com.). In 2002, the type E strain was found in Lake Ontario and in late fall of 2006, several hundred loons died on the lake. Because the migration through Lake Ontario is significantly greater than Lake Erie, more serious population-level effects could be forthcoming.

Common Loons are prone to aspergillosis infection, particularly if their immune system is weakened. Aspergillosis is usually considered a secondary infection that follows stress from disease, nutritional deficiencies, or other primary reasons that suppress the immune system. This fungal disease is the primary reason for low survivorship in captivity. Prevalence of aspergillosis in breeding populations was 2% in Ontario (Frank et al. 1983) and 2% in New England (Miconi et al. 2000). In Minnesota, Ensor et al. (1993) found that 7% of the dead and dying loons sampled had severe cases of aspergillosis. Forrester et al. (1997) documented 7% of a large sample of wintering loons in Florida with aspergillosis; an early cohort of the estimated dead loons that had Salmonella (White et al. 1976).

On Lake Umbagog, NH, where there have been significant losses of adult loons over multiple years since 2002, individuals were found to carry both avian influenza and paramyxovirus (Evers et al. 2006b). West Nile Virus has been documented in a breeding loon on Lake Umbagog (K. Taylor, pers. com.) and in an entire breeding family in Minnesota (J. Marcino, pers. com.).

Emaciation Syndrome

Forrester et al. (1997) identified emaciation syndrome as a regular mortality problem in winter. They described an ecological string of events where inclement cold weather and storm-induced turbidity in feeding areas caused stress. During and following such weather events, loons generally need to switch foraging emphasis from fish to crustaceans. Compared to fish, crabs and shrimp have higher salt and parasite loads, which may result in increased physiological stress. Individuals are usually able to withstand such dietary changes, but imbalances may occur during times of energetically-demanding physiological changes, such as simultaneous remigial molt. Greater-than-normal physiological stress would result in (1) increased metabolism of fat reserves and catabolism of muscle tissue, (2) remobilization of contaminants stored in both fat (organochlorines) and muscle (Hg), and (3) behavioral changes that impact foraging efficiency. Loons then starve and die from emaciation.

Forrester et al. (1997) attributes the large die-off of wintering loons documented by Alexander (1991) in the early to mid-1980s in Florida’s panhandle to emaciation syndrome. An estimated 13,000 loons died during that epizootic event in late winter of 1983 (Forrester et al. 1997). Spitzer (1995) described a similar scenario for wintering loons along the mid-Atlantic Coast. Emaciation syndrome has also been documented on the breeding grounds of Ontario (Frank et al. 1983) and Minnesota (Ensor et al. 1993), and was considered responsible for 12% and 20% of the dead loons collected from these studies, respectively.

Management

Conservation Status

Not currently, and has not formerly been listed under the federal United States Endangered Species Act. Formerly designated a species of special management concern by the USFWS in Regions 1, 3, 4, 5, 6, and 7 (USFWS 1995) but is no longer on the national list of Birds of Conservation Concern (USFWS 2002). In the northwestern U.S., the Bureau of Land Management considers it a sensitive species for Region 1 and the USDA Forest Service (USFS) designates it a species of special status.

At the state level currently listed as Threatened in New Hampshire and Michigan. A species of Special Concern in Connecticut, Idaho, Massachusetts, Montana, New York, Washington, and Wisconsin. In Alaska, it is considered an “injured species” that has not recovered in Prince William Sound.

Among other countries, it is designated as a species “not at risk” by the Committee on the Status of Endangered Wildlife in Canada (Vogel 1997); but the Migratory Bird Convention Act of 1994 protects it from purposeful, non-subsistence related take. Europe has placed Icelandic populations on the IUCN Red List of Threatened Species (Hilton-Taylor 2000).

Measures Proposed And Taken

Many federal, state, and regional conservation groups and organizations participate in collaborative programs to protect the Common Loon. These groups and others have produced specific management and conservation strategies that have helped to protect loons in North America; some of these strategies are described below.

Water Level Management

Regional stakeholders have become more involved in FERC relicensing procedures for reservoirs over past decade. Agreements have included stringent management mandates to ensure loon sustainability. Two primary hydrological regimes are used to manage reservoir water levels for optimum loon productivity. For reservoirs that have the hydrological flexibility to maintain relatively steady water levels, loon nests are most successful when water levels do not increase more than 15 cm (6 inches) or decrease more than 30 cm (12 inches) during any 28-day period within the peak nesting season (Fair 1979). A FERC license and an agreement by Central Maine Power Company (now owned by NextEra Energy) set this precedent on Lake Umbagog (a National Wildlife Refuge on the border of Maine and New Hampshire) (J. Fair, pers. com.).

Management of stable water levels for many reservoirs is more difficult, particularly when (1) reservoirs are interconnected, (2) there are downstream-user requirements, and (3) peaking facilities are operating. In these cases, storage reservoirs that usually have slow drawdowns through the summer require rafts for loon nesting success. Precedent-setting loon management plans in Maine by NextEra Energy employ a reservoir-wide artificial nest platform (rafts) program. On peaking reservoirs, with daily fluctuating water levels of around a meter, rafts are also required and are integral parts of loon management monitoring programs.

Artificial Nest Platforms And Avian Guards

Use of artificial nest platforms or rafts is a well-established management tool (Mathisen 1969, McIntyre 1977b, Fair 1993, DeSorbo and Evers 2002, Piper et al. 2002, DeSorbo et al. 2008). Recent summaries of raft use and loon reproductive success demonstrate that rafts provide suitable compensation for loss of productivity and can exceed normal levels by 50% (DeSorbo et al. 2007), although their placement should account for density dependent factors, such as escalated male-male contests (Mager et al. 2008). Proper construction is important to maximize use by loons and for longevity. Rafts are generally constructed from cedar logs, with galvanized bolts or nails and plastic mesh fencing which is attached using 1-1/2 inch galvanized fencing staples (Fair 1993, DeSorbo et al. 2008). Rafts need to be lined with material such as sphagnum moss, grasses, and other vegetation. Loons occupying rafts will typically add nesting material gathered from the immediate vicinity of the nesting site, but it is important to have a natural base. Rafts require regular monitoring to insure proper placement, buoyancy, and sufficient nesting materials throughout the season. Rafts should be removed from the water soon after nesting has ceased to dry and increase the longevity of the raft.

Raft positioning and location is determined by knowledge of (1) wind and wave action patterns relative to each territory, (2) loon territorial boundaries and proximity to other territories, (3) previous traditional and non-traditional nest site locations, and (4) boat traffic and human activity patterns relative to the specific territory; this is particularly important relative to the orientation of the avian guard (DeSorbo et al. 2008).

Avian guards are effective in (1) reducing egg exposure to avian predators, (2) lessening raft visibility by recreationists, and (3) increasing the probability that incubating loons remain on the nest during close approaches by recreationists and potential predators (DeSorbo et al. 2008). Avian guards therefore reduce flushing events and related disturbances to nesting loons. Fair (1993) found nesting success increased when employing avian guards on territories with regular avian predation of raft nests. Avian guards are made of metal fencing and camouflage mesh. Burlap camouflage mesh is a useful surrogate and is adequate for single-season use. Camouflage mesh material should be removed at the end of the season to avoid further degradation.

Signs, Buoys, And Roping

Recreational activities likely play a role in loon hatching and fledging success (see section on Human Intrusion). In response to this pressure, ropes and floating signs to cordon off high-risk territories can be effective, especially where enforcement of exclosures is possible. On highly developed lakes in New Hampshire, territories with signs and floatlines surpassed the hatching success of territories without such restrictions (Taylor and Vogel 2003). Use of voluntary enclosures should be based on site-specific nest failure history and an understanding of typical lake use patterns. Kelly (1992) recommends floating 3-6 signs, approximately 137 meters from the nest site for optimal buffering capacity. Enclosures should be removed immediately following hatch, or when the adults have moved young to another location. This will maximize public acceptance and compliance. Although signs and floatlines can serve to draw attention to a nest site, they can also effectively create a buffer that minimizes human impacts to nesting pairs.

Policy Actions

Lead

Lead fishing sinkers and jigs ≤ 1 ounce regularly kill Common Loons across North America; the birds apparently ingest the jigs and sinkers along with bait they eat, or pick them up off the bottom in their search for gizzard stones (see Food Habits: food capture and consumption). The impacts of lead sinkers on Mute Swans (Cygnus olor) and other wildlife spurred a 1987 ban in Great Britain. In Canada, the use of Pb fishing sinkers and jigs in national parks and national wildlife preserves has been banned since 1997. In the United States, three states have passed legislation on the use and sale of Pb fishing tackle. New Hampshire passed a ban, effective January of 2000, on the use of Pb sinkers ≤ one ounce (28g) and Pb jigs smaller than one inch (2. 54 cm) along its longest axis. In Maine and New York, legislation banning the sale of Pb sinkers ≤ half ounce went into effect in 2002 and 2004, respectively. In 2002, the U.S. Fish & Wildlife Service banned the use of Pb tackle at Red Rock Lakes National Wildlife Refuge, Montana; National Elk Refuge, Wyoming; and Seney National Wildlife Refuge, Michigan, with future bans discussed for all refuges with breeding loons and trumpeter swans.

Other Pb bans are being considered in Massachusetts, Michigan, Minnesota, and Vermont. A bill prohibiting both the sale and use of Pb sinkers was introduced in the Minnesota Senate in January of 2003. Massachusetts and Vermont have begun limited outreach efforts to encourage anglers to voluntarily switch to non-toxic tackle.

Habitat Protection

Breeding populations occur in a wide range of federal, tribal, and state protected areas. Protected loon breeding habitats in U.S. National Parks include lakes in Acadia, Glacier, Isle Royale, Voyageurs, and Yellowstone. Important National Wildlife Refuges include Lake Umbagog and Seney in the contiguous U.S. and many of the Alaskan National Wildlife Refuges south of the Brooks Range (e.g., Kenai). Important National Forests include Chequamegon-Nicolet (Wisconsin), Chippewa (Minnesota), Flathead (Montana), Hiawatha (Michigan), Ottawa (Michigan), and Superior (Minnesota). Major state areas include Adirondack Park of New York State. Tribes that provide important protection for breeding loons include, but are not limited to, Chippewa, Colville Confederated, Passamaquaddy, and Penobscot.

Major Canadian National and Provincial Parks that provide protection are: Atikaki (Manitoba); Nahanni (Northwest Territories); Kejimkujik (Nova Scotia); Algonquin and Quetico (Ontario); La Maurice and La Verendrye (Quebec); and Prince Albert (Saskatchewan).

Wintering populations exist within areas protected by National Oceanic and Atmospheric Administration and National Marine Fisheries Service programs, such as Apalachicola, Chesapeake Bay, and North Carolina National Estuarine Reserves. These areas should be focal points for oil spill prevention.

Monitoring

Monitoring occurs at state, regional, national and international scales. Some efforts are coordinated by government agencies and others are collaborative efforts organized by non-profit organizations. The National Park Service and collaborators actively monitor loon distribution and breeding success with an emphasis in National Parks with breeding loon populations; these include Acadia (Maine), Glacier (Montana), Isle Royale (Michigan), Voyageurs (Minnesota), and Yellowstone (Wyoming) National Parks.

The USFWS’s Office of Migratory Bird Management monitor breeding and wintering loon populations across North America. Most monitoring activities during the breeding season are based on aerial surveys and are standardized counts conducted over large regions to determine breeding waterfowl populations. During these counts, Common Loons are regularly counted. Similar aerial surveys for wintering waterfowl are conducted with a secondary emphasis on counting loons. National Wildlife Refuges actively count loons with a special emphasis on breeding populations. Most refuges with breeding loon populations contribute to standardized ground counts, including Kenai (Alaska) and Seney (Michigan), or aerial counts including many of the larger Alaskan refuges.

The Canadian Wildlife Service also conducts aerial surveys of breeding and wintering loons, often times during waterfowl population counts. Some extra efforts also occur, particularly in National Parks including Kejimkujik (Kerekes et al. 1994) and La Maurice (Kerekes and Masse 2000).

Effectiveness Of Measures

Conservation-oriented efforts and programs on behalf of the Common Loon have created one of the more successful wildlife recovery efforts in the United States. Even though populations in Canada remained robust and widespread, those in the United States were shrinking after the turn of the 20th century. By the mid 1900s, Common Loon densities in the United States continued to decline and the breeding range retracted, with several states experienced extirpations.

The creation of the North American Loon Fund and New Hampshire’s Loon Preservation Committee in the mid 1970s highlighted the need to protect and manage loon populations. A key mission for both non-profit organizations was to enlist volunteers to help safeguard nests and nursery areas through public education and other outreach efforts. The success of these early programs spawned other affiliate groups in many of the states inhabited by breeding loons. Many of those affiliate groups exist today and continue their mission to protect and conserve loons – those efforts are working as the Common Loon has recently been removed from its threatened status in New Hampshire and Vermont.

Agreements established by the Federal Energy Regulatory Commission (FERC) in some areas of the loon’s range have also spurred further protection of breeding pairs on reservoirs. Some reservoirs with dams that require FERC licenses are now legally required to either hold water levels relatively steady for the prime breeding season or employ a standardized artificial raft program to compensate for the projected loss of loon nesting success.

There has been some measure of success in response to reducing contaminants, including lead sinkers and airborne mercury from the loon’s breeding lakes thanks to both voluntary and legislative actions. In a precedent setting case, the USFWS’s Natural Resource Damage Assessment program was able to document injury to loons from an oil spill and the responsible party paid for loon-years lost to governmental trustees to be used for habitat protection.

Recent decisions to use the loon as a primary sentinel species to monitor mercury emission regulations in Canada and the United States sets a new precedent for formally using a bird species as a regulatory endpoint. This action not only improves funding for monitoring and research needs for the species, but it also elevates its status as a keystone species for policy making. Such an approach is promising at a global level. The recently formed International Center for Loon Conservation (a center under BioDiversity Research Institute) is striving to use the successfully-developed template from North America across the northern Hemisphere to help combat widespread issues that are not limited to political or hemispheric boundaries.

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