By the time the dragon had been killed they were very hungry and set up a clamour for food .<br>The prince therefore cut up the dragon and fed them with it , bit by bit , till they had eaten the whole .<br>He then washed himself and lay down to rest , and he was still asleep when the Simurgh came home .<br>As a rule , the young birds raised a clamour of welcome when their parents came near , but on this day they were so full of dragon-meat that they had no choice , they had to go to sleep .<br>As they flew nearer , the old birds saw the prince lying under the tree and no sign of life in the nest .
the young birds caused a clamour when their parents arrived
The context states that the young birds usually caused a clamour, but this time they were so full of dragon meat that they didn't. The system could likely not understand that the sentence 'the young birds raised a clamour of welcome when their parents came near' was talking about past occasions, not this one. 
( z1 clamor :ARG0 ( z2 bird :mod ( z3 young ) ) :time ( z4 arrive :ARG1 ( z5 person :ARG0-of ( z6 have-rel-role :ARG1 z2 :ARG2 ( z7 parent ) ) ) ) )