A New Digital Guide to Ageing and Sexing of Birds

Magnus Hellström

“New species will be added, and bad photographs will be exchanged for better ones. But with new birds, new camera models and new light-systems pouring out each year, chances are that we will never reach a state where we will feel we have fully arrived. But that’s in the nature of the project. And part of its appeal.”

 

The short version:

Are you interested in the ageing and sexing of northern European birds?
Visit our new online guide: www.ringersdigiguide.ottenby.se.

The slightly longer version:

Every keen birdwatcher or ringer puts a lot of effort in ageing the birds in front of them. Why? A simple answer could be ‘because it’s fun’. Yes, I agree, it really is fun! But in a larger context the methods for ageing and sexing are also important tools that may tell us things about the state of our environment. Without such tools we would not know much about breeding success, winter survival, age- or sex-related differences in the timing of the migration or in the choice of wintering areas etc. The list could be made much longer, and by recording the age and sex of your birds, the importance of your notebook will grow significantly. And, it’s fun…!

Black Redstarts are a joy to every birder! Did you know that it is possible to age and sex some of the female type birds, even in field?

Black Redstarts are a joy to every birder! Did you know that it’s possible to sex a few of the female-type young birds, even in the field? The details are explained in the new guide, but in these two birds (that have conducted a more extensive post-juvenile moult than average), the tertials indicate both the age and the sex. The upper bird included all tertials in the moult, showing a good contrast with the still juvenile (and worn) secondaries, clearly visible in the small image to the right. The lower bird included the two inner tertials which contrasts to the still juvenile longer one. In this species, post-juvenile tertials (as well as the future post-breeding generations) can be used for sexing since males show silvery white edges to, at least one or two, of these feathers, while females don’t. Hence, a young female above, and a young male below.

At Ottenby Bird Observatory, SE Sweden, ringing of birds have been carried out since the end of World War II. A lot of knowledge has evolved from this activity, and ringers have been passing their increasing skills further to younger generations for decades now. During the last 20 years, the digital revolution have blessed us with (among other things) the internet, as well as the digital camera. Two great inventions without which the world would be a lot more boring. The ringers at Ottenby started to digitally document birds of different ages in the early 2000’s. In the beginning, the photos were terribly bad, but practise combined with technological achievments soon made us realize that the results may actually be very useful when training young and promising ringers. The idea of a ‘digiguide’ was born! And since the images were digital, why not put them on the internet in order to make the biggest possible use of them…

asotu

A 3cy+ Long-eard Owl, October. Birds showing moult contrast in the secondaries, and where the retained (worn) generation shows the adult type pattern, with similar barring to the adjecent fresh feathers, are possible to specify as 3cy+.

Today, more than a decade later, Ottenby B.O. sits on a hard disc drive containing close to 70.000 images of 3.900 individual hand-held birds of more than 230 species. Compiling these into an appropriate format, suitable for public viewing, is a huge task! But now we have started.

Since a couple of days ago, the doors have been open on the following address:

www.ringersdigiguide.ottenby.se. Here you will find a user-friendly, practical and accurate guide to ageing and sexing of the birds passing through the Baltics (which are generally very similar to the species passing through British and other West European Bird Observatories). Initially, just above 30 species are included, but this number is planned to grow significantly during 2015.

acro

Reed or Marsh? Or both? The guide will focus on ageing and sexing, but in a few cases we will also include some help for the species ID. In the photo shown here, a Marsh Warbler is seen to the left and a Reed Warbler to the right. Among other things, note the difference in coloration, proportions of the bills and the Reed Warblers tendency to show a slightly more contrasting eye-ring.

So, what are the high-lights? Well, as a ringer I would perhaps vote for pedagogical birds such as the 2cy Tree Pipits showing three different generations of coverts (remember to click each photo in order to view in large format). But as a birder with a Western European perspective I believe I would go for the beautiful images in the sexing chapter of autumn Red-breasted Flycatchers! Smashing birds! And how many of you have seen the plumage of the lower bird on that page? And don’t miss the Long-eared Owls. Or the Nightjars. Or the Snow Buntings…

pctri

A tristis-Chiffchaff in October. Can you find the moult contrast, proving the bird as a 1cy?

Ringers’ DigiGuide (yes, that’s what we chose to call it) is a living document. New species will be added, and bad photographs will be exchanged for better ones. But with new birds, new camera models and new light-systems pouring out each year, chances are that we never reach a state where we will feel we have fully arrived. But that’s in the nature of the project. And part of its appeal.

grfin

A beautiful Greenfinch! Adult or young? Male or female?

So, go a head and have a look around. The pages are not responsive, but the layout was chosen in order to work properly on smartphones and tablets as well. In that way we hope it will be of good use also in the field.

nägal

In many species the colour of the birds’ iris undergo a general development during the first year of living, basically turning warmer with age. Two autumn Thrush Nightingales shown here – a young to the left and an adult to the right.

6 thoughts on “A New Digital Guide to Ageing and Sexing of Birds

  1. Laurie Allan

    This looks to be a useful resource, along the lines of that Spanish site whos name escapes me, altho i won’t be binning my (autographed) ‘Scillies-era’ Svensson quite yet!…..Laurie

    Reply
    1. Grahame Walbridge

      The site is easy to use and the superb images of uniform quality. I have no doubt the site will become an essential reference to anyone with an interest in sexing/ageing of birds in our region, professionals and amateurs alike.

      Eagerly await the addition of new materiel.

      Well done Magnus!

      Reply

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