So what is this programme? Well you can download it here http://www.serpwidgets.com/Apps/measure.html and it works for snakes by taking a photo of a snake next to a known length ie a ruler. Then you measure the length of the snake and it uses ratios to tell you how long your pet is.
Now this got me thinking, Glaucous Gulls on the whole have a deeper bill than Iceland Gulls (don't have BWP/i or any ringing books so can anyone confirm this for me?) and so could I use this programme to get some kind of comparison between two different photos?
Now the first flaw to this is that it would be kinda tricky to take a photo of these gulls conveniently posed next to a ruler! However I thought maybe I could use the eye to get a scale of eye to bill depth.
So heres how I did it, I got some photos of the internet of various Iceland and Glaucous Gulls and used this programme to obtain a ratio for eye size to bill depth. Eye length was measured from the bottom to the top of the actually eye in a vertical line and bill depth was measured from the tip of the gonys angle vertically up (so on some I had to compensate depending on the angle the bird was holding its bill at)
So the results from a quick experiment involving 3 Glaucous Gulls and 3 Iceland Gulls from google images.
Ratios as Eye:Bill Depth
Glaucous Gull 1= 1:1.911
Glaucous Gull 2= 1:2.408
Glaucous Gull 3= 1:2.058
Iceland Gull 1= 1:1.991
Iceland Gull 2= 1:1.701
Iceland Gull 3= 1:1.756
So even in this tiny study size you can see that Glaucous Gull ratios range from 1.9-2.4 and Iceland 1.7-1.9.
Of course it would be a lot more accurate to do more birds and maybe I'll get round to it at some point.
Now the whole inspiration for me to do this was a post by Alan Tilmouth (nothing to do with me having a reading week at uni!) of a bird he'd seen and wasn't sure if it was Glaucous or Iceland. http://dustybins.blogspot.com/2011/02/not-every-matchstick-is-swan-vesta.html
So I thought I would use the programme on a photo from this post and got a ratio of 1:1.608 so from my small study above falls into the Iceland Gull category.
Also found this thread on surfbirds http://www.surfbirds.com/forum/showthread.php?t=7932
Again even though this bird was settled as a Glaucous Gull I did the ratio on the bird above and it came out as 1:2.423 so in the Glaucous category.
Be interesting to hear of some feedback of what people think to this.
Could this be a useful tool for IDs of birds like this and similar?
Anyone else wanna have a play with the programme and see if you get similar results as me?
Any other species/taxa groups this could be useful for?