Podoces
Volume:13 Issue: 1, 2018

There are 28 islands in Karun River in Ahwaz City that one of them is Ali Siah. The islandis covered by Phragmites australis, Populus euphratica, Prosopis sp. and Tamarix sp. This study assessed the species composition, relative abundance and species diversity of waterbirds found on and around this island. A total of twenty one species, seven families and two orders were identified. From each twenty one species, nine species belonged to waders and wading birds and 12 species belonged to waterbirds. Five species of Ardeidae, namely Little Egret Egretta garzetta, Cattle Egret Bubulcus ibis, Black-crowned Night Heron Nycticorax nycticorax, Squacco Heron Ardeola ralloides and Grey Heron Ardea cinerea were breeders. Nests of five mentioned species counted in nine years 2002–2015 on this island. Breeding population reduced from 736 in 2002 to 312 pairs in 2014 and zero in 2015. The reduction was 57.61% in 2014 and 100% in 2015. The Little Egret was dominant in winter and in breeding colony (maximum 365 individuals in winter 2003 and maximum 245 pairs in 2007 and 2010 respectively). Wintering population reduced from 946 to 32 individuals. The reduction was 96.6% in 2014 and 100% in 2015. The reason of absence of breeding and wintering population of birds in 2015 was elimination of Ali Siah Island.

In this study we studied fruit eating behaviour of birds through two methods, i.e. direct observation and bird dropping. Data of 100 hours of field observation were collected and 17 bird species were recorded. The majority of bird species (N=17) was attracted by Solanum mauritianum and Rubus niveus with the total visits of 240 and 215 followed by 16 bird species attracted by Cestrum aurantiacum with the total visits of 239. On the other hand, Phytolacca americana was attracted by fewer number of bird species (N=8) with 191 sightings during the survey period. Among 17 bird species, the Red-whiskered Bulbul Pycnonottus jocosus, Oriental White-eye Zosterops palpebrosus and Jungle Myna Acridotheres fuscus were found predominantly feeding on the exotic plants (non- native plants) and proved them as perfect frugivores. Totally two hundred bird droppings belonging to four abundant bird species namely Jungle Myna Acridotheres fuscus, Oriental Whiteeye Zosterops palpebrosus, Pied Bush Chat Saxicola caprata, and Redwhiskered Bulbul Pycnonottus jocosus were collected from three different localities, under nests (N=109), under trees (N=77) and few of them (N=14) were collected in other places such as human traits and paths. Seeds of five plant species, namely Cestrum aurantiacum, Pytolacca americana, Rubus ellipticus, Rubus niveus and Solanum mauritianum were recorded. It was interesting to note that all these plants were exotic species. The high variations were seen in the Jungle Myna droppings where Solanum marutianum seeds were seen high in number in the droppings (22.23±11.45, N=978) because Solanum maruritianum fruit contain more number of seeds compared with that of other fruits. This study clearly indicates that the exotic plants attract bird communities than native plants by providing food for them and thereby they vigorously disperse their seeds than native plants.