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1

Growth, size, and fat reserves of the raccoon dog in Finland

100%
Kauhala K.
Acta Theriologica
|
1993
|
tom 38
|
nr 2
The growth, size, and fat reserves of the raccoon dog Nyctereutes procyonoides (Gray, 1834) were studied in Finland in period 1986 - 1990. There was no sexual dimorphism in mean body size. Juveniles reached the mean adult body length at the age of 5 - 7 months. The weather in spring seemed to cause both annual and regional variation in the weight and fat reserves of juveniles in late autumn. Some of these differences could be seen as late as the following March, the breeding season of raccoon dogs. The adults had the least fat reserves in May and the most in October — November. The abundance of food, especially that of voles in early spring, seemed to affect the fat reserves of adult females in March.
2

Reproductive strategies of the raccoon dog and the red fox in Finland

100%
Kauhala K.
Acta Theriologica
|
1996
|
tom 41
|
nr 1
Reproductive strategies of the raccoon dog Nyctereutes procyonaid.es (Gray, 1834) and the red fox Vulpes vulpes (Linnaeus, 1758) were studied in southern Finland in 1986-1995. Litter size and relative litter weight, body size, population status and ecology were compared. Although the body size is almost equal, diet rather similar and both raccoon dog and fox populations have been rather stable during the study period, the litter sizes and relative litter weights differ greatly. The mean litter size of the raccoon dog was 9.0 and that of the red fox 5.1. The mean relative litter weight was 18.3-24.0% for the raccoon dog and 10,4-12.5% for the red fox. Thus, raccoon dog females are able to invest relatively more in reproduction than the red fox. There are several features in the ecology and behaviour of these species which can explain the different strategies. First, vole cycles have a strong effect on red fox reproduction, but have only a week effect on the litter size of the raccoon dog. Second, the raccoon dog sleeps during harsh winters and females are in good condition in the breeding season regardless of the weather and food supply during the winter. The red fox is always active in winter when food availability may be low and moving in snow is energetically costly. Omnivory, the ability to accumulate large fat reserves and winter dormancy guarantee the good condition of raccoon dog females even in fluctuating environments by reducing the relative costs of reproduction. Third, raccoon dog pups are easy prey to other predators, and mortality during their first year is very high. If mortality rate before the reproductive age is high and independent of litter size, natural selection will favour large litters. Juvenile mortality among red foxes is lower, and it probably would increase in larger litters due to eg starvation.
3

Habitat preferences of the native badger and the invasive raccoon dog in southern Finland

63%
Kauhala K., Auttila M.
Acta Theriologica
|
2010
|
tom 55
|
nr 3
231-240
We compared the habitat preferences of the alien raccoon dog Nyctereutes procyonoides (Gray, 1834) and the native badger Meles meles (Linnaeus, 1758) in two areas (Ruissalo and Tuulos) in southern Finland by radio-tracking the animals during summer from 2005 to 2008. We assumed that the habitat preferences of these two medium-sized carnivores differ to some extent (ie they are able to share the resources), because they have been sympatric for more than 50 years in southern Finland and populations of both species have increased during that period. The results indicated that the habitat preferences of these species are indeed different: raccoon dogs favoured meadows, gardens and open woodlands with tall and abundant undergrowth, whereas badgers favoured both pine forests and deciduous and mixed forests with thick canopy but sparse undergrowth. However, fields were favoured by both species in one study area (Tuulos). The results show that although both species are flexible in their habitat use and share some habitat preferences, the most favoured habitats differ between the species.
4

Age determination of the raccoon dog in Finland

63%
Kauhala K., Helle E.
Acta Theriologica
|
1990
|
tom 35
|
nr 3-4
5

Impact of landscape and habitat diversity on the diversity of diets of two omnivorous carnivores

63%
Kauhala K., Ihalainen A.
Acta Theriologica
|
2014
|
tom 59
|
nr 1
The impact of landscape and habitat diversity on diets of invasive and native species is an important issue when planning management or conservation of wildlife. The aim of the present study was to examine the impact of the environment on the diets of invasive raccoon dogs Nyctereutes procyonoides and native badgers Meles meles in two spatial scales in southern Finland. We studied the relationship between habitat diversity and diet in several study areas in southern Finland (landscape scale) and the relationship between diet and different habitat patches around latrine sites in one study area (local scale). Diets of both species differed between the study areas. The higher was the diversity of habitats in the landscape, the higher was the diversity of diet. Diversity of diet of omnivorous carnivores may thus be used as an indicator of habitat diversity. Also, the higher was the proportion of gardens, the higher was the diversity of raccoon dog diet. Raccoon dog diet was in all areas more diverse than badger diet. Overlap of diets was the smallest in the most diverse area and highest in a managed area with fields and industrial forests. In local scale, positive relationships between habitat types and raccoon dog diet included those between birds and gardens, small mammals and spruce forest and meadows, and frogs and gardens and deciduous forests. The models for badgers included those between birds and reed beds, frogs and deciduous forests, and cereal and earthworms and fields.
6

Optimal radio-tracking strategy - The best results with the least effort?

63%
Kauhala K., Holmala K.
Acta Theriologica
|
2008
|
tom 53
|
nr 4
We tested the need to radio-track nocturnal mammals, such as raccoon dogsNyctereutes procyonoides (Gray, 1834) and badgersMeles meles (Linnaeus, 1758), throughout the night for reliable estimates of home range size and habitat selection. We also tested the possibility to reduce the tracking effort by decreasing the number of tracking-nights. The results indicated that the locations collected before midnight gave good estimates of home range sizes but those collected after midnight or by reducing the number of tracking-nights resulted in smaller home ranges than those estimated using the total data. Thus, if one aims to estimate only the home range size, locations before midnight would be adequate. Locations of raccoon dogs taken only before or after midnight did not reveal all habitats, which were favoured on the basis of the total data. Although locations of badgers before midnight seemed to give correct results of habitat selection, we recommend radio-tracking also badgers at least few times through the night, because their core areas shifted during the night. In the case of badgers, but not of raccoon dogs, we obtained correct results of habitat selection by reducing the tracking effort by decreasing the number of tracking-nights.
7

Home ranges and densities of medium-sized carnivores in south- east Finland, with special reference to rabies spread

51%
Kauhala K., Holmala K., Lammers W., Schregel J.
Acta Theriologica
|
2006
|
tom 51
|
nr 1
1-13
Home ranges and densities of medium-sized carnivores were studied in south-east Finland by radio tracking. The species studied included potential vectors of rabies: the raccoon dogNyctereutes procyonoides (Gray, 1834), red foxVulpes vulpes (Linnaeus, 1758), European badgerMeles meles (Linnaeus, 1758) and domestic catFelis silvestris catus (Schreber, 1777). Home ranges of badgers were largest (mean 14.7 km2) and those of cats smallest (1.5 km2). Home ranges overlapped largely, both within and between species. Most home ranges were larger and population densities lower in south-east Finland compared with those in Western Europe. The pooled density of medium-sized carnivores with overlapping home ranges was, however, high, which may indicate a high risk of a rabies epizootic in this multi-host community. Rabies might also spread rapidly to new areas, because of the large home ranges and, consequently, long dispersal distances.
8

Diet of the raccoon dog Nyctereutes procyonoides - a canid with an opportunistic foraging strategy

51%
Sutor A., Kauhala K., Ansorge H.
Acta Theriologica
|
2010
|
tom 55
|
nr 2
165-176
We examined the raccoon dog’s Nyctereutes procyonoides (Gray, 1834) diet in two agricultural landscapes of Germany and compared these results with other diet studies from its native and introduced ranges. The diet composition was influenced as well by the landscape structures as by the seasons: in the waterrich study area 2 amphibians (54.1%) and fish (10.8%) occurred more frequently in the samples. In study area 1 amphibians (19.0%) and invertebrates (69.4%) gained more significance in the diet in summer, whereas in winter samples maize (32.8%) was an important food item. The diet composition shifted according to the availability of different food items. Raccoon dogs, ability to feed temporarily on one food source may possibly cause a serious problem to endangered small populations of birds and amphibians. The review of 81 data sets from nine countries showed that seasons and locality affected the occurrence of most food items. However, comparable to the present study, small mammals, insects and plants were identified as important food items both in native and introduced ranges of the raccoon dog. In regard to its diet composition, gathering foraging strategy and inactivity during winter, the raccoon dog probably preys less often on game animals and birds than the native red fox Vulpes vulpes.
9

Habitat impact on raccoon dog Nyctereutes procyonoides home range size in southern Finland

51%
Kauhala K., Schregel J., Auttila M.
Acta Theriologica
|
2010
|
tom 55
|
nr 4
Monogamous canid home range size is often negatively correlated with population density. Home range size, in turn, may be affected by the habitat. Here we examined landscape features that may affect home range size of the invasive raccoon dogNyctereutes procyonoides (Gray, 1834), an important vector of diseases and parasites in Europe. The aim was thus to reveal the habitats where population density and the risk for epizootics is highest. We radio tracked 42 raccoon dogs in three areas in southern Finland between 2001 and 2007. There was an inverse relationship between home range size and the proportions of meadows and gardens, as well as habitat richness. Also mixed forests were more common in areas where home ranges were small. The risk for epizootics, such as rabies, is thus highest in areas which constitute of a mosaic of small patches of meadows, gardens and mixed forests. The preventive measures, such as bait vaccinations, against epizootics should therefore be concentrated in these areas which are mainly in and around villages.
10

Time allocation of male and female raccoon dogs to pup rearing at the den

51%
Kauhala K., Helle E., Pietila H.
Acta Theriologica
|
1998
|
tom 43
|
nr 3
The proportion of time that male and female raccoon dogs Nyctereutes procyonoides (Gray, 1834) spent at the den during pup rearing was studied in Finland using radio- tracking. Results were compared with the behaviour of some other canids. Male raccoon dogs spent even more time at the den than females, especially during the day when males remained almost 80% of the time at the den, but females only about 60%, The behaviour of males and females did not differ at night. Consequently, the behaviour of males differed at various times of day and night, but that of females did not. During the 1st month after birth pups were seldom left by themselves: during day both parents were often at the den, but at night only one of them was usually at the den. That males spend more time at the den with pups than females is common behaviour in the raccoon dog and the bat-eared fox Ofocyon megalotis. These canids feed on small food items that are difficult to carry to the den, especially if food is scarce and widely distributed. Instead, the female forages and nurses the pups, and the male guards the litter. In species with larger food items, the males usually carry food to the den. When food items are very large they cannot be carried to the den, but males and other pack members feed from the carcass and regurgitate food at the den.
11

Habitat use of the mountain hare Lepus timidus in summer: the importance of different vegetation layers

51%
Hiltunen M., Kauhala K., Linden H.
Acta Theriologica
|
2004
|
tom 49
|
nr 4
The aim of the present study was to examine how the vegetation structure of the forest, shrub and field and ground layer affect the habitat use of mountain haresLepus timidus Linnaeus, 1759 in summer (May–September) in southern Finland. The structure of each vegetation layer in woodlots throughout the entire study area of 20 km2 was measured. We analysed the vegetation data using principal component analyses (PCA) that arranged the woodlots along a gradient within each vegetation layer. Data on habitat use was gathered between 1998 and 2000 from 11 radio-collared mountain hares. The core areas of the home ranges of hares were determined and the vegetation structure of these areas was compared with the mean of the entire study area (core area, periphery area and control area). A similar shrub layer gradient was identified by PCA for seven out of the 11 hares. Hares preferred thickets of willowSalix spp., downy birchBetula pubescens, and sprucePicea abies. The hares did not show a consistent preference for the forest and ground levels. The results suggest that dense understories are important in the mountain hare’s habitat use, probably because they offer both food and shelter.
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