Ringing flights through O/C

[Tony James]

Can I ask how much of a significance is the learning curve in sustaining the Merlins willingness to ring.

I have flown a number of passage Merlins & found them very much fixed in employing technique rather than a use of full power much the same as passage accipiters using sneak attacks & refusing more challenging slips.

Are these Merlins you speak of really lacking in power, or are they just wising up to the survival learning curve?

I have friends who have flown passage merlins at skylarks, and as history bears out, they are not necessarily to be preferred to eyasses, hacked or unhacked, for the very reason you hint at.
In a similar vein, few intermewed merlins have as much potential for the ringing flights at skylarks, not for any physical reason, but because of their changed mentality.

Best wishes,

Tony.