I always hear that whenever there is Azan being recited, specially at night, the jackals start howling.
Why jackal howls when Azan is being recited?
This is not true and Jackals don't howl because of Azan in any meaning, It might be just the sound itself that they hear and based on their nature respond to it!!
The golden jackal has been recorded to howl upon hearing church bells, sirens or the whistles of steam engines and boats. It typically howls at dawn, midday and the evening.
When in the vicinity of tigers, leopards or any other cause for alarm, the golden jackal emits a cry that has been variously transliterated as "pheal", "phion" or "phnew".When hunting in a pack, the dominant jackal initiates an attack by repeatedly emitting a sound transliterated as "okkay!".
These howls are used to repel intruders and attract family members. Howling in chorus is thought to reinforce family bonds, as well as establish territorial status
Please consider it that we need to focus on our wisdom and think about everything, and not to make guesses and relate natural things with spirituals, If God ever wanted to prove his existence and the righteousness of Islam with such things he would just consider bringing down angels from heaven and showing them to us!