The dynamie s of changes in partridge population (Perdix perdix L.) in the hunting regions of the eentral-eastern Poland in the years

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1 Roczniki Naukowe Polskiego Towarzystwa Zootechnicznego, t. 5 (2009), nr 4 The dynamie s of changes in partridge population (Perdix perdix L.) in the hunting regions of the eentral-eastern Poland in the years Elżbieta Bombik, Anna Wysokińska, Krzysztof Górski, Stanisław Kondracki University of Podlasie, Department of Reproduction and AnimaI Hygiene, Prusa 14, Siedlce The studies were conducted over 9 hunting seasons 1998/ /2007 in 8 hunting districts of central-eastern Poland. The following hunting districts were examined: Warsaw, Biała Podlaska, Ciechanów, Ostrołęka, Płock, Radom, Siedlce and Skierniewice. The total area of the districts was ha, the farmland covering ha, which constituted 76.98% octhe total area. The size and density of partridge population was determined in individual districts in addition to harvest from the hunting grounds over 9 hunting seasons inciuded in the study. The size of partridge population in individual districts was estimated during counts performed by the strip method to assess hare population (November). Additionally, we counted partridge coveys, numbers of birds in individual coveys during the period of snow Iying on the ground, and calling males (spring) at randomly selected points. It resuited in numbers as of the 31 st of March each year. Harvest of partridges was estimated as a total of all birds shot in a district in a given hunting season, that is, from the 1 st of April to the 31 st of March the next year. The values of population exploitation levels were subjected to statistical analysis. Substantial dynamics of change in the partridge population was observed in the region of central-eastern Poland as reflected in the varied size and density of the population. Over the study period, there occurred a significant deciine in the exploitation intensity of partridge populations accompanied by a slight increase in density. The number of partridges slightły increased over the examined hunting seasons, which was predominantiy associated with restricted or even banned hunting in some regions. As the situation of this game bird continues to be unfavourable, further restrictions on partridge hunting are recornmended as well as undertaking more research and measures to increase the size of partridge population. KEY WORDS: partridge / number / harvest / exploitation of population One of important elements of hunting management is to create optimal conditions for game animals and protect endangered species as they help to maintain biological 229

2 balance in nature. Small game is an important component of biological diversity of the natural environment. In Europe and Poland there has been observed a marked decline in the num ber and harvest of partridges since the 1970s and 1990s, respectively [6, 12]. In 2006 the number of partridges in Poland decreased almost three times compared with the 1990s (from 960 birds in 1995 to around 367 birds in 2006). At the same time, there occurred an over ten fold decrease of the number of harvested animals which, in the hunting season 2005/2006, reached the value of 18 birds [13, 14]. The occurrence of partridges varies in al! the voivodeships in Poland [23]. According to GUS (Main Statistical Office), in the year 2006, the largest spring partridge population was in the Mazowieckie, Łódzkie and Świętokrzyskie Voivodeships whereas the smallest were the populations of partridges in the Opolskie and Lubuskie Voivodeships [14]. AIso, analysis of partridge num bers recorded in the recent years might indicate that, despite slight fluctuations, the trend towards decline in the population size of partridge has been successfully restricted. It is possible to improve the present situation if hunters, foresters and hunting lovers are more involved in, among others, constant monitoring of small game population sizes and changes in the agriculturallandscape [11]. There are a lot of factors that influence the partridge population size. One of them is a substantial los s of nests and nesting females, which results in a small portion of parental pairs successfully rearing their offspring [9]. Losses during the nesting period may be reduced by providing partridges with adequate nesting places which are protected by grassy and weed covers and are not used for farm ing purposes. During the reproduction period, it is important that birds can make use of safe shelters like mid-field hedgerows. It is also possible to increase partridge population density by ensuring chieks have got the appropriate conditions to grow in the first period of their life and in winter. It can be attained by establishing rnid-field protecting and feeding plots, establishing new or improving the already existing winter coverts, and planting bush es and trees in fields. It is also recommended to provide shelter from wind and intensively feed the birds [3, 5, 11, 20]. Populations of small game are threatened by wild predators such as the raccoon dog, badger, marten, American mink, raccoon and in particular, fox whose population has markedly expanded as a result of introduction of oral rabies vaccines which are annually distributed by air to prevent the disease [3, 7, 15, 18,20, 22,26]. Intensity of partridge hunting has been reduced due to a marked decline in partridge population. The period of hunting for the species was shortened by 2 weeks whereas the fox hunting period was increased by l month [21]. AIso, there are many centres which eonduet breeding in large outdoor enclosures and reintroduce the partridge to the naturai habitat in order to increase the population of this game bird [2,4,25]. Successful actions undertaken to protect and reverse negative changes in partridge populations to a great extent depend on information on dynamics of change in the numbers of partridge populations. The objective of the present work was to analyze the dynamics of exploitation of partridge populations in sełected hunting districts in central-eastern Poland. 230

3 Materiał and methods Studies were conducted over 9 hunting seasons 1998/ /2007 in 8 hunting districts. The following districts were analysed: Warsaw, Biała Podlaska, Ciechanów, Ostrołęka, Płock, Radom, Siedlce and Skierniewice. The total area of the districts examined was ha, the agricultural land covering ha, which constituted 76.98% of the total area. Calculations were performed using data from 46 areas of the Warsaw district, 15 areas of the Biała Podlaska district, 102 areas of the Ciechanów district, 113 areas of the Ostrołęka district, 60 areas of the Płock district, 125 areas of the Radom district, 124 areas of the Siedlce district and 19 areas of the Skierniewice district. The average area in individual districts did not markedly vary and ranged between ha in the Ciechanów district to ha in the Ostrołęka district. The work is based on data and information from records kept by the Game Research Station of the Polish Hunting Association in Czempiń. For each district examined in the study we estimated the size and density of partridge population as well as harvest of partridge from hunting grounds over the nine hunting seasons. The size of partridge population in individual districts was estimated during counts performed by the strip method to assess hare population (November). Additionally, we counted partridge coveys, numbers of birds in individual coveys during the period of snow Iying on the ground, and caliing males (spring) at randomly selected points [8,10,16,25]. It resulted in partridge numbers as of the 31st of March each year. Harvest of partridges was estimated as atotal of all birds shot in a district in a given hunting season, that is, from the 1 st of April to the 31st of March the next year. Moreover, partridge densities were calculated per 100 ha of arabie area as well as the exploitation level of partridge population in individual hunting districts and seasons. An index of exploitation level of partridge population in individual districts was calculated according to the following equation: exploitation level ar partridge population = (average number ar harvested partridges / average size ar partridge population as ar 31 st ar March) x 100%. The results of estimation of exploitation level of partridge population were statistically analyzed according to the following model: where: Yij = fl + a; + b] + eij Yij - level of hunting ground exploitation for the r-th district an j-th season, fl - population mean, at - district effect (a=s), b] - hunting season effect (b=9), eij - random effect. Mean separation between variabies was obtained by Tukey 's Least Significant Difference test. 231

4 Results and discussion Table l presents data ref1ecting the status and exploitation level of partridge populations in individual hunting districts in central-eastern Poland. The greatest number of partridge population was recorded in the Radom (on average, birds per season) and Siedlce district (on average, birds per season). The third most abundant district, in term s of partridge number, was the Ostrołęka district (on average birds). In the years the districts were most abundant in hares [l]. An average harvest of partridges per season ranged between 91 birds in the B iała Podlaska district and 1146 in the Ostrołęka district. There were observed substantial differences in the average partridge density per season between individual hunting districts. The average density ranged between 2.06 birds per 100 ha arabie land in the Ciechanów district to 7.51 birds per 100 ha arabie land in the Skierniewice district. Most of the examined hunting districts were characterized by the density level of less than 5 partridges per 100 ha which is assumed to be a critical value [19]. In many districts hunting is temporary banned when the density is under 10 birds per 100 ha. When there are between 10 and 20 birds per 100 ha, the permissible harvest is at the level of 5%, and when the population size exceeds 20 birds per 100 ha, the level is increased to 10% of the autumn status [2,25]. There are marked differences in partridge densities in Poland. Low density of partridge population has been observed in the buffer zone of Ojcowski National Park. Over five years of performing counts it amounted to la birds per 100 ha [16]. By contrast, it was the highest in the Piotrków district and equalled 23.3 birds per 100 ha in 2003 [5].,! I Table 1 - Tabela 1 Exploitation level of partridge (Perdix perdix L.) in individual districts of central-eastern Poland (means for the 9 hunting seasons /2007) Poziom eksploatacji populacj i kuropatwy (Perdix perdix L.) w poszczególnych okręgach środkowo-wschodniej Polski (średnie z 9 sezonów łowieckich 19981l ) Hunting Numbers Harvest Pertridge density Exploitation level distrier (birds) (birds) per 100 ha of population Okręg Liczebność Pozyskanie Zagęszczenie Poziom eksploatacji lowiecki populacji kuropatw kuropatw populacji (szt.) (szt.) (szt.lloo ha) (%) Radom B Siedlce AB Ciechanów c Ostrolęka c Plock BC Warsaw A Warszawa Skierniewice AB Biala Podlaska AB A, B, C - values in column marked with different letters differ significantly at P~O.OI A, B, C - wartości w kolumnie oznaczone różnymi literami różnią się istotnie przy ~O,Ol 232

5 Data displayed in tab le l show that the highest exploitation levels of partridge population were observed in the Ostrołęka (9.00%) and Ciechanów (7.60%) districts. The levels were by over 4.5% higher than in the Warsaw (2.48%) and Skierniewice (2.80%) districts (P$O.Ol). Table 2 contains data describing the exploitation levels of partridge populations in individual hunting seasons. The greatest size of partridge population, ca1culated as a mean across the eight districts of central-eastern Poland, was recorded in the last two hunting season, that is and The size exceeded 11 thousand birds. Data in table 2 indicate that there was an increase in the partridge population size. According to Panek et a\. [15], the number of young partridges in 2001 was greatest over the last several years but was still tog low to initiate a marked increase in the population size. As revealed by data collected by GUS [14], in the years there was observed an increase in the number of partridges in the whole area of Poland. In 2006 the Mazowieckie Voivodeship was most abundant in partridges. The next voivodeships, in terms of abundance, were the Lubelskie and the Świętokrzyskie Voivodeships. The lo west was the number of partridges in the Opolskie Voivodeship. There was observed a decline in partridge harvest over the period of the nine hunting seasons from 675 birds hunted in 1999/2000 to 341 birds hunted in 2006/2007. However, there was found an increase in partridge density per 100 ha from 2.83 birds in 1998/1999 to 3.82 birds in 2006/2007. The exploitation level of partridge population in the analyzed hunting seasons decreased gradually from 7.51% in 1998/1999 to 3.06% in 2006/2007. Table 2 - Tabela 2 Exploitation level of partridge (Perdix perdix L.) in individual hunting seasons (means for 8 districts of central-eastern Poland) Poziom eksploatacji populacji kuropatwy (Perdixperdix L.) w poszczególnych sezonach łowieckich (średnia z 8 okręgów środkowo-wschodniej Polski) Number Harvest Average partridge Exploitation level Season (birds) (birds) density per 100 ha of population Sezon Liczebność Pozyskanie Średnie zagęszczenie Poziom eksploatacji populacji kuropatw kuropatw populacji (szt.) (szt.) (szt./100 ha) (%) 1998/ c 1999/ c 2000/ n c c 2002/ BC 2003/ BC 2004/ AB 2005/ AB 2006/ A A, B, C - values in column marked with different letters differ significantly at P~O.OI A, B, C - wartości w kolumnie oznaczone różnymi literami różnią się istotnie przy P$O,OI 233

6 Fig. 1 presents changes in the num ber of birds in partridge population in individual districts of central-eastern Poland in the hunting seasons 1998/ In the study period, most partridges were recorded in the Radom district. An increase in the number of partridges was observed in the following districts: Siedlce, Ostrołęka, Biała Podlaska and Skierniewice. In the remaining districts the size of partridge populations remained relatively constant. units - szt Radom -- Ostrołęka _ Skierniewice Siedlce -- Płock Biała Podlaska Ciechanów Warsaw :;; B : : ' - -.~.~ " ~,-;.-> , _ ,...,.;0" / / / / / / i /07 hunting season - sezon łowiecki Fig. l. The number of partridge in individual districts of central-eastern Poland in the hunting seasons 1998/ Rys. l. Liczebność populacji kuropatwy w poszczególnych okręgach środkowo-wschodniej Polski w sezonach łowieckich 1998/ /2007 Fig. 2 demonstrates harvests of partridges in the hunting districts examined in central-eastern Poland in the hunting seasons 1998/ /2007. Partridge harvest in the Radom district increased by 676 birds (from 629 birds in 1998/1999 to 1305 birds in ) in the study period. The greatest number of partridges in the Radom district was probably the reason for this increase. In the remaining districts partridge harvest was being restricted. In the Biała Podlaska district it was banned over three hunting seasons. As a result, the size of partridge population increased in many districts. Kamieniarz and Panek [9] reported that in the years there was observed a marked decrease (over 20%) in partridge harvest in the districts of central and southern-eastern Poland. However, the num ber of partridges remained at a relatively constan t level over this time. To sum up, in the region of central-eastern Poland there were observed substantial changes in the dynamics of partridge population, which was reflected in chan ges in population size and density. There was observed a significant decrease in exploitation 234

7 units - szt Radom ~ Ostrołęka _ Skierniewice Siedlce -- Płock Biała Podlaska ", 800 ' 600, 400 " '.. '-- Ciechanów Warsaw Ol _ '..:: ~.-.-._. _ ~l-~-~-~-~-~-~::-=-,~~~:~,: ~~~=-~~~~~~:S;-~-i-~-~-~-~-~~~~~~~::~~--, 1998/ / / / / / /07 hunting season - sezon łowiecki Fig. 2. Harvest of partridge in individual districts of central-eastern Poland in the hunting seasons Rys. 2. Pozyskanie kuropatw w poszczególnych okręgach środkowo-wschodniej Polski w sezonach łowieckich /2007 intensity of partridge population accompanied by a slight increase in density. Numbers of partridges slightly increased over the examined hunting seasons, which was predominantly associated with restricting, or even banning in some districts, of partridge harvest. In order to improve the still unfavourable situation in this group of animals, it is recommended to further restrict harvest of this species and eonduet research and introduce measures aiming at increasing the size of partridge population. The authors are greatly indebted to the workers the Game Research Station oj the Polish Hunting Association in Czempin Jor the date utilized in this paper. REFERENCES l. BOMBIK E., WYSOKIŃSKA A., KONDRACKI S., Ocena zmian liczebności i eksploatacji populacji zająca szaraka tlepus europaeus PalI.) w rejonie województwa mazowieckiego. Roczniki Naukowe PTZ l (2), BOMBIK P., Ratowanie zająca i kuropatwy. Łowiec Polski 6, BOMBIK P., Przepis na sukces. Łowiec Polski 8, BUNER F., lenny M., ZBINDEN N., NAEF-DAENZAL B., Ecologically enhanced areas - a key habitat structure for re-introduced grey partridges Perdix perdix. Biological Conservation 124, l. 5. CHOJNOWSKI A., Odbudowa populacji. Łowiec Polski 6,

8 6. DE LEO G.A., FOCARDI S., GATTO M., CATTADORI LM., The decline of the grey partridge in Europe: comparing demografies in traditional and modem agriculturallandscapes. Ecological Modelling 177, FLIS M., Efekty szczepień przeciw wściekliźnie a dynamika liczebności lisów. Medycyna Weterynaryjna 65 (3), GRUBESIC M., SEGRT V., KONJEVIC D., Analysis 01' counts of grey partrigde (Perdix perdix L.) in naturai breeding grounds in central Croatia. Vetetinarski Arhiv 76, KAMIENIARZ R., PANEK M., Mniej zajęcy, więcej kuropatw. Łowiec Polski 2, LO. KAMIENIARZ R., PANEK M., BRESIŃSKI W., Metody oceny liczebności zwierzyny drobnej (2). Łowiec Polski 3, li. ŁOGIN M., Kuropatwy nad Bałtykiem. Łowiec Polski 8, MIELNIKIEWICZ K., Zwierzyna drobna - stracona szansa? Łowiec Polski 8, 8-9. l3. OCHRONA ŚRODOWISKA, GUS, Warszawa. 14. OCHRONA ŚRODOWISKA, GUS, Warszawa. 15. PANEK M., KAMIENIARZ R., BRESIŃSKI W., Co dzieje się ze zwierzyną drobną? Łowiec Polski 2, PANEK M., Roczne plany łowieckie. Łowiec Polski 4, l7. PIS T., RYGLOWSKA J., WACHOWICZ 1., Zwierzyna drobna krakowskich i podkrakowskich pól (II). Brać Łowiecka l, PRZYBYLSKI A., Zwierzyna drobna a drapieżniki. Łowiec Polski 10, Regionalny program rozwoju populacji zająca i kuropatwy w okręgu siedleckim, Opracowanie Zarządu Okręgowego PZŁ i Komisji Hodowli przy ORŁ w Siedlcach. 20. REMUSZKO M., Jak pomóc kuropatwie. Brać Łowiecka 6, Rozporządzenie Ministra Środowiska z dnia 16 marca 2005 r. w sprawie określenia okresów polowań na zwierzęta łowne. Dz.U TAPPER S.c., POTTS G.R., BROCKLESS M.H., The effect of an experimental reduction in predation pressure on the breeding success and population density of grey partridge Perdix perdix. Iournal oj Applied Ecology 33, WIŚNIEWSKI G., Zwierzyna drobna jako elementy bioróżnorodności środowiska przyrodniczego. Łowiec Polski 4, WIŚNIEWSKI G., Szansa dla kuropatw. Łowiec Polski 12, WIŚNIEWSKI G., Policzyć zwierzynę drobną. Łowiec Polski 2, ZA W ADZKA D., Ptaki krukowate - drapieżniki czy oportuniści? Brać Łowiecka 6,

9 Elżbieta Bombik, Anna Wysokińska, Krzysztof Górski, Stanisław Kondracki Dynamika zmian populacji kuropatwy (Perdix perdix L.) w latach w wybranych okręgach łowieckich środkowo-wschodniej Polski Streszczenie Badania przeprowadzono w 9 sezonach łowieckich 1998/ /2007 na terenie 8 okręgów łowieckich środkowo-wschodniej Polski. Analizie poddano okręgi: warszawski, bialskopodlaski, ciechanowski, ostrołęcki, płocki, radomski, siedlecki i skierniewicki. Powierzchnia badanych okręgów wynosiła ogółem ha, z czego powierzchnia polna stanowiła ha, czyli 76,98% ogólnej powierzchni. Dla każdego z badanych okręgów oszacowano liczebność i zagęszczenie populacji kuropatwy oraz pozyskanie z łowisk w 9 sezonach łowieckich objętych badaniami. Liczebność populacji kuropatwy w poszczególnych okręgach oszacowano podczas inwentaryzacji metodą taksacji pasowej razem z taksacją zajęcy (listopad), liczenia stad i poszczególnych osobników w stadach w okresie występowania pokrywy śniegowej oraz liczenia w wybranych losowo punktach odzywających się samców (wiosna), uzyskując stan na 31 marca każdego roku. Pozyskanie kuropatw szacowano jako sumę zwierząt odstrzelonych w okręgu w danym sezonie łowieckim, tj. w okresie od l kwietnia do 31 marca roku następnego. Wyniki poziomu eksploatacji populacji poddano analizie statystycznej. W rejonie środkowo-wschodniej Polski obserwowano znaczną dynamikę zmian populacji kuropatwy, co wyrażało się zróżnicowaną jej liczebnością i zagęszczeniem. W analizowanym okresie nastąpi! istotny spadek intensywności eksploatacji populacji kuropatwy przy niewielkim wzroście zagęszczenia. Stan liczebny kuropatwy na przestrzeni badanych sezonów łowieckich uległ nieznacznej poprawie, co związane było głównie z ograniczeniem, a nawet wstrzymaniem, na terenie niektórych obwodów, jej pozyskania. W celu poprawy istniejącej, ciągle złej sytuacji wśród tej grupy zwierząt, wskazane jest dalsze ograniczenie pozyskania tego gatunku oraz badania i zabiegi zmierzające do zwiększenia jego stanu liczebnego. 237