several dozen stray cats
... that the Canadian Parliament Buildings have housed several dozen stray cats since the 1970s?
... that the <a href="./Parliament_Hill" id="mwApk" rel="mw:WikiLink" title="Parliament Hill">Canadian Parliament Buildings</a> have housed <b id="mwApo"><a class="mw-redirect" href="./Parliamentary_cats" id="mwAps" rel="mw:WikiLink" title="Parliamentary cats">several dozen stray cats</a></b> since the <a href="./1970s" id="mwApw" rel="mw:WikiLink" title="1970s">1970s</a>?