Podoces
Volume:14 Issue: 1, 2019

The breeding ecology of the Little Egret Egretta garzetta was studied during the breeding season of 2016 in two sub-colonies in Anzali wetland. Trees of second sub-colony were younger and the height and diameter of threes were less than half of the first one. Breeding in the second sub-colony done about one month later. The variables tree diameter, the height of nests from the ground and the distance of nests from the top of tree canopy were significantly different. The breeding activities in first sub-colony started from late April and lasted to late July and the second one from 22 May to the middle of August. The mean egg size and volume in the two subcolonies were significantly different. The average clutch size did not differ between these two sub-colonies. Breeding success in the first sub-colony (82%) was higher than the second sub-colony (74%), however, no significant difference was found at the fledging. Based on generalized linear model, the clutch size and breeding success appeared to be independent of the structural variables of the nesting site in these two subcolonies. Fish dominated the diet of the nestlings, particularly Eastern Mosquitofish Gambusia holbrooki, in terms of the number and Carassius gibelio, in terms of the volume percentage.

Pollutants in urban environments can influence on human health and other organisms such as birds living in the same regions. Therefore, the study of these species, as a sentinel, can realized on the health status of urban environments. The present research was conducted to measure Benzo a pyrene (BaP) concentration in different tissues of Rock Dove Columba livia as a sentinel species in in vitro and in vivo conditions. For this purpose, five groups were exposed to different concentrations (0.1, 2.5, 5, 7.5 and 10 mg.kg-1 bw) of BaP. Also, for the comparison of in vitro results with urban conditions, 12 body samples were captured from the Tehran megacity. Results showed different accumulation patterns among the studied groups, which can be due to different intake pathways of pollutants by these birds. According to the results, in case of bioaccumulation factor, the rapid biotransformation rate of BaP in tissues of pigeons might affect their amount. Overall, the fat tissue at first and after that, the muscle tissue of C. livia could serve as a suitable biomonitor for BaP in the Tehran megacity.