BIRD DIVERSITY IN SHENDI AREA, SUDAN

Birds are among the best known parts of the Earth’s biodiversity (Pomeroy, 1992; Bibby et al., 1998). They have long served humans for game, food, and feathers, as well as in their predatory capacity as destroyers of insects and rodents (Collins, 1981). In addition, they are considered as good indicators of the degree of human disturbance in the various ecosystems worldwide. Their population abundance has been found to change considerably due to anthropogenic activities (Askins et al., 1990; Bock et al., 2001).


INTRODUCTION
Birds are among the best known parts of the Earth's biodiversity (Pomeroy, 1992;Bibby et al., 1998). They have long served humans for game, food, and feathers, as well as in their predatory capacity as destroyers of insects and rodents (Collins, 1981). In addition, they are considered as good indicators of the degree of human disturbance in the various ecosystems worldwide. Their population abundance has been found to change considerably due to anthropogenic activities (Askins et al., 1990;Bock et al., 2001).
In Sudan, studies of the avifauna and its seasonal variation have been carried out by many ornithologists in various locations, including Dinder National Park, Sunut Forest and Tuti Island (Hamad, 1998). The avifauna of Sudan numbers more than 630 species, of which the majority is resident and some are regular seasonal migrants (Dowsett et al., 2016). The objective of the present study was to provide a baseline of information on the biodiversity of birds within the area of Shendi, a city located in the northern part of Sudan.

2.1.STUDY AREA
The present study was conducted in Shendi, a city situated on the east bank of the River Nile, in northern Sudan, its geo-coordinates being 16°40'52"N and 33°25'7"E. This area has a semi arid climate with a short rainy period between August and September with a mean precipitation of 29.3mm, and an annual temperature ranging from 28-41°C. The flora of the Shendi area is poor and sparse in the desert zones, and is virtually absent except along the banks of the River Nile, where there are agricultural lands used for fruits, vegetables and other crops. The inhabitants of the area have diverse occupations ranging from farming and fishing to trading activities.

2.2.BIRD OBSERVATION
The Birds were observed and recorded at different locations from July to December 2015 within Shendi city and its adjacent areas, including the River Nile bank opposite the study area. The bird observation and sighting was conducted weekly, in the morning and evening for two to three hours, using field binoculars (Comet, 8x42 . The numbers of individuals observed were counted when numbers were limited or estimated when numbers were huge. Birds were photographed using a digital camera (Samsung, 13 Mega pixels) whenever that was possible.

RESULTS
Thirty-five bird species with various abundances were observed in the present study belonging to 22 families ( Table 1). The highest number of birds observed was in September (Table 1). While the families observed with the maximum numbers of different species were Columbidae, Meropidae and Nectariniidae (Tables 1 and 2).
The monthly number of birds observed during the study period was as shown in table (1) and their species status is shown in table (2). Photographs of some of the birds observed appear as figures 1-18. Out of the 35 species observed, 22 (62.9%) are residents in the country as confirmed by breeding records and six (17.1%) are migrants which are known to breed in the area, including those in passage across the country as also confirmed by breeding records. Two (5.7%) species breed in the Palearctic and winter in the area, one (2.9%) is a species with both a resident breeding population and a wintering population, one (2.9%) has both a migrant breeding population and a wintering population, one (2.9%) breeds in the Palearctic but is not recorded previously as wintering in the area, and one (2.9%) species is resident although there is no record of it breeding in the area (Table 2).

DISCUSSION
In the present study, 35 species of bird were observed. This result reflects the richness of the avifauna of the Shendi area, especially during the migration season in the autumn. This richness is probably due to the use of the area for gardens and orchards and hence the availability of food, as well as the flora of the River Nile banks, which is diverse and contains a wide range of different trees providing a wide range of microhabitats for different species of birds. It is well known that vegetation cover has a strong influence on the avifauna (Scott-Mills et al., 1989). The River Nile is an important flyway for migratory waterbirds moving between Africa, Europe and the Middle East. It provides a considerable amount of suitable habitats for feeding, nesting or resting sites for birds. Variations in the structure of the bird community noted during the study period could be attributed to bird migration, with some migrating birds arriving in the area for breeding or using it as a stopover site for food supply. Previous studies in Sudan have recorded more than 160 species of birds from the Dinder National Park, 24 species from Sunut Forest, 30 species from Tuti Island and 23 species from the El Ga'ab depression (Salah and Idris, 2013;Mahmoud et al., 2015).
The relatively high diversity of birds observed in the present study suggests that the habitat of the area is suitable for birds. However, increasing anthropogenic activities are a matter of great concern when considering the future existence of these species. Sudan has lost a number of wildlife species in the last two decades and this is mostly due to habitat destruction; several varieties of grasses and herbs have disappeared due to overgrazing, and repeated droughts and fires. In the Shendi area, the main threat that affects birds is the destruction of their habitat by tree cutting for agricultural use. This practice reflects low awareness and sensitivity to environmental issues among both the public and policy makers. Moreover, development and construction projects in the Shendi area may have a negative impact on bird habitats, for example, the construction of El Mack Nimer Bridge and the cutting of old large trees such as Acacia spp. and Azadirachta sp. or Neem trees near the main market to facilitate new buildings constructed for the purpose of investment has resulted in the destruction of the nests and resting sites of many bird species, including the Cattle Egret and Abdims Stork. Previous studies have concluded that urbanization, industrialization, the draining of wetlands and the widespread use of pesticides pose a threat to birds (Donald and Gregory, 2002;Liven-Schulman et al., 2004). Moreover, many wildlife species are endangered because of illegal hunting or over-hunting (Yom-Tov, 2003).
In conclusion, this study will provide a baseline of information for future studies concerning the birds of the Shendi area.