Article: Coronis, was daughter of Phlegyas, King of the Lapiths. Pregnant with Asclepius, Coronis fell in love with Ischys, son of Elatus. A crow informed Apollo of the affair. When first informed he disbelieved the crow and turned all crows black (where they were previously white) as a punishment for spreading untruths. When he found out the truth he sent his sister, Artemis, to kill Coronis (in other stories, Apollo himself had killed Coronis). As a result, he also made the crow sacred and gave them the task of announcing important deaths. Apollo rescued the baby and gave it to the centaur Chiron to raise. Phlegyas was irate after the death of his daughter and burned the Temple of Apollo at Delphi. Apollo then killed him for what he did.

Now answer this question: How was Apollo informed of the affair between Coronis and Ischys?
A crow