[Hybrid Wigeon?]

11 hours ago, RobinHood said:

On the basis that adults should have been in breeding plumage for a while now, isn't this likely a 1st year bird transitioning to adult plumage? Anyone else?

This is the only reason I said it's probably a 1st year.

[Hybrid Wigeon?]

I believe that's a Eurasian widgeon (probably juvenile), that is a little slow in getting all of his breeding plumage. I don't see anything to suggest American widgeon plumage.

[Unidentifiable birds in painting--just for amusement]

9 hours ago, Jerry Friedman said:

I think the figures on the left are people with umbrellas.  One umbrella is red.

You are correct. That definitely impacts the meaning of the painting as a whole. This reinforces my belief of water birds, as behavior is important in this painting more than color or exact shape. 
Of course, others interpretations may vary.

The painting is by Arthur Lawrence Jones (1910 – 1996), who painted under the name Lawrence Arthur. This was an interesting diversion, thanks for posting Jerry. However please do not post any paintings of birds by Picasso for identification.

[Unidentifiable birds in painting--just for amusement]

I believe they are water birds but not waterfowl. The line is bending and a line of geese would be straight.  I eliminated crows because I've seen many many crows in my life but I've never seen any flying in any formation that resembles a straight line, ravens don't flock at all but are solitary or paired. They seem to  represent gulls, cormorants or little blue herons to me. I'm also influenced by what I perceive as a yellow sunset sky and water the birds are flying towards.

Also, in the lower left of the painting that appears to be a flock of redwinged blackbirds.

 

[Question about a wood duck]

That's an adult male. The bill would not be that rich and bright in color if it were a first year bird.

[Painted Bunting Question]

I believe it's an immature male molting into adult plumage. The breast has yellow/green feathers and an adult male should show just red. It's unlikely but it could be an intersex bird. I say unlikely because the feathers look like they are molting and I'm not familiar with intersex buntings.

[Molting?]

Based on the fact the feather loss is on the head and in a big clump, it is almost surely mites

[Mockingbird behavior? Central Texas 78070]

I am aligned with the "shadow" crowd. Mainly because I've heard it for 50 years and never heard the "white patch" theory until this thread. It has to be related to scaring insects. They appear to be forging whenever they do it. 

Mockingbirds appear to be the bravest bird around cats. Charlie, can you develop a methodology for me to test that hypothesis?

[Teal]

Due to bill size and the dullness of the angle of the bill and forehead I say BWTE

[The fair skinned, blond haired damsel ...]

Just based on probability I'm going to say it's domestic genes. I'm not familiar with much leucism in wild mallards and I've seen many light-colored domestics. I wouldn't put much stock that she was with a greenhead, it ain't the color of her plumage that he's after. Male ducks aren't drawn to color like a female in choosing a mate.

[Cackling Goose?]

Agree, both are Canadas. The bill is shorter and the forehead/bill angle is much sharper on a Cackling.

[Snow goose questions]

It's an immature blue morph. Notice how the feet and bill have not turned completely pink as they would in any mature snow goose

[Ross's or Snow Goose? S. WI]

 

The second picture – a classic view of geese flying directly away from you. Since there is no depth perception you don't know if those six geese are flying in a line or in the V. But there most definitely in formation. Notice how every goose's wings are in the same position i.e. essentially horizontal to the ground and they are equidistant apart. They probably only moved about 100 yards since the first picture and is highly improbable they would have changed positions and be back in line in that short of distance.  So the white goose has one Canada about 3 yards ahead of him to the left and one Canada about 3 yards behind him and to the right in each picture

first picture – there is what is obviously the lead goose, the two uppermost geese form the "left" side of the V looking from the rear as in the second photograph. The white goose is the first goose on the right side followed by two Canadas (third from the right just like in the second photograph). When you look at the picture looking at each "line" including the lead goose, you see the left line is straight and right line is fairly straight but a little off because the white goose is not creating the same wind current. So in this picture the lead goose will be slightly closer to the camera than the white goose and the two Canadas in the lower right of the photograph will be slightly further away.

Edit: the first picture looks weird because the white goose is so small. Take him out and you can see the V. But he must be in formation based on the second picture.

 

[Ross's or Snow Goose? S. WI]

Charlie, when you look at both of those pictures together, you can tell those geese are flying in perfect V formation. 
So, I don't think the large size difference is an illusion. I don't think the photo shows the goose well enough to rely on anything other than size. Even the snow goose is going to look small flying with Canadas, but that goose looks really small. I surely wouldn't say conclusively it is a Ross's but with the size difference so great, I would give it a strong probability.

[Mallard question.]

I used to feel like it was a poor term because just the plumage is what you generally see. However, several years ago I talked to a wildlife biologist about it and he said that in extreme cases of a estrogen loss there will be physical changes in the sex organs. In cases like this the bill is a bright orange yellow .  So, I would guess a slight estrogen loss would mean a slightly curved tail feather and extensive loss could end up with a non- fertile male. The reversion to male has something to do with birds X and Y chromosomes. Not sure why but most of these birds seem to be mallards. Cardinals seem to be prone in the passerines.

[Ca. Geese, three sizes]

After further review, I partially agree with Robin Hood and the questionable goose is probably not a Cackling but an intermediate size lesser Canada. However, I don't think it can be definitively classified as too large to be a Cackling. In the first picture the middle goose does look much smaller, but it is turned at a slight angle to the photographer. In the second picture it is only very slightly shorter from chest to tail (being retired with nothing better to do, I measured). The "right" goose appears to have a longer neck but that may be due to posture. Also, individuals of the same species do vary in size.

Regardless, interesting photo Jerry and you probably when the Canada Hat Trick Award for a picture of three Canadas and all are different species.
 

[Ca. Geese, three sizes]

Left)  Not much angle where the bill and forehead meet in the second picture, long neck, and is just too big compared to the others to be anything but  Canada

Middle) Small, very sharp angle with stubby bill – Cackling
Right) kind of small, sharp angle and bill appears short – probably Cackling but could be some other lesser Canada

[Canada Goose: hybrid? moulting?]

Canada x Snow.  pinkish bill, grin patch is small but looks great for snow hybrid, neck feathers show ridges. Definitely Canada x Snow.

Snow geese breed in northern Canada

[Are these Mottled Ducks?]

The first sentence should read "The upper left duck"

[Are these Mottled Ducks?]

The upper right duck is a male (yellow bill). You can see that the tail feather has a very slight upward turn. This means there are mallard genes in its ancestry as a mottled duck's tail feathers should be straight. The gape spot is not a real good identifier for pure mottled as most hybrids have them. A small deformed gape spot is usually an indicator of mallard ancestry but a perfectly formed one does not mean it's pure mottled.

The female appears to be rather light-colored but that's probably just the sun. There really needs to be a photograph directly from the side so you can clearly see the gape spot and the length of the eyeline . This one appears to have a short eyeline which would indicate pure mottled. The eyeline length is one of the better indicators of a pure mottled as they stop just behind the eye and a mallards almost reaches the dark feathers on the back of nape.

[Help with geese]

Assuming they're smaller and short neck, stubby bill at an angle to the forehead means Cackling.

[Woodpecker on book cover]

I feel comfortable calling that a comic book ivory bill.

[Gadwall, hybrid, neither?]

34 minutes ago, Avery said:

What features point you to the hybrid possibility? I’m having trouble finding any spots that seem out of place for Gadwall

agree

[Yellowstone NP Waterfowl]

While it's too blurry for a positive identification. Two of the ducks, in the lower right-hand side of the photo, are so small they must be green winged teal.

[Teal.]

The two birds in the first picture are definitely mallards. The one on the right with the yellow bill is a male in eclipse plumage or possibly a juvenile.
The second picture – the three birds in front are mallards as you can clearly see white tails on all of them. I'm unsure of the bird in the back as you cannot see the tale or shape due to the shadows and the bill sure looks solid black. It's probably a female juvenile mallard whose bill is just starting to turn, but I can't eliminate teal. Maybe others can point out something distinctive in that bird to say why it is a mallard.