* Chapter 5:
Grouping of Tigers in the Long-Term Study Site in the Past and During the Period of our Investigations
The rapid fall in the population size of the tigers, which had begun in Primorskii Krai in the first years of the present century, also occurred in the basin of the Bol'shaya Ussurka River, and in particular along the Malinovka River, one of the largest rivers of this basin.š The numbers of tigers decreased here mainly due to the shooting of adult animals.š For example, one single individual from the settlement of Bogolyubovka (near the Orekhovka River), N.N. Peknich, killed 19 tigers during the years up until 1927 (source: M. V. Ganzei).š The capture of tiger cubs over a period of many years turned out to be no less destructive to the local population of tigers.š From 1920 up until the beginning of the 1970s, over 130 tigers were caught in Primorskii Krai, of which over 100 were from the basin of the Bol'shaya Ussurka River (Yudakov & Nikolaev 1973).
In the second half of the 1930s, tigers were still occasionally to be found in the basin of the Malinovka River.š The greatest depression in their numbers occurred during the period from the end of the 1930s to the middle of the 1940s.š Tigers disappeared from the majority of the territory along the basin of the Malinovka River, including such large tributaries of this river as the Orekhovka and the Gornaya Rivers.š In the period from 1943-1946, N. P. Uksumenko, together with a team of nine men, hunted along this river in order to stockpile the meat of wild animals for the needs of the army.š During this time, the hunters did not find any tracks of tigers nor did they hear of encounters with tigers by the local inhabitants (source: V. A. Yarychev). š
Tigers continued to hold out mainly along the upper course of the Malinovka River.š This part of the basin adjoined a "tiger refugium" that occupied the plateau between the Zhuravlevka, Malinovka, Kabarga, and Krylovka Rivers. This tiger refugium also preserved itself during the time of depression in tiger numbers in the period from 1920-1945 (Yudakov 1971).
The first signs of an increase in the numbers of tigers in the basin of the Malinovka River appeared beginning in the second half of the 1940s.š The growth of the population on this territory was promoted by the following factors: the stability of the neighboring refugium inhabited by tigers, which included the upper part of the basin of the Bol'shaya Ussurka River; the ban on hunting tigers beginning in 1947, and also the cessation of the capture of tiger cubs during the Second World War (Abramov 1956).
The tigers' secondary colonization of different sectors of the basin of the Malinovka River did not take place simultaneously in all areas.š In the period from 1945-1946, a certain increase in their numbers was noted along the upper course of the Malinovka River, where one tiger had already been killed by that time.š We have the evidence of V. B. Dubinin (1949) on the appearance of tigers here at that time; in the autumn of 1946, their tracks were observed in the neighborhood of the settlement of Ariadnoe.š An increase in the number of animals apparently occurred at that time not primarily at the expense of breeding by the surviving group, but rather as a result of the immigration of tigers from the basin of the Zhuravlevka River, which flows into the Ussuri River.š The main travel routes of tigers across the divide between the Malinovka and Zhuravlevka Rivers ran along the upper reaches of the right tributaries of the Zhuravlevka River, the Otkosnaya and the Bystraya Rivers.š We also noted a tiger's crossing from the basin of the Malinovka River into the basin of the Zhuravlevka River during the tracking period.š The animal walked across the valley of the Komsomolka River (a left tributary of the Malinovka River) to the Otkosnaya River.
Tigers appeared along the upper reaches of the Orekhovka River somewhat later (at the end of the 1940s).š By the summer of 1951, instances of attacks by tigers on domestic animals had already been observed here.š The tigers arrived here from the basin of the Bol'shaya Ussurka River, most probably traversing the upper reaches of its left tributaries, the Naumovka and Pereval'naya Rivers.š According to the data of L. G. Kaplanov (1948), tigers continuously inhabited these rivers in the period from 1930s to the 1940s.š At the end of the 1940s, an increase in the numbers of tigers was observed along the Naumovka River (Rakov, 1965).š We noted the passage of tigers across the divide between the basin of the middle course of the Bol'shaya Ussurka River and the valley of the Orekhovka River in two areas: the Podgornaya River (a right tributary of the Orekhovka) --Naumovka River, and the upper reaches of the Orekhovka -- Pereval'naya Rivers.
At the beginning of the 1950s, tigers also began to be encountered more frequently in the middle part of the basin of the Malinovka River (i.e., along the upper reaches of the Bystraya, Titovka and Lazarevka Rivers).š By 1953, tiger cubs had already been captured here.š Most probably, the animals arrived in this territory from a neighboring refugium, dispersing in a northwest direction.š The fact that they appeared later on the Titovka and Lazarevka Rivers than on the Kabarga River (which flows further to the south and discharges into the Ussuri River) is evidence in support of this direction of dispersal.š Migrations of tigers were noted that crossed the divide between the basin of the middle course of the Malinovka River and the adjoining territory of the basin of the Ussuri River going into areas along the upper reaches of the Krylovka, Malaya Kabarga and Bol'shaya Kabarga Rivers.
A particularly striking increase in the numbers of tigers in the basin of the Malinovka River was observed after 1955.š At precisely that time, a prohibition on the capture of tiger cubs was introduced to last for a period of 5 years.š Only along the Gornaya River were the animals not present (as they had been previously); tigers appeared here only in 1966.š Tigers could arrive in the basin of the Gornaya River, which occupied the central territorial position in our study site, only from the side near the Malinovka and Orekhovka Rivers where growth in the tigers' numbers had occurred earlier.š Entries by tigers via another route (i.e., arrival in the upper reaches of the Gornaya River from the Pereval'naya River) were not observed by us during the tracking period, although their footprints were found along this river at a distance of 5-10 km from the divide.š Apparently, tigers had also not crossed over the divide into this sector earlier.š Their avoidance of these sites is explained by the presence of a belt of montane spruce-fir forests that fringed the upper reaches of the Gornaya River in a horseshoe-shaped pattern.
At the end of the 1960s, the population size of tigers along the rivers in basin of the Malinovka River reached a level that was also maintained during the years of our investigation.š In 1970, the population density of the tiger (in relation to the total area of occupied habitat) equaled 2-3 individuals per 1000 km2 here.š The extreme level of exploitation of this local group of tigers (the capture of tiger cubs) and illegal shootings restrained growth in its numbers to a significant degree.
The tigers on which we conducted observations inhabited the basin of the upper course of the Malinovka River.š Information on the density and composition of the groups of tigers on the long-term study site was produced beginning with the winter season of 1971-1972, since the boundaries of individual territories of the tigers were not completely determined in the winter of 1970-1971 because of the limited duration of tracking.š In 1971-1972, family of tigers lived on a territory of approximately 600 km2 with the family including a male, a female and two second-year cubs during the first half of the winter.š By spring, only the two adult animals remained here.š Until the loss of her cubs, the female limited her travels to an area of approximately 100 km2. š
Five to six tigers lived in an area on the order of 1000-1100 km2 in 1972-1973.š During the first half of the winter season, three males and two tigresses (one of them with a cub) lived here.š In the second half of the winter, there was one fewer male (he died in January as a result of a fight with another tiger).š Furthermore, the individual territory of still another female (with two cubs) partially overlapped this same area.š One litter of two cubs was captured at the end of 1972 on the left bank of the Malinovka River.š The travels of the family of tigers that we had under observation during the course of almost four years were inscribed in an area of 600-700 km2.š During different periods of our study, this family consisted of either only adult animals or else it included one or two cubs.
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Naturally, the composition of the local group of tigers changed during the years of our study (as well as later).š Several individuals died (mainly through the fault of people).š Cubs were captured.š Litters appeared regularly.š Four tigers perished here during the period in question (observations had been conducted on three of them up until their deaths).š In January, 1971, one tiger was killed along the border of the long-term study site in the upper reaches of Pravyi Igristyi Stream (Gornaya River).š In January of the following year, a litter of two cubs, which had been under observation, perished due to poachers in the district around Khvoinyi Stream (Orekhovka River).š During tracking in January, 1973, a male was found along Petrov Stream (also known as Yurta Stream, in the basin of the Gornaya River) that had died after a fight with another tiger.
The appearance of litters, not counting the one that perished, was observed three times.š In 1972, the tigress, having lost her cubs, brought forth a new litter consisting of one cub.š This mother and cub kept to the basin of Bystraya Stream (Orekhovka River) during the winter of 1972-1973.š Another female, which had two cubs, also lived there.š On the opposite (i.e., the south) border of the long-term study site along the Malinovka River the tracks of still another litter of two cubs were encountered in December, 1972, a litter which had, by December 30th of that same year, already been caught by a team of tiger catchers in the district near Ladoshina Stream.
The sex ratio among those adult individuals that had been censused on the long-term study site ranged from 1:1 to 1:2 for various years and different parts of the territory (the number of males is taken as 1).š For the entire basin of the Malinovka River, females predominated over males by a factor of two during the 1970 census.
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Copyright ¿ A. G. Yudakov,I. G. Nikolaev
Copyright ¿ K. Lofdahl, A. Shevlakov, 2004 (English translation)