
Addendum - on reading the above the ever helpful Alf King reminds me that the Visitors' Centre here has maps and leaflets about the area including one that shows the 'northern arm' of the Tres Amigos sendero as being legitimately accessible. He also tells me that the principal interest here isn’t ornithological but historical as the site has a late 13th century flour mill powered by the rising and falling tides. This was one of a network of hundreds of such mills stretching from Faro to Cadiz Bay and they were the main means of milling in that period.

On paper at least, NW 16.2 has good potential but access is problematical and I've not been able to check in person. Only one of the three suggested walks (Collejon del Mollino) is featured in the “300 senderos” booklet (https://issuu.com/cadizturismo/docs/300senderoscadiz/1?ff=true&e=3220287/1858612), the others being derived from a search of GoogleEarth. This suggest that access may not be straight forward. The 6 km walk through Salina de San Ramón y la Pastorita (b) takes you to the main channel and should allow good views across of the centre of the marshes. In all likelihood you’ll see few birds you won’t find at the more convenient NW 16.1 (which also has the advantage of offering refreshment and a panorama across the salinas from a covered viewpoint) but may interest the adventurous. About 500m further along the Calle Molinos another sendero, Collejon del Molino (c) - Walk 167 in the “300 senderos" booklet - also promises a route into the salinas (but is not shown on GoogleEarth). The wild card here is the Coto de la Isleta, a wooded island in the centre of the marshes, which should be an interesting destination but access is open to doubt. “Wikiloc” shows a sendero linking it to the village of La Coquina (d). However, a close look at GoogleEarth seems to show that the causeway connecting the island to the village has been breached and therefore that the island is inaccessible. I've left it in just in case foot bridges have or may yet be constructed. Even so it may still be worth exploring this area as some roads/tracks may offer good views over the marshes/salinas. Another option for the adventurous....
I've tried to drive through Los Gallos to (e) several times but the maze of narrow one-way streets in the urbanisation are such that I've got lost every time! I've revised my directions to take what seems a longer, but should be quicker route (as you're less likely to get lost!), via the suitably named Calle Carboneres, which involves only two turns and no one way routes! Essentially, you head north on the Avenida de la Diputacion and when you've negotiated roundabout betwixt the Mercadona and Lidl supermarkets the left-hand turning into Calle Carbonares is another 650 m (although it may be easier to continue a further 150m to a roundabout and return the way you came to make it an easier right-hand turn). Follow this road almost until its end (c1 km) and then turn left and shortly afterwards right into the Calle Codorniz where you can pull off onto rough ground and explore the sendero. Access via (f) is much less complicated since the white 'Puerta de Carboneros' makes the start of the sendero obvious whilst parking in a nearby side road is convenient. You can even reach this starting point by bus (routes L8 & L11).