Hi, The scale is hard to judge from this picture, but it is big. The tamarins are often hard to spot as they disappear into the canopy of the two mature willow trees. If I had to guess I would say that the island measures about 6m by 4m, and the willow trees must go up at least 10-12 metres. They appear to have had a bit of a hair cut this year also. Viewing of the island is either from this elevated walkway which cross the lake (flamingos are on the other side), or from ground level (on the left of this picture).
South American tapirs and capybara also share this lake (and the rest of the exhibit)!
Thanks for the reply. I asked because, like you said, it's hard to judge from this photo but sounds big enough. And you answered my next question by saying that tapirs and capybaras share the exhibit and giving the small fence a purpose.
As a whole this park seems to build their exhibits to be very large. This island and the lake are part of a larger South American area, which must be close to six or seven acres in size. Along with the tapirs and capybara I saw mara, rhea, agouti and alpacas.