Yesterday Markus Craig reported a presumed Grey-throated Martin Riparia chinensis together with a Pale Martina Riparia diluta. Today he relocates the birds alert us in WhatsApp group. I rushed right away to find the four birds perching on a barbed wire next to a Barn Swallow. The four birds kept together hawking insects over the marsh. Although it was cloudy, but I managed to get some photos for identification.
There is the possibility of Brown-throated Martin Riparia paludicola, the African species which consists of seven subspecies according to IOC. While the Grey-throated Martin Riparia chinensis is possible which is an eastern species, consisting of two ssp, the nominate is distributed from Tajikistan and n Afghanistan to s China, Indochina and Taiwan, the tantilla ssp is considered unlikely, from Luzon (n Philippines).
The identification of both is uncertain and bending further study. Both records are under review by KORC.
In the photos there are some juveniles that look fresh with pale fringes to wing coverts and also adults moulting inner secondaries.