1. One sings in a cage cautious giving out initial warning (6)
2. Copy section about redstart and duck (6)
3. Picked up fuel, one seen in flight overseas (6)
4. One wades in with a bill say? About time (5)
4, Egret?
"eg" is say/for example.
"re" is about/concerning.
"t" is short for time.
I do not see where "bill" comes in, but an egret is a wading bird like a heron.