I can't add to Colin's excellent answers above on the Cormorant issue.
I think the penny may have dropped
It
really doesn't matter* which metering mode you use;
there is only one correct exposure for a given scene and desired outcome**, you can arrive at that via
any metering mode
plus a different amount of EC***.
* Sure; sometimes, especially with rapidly changing "scene dynamics" , one mode will be more likely to provide consistent results than another
** If you know this, and the "scene dynamics" are not changing; e.g. sun always on subject and always from 'your' side (front lit) and the background isn't going to cause problems, the I'd suggesting go manual with that set of exposure values.
*** Sometimes just a click more in one direction or other, but sometimes an apparent reversal - for example, a sunlit
swan spot metered will likely need +EC to prevent under exposure, but if it is part of a bigger scene that is predominantly darker in shade and you use evaluative/average metering, you're going to need -EC to prevent the swan blowing - at least until it swims right up to see if you have food (and fills the frame, then even average metering may need +EC to prevent underexposure.
However, particularly for birds in flight, the "scene dynamics" very often
are a huge problem; when we first 'lock on', the subject might not be filling much of the frame (so ratio subject to background; blue sky, sunlit cloud or trees) can vastly affect the exposure reading indicated if not in spot mode, but if you are in spot mode and lose placement of the spot on the subject momentarily as you take a snap, the exposure may again be incorrect. As it might if (when closer) the spot moves from a dark neck/head on to the much lighter area of eye or beak/bill.
So here's your worst nightmare; shooting say a
Canada Goose flying under trees on a "4/8 cloud" day - the birds has black and white areas and will be moving from sunlit patches between tree/cloud shadows and be against a background of trees, water and sky, some of it with brightly lit clouds in. This is much like Colin's "sunlit bride and groom in black suit in shadow" problem, except that for us it changes from second to second, so you should expect that not all exposures will be correct, because for these "scene dynamics",
there is no single correct exposure that lasts long enough. This situation is now about the only time I
don't shoot manual exposure, but I'll still keep my thumb ready to spin the EC wheel as the subject moves from sunlight to shadow to offset any metering error I can predict happening. If I succeed at this, I'll just find it was out of focus - the message here is: you can't always win - but sometimes you do and when that happens!!!!!
My suggestion is to
think about
what you intend to photograph - what are the subject issues?
ratio of bright to dark areas of plumage
how bright and where is it
(e.g. coot with that bright white crest right on top of its head)
will it be passing close by, presenting different aspects, altering the above
will it be wet, with specular highlights off beaded water and/or wet feathers?
but also think about
where you intend to photograph it:
against shady trees
sunlit grasses
sky in shot? sunlit clouds or blue sky
and of course,
how will it be lit?
front lit (all lit)
side lit (some parts in shadow)
backlit (betcha blow the highlight of the beak/bill on these!)
in shadow (likely diffuse and low level lighting)
... and from these decide
first whether you should be shooting Manual mode (i.e.
not using auto-ISO) for exposure, if so, take test shots, determine correct exposure (blinkies and histogram) and shoot away
(with one less thing to worry about)
If not,
then decide which meter mode is most likely to give success dependent upon subject size changes in frame, aspect changes, backgrounds you're going to shoot against, etc. - and (I hardly need say this to you), practice a lot.
Hope that helps,