Genetic analysis of a Western Reef Egret Egretta gularis from Israel

摘要

The Western Reef Egret Egretta gularis is a small Palearctic heron with two subspecies, E. g. gularis in West Africa and E. g. schistacea in East Africa and the Middle East, east to India. It occurs in pale, dark and 'intermediate' plumage morphs. On 7 May 2015 EF, TJ and CR visited a large sewage lake a few km north of Eilat, southern Israel, a site known locally as K19. Ten species of heron had been seen there spring 2015, and an outflow at the north end of the lake, which attracts thousands of small fish, constantly has herons fishing around it. There were numerous Little Egrets Egretta garzetta and Black-crowned Night Herons Nycticorax nycticorax feeding at the outflow. EF, TJ and CR caught an intermediate morph Western Reef Egret (Plates 1-3) that had been present at the site a few days previously. Western Reef Egrets breed in Kuwait (Pope & Zogaris 2012) but otherwise are found extremely locally in the Western Palearctic with small numbers of birds seen regularly in Eilat and at some sites in Morocco, along with some occasional vagrants sighted in the Mediterranean. Identification as a Western Reef Egret was confirmed by the following features (Cramp & Simmons 1977, Dubois & Yésou 1995): it was noticeably larger in the field compared to the surrounding Little Egrets and with more aggressively dominant behaviour; the bill was long, thick and slightly decurved with a yellow lower mandible (not slender, pointed and all-dark); yellow colouration extended all the way up the tarsus (not confined to just the feet) and several of the wing feathers were tipped or completely dark grey (Plates 1-3). There were no abnormalities that might be indications of hybrid origin. Few, if any, Western Reef Egrets have previously been ringed in Israel. The bird was metal ringed (number G23994), full biometrics were taken (Table 1) and it was released on site after ringing. During the ringing process a feather was shed which was kept for DNA analysis, as no sequence from this species had been deposited in public databases.