Scaup - greater or lesser?: Merritt Island, FL - March 2013 (2 Viewers)

[General Melchett]

Presumably Greater as can’t see much of a tuft? Thanks

 

[aeshna5]

I'm getting more of a Lesser Scaup vibe from the head shape in the group shot. Also don't look as bulky to me as Greater.

 

[Butty]

Which? All of them?
1. Most (at least) are lesser scaup - rear head shape.
2. Right = possible greater scaup - very rounded-looking rear of head, but I'd rather see it with its head up.

 

[General Melchett]

Ah then I guess the lesser tuft is more subtle than I thought. Cheers both

 

[rkj]

Which? All of them?
1. Most (at least) are lesser scaup - rear head shape.
2. Right = possible greater scaup - very rounded-looking rear of head, but I'd rather see it with its head up.

I think I agree with Butty, but I am not sure to what Butty's point 2 is referring. If it is that in the second photo the right-side bird is a possible Greater Scaup, than I do agree with that, and I agree the the rest in both photos are Lesser Scaup.

 

[qwerty5]

The female in the second photo looks like it has its head feathers sleeked down tight. Meaning there's little evidence to call it Greater (but there also isn't evidence to say it's not).

 

[Butty]

...looks like it has its head feathers sleeked down tight

I dont follow your point. There's plenty of intermediate/indeterminate-looking scaup to be found, but, when a scaup is exhibiting this feature of the rear head clearly, it is a greater scaup - because lesser scaup (and tufted duck) don't show it.

 

[qwerty5]

I dont follow your point. There's plenty of intermediate/indeterminate-looking scaup to be found, but, when a scaup is exhibiting this feature of the rear head clearly, it is a greater scaup - because lesser scaup (and tufted duck) don't show it.

Perhaps there's more here than I know about (I'm far from expert), but I always understood that a Lesser Scaup can look very similar to a Greater when the head feathers are pulled down tight and unrelaxed (while active and diving). Sibley has a good illustration of this. In the field, one can usually get a prolonged look at how the head shape changes over time, but a single photo can be deceiving.

 

[tom baxter]

Perhaps there's more here than I know about (I'm far from expert), but I always understood that a Lesser Scaup can look very similar to a Greater when the head feathers are pulled down tight and unrelaxed (while active and diving). Sibley has a good illustration of this. In the field, one can usually get a prolonged look at how the head shape changes over time, but a single photo can be deceiving.

I believe you are both correct. Butty makes a valid point that the female in photo 2 appears that it could be a Greater Scaup, but would want to see the head out of the water to have a better chance at identifying it with confidence. You then correctly pointed out that when diving, the head shape of these two species is unreliable and there isn’t much evidence to suggest that it is or isn’t a Greater Scaup from these images. Valid on both sides in my opinion, and you raise a good point that is consistent with my field experience. Active hunting scaup can be very hard to identify.

 

[Indobirder]

First Photo: front left female = Greater
the rest (all?) Lesser

Second Photo: right bird looks OK for greater to me. appears larger and head shape is better for it.

I wouldn't bet my life on it, but I'm quite confident 😅

 

[tom baxter]

How much precedent of knowledge is there for frequency of Greater and Lesser Scaup intermingling? In most places one species or the other is notably more common, at least seasonally. From field experience in these cases, I find it rare that there is intermixing, and when it does occur it usually seems nuanced in some way. For example, both species may be present at times, but are they really intermixing in rafts? Or are they simply sharing the same vicinity and hanging with their kin. I think it’s usually the latter from my field experience, but I don’t have a good way to quantify any of this or to know for certain that I am onto something. Surely mixing happens where an individual is out of place amongst a larger group of its alternative species, but in cases of other species such as dowitchers it is surely unusual for a large number of short billed dowitchers to mix with a large number of long billed dowitchers and vice versa. Singles among a foreign group are not crazy rare but they are generally unusual. I suspect that the same may be true about scaup. I agree with butty and indobirder that the two birds suggested as Greater Scaup have the appearance of Greater Scaup, but given the variability of head shape with posture and behavior, how do we know we are not misidentifying birds through the use of general impression, size and shape? Some people who are experts with ducks may truly know the answers to these questions but advanced birders in general probably don’t.

 

[Butty]

when diving, the head shape of these two species is unreliable

I don't think this is true. I'm not used to seeing lesser scaup bobbing up and initially looking like greater scaup and then slowly looking more like lesser scaup (ditto with tufted ducks). Nor have I ever heard that this is a pitfall to look out for - and it certainly would be one if it were correct, given that diving ducks spend a lot of their time, err, diving.
The reason I'm not happy about judging the bird in pic 2 is simply that it has its head bent forward - and judging shapes in a non-standard posture is always inadvisable (thus nothing to do with the fact that it may or may not have dived recently).

 

[tom baxter]

I don't think this is true. I'm not used to seeing lesser scaup bobbing up and initially looking like greater scaup and then slowly looking more like lesser scaup (ditto with tufted ducks). Nor have I ever heard that this is a pitfall to look out for - and it certainly would be one if it were correct, given that diving ducks spend a lot of their time, err, diving.
The reason I'm not happy about judging the bird in pic 2 is simply that it has its head bent forward - and judging shapes in a non-standard posture is always inadvisable (thus nothing to do with the fact that it may or may not have dived recently).

It is established in the app version of Sibley’s guide that there is much overlap in head shape. I am not sure what it says in the field guide since mine is not available for me to look at right now. From my experience, I think there is a difference in appearance of Lesser Scaup head shape specifically tied to diving behavior. I can only speculate on why, but it makes sense to me that this is the case because many birds sleek down their crown feathers. Maybe I’m just biased since it is easy to associate “sleek” with efficient diving eg. swimmers and swimmer caps, but I am pretty certain that I observe this appearance most often on active, diving individuals. It could be a coincidence that I frequently see this sleeked down scaup appearance on active diving birds, but I don’t think it is, simply based off of anecdotal field experience. Either way, in some cases of in between individuals, Scaup are a species that I really have to observe in the field, and watch them for a prolonged period, before feeling confident in the identification. This is the more important thing getting back to the original photo and original question. It can be very hard to be certain of which species is represented in still photos and head shape is helpful but not necessarily reliable. Also, I think it is far more likely for a Lesser Scaup to superficially look like a Greater than vice versa.

 

[Indobirder]

How much precedent of knowledge is there for frequency of Greater and Lesser Scaup intermingling?

There's a spot I know of where it is fairly common to get both species in the same flock. https://ebird.org/hotspot/L458893

Almost every time I go (during the right time of year), there are both Greater and Lesser Scaup, and they are often in the same general group. (there's a sheltered lagoon)

how do we know we are not misidentifying birds through the use of general impression, size and shape?

If it looks like and duck and quacks like a duck ...

I'm not sure I understand this point. General impression is more reliable in many cases to plumage I feel. (obviously you should take everything you can into account)
Sure photos can be misleading, but can we actually prove anything anyways?



Usually I find that I have trouble with all lessers, in trying to turn them into Greater, but when I see a Greater it's "obvious". Similar to Vaux's and Black Swift. Every Vaux's gets scruitinized to try and turn it into Black, but when a Black comes along it's clear - no hard time excluding Vaux's ... (which one you scruitinize probably just depends on what you are used to seeing most often)

 

[qwerty5]

It is established in the app version of Sibley’s guide that there is much overlap in head shape. I am not sure what it says in the field guide since mine is not available for me to look at right now. From my experience, I think there is a difference in appearance of Lesser Scaup head shape specifically tied to diving behavior. I can only speculate on why, but it makes sense to me that this is the case because many birds sleek down their crown feathers. Maybe I’m just biased since it is easy to associate “sleek” with efficient diving eg. swimmers and swimmer caps, but I am pretty certain that I observe this appearance most often on active, diving individuals. It could be a coincidence that I frequently see this sleeked down scaup appearance on active diving birds, but I don’t think it is, simply based off of anecdotal field experience. Either way, in some cases of in between individuals, Scaup are a species that I really have to observe in the field, and watch them for a prolonged period, before feeling confident in the identification. This is the more important thing getting back to the original photo and original question. It can be very hard to be certain of which species is represented in still photos and head shape is helpful but not necessarily reliable.

I also see scaup head shape changing specifically while diving. It's often fairly obvious since they usually fluff their feathers back up, at least partly, between dives.

The Sibley field guide says "The head shape of both species of scaup varies depending on activity, from active diving to relaxed. Differences between the species are most apparent when relaxed and largely disappear when birds are active."

 

[tom baxter]

There's a spot I know of where it is fairly common to get both species in the same flock. https://ebird.org/hotspot/L458893

Almost every time I go (during the right time of year), there are both Greater and Lesser Scaup, and they are often in the same general group. (there's a sheltered lagoon)




If it looks like and duck and quacks like a duck ...

I'm not sure I understand this point. General impression is more reliable in many cases to plumage I feel. (obviously you should take everything you can into account)
Sure photos can be misleading, but can we actually prove anything anyways?



Usually I find that I have trouble with all lessers, in trying to turn them into Greater, but when I see a Greater it's "obvious". Similar to Vaux's and Black Swift. Every Vaux's gets scruitinized to try and turn it into Black, but when a Black comes along it's clear - no hard time excluding Vaux's ... (which one you scruitinize probably just depends on what you are used to seeing most often)

The point is that when birders use unreliable field marks to identify a challenging species, it creates an entire culture of misidentifying birds. This is entirely the case with people misidentifying dowitchers in droves by the field mark of “grapefruit shaped body” or “flat backed”. Birders will jump on the bandwagon and popularize ID methods that are nuanced without honing the nuance for themselves.

I completely agree that general impression is a great method for identifying birds but it also has inherent flaws that may arise with more challenging identifications.

Thank you for sharing your observations of scaup. I used to see both species a lot but it has been many years and now l only see them a few times a year.

 

[qwerty5]

The point is that when birders use unreliable field marks to identify a challenging species, it creates an entire culture of misidentifying birds. This is entirely the case with people misidentifying dowitchers in droves by the field mark of “grapefruit shaped body” or “flat backed”. Birders will jump on the bandwagon and popularize ID methods that are nuanced without honing the nuance for themselves.

I completely agree that general impression is a great method for identifying birds but it also has inherent flaws that may arise with more challenging identifications.

I agree 100%. The problem is, I think, that GISS is learned by experience, looking at the same species multiple times. Then beginners try to use these subtle characteristics before they have developed a good knowledge of the birds. In Advanced Birding, Kenn Kaufman compared bird ID to learning to read. We teach kids to read by phonics, where they have to look at the individual letters and sound out the word. They can't just look at a word and know immediately how it sounds without looking at the details. However, those of us who have been reading for years don't have to sound out words like "identification", we just know the word. It's the same with bird ID, beginners just aren't able to look at a bird's shape and immediately know what it is. They have to build up a base of knowledge first by studying and looking at the details.