Always something to see and photograph at Slimbridge, even if it gets busy
Rushy Hide: See Pintails, Bewicks Swans, Tufted Ducks and possibly some waders quite close ... Wagtails and Goldfinches often visit to drink and Goldcrests can sometimes be seen in the hedge at the side of the hide.
Martin Smith Hide: More Pintails, resident Water Rail, occasional Little Egret, Grey Heron and Buzzard again quite close, occasional Kingfisher.
Robbie Garnet Hide: More Pintails, Bewicks Swans, Shovelers and gulls ... some small birds in the reeds and Cranes farther out across the field.
Willow Hide: Small birds using feeders, inc Sparrows, various finches and occasionally a GSW ... and rats and mice!
Knott Hide: Grazing Wigeon, small birds in the trees and hedges.
Holden Tower: Small birds in the Hawthorne/Blackthorn in front, Cranes often in the field to the right and sometimes a Buzzard or two ... Peregrines quite often and occasionally a Merlin and a Kestrel. Pool to the left with Wigeon, Shovelers and various other species inc occasional Kingfisher.
Discovery Hide: Great Crested Grebe, Cormorants, gulls, Shovelers, Tufted Ducks, various waders.
Van de Bovenkamp Hide: Look straight across to the reedbed to watch out for the two Bitterns ... Wigeon & various duck grazing in front of the hide or in the water.
Kingfisher Hide: Small pool with Little Grebe, Gadwall, Shoveler, occasional Heron and Sparrowhawk ... in the reeds a resident Water Rail and possibly one of the Bitterns and currently a regular Song Thrush searching for food in the grass near the metal gate. In the field more Wigeon, Lapwing, Dunlin and occasional Peregrine. Feeders with selection of small birds, occasional visit from a GSW and regularly passed by Roe Deer.
Zeiss Hide: Most things a bit far off for photography but occasionally a Heron, Reed Buntings and a Water Rail close in front of the hide.
Around the grounds: Goldfinches, Goldcrest, Wrens, Dunnock, Long-tailed Tits etc plus 'captive' species eager to be photographed from Avocets to Flamingos.
Hope that helps.