Hi Peter
Organisations occasionally post for volunteers on these forums and individuals working in the field do but it’s seldom
- if you are a ringer, it’s very easy to get ringing work at bird camps or obs round the world for specific projects or for peak migration studies such as this
https://environmentjobs.co.uk/green-jobs/bird-ringing-camp-volunteer.57673.htm
and most ringers would contact these groups directly too. Keep your eye on the ringing forum as people post opportunities on there sometimes.
If you are not a ringer, then a good place to source volunteer opportunities is through Birdlife who co-ordinate a massive amount of volunteering work around the globe
http://datazone.birdlife.org/around-the-world-volunteers-underpin-much-of-birdlife's-work
Again, keep your eyes open on the forums for small project group leaders sometimes posting opportunity for survey work. Most of the more independent/smaller projects will require a good level of experience/identification skills though as there is less capacity to accommodate volunteers due to costs so they can’t afford to ‘carry people’ (You may also need latin! - the first survey work I carried out abroad years ago no one spoke english and all the sheets were written in latin, so I spent the evenings literally studying Collins!)
Other work, like helping out at some if the big migration camps wont necessarily require much experience or any at all as you will be given lots of help and not too much responsibility - but be aware, these are often in areas where there are high levels of raptor persecution and migrants being shot down as you count them. These opportunities can be found on the Birdlife link above and also in bird magazines, environmentjobs.uk on the link above.
