Belcher's gulls
... that Belcher's gulls pester Guanay cormorants to make them regurgitate their prey?
... that <b id="mwAYs"><a href="./Belcher's_gull" id="mwAYw" rel="mw:WikiLink" title="Belcher's gull">Belcher's gulls</a></b> <i id="mwAY0">(pictured)</i> pester <a href="./Guanay_cormorant" id="mwAY4" rel="mw:WikiLink" title="Guanay cormorant">Guanay cormorants</a> to make them regurgitate their prey?