Tuesday 15 November 2011


Yet again there’s a thread in progress on Birdforum about an apparent hoax – this time an anonymous Twitter report of an Eyebrowed Thrush in a private garden at Hunstanton last weekend. I have to say that on the evidence available so far this one is looking like a hoax, but some of the arguments regularly trotted out on BF on these threads are somewhat spurious, to say the least. In particular a lot of people seem to have become fixated on ‘EXIF data’ whenever a photo of a contentious bird appears. Look at the EXIF data – that proves it’s a hoax. Someone’s removed the EXIF data – must be a hoax. No, it’s gen – the EXIF data fits with the claimed time of the sighting. Etc, etc.

OK, if the bird was claimed to have been seen at a particular time and the EXIF data is completely at odds with this (weeks or months out), then yes, be suspicious, but it doesn’t prove anything on its own. Many cameras will have incorrect times and dates – I just checked mine for the first time since I first set it up nearly three years ago, and although the date was right, the time was an hour and fifteen minutes ahead! Doesn’t say much for the clock chips Canon use. EXIF data can also easily be edited using various free programs, so even if it does fit with the claimed time and date of a sighting it’s completely irrelevant as evidence to support a claim.

But what about a total lack of EXIF data, as is the case with the Eyebrowed Thrush photo? Anyone who knows even a little bit about web design should be aware that photos should ideally be ‘saved for web’ to minimise browser loading times. This is even more important these days with so many people using mobile devices to browse the Internet. Obviously the majority of people don’t know this, which is why you see so many HUGE photos around that take forever to download on a phone. And many photos saved at low jpeg settings, which consequently look a lot worse than they would if they were properly optimized. But people who do know what they’re doing save everything for web in Photoshop. As well as optimizing the image so you get the best possible quality whilst keeping the file size small, this also completely removes the EXIF data. There is absolutely nothing sinister or suspicious about this – in fact in an ideal world it would be normal practice for anyone uploading photos to the web.

If you look at any photo of mine anywhere on the Internet (flickr, LROS website, this blog etc) you will not see any EXIF data, and the date shown will be the date I saved the file (which could be months later), not when the photo was taken.* Does that mean I’m a hoaxer? Well, I was in Hunstanton on Sunday......

* - a perfect example of this is the first Humming-bird Hawk-moth photo on my flickr page - it says authoritatively: 'This photo was taken on November 6th 2011'. No, it wasn't - it was taken on September 27th 2011, but because there's no EXIF data, flickr gives this completely spurious date, which is just the date the file was created. As far as I know there's no way of turning this off - if I could, I would.