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Saturday, February 10, 2018

Lesser Scaup Identification

Lesser Scaup, male

Lesser Scaup, male

Lesser Scaup, male

Lesser Scaup, female

For at least two weeks or longer the Scaup that have been in Ding Darling are Lesser Scaup. There have been 4-6 birds. Mostly they are seen by the tower, one has also been seen on pond 2 a few days ago. They are frequently misidentified as Greater Scaup. We have been studying them carefully and over time. Here’s a list of clues and photos as to why they are Lesser Scaup, not Greater Scaup. There are also Lesser Scaup at the Pond Apple ponds and the Dunes golf course.

1. Head Shape. 
Head shape is touted as one of the biggest clues, with Lesser’s head having a steep forehead rounding off to a high, short, somewhat peaked crown with a slight “corner” visible at the rear. In general head height is greater than length (the opposite in Greater Scaup), creating a vertical appearance to head. Long crown feathers give the Lesser’s head the peak at rear. On Greater the head has a steep forehead which rounds out into a fairly long crown and head has horizontal, sometimes slightly rectangular appearance. In general, head length is greater than height (the opposite in Lesser Scaup). From head-on Greater’s head is broader cheeked: Lesser’s is more even width throughout although this is sometimes hard to judge. Lesser has a thin neck, Greater’s is thicker. HOWEVER, head shape varies considerably depending on what the birds are doing, such as feeding, sleeping, alert, etc.. When actively feeding head shape differences are negligible, the head of Lesser is sleeked back, peak not visible. Much of the misidentification of these Ding birds is because the observer has been relying on head shape alone, and as stated, that can vary considerably. You need multiple clues to ID these birds.

2. Wings. 
On Lesser Scaup, the broadly white secondaries, create a white stripe along inner wing, on Greater Scaup the white extends onto the inner primary feathers making the stripe longer. This can be an excellent clue. Note the wing photos of the Ding birds and you can see that the bright white occurs on the secondary feathers and then stops and does not extend along the primary feathers as a continuous and longer bright white stripe. Beware looking at photos of the Ding birds where the bright sunshine reflects too much off the wing, it can make the wing look like it has a long white stripe.

3. Head and Body Color. 
The head of male Lesser in good light can have purplish to greenish gloss. In dull light or back lit, the head looks dark. The sides are washed with pale gray. In Greater Scaup the male’s head, in good light, has greenish gloss. Greater’s sides are mostly whitish with underpart vemiculation finer than on Lesser. Again beware photos that blow out the whites which can make the Ding bird males look like they have cleaner whitish sides, more like Greater Scaup. Females of both species similar, have brown heads, gray-brown back and sides and white oval patch at base of bill. Lesser Scaup can appear shorter-bodied and often rides higher on water than Greater. Greater is a slightly bigger bird (18 inches) than Lesser (17 inches) although this may be hard to judge.

4. Bill. 
The bill of Lesser is bluish and about 2/3 length of head, black nail at tip. Greater’s similar bill is slightly longer, about 3/4 length of head with bill broader and flaring toward tip and black on nail can bleed down off nail, hard to see at a distance.

So to ID the birds in Ding, look closely, over time at more than one clue. The clues for head and wings are some of the most helpful. Lesser Scaup are the species most commonly seen here in winter, Greater Scaup would be more rare. For more detailed clues consult a good field guide or specialty guide.

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