Mission nearly aborted....l

I set out today with my really big telezoom (Sigma 100--300mm f2.8) with the intention of capturing some birds in flight (bifs) as I had not done one for some time. When I am looking for birds flying around I generally end up at the harbour as you can be sure of some bird movement there. However, as I was heading off after my morning swim I noted some swallows nesting in the eaves of the swimming pool and wasted a good half hour trying in vain to capture their flight. Down at the harbour my efforts were concentrated on gulls in flight but I did not have much more success as I was continually trying to autofocus against very cluttered backgrounds. In the past I have managed much better with a 200mm prime lens even with added extenders. My big telezoom is so unwieldy I have to use it with a monopod whereas I can hand hold with the prime lens as long as I have ratcheted up the ISO. The two images I have included as my blip seem a bit unsettling as we re not used to seeing birds flying underneath boats. Of the two I probably like the right-hand one as the ripples on the water give a sensation of rapid movement. I have compensated for my limited success by including a close-up of some herring gulls on the harbour edge as the details of their plumage is just so sharp you can almost feel the texture.