Predation by golden eagle Aquila chrysaetos on semi-domesticated reindeer Rangifer tarandus calves in northeastern Finnish Lapland

Norberg, Harri; Kojola, Ilpo; Aikio, Pekka; Nylund, Minna

doi:10.2981/0909-6396(2006)12[393:pbgeac]2.0.co;2

Cited by 46 publications

(48 citation statements)

References 36 publications

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“…Round-ups were performed between 20 June and 15 July. The number of calves counted varied between days, but such variation could only marginally influence the calf/female ratio because the critical first few weeks of life occurred before round-ups and mortality during the round-up season is low (< 2%) in this herd (Norberg et al 2006). Because reindeer is monoparous, the number of calves is the same as the number of females with calves.…”

Section: Parametersmentioning

confidence: 89%

Reproductive Rate and Calf Body Mass in a North-Boreal Reindeer Herd: Effects of NAO and Snow Conditions

Aikio

Kojola²

2014

Annales Zoologici Fennici

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Aikio, P. & Kojola, I. 2014: Reproductive rate and calf body mass in a north-boreal reindeer herd: effects of NAO and snow conditions. -Ann. Zool. Fennici 51: 507-514.Population demographics of northern ungulates are influenced by density and weather conditions. For caribou and reindeer (Rangifer tarandus) that dig in the snow for winter food, snow accumulation and duration of the snow layer are suggested to be influential. Indices based on large-scale alterations of atmospheric pressure such as the North Atlantic Oscillation (NAO) are connected to climate change and may predict ecological processes better than does local weather. Some empirical evidence of the effects of climate variation is available for Arctic and alpine populations but practically none for sedentary, boreal reindeer. We examined the effects of population density, winter and spring NAO, snow accumulation, and the timing of snowmelt on reproductive success (here the calf/female ratio) and on mean summer body mass of calves in a north-boreal, free-ranging herd of semi-domesticated reindeer in northeastern Finland. In this herd, day of snowmelt explained variation in the calf/female ratio and in the midsummer body mass of calves, more so than NAO, winter snow depth and population density.

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Section: Parametersmentioning

confidence: 89%

Reproductive Rate and Calf Body Mass in a North-Boreal Reindeer Herd: Effects of NAO and Snow Conditions

Aikio

Kojola²

2014

Annales Zoologici Fennici

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“…Natural predators were reported to travel along power line ROW (Foster, 1956in Ball, 2012Paquet et al, 1996;Gurarie et al, 2011). Power lines provide nesting and perching opportunities for golden eagle (Aquila chrysaetos) (Steenhof et al, 1993;Prather and Messmer 2010), which preys on ungulates (Nybakk et al, 2002;Norberg et al, 2006;Johnsen et al, 2007;Hamel and Côté, 2009;Nadjafzadeh et al, 2013).…”

Section: Potential Demographic Impactsmentioning

confidence: 99%

The effects of power lines on ungulates and implications for power line routing and rights-of-way management

Bartzke¹,

May²,

Bevanger³

et al. 2014

Int. J. Biodivers. Conserv.

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Thousands of kilometres of power lines exist and more are planned. Ungulates that range over large areas are likely to encounter power lines, but a synthesis of power line effects on ungulates is lacking. Reindeer (Rangifer tarandus tarandus) are suspected to avoid power lines up to distances of 4 km. In contrast, some forest ungulates preferentially forage in power line rights-of-way, cleared areas under power lines. We reviewed the factors that possibly influence avoidance and attraction effects of power lines on ungulates, construct a conceptual framework, and make suggestions on how to mitigate avoidance effects through power line routing and rights-of-way management. Power line construction, noise and electromagnetic fields are possible sources of disturbance, while rights-of-way management influences habitat use under power lines. Disturbance and altered habitat use can induce barrier and corridor effects, thereby influencing connectivity. Species-specific effects influence behavioural disturbance and habitat use. We found little evidence for behavioural disturbance of reindeer or forest ungulates under power lines. Forest ungulates could benefit from browsing in power line rights-of-way if they are managed to provide abundant and preferred forage as well as sufficient cover. However, power lines may facilitate access for hunters and predators. As a precaution, construction of power lines should be avoided in calving areas. To establish a causal relationship between the construction of power lines and potential avoidance, before-after-impact-control studies are recommended. More research is needed to make recommendations for the optimal design of power line networks.

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“…Many studies have shown the major role of large terrestrial carnivores on the neonate mortality of large and medium-sized ungulates (see Linnell et al, 1995). Calf mortality is also an important factor in the population dynamics of many reindeer and caribou herds, and predation is suspected as the primary cause of mortality (Miller & Broughton, 1974;Page, 1985;Mahoney et al;, Skogland, 1991Whitten et al, 1992;Adams et al, 1995;Valkenburg et al, 2004;Norberg et al, 2005Norberg et al, , 2006Nieminen, 2010). Caribou herds exposed to predation may lose even 50% of the annual calf crop prior to six months of age (Bergerud, 1980).…”

Section: Introductionmentioning

confidence: 99%

Mortality and survival of semi-domesticated reindeer (Rangifer tarandus tarandus L.) calves in northern Finland

Nieminen¹,

Norberg²,

Maijala³

2011

Ran

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During the period 1999 to 2004 the reindeer calf survival and mortality were studied in two reindeer-herding cooperatives and in five herding-groups in northern Finland, where in total 1725 calves were fitted with mortality indicating radio-transmitters fixed on expandable neck collars. The calves were weighed and marked at the age of 2-5 days in calving corrals and also during earmarking in June/July, when the age of calves was 2-8 weeks. The rate, timing and causes of mortality of calves were investigated. In 1999-2001 in Ivalo reindeer-herding cooperative 4.6% of radiocollared calves and in 2002-04 in Käsivarsi reindeer cooperative 5.2% was found dead. The average mortality of the calves radio-collared during calving time in May, and monitored to the end of October, was 6.7% in Ivalo and 9.0% in Käsivarsi. From July on, the average mortality rates varied between 1.8-5.7% among reindeer herding-groups. On average 54 and 42% of all radio-collared calves found dead in Ivalo and Käsivarsi cooperatives were attributed to predation, and golden eagle was the most significant cause of death in both cooperatives killing 0-3.5% of radio-collared calves in different study areas and years. Golden eagle predation accounted for 33-43% of all radio-collared calves found dead, 55-59% of the cases with identified cause of death and 80% of all identified predation. Most of the calves killed by golden eagle were found during July and August mainly in the open areas, as in highlands, bogs and clear-cut forest areas. The mean body weight of the calves radio-collared in May (weights adjusted on June 1 st ) and found dead during the summer was significantly (P<0.01) lighter than the mean weight of survivors both in Ivalo and Käsivarsi. Furthermore, the midsummer body weights of the calves (weights adjusted on July 1 st ) killed by all predators and by golden eagles were significantly (P<0.001) lower than the mean weight of surviving calves in both cooperatives. However, the weights did not differ between depredated calves and those calves that succumbed due to other causes than predation. The results of this study emphasize the relative importance of golden eagle as a mortality factor for reindeer calves in the northern part of the Finnish reindeer husbandry area.

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Predation by golden eagle Aquila chrysaetos on semi-domesticated reindeer Rangifer tarandus calves in northeastern Finnish Lapland

Abstract: Calf losses are an acute issue in Fennoscandian reindeer Rangifer t. tarandus management. We studied calf mortality in northeastern Finnish Lapland using 621 calves (304 in 1997 and 317 in 1998) marked with silent mortality transmitters and followed their survival during

Cited by 46 publications

References 36 publications

Reproductive Rate and Calf Body Mass in a North-Boreal Reindeer Herd: Effects of NAO and Snow Conditions

Reproductive Rate and Calf Body Mass in a North-Boreal Reindeer Herd: Effects of NAO and Snow Conditions

The effects of power lines on ungulates and implications for power line routing and rights-of-way management

Mortality and survival of semi-domesticated reindeer (Rangifer tarandus tarandus L.) calves in northern Finland

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