Most of the breeding bird activity is over, but in most years there will be a few terns, Oystercatcher and Ringed Plover still with dependent young and some broods of Tufted Ducks may have only just hatched. Many summer visitors will be departing as others from further north move through.
At dusk and high tides there may be large roosts of Sandwich and Common Terns at Ternery Pool and perhaps the occasional Roseate or Black Tern. This is the best month for many wading birds including Little Stint, Curlew Sandpiper, Greenshank, Green Sandpiper, Common Sandpiper, Ruff, Black-tailed Godwit and Little Ringed Plover. The populations of ducks on the larger pits also increase as they flock together to moult after the breeding season. These include Teal, Shoveler and often a few Garganey.
The Little Egret numbers will increase to its autumn peak and there is a good chance of seeing a Marsh Harrier, Hobby and Barn Owl. In the fields Yellow Wagtail and Wheatear numbers start to build up, whilst the scrub supports increasing numbers of warblers such as Whitethroat and Willow Warbler. Most Swifts will have departed by the end of the month. Throughout the month there is a chance of a rarity turning up.
The Least Lettuce and Red Hempnettle continue to flower and late flowering species emerge such as Autumn Lady’s-tresses at Castle Water. Many commoner plants will still be in flower such as Viper’s Bugloss, Yellow Horned-poppy and Wild Carrot.
A great variety of moths will be on the wing including the scarce Jersey Tiger. Common species will include Large Yellow Underwing and Common Rustic. It’s a good time of year to see a variety of butterflies, bumblebees and grasshoppers including the scarce Grey Bush-cricket. Many dragonflies will be active including Black-tailed Skimmers, Emperors, Migrant Hawkers and Ruddy Darters. The new colonist to Britain, the Southern Migrant Hawker may also be seen at Castle Water.