Dependence of bobak marmot’s period of hibernation on conditions of fodder resources. Zavisimost’srokov zaleganiïa v spïatchkou stepnogo sourka ot sostoïaniïa kormovykh resoursov. [Dépendance de la période d’hibernation de la marmotte bobak aux conditions des ressources en fourrage].

Résumé

Periods of bobak marmot's hibernation were studied in the area under study 1999 through 2004 (village Nesterivka, Velikoburluk district, the Kharkov province). A main criterion was appearance of external plugs in the wintering holes. Long-term observations showed that hibernation in the colony under study that inhabited sites with different fodder capacity began in different time. The first to begin hibernation (in the first half of September) were the animals inhabiting sites with no livestock grazing. Hibernation of the animals begins in relatively the same time and does not depend on weather conditions. Hibernation is preceded by a period during which vegetation gets dry. The last to close are holes located at places of livestock grazing and having the most favorable fodder conditions, as we earlier noticed (Ronkin, Savchenko, 1993, 1996, 1999). In this case hibernation is preceded by a period of poor vegetation. When autumn is dry hibernation begins within a shorter period (from the beginning to the end of October), than when autumn is wetter (from the beginning of October to the end of November). Change offodder conditions at the same site affects the beginning of hibernation. Hibernation of marmots in any habitat is preceded by at least a two-week period with un favorable fodder conditions, which, probably, gives warning of the forthcoming beginning of hibernation. Even if such a period is followed by that of intense vegetation marmots get dormant, anyway. If fodder conditions are stable (in case of evenly wet autumn) the period of activity for some animals may last before the third ten-day period of November. The beginning of hibernation may serve as criterion of favorable fodder conditions. Dynamics of the beginning of hibernation reflects ratio of ??family plots?? quantity with various fodder conditions and the difference in fodder conditions between the ??plots??.