[goosepimple]

'original poster', that's me  , is not buying anything just now, just cooping our ducklings until they are 3 weeks old so they're too heavy for the crows to take.  Would have to wait quite a bit longer so the Herons don't take them but they'll have to take their chance with them, can't shoot herons anyway they're protected (not that I'd want to, they are pests here but lovely). 
 
Will try to live alongside nature for the time being.