A landscape-scale model of yellow-billed loon (Gavia adamsii) habitat preferences in northern alaska

Abstract

We modeled yellow-billed loon (Gavia adamsii) habitat preferences in a 23,500 km 2 area of northern Alaska using intensive aerial surveys and landscape-scale habitat descriptors. Of the 757 lakes censused, yellowbilled loons occupied 15% and Pacific loons (G. pacifica) 42%. Lake area, depth, proportion of shoreline in aquatic vegetation, shoreline complexity, hydrological connectivity (stream present within 100 m or absent), and an area-connectivity interaction were positive, significant predictors of yellow-billed loon presence in a multivariate logistic regression model, but distance to nearest river or Beaufort Sea coast were not. Predicted yellow-billed loon presence was 13 and 4.7 times more likely on deep and medium lakes, respectively, than on shallow lakes that freeze to the bottom. On small lakes (<60 ha), predicted yellowbilled loon presence was 4.8-1.7 times more likely on lakes with hydrological connectivity than without, but connectivity was not important at most lake sizes (65-750 ha). Yellow-billed loon broods depend on fish available in the brood-rearing lake, and we suggest that a dependable supply of fish is more likely in larger lakes, those deep enough to have open water under winter ice, and those near streams. Highly convoluted shorelines and those with aquatic vegetation provide loon nesting and brood-rearing sites, as well as fish habitat. Pacific loon absence was a significant, positive predictor when added to the habitat model, indicating that yellow-billed loons were four times more likely on lakes without Pacific loons.

Modeling Habitat Associations for the Common Loon (Gavia immer) at Multiple Scales in Northeastern North America

“…The best statewide model also describes loon preferences for open water surrounding the lake (e.g., hydrological connectivity). Earnst et al (2006) also found that Yellow-billed Loon in northern Alaska select breeding habitat based on landscape-scale features such as hydrological connectivity. The explanatory variable minimum-distance-to-human-populationcenter was featured at every scale in the statewide models, providing evidence that loons prefer to situate nests on lakes further from human disturbance.…”

“…The odds ratio represents the change in odds of observing loon nest presence for a unit change in the explanatory variable. The odds ratio of an explanatory variable is calculated as e (b × unit change) , where b is the parameter's coefficient in the multivariable model, and the test of whether b > 0 is equivalent to testing whether the confidence interval of the odds ratio crosses 1.0 (Earnst et al 2006).…”

“…A hierarchical approach is warranted and recommended for developing, evaluating, and implementing conservation plans for avian species to provide a broader understanding of avian-habitat associations within a landscape context (Saab 1999, Freemark et al 2002, Earnst et al 2006, Thogmartin and Knutson 2007.…”

Comparative nest survival of three sympatric loon species breeding in the Arctic

“…Adult loons of all species are highly territorial suggesting that loons are limited by resources on their breeding areas such as food, space, or quality nesting sites. The yellow-billed loon, the largest (5-6 kg) and behaviorally dominant loon species in northern Alaska, nests on large, deep connected lakes (Earnst et al 2006) and excludes other loons from their territories (Haynes et al 2014a). Pacific loons are medium sized (2-3.5 kg), often nest on smaller, less productive lakes, and almost exclusively feed their chicks invertebrates from the nesting lake (Kertell 1996, Russell 2002, Rizzolo 2017.…”

Ice roads through lake-rich Arctic watersheds: Integrating climate uncertainty and freshwater habitat responses into adaptive management

“…Yellow-billed loons (YBLO; Figure 7A), for example, are an avian species of interest on the ACP because of their low population size, their restricted breeding range, and the probability that resource extraction may encroach into high-density nesting areas (Schmidt, Flamme, and Walker 2014). Inventory and behavioral studies of YBLO and Pacific loons (PALO) in the FCW suggest that preferred nesting habitats on lake shorelines are related to connectivity, lake depth, and lake area ), similar to other regions of Arctic Alaska (Earnst, Platte, and Bond 2006;Schmidt, Flamme, and Walker 2014). Predicting which lakes will be used for nesting by these species relates both to interspecific competition between YBLO and PALO and the abundance of forage fish populations, such as ninespine stickleback and Alaska blackfish (Haynes et al 2014b).…”