Hi.
Thanks for all the replies.
Yes, the PIRs will be fed from the same circuit. The plan is to wire a photosensor trigger, whose output goes live in darkness, to a relay, such that I get a "on" switch in daylight only. The two PIRs will both be supplied by the same output of that relay so that they are active in daylight only (which is what I need). Both PIR outputs will be connected to the same power terminals of the single device that I intend to have them control, which, in turn, ought to keep herons away from my pond! Lol.

Cheers. Terry.