There's some great detail here, Ian! I love the wingspread and good job getting separation and a nice HA from each of the ducks. The comp feels very strong - nice balance between the negative space and the birds. I think this is one of my favorites that you've done in ETL!
Very nice image. Tough to get good head angles and no overlapping wings.
I also noticed the halo Ben mentioned.
Was this a large crop? The ducks look soft, almost noise reduction smooth.
It looks like you could pull more detail out with a little more USM.
A fast way is Smart USM using a background layer. Multiple passes (2-3) at 40 - .3 - 0
If it's too much just use the opacity slider to reduce it.