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International Journal of Marine Science 2013, Vol.3, No.25, 193-200
http://ijms.sophiapublisher.com
194
Figure 1 Location of four islands in Persian Gulf
island, island and furthest offshore, is c. 35 ha
(Figure 1), and composed mainly of sand with some
rocky shores in the south and west. There is a small
brackish pool near the south end of this island.The
largest one is Khan (or Morghu, 27°29'N, 51°16'E,
108 km SE of Bushehr, Figure 1), covers an area of
800~1000 hectares (this variation in area is due to
changes in tidal level), consisting of a broad expense
of bare mudflats without any vegetation. All four
islands are devoid of fresh water and uninhabited.
These islands are hot in summer (45
℃
) and moderate
in winter, their main inhabitants are the seabirds, but
also sea turtles are present annually in spring and
summer.The sea birds are considered to be the most
important species to occupy the islands, endowed with
good texture of soil, adequate plant covering and rich
marine water. These islands are propitious environment
for nesting and breeding for migratory waterbirds as
well as sea turtles so that they are occupied annually
in spring and summer.
1.2 Estimation of bird populations
Counts were done in mid-May every year in all islands,
after all species established nests and laid egg. We
estimated the area of the breeding habitat of the Bridled,
Lesser Crested and Swift terns By GPS system. Nest
numbers of Bridled Tern
Sterna anaethetus
, Lesser
Crested Tern
Sterna bengalensis
and Swift Tern
Sterna
bergii
were estimated using Sampling method by plots
(20×20 m for Bridled tern (ten plot) and 1×1 m for the
other two species (ten plot, Figure 2) base don which
the breeding population of these species was estimated
(Blaber et al., 1998). The plots selected randomly in the
breeding place of these three species. The nest with the
Figure 2 Plot Method counts of the Lesser Crested and Swift
terns’ nests in Islands
eggs counted in the each plots. Counts were done only
once during the breeding season of each year (between
18-25 May 2008-2012). The breeding time chronology
was also observed. Total count method was used to
obtain the census of the nests and breeding population
of Crab Plover
Dromas ardeola
, Reef Heron
Egretta
gularis
, White-cheeked Tern
Sterna repressa
, Caspian
Tern
Sterna caspia
and Gull-billed Tern
Sterna nilotica
.
This time was obtained by searching these breeding
colonies since 2004-2008 (Behrouzi-Rad and Taifeh,
2008).
2 Results
2.1 Birds of the islands
Thirty three species of water and terrestrial birds have
been identified in these islands since 2008-2012 of
which 23 species were waterbirds and 11 species were
landbirds (Table 1).
2.2 Species and populations of breeding birds on
islands
Breeding species and maximum number of pairs
estimated in 2008-2012 and 1975 are shown in Table 2.
Eleven species bred in 1975 and 10 species in 2008-2012.