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MIGRATION PARAMETERS OF SOARING BIRDS CROSSING WIND FARMS OF GABEL AL-ZEIT CORRIDOR ON THE RIFT VALLEY/RED SEA FLYWAY, EASTERN DESERT, EGYPT

Egypt includes a great part of the Great Rift Valley/Red Sea flyway; the second world’s most important flyway for migratory soaring birds. It acts as a corridor between Eurasia and Africa. The aim of the present study is to study the phenology and survey the numbers of species and individuals of migratory soaring birds that pass through a wind farm (240 Megawatts (MW) wind energy project of Kreditanstalt für Wiederaufbau (Germany’s development bank) (KFW) located in Gebel Al-Zeit area, Red Sea Governorate, Egypt. Bird monitoring was conducted by visual observations, for eight hours during daytime at the whole survey period in two fixed observation points, during the period extending from March 4 to May 10, 2018. This observation period covered a four-week peak of spring migration season. A total of 143,906 soaring birds belonging to 32 species were counted. The most common bird species was the white stork (63.1%), the northern steppe buzzard/common buzzard (13.21%), the great white pelican (7.42%), the European honey buzzard (6%), the Levant sparrowhawk (2.38%), and the black kite, (2.17%). Globally threatened (vulnerable, endangered, and critically endangered) migratory soaring bird species recorded in the study area surpassed 1% of the flyway population. These species include the Egyptian vulture (1.2%) and the steppe eagle (3.02%). Two other near threatened bird species; i.e., the pallid harrier (6 individuals), and the red-footed falcon (two individuals), were also observed. These results Journal of Environmental Sciences (JES) Faculty of Graduate Studies and Environmental Research, Ain Shams University


INTRODUCTION
Egypt includes a great part of the Great Rift Valley/Red Sea flyway; the second world's most important flyway for migratory soaring birds. It acts as a corridor between Eurasia and Africa, and is characterized by wide geographical, geological, and meteorological variations with sporadic urban and religious establishments, and scattered human societies (Riad, 2019;Riad & Mahmoud, 2020). It is an important passage for migrating soaring birds between Eurasian breeding grounds and African wintering grounds (Bergen, 2007;CarlBro, 2010;Bergen & Gaedicke, 2013).
At the core of the Rift Valley/Red Sea Flyway lies the Gulf of Suez with few bottlenecks represented by Gabel Al Zeit, Suez, Ain Sukhna, Ras Mohamed National Park, and the Qaa' Plain, which are universally perceived as Important Bird Areas (IBAs) (Baha El Din, 1999). Hundreds of thousands of migrating raptors, storks, and pelicans pass each autumn and from their breeding areas in Eurasia to sub-Saharan Africa, where they spend the winter, and then return back in the next spring to their homelands (Moreau, 1972).
Migratory birds face extremely hard conditions as they cross extensive areas of seas and deserts. The greater part of bird species, especially small ones, perform immediate and active flights, choosing the shortest way between breeding and wintering grounds (Riad et al. 2019). Soaring birds, on the other hand, are almost entirely dependent on the updraft of warm air to sustain their migration trip which greatly reduces their free choice of migration routes and restricts them along very narrow ones. The lack of updrafts over large areas of water prevents them from flight over water except at the narrowest of straits (Newton, 2008). Many soaring birds that migrate to and from East Africa even avoid crossing the Gulf of Suez and convolute via Suez instead. Other birds that migrate to Sinai in spring converge at Zeit Bay because it is the narrowest crossing point in the southern part of the Gulf of Suez.
Globally threatened species such as eastern imperial eagle, (vulnerable), greater spotted eagle, (vulnerable), Egyptian vulture (endangered) and the near threatened pallid harrier, are known to migrate through this area. The most numerous species reported over the Eastern Desert of Egypt include the white stork, and the Levant sparrowhawk, (Baha El Din, 1999). The main migration route of the white stork passes through Zeit Bay, and the entire world population of the Levant sparrowhawk migrate through this area, usually in large flocks, in few days (Baha El Din, 1999;Schulz, 1988;Berthold et al. 2001 were collected on the species, number, altitude and direction of soaring birds during their spring migration between the African and Eurasian grounds across the part of the Great Rift valley/Red Sea flyway that lies in Egypt.

Study area:
The study site is the KFW 240 MW wind farm, located on the Red Sea coastal plain that stretches between Sabkhet Ras Shukhair and the foothills of the Red Sea Mountains. It is located on the western bank of the Gulf of Suez, about 10 km away from Ras Shukair, 120km to the north of Hurghada, and about 5km to the West of the Hurghada -Suez Road (Fig. 1).
It has a total area of about 38.5km 2 with a maximum extension of about 6.5km (west to east) and about 9.3km (south to north) of the KFW wind farm.
The eastern part of the site is flat or slightly undulating, with increased elevation and topographic complexity in the western part.
There are 120 wind turbines arranged in seven parallel arrays and are oriented from the northeast to the southwest. The distance between adjacent arrays is about 1.1km and the longest array is 5.2km long. A 220-kV power line runs along the eastern perimeter of the wind farm (Fig. 1). The study area was partially monitored, only 8 hours on a daily basis in spring migration The survey covered all point watches for 8 hours/day, 7 days/weekly, from 8:00 a.m. to 16:00 p.m. with an hour break. Bird altitude was recorded using the turbine height as an indicator at time intervals of fifteen seconds, weather conditions (wind direction and speed, temperature, cloud/mist, rains, and visibility) were recorded hourly according to the method followed by Riad (2019). The researcher at each point was supplied by professional binoculars, digital cameras, bird identification filed guide, clipboards, compass and recording sheets and maps.   (Table 1). Four common bird species formed about 90% of the total recorded number. They included the white stork (63.03%), the steppe buzzard/common buzzard (13.21%), the white pelican (7.42%), and the honey buzzard (6.01%). The remaining 28 bird species were rare ones since they formed 10% of the recorded species. The number of records (observations) of a given bird species is not necessarily proportional to its total number during these records. For example, the black kite is one of the rare bird species, however, the number of its records formed (12.51%) of the total number of records. Other bird species which were frequently recorded were the steppe buzzard/common buzzard (39.46%), the steppe eagle (11.16%), and honey buzzard (8.93%). All globally threatened (vulnerable, endangered, and critically endangered) migratory soaring species recorded in the study area surpassed 1% of the flyway population. These species include the Egyptian vulture (1.2%), the steppe eagle (3.02%). Two other near-threatened bird species; i.e., the pallid harrier and the red-footed falcon were recorded. Only  on the other hand, was slightly higher during the afternoon hours (12:00 pm to 4 pm) since it formed about 53% of the total number of birds (Fig. 3). Flying altitudes of common bird species: In the present study, the white stork, steppe buzzard, Levant sparrowhawk, honey buzzard, black kite, and steppe eagle common bird species, were mostly recorded flying at altitudes of more than 200 m (Fig. 5 A and B). The white pelican, which is also a common bird species, flew at lower altitudes since a high percentage (69%) of this bird was recorded flying at altitudes ranging from 100 m to 200m.  In all flight directions, the highest percentage of the bird's numbers has been recorded at more than 200m. Also, we recorded more than 20% of birds between 100-200m (Fig. 7).

DISCUSSION
The present study describes substantial migration of birds across the Eastern Desert of Egypt. In the spring; migratory birds are under the pressure of time as they must reach their summer breeding grounds early enough to successfully compete for a suitable breeding site. They have to mate, incubate eggs and raise young before they leave back to African wintering grounds the next autumn. Birds arriving too late or too exhausted will not be able to reproduce successfully (Hilgerloh, 2009).
In some studies, migratory birds did not show preference for special routes through the study area. Raptors mostly migrate individually or in small groups and show a somewhat regular migration pattern. Soaring birds (storks, pelicans, and cranes), on the other hand, mostly migrate in massive herds, thus producing very distinct regional fluctuations (Langston & Pullan, 2003;Drewitt, & Langston, 2006& Langston, 2006Riad, 2020). While the researcher in this study indicated that soaring birds were recorded in vantage point 2 (VP2) at a far distance from the coast of the Gulf of Suez to have enough time to raise up and reach a considerable height to be able to cross the bay easily at its narrowest point at Ras Shukier or Ras Gharib.
The study results showed that many threatened species; i.e., steppe eagle, Egyptian vulture, greater spotted eagle, eastern imperial eagle, and pallid harrier, use this pathway of migration from Africa to Eurasia. Many recorded numbers were seen flying at altitudes less than 200 meters, which suggests that they will continue to migrate north and cross the Gulf from Ras Gharib or may continue to the end of the Gulf at the city of Suez. According to these results, some individual migrants observed to the south of the study area often Egypt between Ras Gharib and Ras Gamasa (Christensen & Jensen, 2002).
However, more observations are needed to accurately determine their migration pathway (Grieve, 1996& Baha El Din, 1999.
Observations carried out during the present study showed that migrants fly along the foothills of the Red Sea Mountains and then to the coastal hills of Gabel Al Zeit or the coast adjacent to the northern area. Large portions of the population of bird species such as the white stork and this was in agreements with other studies (Creutz 1985;Schulz 1988;Goodman & Meininger 1989& Berthold et al. 2001, levant sparrowhawk (Grieve, 1996& Baha El Din, 1999 and common crane regularly cross the Gulf of Suez.
Consequently, many birds have no choice but to cross the study area. Other bird species such as the lesser spotted eagle, a species that avoids any sea crossing, continue to migrate to Suez (Grieve, 1996;Meyburg et al. 2002;Riad et al. 2020

CONCLUSION
This study indicates the significance of the Gabel Al Zeit as an important bottleneck for soaring bird spring migration.
The dominant bird migration course was generally heading northward.
Sixty-two percent of observed birds adopted Northern (N), North Eastern (NE), and North-Western (NW) directions, which is expected for northward spring migration.
Observations of this study showed that migratory soaring birds fly along the foothills of the Red Sea Mountains and then head for the coastal hills of Gabel Al Zeit or the coast adjacent to the northern area, especially in those species such as White Stork and Levant Sparrowhawk. These results clarify the importance of the study area as a bird migration corridor that highlighted the potential impacts and required actions to protect migratory birds.
Although this number significantly represents a high portion of spring migration, the number of birds passed over Gabel Al Zeit does not reflect the real number as many migrating birds cross different areas along the flyway.
In conclusion, soaring bird migration monitoring continuation at this site is important for recording population dynamics and behavior to set the required action plans.

ACKNOWLEDGMENTS
We would like to thank a group of ornithologists and bird watchers who helped us to monitor the migration and collect some data for the study. Also, we thank the Egyptian New and Renewable Energy Authority (NREA),

Migratory Soaring Birds project in Egypt and Egyptian Environmental
Affairs Agency (EEAA) for their support and facilitation of obstacles during the study.