Hi AxelJ
I went to Dalyan for a couple of days in September 1992. I'm afraid I can't give you precise details of where to go and what to see because it's a long time ago and I have no idea where my notes are. I also don't know how much development there has been since then. But, as no-one has posted a reply I thought you might be pleased to get some general info about the area.
I had good birding. There are tourist boat trips around the delta reedbeds and lagoon. From these boats I saw Pygmy Cormorant (common), Ruddy Shelduck, Pallid Harrier, Penduline Tit and Moustached Warbler. I was told Pied Kingfisher is there, but I did not see one. I saw Levant Sparrowhawk in the area, but you might be too late in the year for that. Other raptors included (resident?) Long-legged Buzzard, migrating Lesser-spotted Eagle (small flocks) and Osprey.
I spent most of my holiday in the Fetiye area (spelling probably wrong, but it's a largish port and you should be able to find it on a map). The birding was good, with lots of migrants around. Middle-spotted Woodpecker was common, as was Rock Nuthatch in rocky areas (including around Lycian burial chambers, of which there are some great examples at Dalyan so I would try around them if I were you). I saw Audouin's Gull in the harbour and others saw Spur-winged Plover from a boat that crossed the bay. Slender-billed Gull was also present in the harbour and around the coast. Also saw Cinerious Bunting and Masked Shrike, but again I don't know if they will still be around in October. Collared, Semi-collared and Pied Flycatchers were all was migrating through, making ID easier than with lone birds, as were lots of Pied and Black-eared Wheatears (more ID fun!). I went up in the mountains inland and found a Finsch's Wheatear, but I think most had moved on by that time of year. I met someone who saw this species at those strange white rock formations with pools that tourists love to visit (can't remember their name, but they are on all the tourist posters).
At that time, the guy who now runs Birdguides (Dave Gosney) had published a little booklet on sites in that area of Turkey, but I don't know if it is still available and doubt it will have been updated. However, you might get some info from
www.birdguides.com
Hope that vague info helps. I'm sure you'll have some good birding just by checking out the various habitats in that part of Turkey.
Cheers
John