PostDocs are associate members of graduate union, though postdocs do not have their own union.
http://www.cam.ac.uk/societies/pdoc/ What's PdOC About?
PdOC is looking for motivated people with innovative ideas to join us and help both current and future generations of Postdocs at Cambridge. We are a young organisation run by Postdocs for Postdocs. Established in 2001, in the years since its inception PdOC has flourished and grown, establishing a strong track record in achieving goals that have been identified university-wide by Postdocs.http://www.ucalgary.ca/~pdac/steve.html
PostDocs in Canada, PostDocs fate? Dismantling the trap
So how do we end this shameful waste of talent? Some have suggested that granting agencies should waste less money on students, since many students must eventually abandon their careers or leave the country. However, this approach does nothing to solve the present problem, and worse, it is fatally shortsighted. Canada needs highly trained and dedicated scientists.
As well, with professors facing cutbacks, shrinking faculties and increased teaching and administrative loads, grad students and postdocs do an increasing share of the research in Canadian universities. Staunch the flow of graduate students and Canadian research would be choked. But this is no excuse for creating a class of well-trained, disposable indentured servants. If we must produce highly qualified people, it's time to offer them opportunities to use their expertise to benefit us all. To do otherwise isn't merely unjust, it's immeasurably wasteful.
Read more from the above Link!!!
there's a continuing crisis in the postdoctoral enterprise: Many postdocs are underpaid and overworked, with little prestige or status to show for their efforts; often, they are treated simply as extra workers, with few opportunities to be mentored or to expand their skills; and, in a job market that continues to remain tight, they are having less success landing those coveted academic positions. Such concerns can even drive undergraduates away from science and into more lucrative fields such as law or medicine.
And anywhere there's a group of highly educated, highly motivated people willing to fight for change, the situation is bound to get better. Postdocs around the country are airing their grievances, reaching out to administrators, even forming unions. And they're getting results. The progress is especially noticeable at Stanford, where fewer and fewer top-flight researchers feel like second-class citizens.
At Stanford, the tide began to turn in 1999 when a group of disgruntled postdocs decided to speak out.