 The call is mostly uttered in flight and is a harsh " tsak tsak tsuk " . The same sound , but softer , is made more conversationally when individuals gather in trees . When angry or alarmed they emit various warning sounds reminiscent of the mistle thrush ( Turdus viscivorous ) . The male has a rather feeble song that he sings in the breeding season . It is a mixture of a few phrases like those of the common blackbird ( Turdus merula ) interspersed with whistles , guttural squeaks and call notes . This is sung on the wing and also from a tree and a subdued version of this song with more warbling notes is sung by a group of birds at communal roosts . 
 The call <a href='drop_aux' title='1'><mark>is</mark></a>mostly uttered in flight and <a href='drop_aux' title='2'><mark>is</mark></a>a harsh " tsak tsak tsuk " . The same sound , but softer , is made more conversationally when individuals gather in trees . When angry or alarmed they emit various warning <a href='uninflect' title='3'><mark>sounds</mark></a> reminiscent of the mistle thrush ( Turdus viscivorous ) . The male <a href='got' title='4'><mark>has</mark></a> a rather feeble song <a href='null_relcl' title='5'><mark>that</mark></a>he <a href='uninflect' title='6'><mark>sings</mark></a> in the breeding season . It <a href='drop_aux' title='7'><mark>is</mark></a>a mixture of a few phrases like those of the common blackbird ( Turdus merula ) interspersed with whistles , guttural squeaks and call notes . This is sung on the wing and also from a tree and a subdued version of this song with more warbling notes is sung by a group of birds at communal roosts . 
Da call mostly uttered in flight and a harsh " tsak tsak tsuk " . The same sound , but softer , is made more conversationally when individuals gather in trees . When angry or alarmed they emit various warning sound reminiscent of tdamistle thrush ( Turdus viscivorous ) . The male got a rather feeble song he sing in the breeding season . It a mixture of a few phrases like those of the common blackbird ( Turdus merula ) interspersed with whistles , guttural squeaks and call notes . dis is sung on the wing and also from a tree and a subdued version of tdissong with more warbling notes is sung by a group of birds at communal roosts .