Life sciences Leaflets 8:214 – 221, 2010. ISSN 0976 - 1098

Published on: 1st October 2010 POPULATION CENSUS OF THREE SPECIES AT FEEDING SITES IN JUNAGADH, GUJARAT S.N. DHANDHUKIA1 AND I.R. GADHVI2 1Bahauddin Science College, Junagadh-362001, Gujarat 2Dept. of Marine Science, Bhavnagar University, Bhavnagar-364002, Gujarat INDIA. [email protected]

ABSTRACT: Population census of three Myna species ( tristis), Bank Myna (Acridotheres ginginianus) and Brahminy Myna (S. pagodarum) has been carried out in Junagadh, Gujarat during 2007 and 2008. Monthly population of shows similar trend both the year. The population of Common myna was the highest in the month of August and September. Bank Myna numbers were recorded high in October. Where as Brahminy Myna population was found highest in February, August and December at the feeding sites. Common Myna was dominant in number followed by Bank Myna and Brahminy Myna. Total population was Common Myna 2660 and 2700, Bank Myna 687 and 755 and Brahminy 445 and 483 (in 2007 & 2008 respectively). Mynas are uniformly distributed in Saurashtra region. However, major resident population is near gardens and urban areas.

KEY WORDS: Population census of Myna., Junagadh

INTRODUCTION: Mynas are one of the common through out India (Ali et al. 1983). The name of these attractive comes from the Hindi word maina. Mynas are classified in order Passeriformes and Family Sturnidae. Mynas are commonly observed in large populations (Ali et al. 1983) in all climatic zones where it can survive. Mynas are omnivores (Sengupta et al. 1976) and could potentially compete with a large range of indigenous species for food and also can cause severe damage to the agricultural crops (Narang et al. 1984) in the local community. In most parts of India, mynas are resident species. Mynas exhibit regional movement with seasonal changes in food availability that allows utilizing productive habitats available in other locations / areas. However, it is difficult to http://lifesciencesleaflets.ning.com/ PEER-REVIEWED Page | 214

Life sciences Leaflets 8:214 – 221, 2010. ISSN 0976 - 1098 understand seasonal pattern of habitat selection and its relation to food availability with short term of field observations. Common Myna often feeds on different food items depending on the time of year. This is due to the change in the availability of certain foods. Bank Myna visits its feeding grounds for the grains as well as insects. Brahminy Myna is habituated in feeding on both fruits and insects. Mynas extensively use cultivable fields particularly fields of cereal crops and fruit orchards. There are several methods to count the vertebrate populations (Davis 1982). However, census techniques show some methodological problems (Bull 1981, Dawson 1981) that many factors can influence the results and applicability of faunal census results. Wiens (1977) provides abundant illustrations of the extent to which methodology is critical to the valid interpretation of the results of bird counts. Appropriate methods for a particular study become more obvious if there is a clear purpose. A recurrent theme of good study design is that method must be tailored to aim. According to Pyke and Recher (1985), each census method has its advantages and disadvantages. It is important to employ a reliable census technique in which the user has confidence for the study of any avifaunal community. Besides the census method, which is being employed, for one species may not be applicable for another species. Therefore before employing any method for a particular species, it is important to assess the reliability of the method. Several expository papers deal generally with the census methods. Kendeigh (1944) reviewed estimates of bird population. Davis (1982) compiled and illustrated a number of census methods. Based on this information, in the present study on the general aspects of population census of three species, Common Myna (Acridotheres tristis), Bank Myna (Acridotheres ginginianus) and Brahminy Myna (Sturnus pagodarum) at Junagadh, Gujarat, India, are discussed.

STUDY AREA The study was confined to Junagadh city a District head-quarter and a picturesque town, which was the former capital of the Princely State of Junagadh. The Junagadh city is located between latitudes 21º 31’N and 70º 49’ E. The city is a gate way to famous Gir Forest which is the natural habitat for the last existing population of Asiatic Lion (Scientific name) in the wild. Jungadh has a tropical monsoon climate with three distinct seasons i.e., monsoon, winter and summer. http://lifesciencesleaflets.ning.com/ PEER-REVIEWED Page | 215

Life sciences Leaflets 8:214 – 221, 2010. ISSN 0976 - 1098

MATERIAL AND METHODS: For intensive study for population censes of mynas, five sites (Lalbaugh-LB, Junagadh Agricultural University-JAU, Gandhigram society-GGS, Timbavadi-TV, Police Training Center-PTC) were selected in and around Junagadh city. Sites were selected on the bases of primary reconnaissance survey for the presence of the three myna species and their populations. All the sites were monitored in the first week each month for recording the number of birds. The foraging habitats of mynas were identified by following in different directions during the early mornings, just after sunrise. The movement of birds was also observed by climbing up on high buildings located in different areas of the city to locate the foraging sites. The information was also gathered by interviewing the local people. Based on the pilot study of consecutive 10 days and the number of mynas at the feeding sites were recorded. It was assumed that the average number of myna at the feeding sites remains constant for a period of at least a fortnight. Censuses were carried out in the first week of every month for 24 months at all the foraging sites in the study area. The observations were taken with the help of a pair of binoculars (8x 40) at a safe distance from the feeding flocks to avoid the disturbance to the birds.The numbers of myna at the foraging sites were counted either during mornings or during late evenings. The morning counts were started with the arrival of the first flock of mynas on the foraging ground.

RESULTS: Monthly population of mynas at feeding sites during both the year revealed a common trend among all species. The Common Myna’s monthly population was found the highest in the month of August in 2007 and September in 2008. Bank Myna numbers were found highest in October during both the years. Brahminy Myna’s number, during 2007 was the highest in February, August and December at the feeding sites. In 2008, maximum number of Brahminy Myna was observed in July followed by February and June (Table 1 and Figs. 1, 2, 3). Common Myna was dominant in number followed by Bank Myna and Brahminy Myna during the study period at feeding sites (Figs. 4 and 5). Percentage distribution of Common Myna at feeding site was the highest at Timbavadi and few at Lalbaug and Police training center. Its population at Junagadh Agricultural University, Gandhigram society and Timbavadi was more or less similar, but gradual increase was observed from Junagadh Agricultural Univarsity to Timbavadi in 2007. Whereas in 2008 http://lifesciencesleaflets.ning.com/ PEER-REVIEWED Page | 216

Life sciences Leaflets 8:214 – 221, 2010. ISSN 0976 - 1098 maximum number was recorded from Agricultural Univarsity which gradually decreased in the order at Gandhigram society, Timbavadi, Police training center and lowest number at Lalbaug (Fig. 6). In case of Bank Myna it was recorded feeding at only two site i.e., Gandhigram society and Timbavadi. Its number was less in Gandhigram society as compared to that at Timbavadi during both the years (Fig. 7). Brahminy Myna showed similar trend during both the years as it was found feeding at three sites only, their number gradually increased from Gandhigram society to Police training center and achieved its maximum at Timbavadi. In 2007 it was observed that the population was slightly higher than that in 2008 at Gandhigram society whereas their number at Timbavadi was slightly low in 2007 than that in 2008 (Fig. 8). Table 1: Monthly population of mynas in 2008 at feeding sites

Month Common Myna Bank Myna Brahminy Myna

Jan. 186 33 41

Feb. 200 52 49 Mar. 169 28 34 Apr. 133 27 33 May 140 33 24

June 219 54 47 July 287 76 62 Aug. 310 81 38 Sep. 316 93 39

Oct. 261 111 37

Nov. 229 91 37 Dec. 250 76 42

Common Myna 350 300 250 200 150 Population 100 50 0 JFMAMJJASOND Month

Fig. 1 :Monthly population of Common Myna in 2007 at feeding sites

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Life sciences Leaflets 8:214 – 221, 2010. ISSN 0976 - 1098

Bank Myna

100 90 80 70 60 50 40

Population 30 20 10 0 JFMAMJJASOND Month

Fig. 2: Monthly population of Bank Myna in 2007 at feeding sites

Brahminy Myna

60

50

40

30

Population 20

10

0 JFMAMJJASOND

Month

Fig. 3: Monthly population of Brahminy Myna in 2007 at feeding sites

445

687 Common Myna Bank Myna Brahminy Myna 2660

Fig. 4: Total population of mynas at feeding sites 2007

483

755 Common Myna Bank Myna Brahminy Myna 2700

Fig. 5: Total population of mynas at feeding sites 2008 http://lifesciencesleaflets.ning.com/ PEER-REVIEWED Page | 218

Life sciences Leaflets 8:214 – 221, 2010. ISSN 0976 - 1098

30.00

25.00

20.00 2007 15.00

Myna 2008 10.00

5.00

Percentage number CommonPercentage of 0.00 LB JAU GGS TV PTC Feeding sites

Fig. 6: Percentage number of Common Myna recorded in different feeding sites (Year – 2007 to 2008)

80 70 60 50 2007 40 2008 30 20 10 0 Percentage number of Myna Percentage Bank LB JAU GGS TV PTC Feeding sites

Fig.7: Percentage number of Bank Myna recorded in different feeding sites (Year – 2007 to 2008)

50.00 45.00 40.00 35.00 30.00 2007 25.00 2008 20.00 15.00 10.00 5.00

Percentage number of Brahminy Percentage Myna 0.00 LB JAU GGS TV PTC Feeding sites

Fig. 8: Percentage number of Brahminy Myna recorded in different feeding sites (Year - 2007 to 2008) Abbreviations: LB = Lalbaugh TV = Timbavadi JAU = Junagadh Agricultural University PTC = Police training center GGS =Gandhigram society

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Life sciences Leaflets 8:214 – 221, 2010. ISSN 0976 - 1098

DISCUSSIONS: Darwin (1859) pointed out the initial fact of population trend towards the stability over a time. It is understandable that a population of wild is subjected to continuous periodic fluctuations in a given time frame. Thus census techniques of any type like direct count, sampling or indices must not require excessive period of time to be completed successfully. In the present study, direct count method at the feeding sites seems to be quite reliable and accurate to estimate the population of the mynas at some selected feeding sites at Junagadh. It was also employed by Gadhvi (2001) for White Ibis. Usually the most common source of error encountered in the census is the difficulty to count accurately when the species in large flocks. However, during the study the arriving or departing flocks at the sites were small sized and easily countable accurately for most of the time. Mynas leave from the foraging site to the near by tree branch shades during the hot hours of the day. Thus direct count method which seems most suitable and precise for the accurate estimation of the population. Population fluctuation due to dispersion and aggregation is a common feature among many wild animals. Seasonal movements are also known to occur in most of the mynas during the breeding season. Whole population of the three species of mynas in the study area was found to fluctuate seasonally and annually. The fluctuation in the population size was quite obvious, probably due to small census area with regular recording of data. It implies that the change in population size was the result primarily due to dispersion and aggregation of the mynas at the study area from the surrounding areas. The population in the study area reached to a peak usually at end of the breeding season (July-October depending on the species) when the juveniles leave the nesting and join the adults for foraging. The population of all the three mynas was found distributed throughout the study area. Local movement of population of mynas did occur. It was observed that all the mynas (especially banded chicks) that remained in the same territory which accounted for the variation in maximum number of mynas during peak in annual population fluctuation. Survey shows that the mynas are uniformly distributed in Saurashtra region. However, major resident population is found near gardens and urban areas. Aridity of land has restricted the growth of large trees and on the other hand, over-grazing of land, clearing pasture land for agriculture and domestic purpose lead to the scarcity of large trees in Saurashtra. However, http://lifesciencesleaflets.ning.com/ PEER-REVIEWED Page | 220

Life sciences Leaflets 8:214 – 221, 2010. ISSN 0976 - 1098 due to the religious feelings of people protect several trees like Peepal (Ficus religiosa) and Elephant fig (Ficus tsiela).

CONCLUSIONS: The fluctuation in the population size was quite obvious, probably due to small census area with regular recording of data. It implies that the change in population size was resulted primarily from dispersion and aggregation of the mynas at the study area from the surrounding area.The population in the study area reached to a peak usually at end of the breeding season (July-October depending on species) when the juveniles leave the nesting site and join the adults for foraging. The population of all three mynas was found distributed throughout the study area.

REFERENCES: Ali, S., and Ripley, D. (1983). Handbook of the Birds of India and Pakistan. Oxford Univ. Press, Bombay. Bull, E. L. (1981). Indirect estimate at abundance of birds, (Ralrh, C. J., and J. M. Scott, eds.). Estimating numbers of terrestrial birds. Studies in Avian Biology 6: 76-80. Darwin, C. (1859). The origin of species. London: Dent. Davis, D. E. (1982). Hand book of census methods for terrestrial vertebrates. CRC Press, Inc. Boca Raton, Florida, pp. 93-103. Dawson, D. G. (1981). Counting birds for a relative measure (index) of density. In: Estimating numbers of terrestrial birds (Ralph, C.J. and J.M. Scott eds.). Studies in avian biology 6: 12-16. Gadhvi, I. R. ( 2001). Ecological and behavioural studies on the White Ibis in Bhavnagar. Ph. D. Thesis submitted to Saurashtra University, Rajkot Kendeigh, S. C. (1944). Measurements of bird populations. Ecol. Monogr 14: 67-106. Narang, M. L., Lamba, B. S. (1984). A contribution to the food habits of same Indian Mynas (Aves). Rec. Zool. Surv. India, Calcutta. Occasional paper 44:1-76. Pyke, G. H., and Recher, H. F. (1985). Estimated forest bird densities by variable distance point counts. Aust. Wildl.Res 120: 307-319. Sengupta, S. (1976). Food and feeding ecology of the Common Myna, Acridotheres tristis (L.). Proc. Indian Natn. Sci. Acad 42(6): 338-345. Wiens. J. A. (1977). On competition and variable environment. Amer. J. Sci 65: 590-597.

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