Abstract:
Waterbirds use many kind of coastal wetlands including swamps, lagoons, estuaries, bays,
mudflats and open beaches. The present study was conducted to assess the community
structure of waterbird families in Thadduvankoddy, Kapputhu and Nagarkovil in Jaffna
Peninsula. Three counting blocks in length of 500 m with open width was selected in each
site and counting of birds was done once a month from December, 2016 to November, 2017.
A total of 67 waterbird species representing 19 families were recorded in three sites (55
species in Thadduvankoddy, 59 in Kapputhu and 51 in Nagarkovil. The highest measures of
species richness (59), mean density of waterbirds ±SE(24.72±3.33birds km-2
), Shannon Wiener diversity (2.91), Pielou’s evenness (0.72), Margalef richness (6.15) and Berger Parker
dominance (0.27) indices were recorded in Kapputhu.Flamingos were the most dominant
group of birds in all three sites (32.65%, 27.30 % and 29.05 % in Thadduvankoddy,
Kapputhu and Nagarkovil respectively, followed by migrant ducks in Thadduvankoddy
(30.54 %) and in Kapputhu (17.07). Cormorants and darters were the dominant group of
birdsfollowed byflamingos in Nagarkovil. The two-way ANOVA revealed that the
abundance of waterbirds significantly varied temporally among different months (p=0.05) in
the three sites. That might be due to the migration of waterbirds and availability of water. The
difference in waterbird species composition and the diversity indices could be due to the
variation in habitat heterogeneity, availability of food and water resources. Thadduvankoddy
provided habitat for wide array of waterbirds from October to March, 2017. Flamingos and
ducks were the most dominant groups of birds in Thadduvankoddy. However, the site in
Thadduvankoddygot completely dry from April to August, 2017 andit was a seasonal wetland
during the rainy season. The availability of sufficient water level throughout the year
makesKapputhu, an excellent habitat for wide variety of waterbirds especially flamingos and
ducks.However, Thadduvankoddy got completely dry during dry season. Comparatively
deeper water (>1 m) and dense mangroves in Nagarkovil provided suitable habitats for
cormorants and darters for feeding and roosting. However, the drop in water level during dry
season made the habitat suitable for wide array of waterbirds including flamingos. Thus, the
findings revealed that community structure of waterbirdsdepend on temporal variation of
water level and availability of sufficient water.
