The status of Great Bustard Otis tarda in Iran

HAMID AMINI TAREH

Surveys of Great Bustard Otis Tarda in Iran in 1990-1994 located birds at 21 sites in the west of the country. Areas of east and north-east Iran known to bold a wintering population of 200-250 birds in the late 1970s were not occupied during this period. Numbers in west Iran appear static at 60 breeding females and 200-300 birds in winter, when numbers are augmented by immigrants from the former Soviet Union states. Three nests were found during the survey and data were collected on food and foraging, potential threats and possible conservation action.

	GREAT BUSTARD Otis tarda is a globally threatened species classified as vulnerable (Collar et al. 1994). In Iran, the species occurs in the west of the country, from the northern provinces to Kermanshah in the centre-west. Habitat destruction and hunting have caused a sharp decline in recent decades. The Department of the Environment (DOE) declared the Great Bustard a protected species in 1967, banning hunting throughout Iran. Following the introduction of strict hunting controls and conservation measures by the DOE in recent years, the Great Bustard population is now stable. In 1971-1978, several surveys were undertaken by the DOE: Scott (1971) estimated 40-100 breeding females in west Iran; A. Eftekhar found 123 birds wintering in east and north-east Iran in 1973; Razdan & Mansoori (1989) 124 wintering in east Iran in 1976; Cornwallis (1983) and E. Kahrom estimated just 40 breeding females in west Iran in 1977; but Kahrom (1979), in an aerial survey in 1978, estimated c. 80-120 breeding females in the same area and c. 200-250 winter visitors in the east and north-east of the country. The present study (1990-1994) visited most potential Great Bustard habitats in Iran, and therefore, attempts a more complete appraisal of the current status of the species in the country.
METHODS
	Great Bustard is known from six provinces in Iran. In undertaking the present survey, a biologist and several game guards in each province assisted me by making weekly visits to the most important sites. In addition, I made monthly trips to each of these areas. Each site was covered twice on each visit: once in early morning and once in late afternoon, when the birds are most active. Nests were discovered by careful observation of females. All population estimates were made on the basis of direct censuses, using line transects and roadside counts with binoculars and a telescope. No aerial surveys were made. A fresh corpse, probably killed by a predator, was analysed and the contents of its crop sent to the Bou-Ali university laboratory to determine its diet.
DISTRIBUTION, MIGRATION AND POPULATION
	The species occurs in large areas of undulating steppe, most of which is cultivated in the west of the country (34o12'-37o58'N and 45o00'-48o07'E), at 500-2100 metres above sea-l evel. Previous studies had demonstrated that Great Bustard occurred in the west, east and north-east of the country. In undertaking this project, I concentrated on those areas that were known to be most important.
1. east and north-east Iran	Known wintering area. The birds probably originate from breeding areas in the former Soviet Union. They arrive in December and depart in March. I and my colleagues were unable to find any birds, although a population of 200-250 wintered in these areas in the 1970s.
2. west Iran	Twenty-one suitable areas in five provinces were identified: seven in west Azerbaijan, one in east Azerbaijan, five in Kordestan, seven in Kermanshah, and one in Hamadan province. A small number survive in a handful of additional areas omitted from the present survey due to their physical remoteness. In some areas, the species is resident, but only ten are suitable for breeding. In severe winters, some move south to e.g. the low-lying plains of Zohab and Gandomban, in Kermanshah. It is probable that some also move to adjacent areas in Iraq and Syria. The most important areas, supporting the largest population are in west Azerbaijan and Kordestan: Sootav plain, Behie-e-Bukan, Zarrineh-Oubatoo and Ghareh-Gheshlagh prohibited hunting region. Winter visitors from adjacent countries arrive in September. It is estimated that there at least 60 breeding females in west Iran. The wintering population is c. 200-300 birds. Although the size of the winter population fluctuates, it appears that numbers in west Iran have remained virtually stable since 1970. Previous surveys, prior to 1978, found 12 localities in the west of the country for Great Bustard. A total of 21 areas with populations of the species was located as a result of the present survey, but five of the original 12 sites certainly no longer hold birds and at another four important sites, the populations have decreased sharply. Most of the localities held birds in autumn and eight probably only held passage birds. Breeding birds were located in ten areas and two new wintering sites were discovered.
Table 1	Table 1. Maximum numbers of Great Bustard Otis tarda in eight survey areas. 0 = no birds found; - = no survey; W = winter; S = spring; SU = summer; A = autumn. 1990 1991 1992 1993 1994 w s su a w s su a w s su a w s su a w Asad-abad - 13 0 13 21 2 0 2 0 0 0 5 7 0 0 1 10 prohibited hunting region - - 0 6 - 4 0 32 0 0 0 7 6 0 0 3 8 34o47'N 48o07'E 12 2 - 16 6 1 0 21 0 0 0 7 2 0 0 13 12 Ghareh Gheshlagh 62 - - - - 41 - 10 - - 4 7 6 - 0 - 48 prohibited hunting region - - 0 15 - - 0 - - 4 - 8 - 2 - 17 73 37o07'N 45o52'E - 0 - 35 13 2 - 47 - 0 7 - 0 2 - 27 - Zarrinch obatou plain 0 0 - - 0 0 2 38 0 0 - - 0 0 - - 0 36o04'N 47o00'E 0 - 11 - 0 - 0 18 0 - - 34 0 3 0 28 0 0 2 18 13 0 3 - 0 0 3 - 0 0 - - 0 0 Chehar douli-Gorveh - - 2 4 0 11 0 - 0 5 0 0 0 3 0 0 0 prohibited hunting region 5 - - 6 0 5 0 1 0 5 0 0 0 0 0 0 0 35o05'N 48o00'E 0 - - 3 0 1 0 11 0 - 0 0 0 0 0 0 0 Akhtachi region - - - - - - - - - - - - - - - - - 36o50'N 46o00'E - - - - - - - - - - - 5 - - - - - - - - - 8 - - - - - - 8 - - - - - Sootay plain - - - - - - - - - - - - - - - - - 36o35'N 46o10'E - - - - - - - - - - - - - - - - 8 - - - - - - - - - - - - - 12 - - 60 Nazloo region - - - - - - - - - - 0 - 0 6 4 - - 37o46'N 45o12'E - 6 - - - - - - - - 4 0 4 3 4 3 7 - - - - - - - - - - 6 - 0 4 - 0 0 Behi-e-Bookan region - - - - - - 0 - - - - 10 - - - - - 36o42'N 46o15'E - - - - - 4 - - - - - 28 - 15 - - - - - - - - 0 - 11 - - - - - 12 - 11 -
BREEDING
	In west Iran, the species breeds in remote cultivated areas subject to little disturbance. Wheat is the main crop, but pea, barley, alfalfa and sunflower are also grown. Nests are usually placed in dry wheat fields. During the survey, three nests were found in 1993: one contained three eggs, another two eggs and a shell, and the third had two eggs.
Plate 1	Plate 1. Great bustard Otis tarda, nest and eggs, Yazibalaghi region, May 1993. (Hamid Amini-Tareh)
	Egg colour was pale olive to pale brown with some dark brown spots. Size and weight of the eggs are given in Table 2. These data accord with those presented in Schanwetter (1967) and Cramp & Simmons (1980).
Table 2	Table 2. Sizes and weights of five Great Bustard Otis tarda eggs found in 1993. Eggs 1 2 3 4 5 mean weight(g) 200 170 130 130.5 120 150.1 length (mm) 81 81 81 79 78 80 width (mm) 57 53 58 60 60 57.6 Display starts in March and the chicks fledge in August. In warmer regions egg-laying often commences in April, while in colder areas laying is considerably later, mainly in early June. Eggs are laid at one-or two-day intervals. Clutches are usually two, occasionally one or three eggs. Hatching in west Iran is in late May-early July. Table 3 demonstrates the relationship between egg-laying time and altitude above sea-level.
Table 3	Table 3. Great Bustard Otis tarda nests and egg-laying chronology in 1993 site name altitude (metres)l latitude first visit second visit eggs laid nest 1 Sootav plain 1470 36o34'N 3 eggs 3 eggs early May nest 2 Yazibalaghi 1640 36o21'N 2 eggs 2 eggs early May nest 3 Kalbaghi 1960 36o10'N 1 egg 2 eggs late May The elevation of the Zarrineh-Oubatoo plain is higher than other areas, and egg-laying consequently starts in June. In the low-lying Asad-Abad refuge, a 7-8-day-old chick was seen on 30 May 1990.
FOOD AND FORAGING
	Great Bustards were observed feeding in crops such as wheat, barley, alfafa, pea and lentil. The crop of the dead bird, and several faeces were analysed. They contained some semi-digested grains of wheat and pea, as well as leaves of clover, alfalfa, and insects from the orders Coleoptera (including some species of Chrysomelidae) and Orthoptera. Food intake is diverse. In summer, mainly in the breeding season, food consisted of terrestrial insects and insect larvae, especially grasshoppers, field-crickets, mole-crickets and beetles. Mice and lizards were also taken during field observations. In winter, birds usually feed from early morning until 11.00, but morning feeding commences and finishes earlier in summer. While feeding, Great Bustards remain vigilant. During the hottest part of the day, birds rest behind a bush or stone, foraging again in the late afternoon until dusk.
LIMITING FACTORS
Plate 2	Plate 2. Great bustard Otis tarda escaping from nest, Kalbaghi region, May 1993. (Hamid Amini-Tareh)
	Disturbance at breeding sites comes from local farmers. In addition to predation and human disturbance, the main threats are as follows.
Illegal hunting	The DOE has declared hunting of Great Bustards prohibited, but the inadequate number of game wardens and the huge areas involved make it very difficult to strictly control illegal hunting. Poachers may be fined c. US$6000 and/or sentenced to between three months and three years imprisonment.
Egg and nest destruction	In spring, the nests and eggs are occasionally destroyed by local people searching for edible plants such as Tragopagon graminifolium and Gundelia spp. Agricultural machinery is responsible for the loss of chicks and eggs in some European countries. As the harvest is practiced in Iran before fledgling, some chicks may be captured and destroyed by harvesting machinery drivers and local people.
Habitat destruction	In recent decades industrial development has increased to the detriment of traditionally farmed lands and the use of agricultural machinery, fertilizers, herbicides and pesticides has increased enormously. Much arable land, previously suitable for Great Bustard, has been irrigated and is under intensive cultivation, which has had an averse effect on Great Bustard populations. Asad-abad and Chehardouli prohibited hinting areas are now heavily cultivated and Great Bustard may be extinct at Chehardouli and subject to a significant decline in numbers at Asad-abad.
CONCLUSIONS AND RECOMMENDATION
	Some important Great Bustard localities have been declared protected areas, by the DOE, in recent decades. There are several other suitable sites which require further protection, and it is hoped that the DOE can bring these under direct protection by employing game guards in these areas. Great Bustard is very sensitive to disturbance. Repeated visits by local people to breeding areas may cause the birds to desert. Most Great Bustard localities are privately owned. In order to prevent habitat degradation and disturbance, I recommend that the DOE purchase suitable Great Bustard areas and manage them for the species. Further DOE surveys of Great Bustard and other threatened species are planned. In addition, an education project is required to inform local people of the need to protect the species. The DOE is interested in collaborating with outside bodies to achieve these objectives.
Plate 3	Plate 3. Great bustard Otis tarda, Zarrineh Obatou Plain, autumn 1993. (Hamid Amini-Tareh)
ACKNOWLEDGEMENTS
	ACKNOWLEDGEMENTS J. Mansoori helped translate my text into English and Guy Kirwan edited the final version. Derek Scott provided helpful comments on the mantuscript.
REFERENCES
	REFERENCES COLLAR, N.J., CROSBY, M. J. AND STATERSFIELD, A. J. (1994) Birds to watch 2: the world list of threatened birds. BirdLife International (BirdLife Conservation Series no. 4), Cambridge. CORNWALLIS, L. (1983) A review of the bustard situation in Iran. In: Goriup, P. D. and Vardhan, H. (eds.) Bustards in decline. Tourism & Wildlife Society of India, Jaipur. CRAMP, S. AND SIMMONS, K. E. L. (Eds.) (1980) The birds of the Western Palearctic. Vol.2. Oxford University Press. KAHROOM, E. (1979) The status, distribution and trends of the Great Bustard in Iran. In: Coles, C. L. and Collar, N. J. (eds.) Symposium papers. The Great Bustard and the Houbara Bustard. The Game Conservancy, Fordingbridge. RAZDAN, T. AND MANSOORI, J. (1989) A review of the bustard situation in the Islamic Republic of Iran. Bustard Studies 4:135-145. SCHÖNWETTER, M. (1967) Handbuch der Oologie. Akademie Verlag, Berlin. SCOTT, D. A. (1971) Preliminary survey of status and distribution of the Great Bustard (Otis tarda) in western Iran. Unpubl. report, Iran Game & Fish Department. Hamid Amini Tareh, Wildlife Research Bureau, Department of the Environment, P. O. Box 5181, Tehran 15875, Islamic Republic of Iran.