Nature Notes: Southward bound
As the wayward jetstream high above slipped southwards again our fleeting glimpse of a mere week of hot weather seems but a distant memory.
It is not only the jetstream moving south but from now on, many summer visiting birds are preparing to leave behind our fitful summer and head back to Africa.
Swifts, one of the last to arrive here in the spring are also the first to depart and most had gone by 8th August.
September is the month when activity begins in earnest. Swallows, warblers, common terns (Pictured) and sand martins among others will be on the move then. However, house martins remain with us until mid-October, trying to squeeze in another brood which hopefully will occur as the species is in steep decline. In my area I used to watch them partially fill the airspace left by departing swifts but rarely see them now.
It is not only birds that fly south to escape our winter. Despite their deceptively flimsy appearance, butterflies are also strong migrants.
We have not enjoyed a strong painted lady year this summer but the offspring of any that did arrive and breed here will try to move back to the Continent in autumn. We will not see them go as they fly high, but red admirals also travel south and can be seen on sunny days flying strongly and fast a metre or so above the grass in open spaces such as Richmond Park.