Travel among roots and tidal channels near Zarumilla. Agree beforehand which part of the national sanctuary you will visit.
This is an outing worth looking at slowly: roots along the water, movement in the mud and birds above a channel. The mangroves are not just scenery beside a beach; tides change how the landscape looks. Ask your guide about local people's use of the area too.
Visit the sanctuary while staying around Tumbes. Confirm the exact meeting point: a tourism name on a leaflet is not a navigation address.
No. Do not treat those names as the same circuit. Ask explicitly whether you will visit Santuario Nacional Los Manglares de Tumbes near Zarumilla and where you board.
That cannot be fixed in advance. Choose the outing for the mangrove landscape. Tell the guide if birds interest you, but do not build the day around a promised species.
Background on the subjects covered here.