>> I'm intrigued by this talk of 'visual birding'. What is that?
Visual birders are primarily concerned with finding birds, and as many species as possible, and as is the nature of most things, they are far more concerned with locally or seasonally rare birds rather than common birds.
Birders "compete" based on the numerous lists they keep. Life lists, state lists, county lists and site lists. Bird photographers mainly "compete" based on the quality of their images.
A "birder", as we know birding here, will spend an entire day trying to get one or a few top notch images of one bird.
A "visual birder" (perhaps my personal tag) will drive 200 miles and spend 4 hours looking for one bird. After all that, that birder will frequently check the bird off his list, and after 5 minutes move on to the next rare bird. If he or she photographs the bird, it is primarily for documentation purposes.
That birder will most likely not spend much time with the bird trying to improve the image or waiting for good light. In many cases it would be hopelessly unlikely to get a picture of the bird in "sweet light". And arguably pointless because that is simply not the primary objective. In many cases just finding and positively IDing the bird is a major accomplishment.
Visual birding is not only extremely competitive (How long is your life list and your home state list?), but there is a huge amount of citizen science going on. Just take a look at ebird.org. You can bring up statistical data by species based on regional and political boundaries (regional, state and county).
I don't want to disparage birders by implying they are only interested in checking off lists. Their knowledge of birds, the appearance, behavior and geographical/seasonal/habitat preferences is vast. But after all that is learned I think it is inarguable that most of the time expended, and certainly most of the interpersonal communication, is dominated by "list talk". What we do is not terribly different but we call them "photo galleries"
Birders establish "hot spots" that include frequently birded and productive birding locations such as state, local and national parks, and even just certain road side stop offs or other informal birding locations.
If you want to photograph a tough bird, you can bring up all the sightings reported to ebird on a Google map. That is mainly how I find birds. All that ebird data is provided by citizen birders.
If you have a good productive local duck pond, it is probably tagged as a hot spot on ebird and you can easily see what species of ducks have been sighted on that pond, when, and what other species (including all other birds, not just ducks) seen in the vicinity.
A very good birder could see and check off 700 birds species in one year, just in the USA. It's ben done. See the movie "The Big Year" or read the book. Now, the question always arises as to accuracy in identification, particularly with locally or seasonally rare birds (or just plain rare birds). A lot of birds pretty much look alike and the ability to ID all these birds is a tremendously difficult skill set.
In my state all this data is distributed literally in real time, with birders descending on the hapless rare bird like a swarm of locusts. In my own state it is done with military precision and organization. I've been told by many out of state birders that my own particular state is more organized than most but every state in the USA has an organized web site or email list where this data is reported and shared.
My state also has a "records committee", which as far as I know is a strictly volunteer group of local and very experienced birders. A rare bird is "review-able" under certain criteria (based on rarity).
The job of the records committee is to vet the accuracy of those rare sightings. We currently have a first in county record Ross's Goose here. Now, a Ross's Goose looks pretty much like a Snow Goose except it is smaller than a Snow Goose. But if there are no other Snow Geese handy for comparison that is not very helpful.
In this case the Ross's Goose is traveling with a flock of a couple hundred Canada Geese. So that pretty much leaves the lack of a "Grin Patch" as the only viable ID.
In the case of this Ross's Goose it has stuck around for a couple of weeks now and its ID is a certainty because at least 50 birders have vetted it. But some bird reports are based on a single sighting, and in some cases it is a fly over (the bird never lands, much less establishes a territory for a day or more for the benefit of local birders).
The records committee has to vet these sightings in order to establish and maintain an official list of species sighted, based on the various political boundaries they work with (basically state and county).
Unofficially birders take even site lists very seriously. Finding a bird never before seen in a particular state park for example, or wildlife refuge, is a big deal.
Like all other avocations, some birders are better than other birders when it comes to IDs.
Obviously since much of this is based on reputation and I guess the ability of any given birder to convince the committee he really saw what he says he saw, it can get very political. A birder whose important report is rejected by the committee (or perhaps the local birders as a whole) is never a happy camper.
Now enter the camera. One picture can take a huge amount of politics out of a sighting. And regardless of politics and reputation, the records committee places far more weight on a photograph than visual reports. Any un-photographed sighting is always shrouded in at least some suspicion.
Interestingly, a Cackling Goose was discovered within the same flock of Canada Geese. That goose is a good bit smaller than a Canada, and a bit grayer, and it has a stubby neck. Otherwise it looks just about like any other Canada.
When I photographed the Cackling Goose I wasn't too concerned with getting it in sweet light. I was looking for a composition where the relative sizes were unquestionable (eliminating perspective distortion). I was also looking for that goose in a pose with the neck outstretched since an image with the neck S curled might be called into question.
A Cackling Goose may be grayer than a Canada but personally I think that is very difficult to ascertain in any given photo or in any given lighting situation. I see a lot of variation in Canada Goose "color" simply due to lighting. We surely know well the "tricks" lighting can play, and the problems of accurate color balance. So for that reason, if that were an important and review-able bird then numerous images, preferably taken over many days, might be required for a slam dunk ID.
I actually got an image in fairly decent light but honestly, I was just happy that I was able to pick out that goose from that huge flock .
There are far, far more "visual birders" out there than there are "photographers" serious enough to spend even $1500 on a lens and $1000 or more on a camera body. But all those visual birders are fighting this battle of getting their better sightings vetted, plus the nature of that avocation is that most birders want to share their sightings and there is no better way than photographs (or, increasingly, videos).
Given the nature of the technological evolution, and the extreme difficulty of imaging rare birds, I consider the "visual birder" community to be a huge market for smart camera makers, and potentially far larger than the "photographer" market. I estimate it at 10:1. And estimates of the "visual birder" population range as high as a million just in the USA but it is certainly a world-wide avocation.
Beyond getting reviews vetted, many species come in a huge variety of flavors. They often look different in fall and spring, the sexes look different and many species just plain come in many different flavors, even in the same sex in the same season. And there are many similar species which have considerable overlap so ID is a highly evolved skill set and a major preoccupation of visual birders.
So building a large collection of decent images of numerous specimens is an important past time and a huge undertaking, especially with the less common or more secretive birds.
From the above, you might get the idea that the requirements of a visual birder, and the funds they might spend on their gear, could be very different than the typical "photographer".
And on the funding side, consider that virtually all advanced birders are carrying Swarovski binoculars, at about $1000 a pop, and most own a high end spotting scope, usually also a Swarovski , that runs around $2500 with a required tripod, so they spend around $3500 just for a minimal set of visual optics.
(obviously there are other brands but the Swarovski duo seems to be the "gold standard" (like owning a Nikon that all others are compared to, and competing optics come at a similar cost.)
So another $4K+ for a Nikon 80-400 + D7100, for example, is a pretty hefty investment. And that is just an entry level camera setup. We all know where that can lead (like a 600/4).