As a group we are interested in many bird species, but regular readers will have gathered that there are some birds which, for various reasons, we are able to study more than others.
One such species is the intriguing Jack Snipe. A small ( hence 'Jack') wader, which doesn't breed in the UK, but which spends the winter months here having bred in northern Europe and Asia. I hope to be telling you more about our work over the coming months, but for now I would like to spend a little time showing you how we age this very poorly studied species.
We have ringed as many as and probably more Jacks than most ringers in the UK--but we are still learning--so these notes are not meant to be the absolute definitive answer--merely the stage at which we are now.
But first, what does a jack Snipe look like? Here's one in the hand which shows the salient points.....
As you can see they are small waders, generally brown and cream on the upper parts, with a brown mottled breast and white underparts. But what really sets Jack Snipe apart from Common Snipe is the relatively short beak--about the same length as the head. In Common the beak is much longer than the head.
Ageing criteria
We think there are several things to look for--and all are not always present-- so we suggest a 'best guess' based on as many of these criteria that can be found.
The first, and probably most important is to look at the outer tail feathers.
This is the tail of a know age adult. The arrows show the quite large white patches on the outer web of the feathers, and the black arrow indicates a quite wide grey area to the tip.
Now have a look at a juvenile ( less than 1 year old) outer tail feathers...
The feathers are narrower and slightly more pointed--but crucially the red arrow shows a thin black line at the tip which is typical of a juvenile.
Now lets have a look at the head and back patterns.....
The bird on the right is an adult and you can see that the stripes are more golden than the buff stripes of the juvenile--and this is similar to the pattern seen on the back......
The top bird also has golden stripes on the back as opposed to the cream stripes on the lower juvenile.
We also think that leg colour is important--although we can't rule out that the chemical nature of the water and mud they paddle in may have a part to play.
The right hand bird had predominantly green legs ( often look a bit blue in photos)--whereas the left hand birds legs are pinkish. We believe that adult legs become gradually pink, and juveniles are green.
Several guides suggest the under tail coverts are useful but we have found them to be as confusing as they are illuminating.
