While photographing birds from Sugar loaf mountain this object was in the sky far higher than my subjects. The daylight was exceptionally clear. We were on holiday. My wife and I observed this object for sometime. I photographed it in relation the high flying birds. It faded into the upper atmosphere. I thought it may have been a kite or even a child's balloon. I checked my camera download, thought that it may be worth reporting. Time on the photo is UK as my camera has never been reset while travelling. I have added the picture taken shortly afterwards, I have the tourist pictures taken before.