Some attemp to improve this Robin pic please?

Another pic i m trying to improve...

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here my first attemp..

I can't see much difference between the two cormorant pics (apart from the second one being cropped slightly). What have you tried doing to it? It looks like your basic issue is one of under-exposure and that's all too easy with this sort of image (light & dark areas alongside each other), especially when using spot metering as would appear to be the case here. You might find you get more keepers by trying a more general metering setting, then using exposure compensation to lighten the image when you take it.
As far as improving the images, try simply increasing exposure/lighten in your software before any more aggressive changes. It will be difficult to recover significant detail however, too much has probably been lost in the shadow

Thanks for your kind advices Joe, apologise for not having seen it before. I tried to enlightened the picture a bit more