You are trying to filter your Recordset results with the url parameter CountType.... this error implies you are accessing the page without the url parameter. You should be linking with something like: BirdListResultsPage.php?CountType=1
You can prevent the error by updating the line:
$rsBirdLists->bindParam("s", "".($_GET['CountType']) ."", "-1"); //colname
to:
$rsBirdLists->bindParam("s", "".(isset($_GET['CountType'])?$_GET['CountType']:"") ."", "-1"); //colname
That will prevent the error, but the Recordset will still not return any results if you don't add a CountType to the url when viewing the page.