cr. pic. http://www.edtguide.com
A lot of beautiful lotus and various waterplants are covered all over the area and will be surrounded you when you are there. There are various types and colours of lotus; i.e. pink, purple, white water lillies lotus, etc. They look like floating garden indeed.
For bird watching, you will find no difficulties to see waterbirds as plenty of them will be constantly moving while you get closer. Among those waterbirds are small ducks, great egrets, storks, etc. In the meantime, you may use binocular to further explore those waterbirds accordingly.
Apart from the magnificent view, you will have good experience with long-tailed boat which is unique style of Thailand and one of the most popular transports for Thai people.
For your information, the recommended period to visit Thale Noi is October to May as there are a lot of waterbirds during that period. Those waterbirds stop at Thale Noi during their annual migration to the north to Siberia or China or to the south to Sumartra or Ausrralia.
I can say that Thale Noi is very wonderful and has tranquil scenery / environment as well. When you come there, you will certainly feel instantly relaxed. If you love nature and are a bird watching, I would recommend you to include Thale Noi in your next trip to Thailand.