Survival and Migration of Rock Ptarmigan in Central Scandinavia

Nilsen, Erlend B.; Moa, Pål Fossland; Brøseth, Henrik; Pedersen, Hans Christian; Hagen, Bjørn-Roar

doi:10.3389/fevo.2020.00034

Cited by 9 publications

(7 citation statements)

References 34 publications

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“…During February and March 2015–2019, we captured a total of 188 willow ptarmigan at night using snowmobiles and large hand nets with prolonged handles, as described in Nilsen, Moa, Brøseth, Pedersen, and Hagen (2020). To prevent birds from flying off before the field personnel were close enough to capture them, a high‐powered headlamp was used to dazzle the birds.…”

Section: Methodsmentioning

confidence: 99%

“…During February and March 2015-2019, we captured a total of 188 willow ptarmigan at night using snowmobiles and large hand F I G U R E 1 Study area (outlined box) showing all marking locations (red triangles) and telemetry positions (blue dots) of the marked birds. The northern cluster of red triangles represents the Lifjellet location and the southern cluster Gusvatnet nets with prolonged handles, as described in Nilsen, Moa, Brøseth, Pedersen, and Hagen (2020). To prevent birds from flying off before the field personnel were close enough to capture them, a highpowered headlamp was used to dazzle the birds.…”

Section: Field Methodsmentioning

confidence: 99%

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Survival and cause‐specific mortality of harvested willow ptarmigan (Lagopus lagopus) in central Norway

Israelsen

Eriksen

Moa

et al. 2020

Ecology and Evolution

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Survival is a key demographic component that often varies as a result of human activities such as recreational harvest. Detailed understanding of seasonal variation in mortality patterns and the role of various risk factors is thus crucial for understanding the link between environmental variation and wildlife population dynamics and to design sustainable harvest management systems. Here, we report from a detailed seasonal and cause‐specific decomposition of mortality risks in willow ptarmigan ( Lagopus lagopus ) in central Norway. The analyses are based on radio‐collared ( n = 188) birds that were monitored across all seasons, and we used time‐to‐event models for competing risks to estimate mortality patterns. Overall, annual survival was estimated at 0.43 (SE: 0.04), with no distinct difference among years (2015/16 to 2018/19) or between sexes. Analysis of mortality risk factors revealed that on the annual basis, the risk of harvest mortality was lower than the risk of dying from natural causes. However, during the autumn harvest season (September–November), survival was low and the dominating cause of mortality was harvest. During winter (December–March) and spring seasons (April–May), survival was in general high and did not vary between males and females. However, during the spring season, juveniles (i.e., birds born last year) of both sexes had lower survival than adults, potentially because they are more prone to predation. During the summer season (June–August), females experienced a higher hazard than males, underlining the greater parental investment of females during egg production, incubation, and chick rearing compared to males. Our analyses provide unique insight into demographic and seasonal patterns in willow ptarmigan mortality risks in a harvested population and revealed a complex interplay across seasons, risk factors, and demographic classes. Such insight is valuable when designing sustainable management plans in a world undergoing massive environmental perturbations.

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Section: Methodsmentioning

confidence: 99%

Section: Field Methodsmentioning

confidence: 99%

Survival and cause‐specific mortality of harvested willow ptarmigan (Lagopus lagopus) in central Norway

Israelsen

Eriksen

Moa

et al. 2020

Ecology and Evolution

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“…Several studies have demonstrated that ptarmigans are migratory (Irving et al, 1967;Hoffman & Braun, 1975;Gruys, 1993;Brøseth et al, 2005;Hörnell-Willebrand et al, 2014;Nilsen et al, 2020b). Hörnell-Willebrand et al (2014) reported large individual variation in seasonal migration distances in willow ptarmigans.…”

Section: Prefacementioning

confidence: 99%

Drivers and Consequences of Partial Migration in an Alpine Bird Species

Arnekleiv¹

2021

Preprint

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1. Partial migration, where a portion of the population migrates between winter and summer (breeding) areas and the rest remain year-round resident, is a common phenomenon across several taxonomic groups. Yet, although several hypotheses have been put forward to explain why some individuals migrate while others stay resident – as well as the fitness consequences of the different strategies – the drivers and consequences of the decision to migrate or not are poorly understood. 2. We used data from radio-tagged female (n=73) willow ptarmigan Lagopus lagopus in an alpine study area in Central Norway to test if i) the decision to migrate was dependent on individual state variables (age and body size), ii) individuals repeated migratory behaviour between seasons, and iii) the choice of migratory strategy was related to nesting performance.3. Partially supporting our prediction that migratory strategy depends on individual state, we found that juvenile birds with small body sizes were more likely to migrate whereas large juveniles stayed resident. For adult females, we found no relationship between migratory strategy and body weight. We found strong evidence for high individual repeatability of migratory strategy between seasons. Migratory strategy did not explain variation in nesting performance among individuals, suggesting no direct influence of the chosen strategy on nesting success. 4. Our results indicate that partial migration in willow ptarmigan is determined by juvenile body weight, and that migratory behaviour becomes a part of the individual life history as a fixed strategy. Nesting success was not affected by migratory strategy in our study population, but future studies should assess other traits to further test potential fitness consequences.

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“…The highest population density of Oriental skylark was observed in habitats where crops were more diverse; as crop types offer more suitable habitats for nest construction throughout the breeding period [15]. Oriental skylark does not inhabit vegetation more than 30 to 35 cm in height [15,16]. Little data are available on the ecology of Oriental skylark in Pakistan.…”

Section: Introductionmentioning

confidence: 99%

Breeding biology and nidology of Oriental skylark (Alauda gulgula) in district Bajaur, Khyber Pakhtunkhwa, Pakistan

Gabol¹

2021

PAB

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A general field survey about Oriental skylark (Alauda gulgula) breeding biology and nest structure (nidology) was carried out during (April, May, June, and July) 2018 and 2019, in district Bajaur. This study was conducted in order to record all the ecological factors that hurdle for the successful breeding of skylark in the study area. For this purpose, we studied 33 nests from egg laying up to the fledging stage. As a result, morphometric measurements of 112 eggs were recorded. Overall eggs were oval dusty white or grey white with black spots and mostly smooth or of somewhat rough texture. Average egg weight 3.0 g, length 2.2 cm, width 3.27 cm 2 and volume 3.65 cm 3. Likewise explored average clutch size 3.39, incubation period 12.07 days, the number of eggs hatched 3.30 (95.19%), fledged 3.18 (97.34%), and breeding success (89.20%). After normal fledging, the floor of nests was recorded. The shape of nests was entirely round to preferential round; the average nest diameter 9.48±0.8 cm, cup diameter 7.86±0.6 cm, cup depth 6.21±0.5 cm, and nest weight 17.61±0.9 g. The main cause of breeding failure and nest loss was brutal nests and egg destruction by locals and a high rate of land as well avian predators.

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Survival and Migration of Rock Ptarmigan in Central Scandinavia

Cited by 9 publications

References 34 publications

Survival and cause‐specific mortality of harvested willow ptarmigan (Lagopus lagopus) in central Norway

Survival and cause‐specific mortality of harvested willow ptarmigan (Lagopus lagopus) in central Norway

Drivers and Consequences of Partial Migration in an Alpine Bird Species

Breeding biology and nidology of Oriental skylark (Alauda gulgula) in district Bajaur, Khyber Pakhtunkhwa, Pakistan

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