scholarly journals Mass occurrence and habitat selection of Common Redpolls (Carduelis flammea) after a large seed crop year: snow-covered ground facilitates food access

Author(s):  
Svein Dale

AbstractIn boreal forests, food supplies typically have cyclic variations, and many species here fluctuate in numbers from year to year. One group of species showing large variations in population size is birds specialized on seeds from masting trees. Here, I analyze spatial patterns of a mass occurrence and habitat selection of the Common Redpoll (Carduelis flammea) during the breeding season in southeastern Norway in 2020 after a year with large seed crops from Norway Spruce (Picea abies) and Downy Birch (Betula pubescens). I found that Common Redpoll numbers increased with elevation and towards the northwest. Numbers were also strongly and positively correlated with snow depth in early April when snow was present mainly above 400 m elevation. Sites with snow cover in early April (30% of all sites) held 96.4% of all individuals recorded. Field observations indicated that Common Redpolls foraged extensively for spruce seeds on the snow until the end of May when young were independent. I suggest that the mass occurrence was due to a unique combination of exceptionally large seed crops of two tree species coinciding in the same year. The masting produced large amounts of food both for overwintering (birch seeds) and for breeding (spruce seeds), and during the breeding season snow cover facilitated access to food resources. Dependency of Common Redpolls on snow cover suggests that climate change may negatively impact some seed-eaters in boreal regions. On the other hand, higher temperatures may induce more frequent masting which may be beneficial for seed-eaters. Thus, climate change is likely to lead to complex ecosystem changes in areas where snow cover may disappear.

Animals ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 182 ◽  
Author(s):  
Ruobing Zheng ◽  
Lacy Smith ◽  
Diann Prosser ◽  
John Takekawa ◽  
Scott Newman ◽  
...  

The Bar-headed Goose is the only true goose species or Anserinae to migrate solely within the Central Asian Flyway, and thus, it is an ideal species for observing the effects of both land use and climate change throughout the flyway. In this paper, we investigate the home range, movement pattern, and habitat selection of Bar-headed Geese (Anser indicus) during the breeding season at Qinghai Lake, which is one of their largest breeding areas and a major migration staging area in the flyway. We identified several areas used by the geese during the breeding season along the shoreline of Qinghai Lake and found that most geese had more than one core use area and daily movements that provided insight into their breeding activity. We also observed the intensive use of specific wetlands and habitats near Qinghai Lake. These data provide interesting insights into the movement ecology of this important species and also provide critical information for managers seeking to understand and respond to conservation concerns threatening Bar-headed Geese, such as landscape and habitat changes.


2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Daniel Y. Choi ◽  
Alexander C. Fish ◽  
Christopher E. Moorman ◽  
Christopher S. DePerno ◽  
Jessica M. Schillaci

1974 ◽  
Vol 38 (4) ◽  
pp. 634 ◽  
Author(s):  
Richard Wallestad ◽  
Philip Schladweiler

The Condor ◽  
2007 ◽  
Vol 109 (4) ◽  
pp. 750-768 ◽  
Author(s):  
Thomas E. Hamer ◽  
Eric D. Forsman ◽  
Elizabeth M. Glenn

Abstract We compared home range areas and habitat selection of radio-marked Spotted Owls (Strix occidentalis) and Barred Owls (Strix varia) in an area of sympatry in the northern Cascade Range of Washington in 1986–1989. On average, home ranges of Spotted Owls were 3–4 times larger than ranges of Barred Owls, and there was little overlap of home ranges during the breeding season. Ranges of both species tended to expand during winter. Home range size of both species was negatively correlated with the amount of old forest, but the negative slope of the regression was much steeper for Spotted Owls than for Barred Owls. For both species, home ranges of individual owls typically had high overlap among seasons and years, indicating high site fidelity. Barred Owls generally occupied home ranges at lower elevations than Spotted Owls (mean  =  386 ± 27 m vs. 750 ± 68 m). Both species tended to use old forests more than expected, but Spotted Owls tended to use other cover types less than expected, whereas Barred Owls used most other cover types in proportion to their availability. We suggest that Spotted Owls may use larger ranges than Barred Owls because they prey selectively on a few species of nocturnal mammals, whereas Barred Owls forage more evenly across a broad range of prey types, including diurnal and aquatic species. The low overlap of Barred Owl and Spotted Owl home ranges suggests that territorial Barred Owls exclude Spotted Owls from their territories, at least during the breeding season, thus reducing the amount of habitat available to Spotted Owls.


2011 ◽  
Vol 22 (3) ◽  
pp. 328-338 ◽  
Author(s):  
MARTIN ŠÁLEK ◽  
MATĚJ LÖVY

SummaryInformation on habitat requirements and spatial ecology is vital in conservation strategies and management of particular species. Little Owl Athene noctua is a highly threatened owl species whose populations have significantly decreased or are locally extinct in many European countries. In this study we report on spatial ecology and habitat selection of Little Owls during their breeding season in an agricultural landscape and discuss key management actions for its conservation. The mean home range size of radio-tracked Little Owls, determined by the kernel method, was 0.94 ha (SD = 0.95, 0.24–2.72 ha) and 4.30 ha (SD = 3.75, 0.88–11.70 ha) for 50% and 95% home range, respectively. The smallest home ranges were recorded in April–June (incubation and nesting period) with a significant increase in July–August (fledging season). The most important foraging habitat during the entire breeding season was grassland (especially pastures) reaching 90% for all locations. Vegetation height and cover were the main factors determining habitat selection: Little Owls significantly preferred sparse and short sward vegetation patches that enabled hunting of ground-dwelling prey. Conservation efforts for Little Owls should focus on the active management of prey-rich grassland habitats in the vicinity of breeding sites.


2018 ◽  
Vol 38 (2) ◽  
Author(s):  
黄慧琴 HUANG Huiqin ◽  
刘涛 LIU Tao ◽  
石金泽 SHI Jinze ◽  
刘鹏 LIU Peng ◽  
张微微 ZHANG Weiwei

2019 ◽  
Vol 28 (10) ◽  
pp. 2669-2685 ◽  
Author(s):  
Jaime Resano-Mayor ◽  
Fränzi Korner-Nievergelt ◽  
Sergio Vignali ◽  
Nathan Horrenberger ◽  
Arnaud G. Barras ◽  
...  

2010 ◽  
Vol 7 (50) ◽  
pp. 1319-1327 ◽  
Author(s):  
Graeme C. Hays ◽  
Sabrina Fossette ◽  
Kostas A. Katselidis ◽  
Patrizio Mariani ◽  
Gail Schofield

Long distance migration occurs in a wide variety of taxa including birds, insects, fishes, mammals and reptiles. Here, we provide evidence for a new paradigm for the determinants of migration destination. As adults, sea turtles show fidelity to their natal nesting areas and then at the end of the breeding season may migrate to distant foraging sites. For a major rookery in the Mediterranean, we simulated hatchling drift by releasing 288 000 numerical particles in an area close to the nesting beaches. We show that the pattern of adult dispersion from the breeding area reflects the extent of passive dispersion that would be experienced by hatchlings. Hence, the prevailing oceanography around nesting areas may be crucial to the selection of foraging sites used by adult sea turtles. This environmental forcing may allow the rapid evolution of new migration destinations if ocean currents alter with climate change.


2018 ◽  
Vol 4 (4) ◽  
pp. 499-512 ◽  
Author(s):  
Kristen Peck ◽  
Alastair Franke ◽  
Nicolas Lecomte ◽  
Joël Bêty

Detecting and planning for ecosystem changes from climate and land-use alteration is limited by uncertainty about the current distribution of many species. This is exacerbated in remote areas like the Arctic, where the impacts of climate change are the strongest and where industrial exploration and development are expanding. Using remotely-sensed environmental information and known nest sites, we estimated the breeding distribution and habitat selection of the peregrine falcon (Falco peregrinus) throughout most of Nunavut, a massive northern Canadian territory (>1.8 M km2) encompassing ∼15% of the world’s tundra biome. Our results show that peregrine falcons selected features of prior known importance such as rugged topography, but also sites with higher than average summer temperatures, more productive land classes, lower mean elevations, and lower mean summer precipitation. Our model identifies several areas of high relative probability of peregrine occurrence, some of which were unrecognized to date. Some of these areas may be targets for future industrial developments and are located in an area where some of the fastest climate changes are expected. Our model will allow managers to identify the areas that could be the most critical for monitoring in the context of future development and climate change.


2021 ◽  
Author(s):  
Hanna Lappalainen ◽  
Tuukka Petäjä ◽  
Timo Vihma ◽  
Jouni Räisänen ◽  
Alexander Baklanov ◽  
...  

Abstract. The Pan-Eurasian Experiment (PEEX) Science Plan, released in 2015, addressed a need for a holistic system understanding and outlined the most urgent research needs for sustainable development in the Artic-boreal region. Air quality in China and long-range transport of the atmospheric pollutants was also indicated as one of the most crucial topics of the research agenda. This paper summarizes results obtained during the last five years in the Northern Eurasian region. It also introduces recent observations on the air quality in the urban environments in China. The main regions of interest are the Russian Arctic, Northern Eurasian boreal forests (Siberia) and peatlands and on the mega cities in China. We frame our analysis against research themes introduced in 2015. We summarize recent progress in the understanding of the land – atmosphere – ocean systems feedbacks. Although the scientific knowledge in these regions has increased, there are still gaps in our understanding of large-scale climate-Earth surface interactions and feedbacks. This arises from limitations in research infrastructures and integrative data analyses, hindering a comprehensive system analysis. The fast-changing environment and ecosystem changes driven by climate change, socio-economic activities like the China Silk Road Initiative, and the global trends like urbanization further complicate such analyses. We recognize new topics with an increasing importance in the near future, such as enhancing biological sequestration capacity of greenhouse gases into forests and soils to mitigate the climate change and the socio-economic development to tackle air quality issues.


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