The authors treat of the following problems: taxonomy, origin and biology of fitchews; fitch - essential anatomy and physiological information; establishment and organization of farm; reproduction; ...rearing young animals; feeding; fitchews diseases; production economics
The authors treat of the following problems: taxonomy, origin and biology of fitchews; fitch - essential anatomy and physiological information; establishment and organization of farm; reproduction; ...rearing young animals; feeding; fitchews diseases; production economics.
The study was carried out on young (2-27 month of age) and grown-up (4-5 years) males and females of sable, on young pole cats (2-7 mo of age) and females of pole cats during rut period. The level in ...blood plasma of estradiol-170, progesterone and active androgens (testosterone and 5a-digydrotestosteron) was determined and histological investigations were carried out. Histological structure of ovary in females of martens at 5 mo of age has been shown to be near to definitive one. This may suggest that the functional state of ovary in females at 5 months of age is near to such as in females during rut period, but at a later time, under the effect of seasonal factors, the activity of gonads decreases. Endocrine activity of adult animals sharply increases in March and thereafter it increases more slowly up to June. So, the dynamics of sex steroid hormones in blood plasma in males and females of sable and polecat reflects the level of gonads functioning: the activity of their endocrine function increase s during rut periods and decreases during autumn-winter season
We surveyed the densities of small mammals on 17 islands in Lake Inari in Finnish Lapland during 5 yr to estimate the degree of spatial synchrony in the dynamics of microtine rodents (Clethrionomys, ...Microtus) and shrews (Sorex). Microtine rodents have a 4-5 yr population cycle in Lapland. Most island populations of microtine rodents were in complete synchrony with the mainland populations and each other, and the same-island rodent and shrew populations showed largely synchronous population changes. The few exceptions included small and isolated populations of Microtus oeconomus fluctuating out of synchrony. The generally high level of spatial synchrony is unlikely to be caused by predation by nomadic avian predators, as has been suggested previously, because they are very scarce in the study area. We present and discuss results suggesting that the synchrony is due to predation by small mustelids, especially the stoat, which may also be the primary cause of the large-amplitude rodent oscillations.
Predator odors have potential as feeding repellents for mammalian herbivores, including Aplodontia rufa, the mountain beaver. However, the repellency of major chemical constituents of natural ...predator scents for this species has not been evaluated. In this study, the effects of several synthetic sulfur compounds from predator scents on feeding by mountain beavers were assessed and compared to the effects of coyote (Canis latrans) urine. Retrieval of food by mountain beavers from bowls scented with either coyote urine, diluted with water to different concentrations, synthetic components of predator scents, or control odorants was studied. The following synthetic compounds were tested: $\Delta^3$-Isopentenyl methyl sulfide (IMS), a compound present in urine from several canid species; 2,2 dimethylthietane (DMT), a major constituent in anal gland secretion from the mink (Mustela vison); a 1:1 mixture of 2-propylthietane (PT) and 3-propyl-1,2-dithiolane (PDT), compounds occurring in anal gland secretions from the stoat (Mustela erminea) and the ferret (Mustela putorius). Habituation to PT plus PDT was studied by measuring consumption of dry pellets during continuous exposure to these compounds for 5 d. In two-choice feeding trials mountain beavers retrieved significantly more food from bowls scented with water than from bowls scented with coyote urine. Dilution of urine had no statistically significant effect on food retrieval, but repellency tended to decrease with decreasing concentration. Mountain beavers retrieved less food scented with a 1:1 mixture of PT and PDT, compared to controls. However, they rapidly habituated to this mixture. None of the other compounds caused an avoidance response. These results show that complex natural predator scents are more effective feeding repellents than some of their major volatile components alone.
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