Ignition Effects are effect that have to be activated manually.
Ignition effects are always Chain Link 1. Ignition Effects have no possible means of chaining to each other.
Ignition Effects can only activate on your turn; never on you opponent's.
How to Identify an Ignition Effect.
You can identify that a monster has an Ignition Effect if it has the following texts:"____ per turn, you can..."
"During your _____, you can..."
No Ignition Effect is mandatory.You can only activate an Ignition Effect during your Main Phase unless otherwise noted.
Blackwing - Gale the Whirlwind
Text: If you control a "Blackwing" monster other than "Blackwing - Gale the Whirlwind", you can Special Summon this card from your hand. Once per turn, you can halve the ATK and DEF of 1 face-up monster your opponent controls.