I agree AerocatS2A and here's the rub re what 2dogs has heard - and that is the 'request for traffic' being the only call made followed by 'leaving the level' and omitting the position and intentions.
Just an extra - this report is not just required in octa but in cta as well.
All gets a bit forgotten I think when ATS jump in first with a clearance to leave cta "no reported IFR traffic for arrival Yxxx" - "contact me on a new freq top of descent" etc etc (not intending to say the exact call - just setting the scene). The "left FL or Alt" call is usually the next call made.
Just a thought 2 dogs - your shrike may have made a broadcast on CTAF while you were calling(talking) at the same time to centre. I know I have been talking/responding to centre or traffic on centre and someone on CTAF has his knickers in a knot because I answer negative to his pained request regarding have I heard him calling me - and we are 30 miles apart.
Muff