Two UFOs snapped over Durban, South Africa

On May 21, 2015, a person was in his office in Durban (South Africa). He decided to catch the trees with his camera. But, on pictures, witness discovered two impressive UFO… What is it?

Witness report:

Today 21/05/2015 around 11am i was standing outside the back of our offices observing the birds making nests in a tree just outside of our property, i took a photo hoping i could zoom in as i wanted to see how many birds have made a nest in the tree, after view my photo and zooming to take a closer look i noticed a weird looking object in my photos, seconds after i had taken the photo i viewed it, then immediately looked up into the sky into the direction the object would have been but it was already gone, i have also tried to reenact the situation to try and figure out what it might be but nothing, its a very clear day with no wind, no clouds, no airplanes in our area, the object was definitely quite a distance as i zoomed in to take a closer look it starts to pixelate and if the object was pretty close you'd be able to view the object properly. I have circled the object in red on the left and the one on the right is a bird to compare the different sizes. I would like to know what the object is please and if you can assist in this regard i would greatly appreciate it, please advise what this object might have been. Thank you.