Black-winged pratincoles feed on insects like beetles, ants, grasshoppers, locusts etc. They often catch airborne insects in the air, flying low over ground or water. They are remarkably accurate and in this photograph you can see the size of the prey they go for. One sometimes sees them foraging very high, often in flocks of hundreds or even thousands of birds. They usually hunt in early morning and late evening, often after dusk, but if food is about, they'll go at it any time of day.
The global population is currently estimated at around 45,000 birds. However, a flock of 800,000 birds in Orange Free State in 1991 (mentioned elsewhere in this thread) indicates that the population was at some stage substantially larger. Recent decline in the total population of Black-winged Pratincole has caused its survival status to be re-evaluated and it is now considered to be facing the threat of extinction.
Black-winged Pratincole breeds mainly in the steppe and desert belt of Eurasia and spends the northern winter in Africa south of the equator. We see them here in South Africa only during our summer, November to March. This year I have seen the best flocks around Standerton ever with some congregations estimated at +1000 birds.
In the shot above of the same bird one can see a weird-looking set of paddles (probably for extra maneuverability) on the sides near the tail. I have never noticed these in any bird before! Anyone with more info as to what these are and the purpose thereof?