Manual of beaver management within the ... - DANUBEPARKS

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Manual of beaver management within the Danube river basinparticularly woody plants are concentrated by beavers to a safe place where they areconsumed. Feeding remnants are lying freely, twigs peeled of bark, bark free of bast.Feeding stool is being located close to the edge of the waterbody on the islands orshelfs, in the bushes.Photo No. 8.: Photo: beaver feeding stool6.4.2.2.1.4. Impressions of teethBeaver gnaw marks character is unique and confusion with the gnaw marks of otheranimals is excluded. Beaver gnaws thick trees around the entire perimeter with typicalshape of an hourglass, or sharpened pencil. When the tree is growing on the slope,beavers gnaw it from one side (in the form of a pit). Thin trunks of 5-6 cm thickness canbe cut by diagonal bite in one pressing of jaws. Traces of incisors are well discernibleon the cut.Upper incisors (incisivus) provide support. Lower incisors (incisivi), leaving traces withtwo grooves, determine the direction and strength. Twigs of about 1 cm thickness arecut through by single pressing of jaws. Such a cut is usually smooth and sloped,depending on beaver head skew. Beaver incisors width increases with age (seeattached Table No. 5). Knowing this, we can roughly determine the age of animalsgnawing the wood. However, it should be borne in mind, that the width of the trace onthe tree is slightly different from the actual width of the teeth, due to the flexibility ofwood. Even greater differences can be observed on lateral gnawing of bark, whengnawing through to the cambium. Widest traces (imprints) should be taken intoconsideration as first. As the first gnaw overlaps with the subsequent one, it is better todeal with transversal gnaws in the toughest wood. This method can not only determinethe age of the animal, but also the number of animals involved in tree gnawing, whichis sometimes a matter of all active members of the beaver family.29
Manual of beaver management within the Danube river basinTab. No 5. Width of incissorsunit Older than 1 year 2 – 12 months old cubLower incisors mm 8 – 9 Up to 7,5 2,6Upper incisors mm 7,5 – 8,5 Up to 7,2 2,51,5 month oldcubType of gnaw Completed AttemptsPhoto No. 9.: Detail of beaver gnaw marks6.4.2.2.1.5. Food cacheTo store fresh cut branches as a winter food supply, beavers stick them into the bottomof the waterbody - similarly to the foundations of their buildings, only considerablysparsely.Photo No. 10.: Food cache30
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Manual of beaver management within the ... - DANUBEPARKS

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