Just sounds to me that Czech Avian Researchers are either really lazy when it comes to writing stuff or really crap at finding birds to write about.
We could equally attribute their lack of published papers to them spending too much time looking at dirty pictures on the internet, playing football or trying to get their Trabants to start in the morning. Talk about tenuous links! For all we know each and every one of the Czech birdwatchers could be teetotal.