Thanks again Chosun, you are obviously more knowledgeable on photographic matters than I am. In the past I have owned film SLRs (Zenith, Olympus OM10, Canon Eos) but probably never pushed them to the limit of their capabilities. There are some excellent tutorial videos on YouTube about the camera (one is 1hr24min) and the Tamron lens, which I will watch as they may tell me more, initially, than the manual. At least you get a manual with this camera and not a disk or online link.
UPDATE: The camera just arrived so the odyssey starts here!
Coming from film gives you all you need to know - just sub ISO for film ASA and away you go. You still want to factor in the reciprocal rule for shutter speed. So with your 70-300 lens, you will want at least 1/500th second (300x1.5) even with VR on. Of course this is really too slow to isolate breeze ruffled feathers, or a quick head twitch, and you're better off with higher shutter speeds, especially for BIF.
For some reason the sensor in the D5600 is about a third of a stop behind my D7200 in DR even though both are 24MP. I try and keep my ISO at or below 400 for good results, and below 200 they are really nice. Still, a lot of other cameras are just waking up at around 2-400 ISO compared to the Nikon, and I've had pretty good results up to ISO 3200. Beyond that I think you're better off going for the 'arty' noisy look.
Just as a quick heads up, when I'm mostly shooting birds with the big Tammy it is hand held, and I use "Auto ISO" mode. I will set a minimum shutter speed of 1/2000th sec and depending on the light at the time, an ISO range of 100-1600 usually up to a max of 3200. This lets you snap away without worrying about each individual setting. I probably do 80% of my shooting like this, and just adjust exposure compensation for each shot or series as necessary. Probably the hardest scenario is with a pied cormorant flying high speed circuits around you - into bright sunshine on one side and shadow on the other. If they come really close and you have to change zoom as well, then you will end up busier than a one arm bricklayer in Beirut !!! :-O
I suppose you are familiar with the concept of ETTR (expose to the right) ie. depending on the situation, lighting and ISO, mostly make sure that you get all the shadows on the histogram, and then it is possible to recover some highlights in post processing. This will keep the noise levels down as much as possible.
Enjoy your new toy ..... and get the Tammy G2 ASAP !
Chosun :gh: