This male Lanner falcon 'Lenny', fitted with GPS transmitter, stooped down from a height of around 200m, before levelling out and heading towards the lure in the Birds of the World display arena. The wing-shape morphs from the classic 'teardrop' shape of the full-on near-vertical stoop, to this 'cupped' shape*, allowing the bird - still with tail furled and the trailing edge of the wings attached to it - to more easily adjust trajectory and speed, whilst fast approaching the prey/lure at a shallow angle - as here - or even horizontally, before it finally extends the wings and unfurls the tail just prior to striking the prey/lure.
* an 'M' shape may also be adopted at intervals during the stoop/approach, with the wingtips detached from the still-furled tail, but not fully extended.
Thanks @Lafone I think I was fortunate: having lost track of him partway down the main stoop, I managed to pick him up again as he levelled out and headed straight for me. Luckily he was still framed against the sky, otherwise I suspect I might not've been able to pick him up in the viewfinder.
