ok heres my experience on this day before yesterday i had gone to see some relative of my father from australia who was my fathers childhood friend i also went through the indias biggest sea link that is bandra worli sea link and then came to hinduja hospital nearby which was mumbai's magnificient sea shore.
the wind was over 15 kmph or a lot more whn i started to observe some of the birds
i saw they took of into the wind and always landed into the wind
second these birds (crows) used flap kind of things in their wing to help them glide
their wings to me seemed to be like uncambered ones
while the turned they used their tail as a v-tailed planed and turned it to stabilize their heading
while flying with the wind they tried to gain airspeed and gain altitude
while land to decrease their speed i also saw spoileron kind of things in their wings to slows them down
i still have a lot to learn about these birds
it would be a lot helpful if any body could elaborate or correct my findings
subbu