[EBB Sightings] Scaups: oiled or not oiled?

Harv,

The only thing I would add to this is that feathers stuck together to 
form triangular, scale-like patches, such as on the breast of this bird:

http://www.pbase.com/gtepke/image/88875411

This is an extreme case, but I don't think duck feathers ever look like 
that on a healthy bird, so I would interpret any triangular clumps as 
probable oiling.  Here is a scaup with a less extreme but still obvious 
case:

http://www.pbase.com/gtepke/image/88875414

This is actually easier to see on a dark bird.  Perhaps that is what you 
meant by "jet black irregular patches or streaks."

Keep up the good work.

Glen Tepke
Oakland


Harv and Monica wrote:

> All;
>  
> I propose we open a discussion on identifying lightly oiled scaups during
> oiled bird surveys. 
>  
> I suspect that many of use are using different criteria for identifying
> them. 
> 
> My own criteria have changed over the last 3 weeks. This means the data I
> have sent OWCN is not consistent. In fact, I revised and resent some of my
> Alameda data to improve consistency.  
>  
> The eye-opener was going to Lake Merritt last week and spending an hour
> studying a lot of male scaups from just a few feet away at the islands. I
> saw a surprising amount of unexpected plumage variation in both greater and
> lesser male scaups and was able to verify I was looking at feather color,
> not oil.  
>  
> For example, I saw males with virtually all-brown flanks. Others had brown
> flanks with unevenly spaced vertical gray lines.  Scaups with mostly brown
> flanks, and especially those with vertical gray lines, are not very common.
> I have been reporting birds with this plumage as lightly oiled, thinking the
> brown is oil and the vertical lines are preening lines. That was probably a
> mistake.
>  
> I saw other birds, usually male lesser scaups, with very dark irregular
> patches on the flanks. This is also an uncommon plumage, and I have logged
> birds with this type of plumage as oiled. Some were oiled. Some probably
> weren't. 
>  
> I am now more conservative about identifying lightly-oiled scaups. Here are
> the criteria I am using:
>  
> 1. The bird is out of the water, regardless of plumage appearance. I do not
> log scaups dabbling in a few inches of water near rocks or beaches. 
>  
> 2. The bird is obviously waterlogged or ill, regardless of plumage
> appearance. Frequently, the bird appears unkempt and has some feathers
> askew. 
>  
> 3. The bird has jet black irregular patches or streaks on the flanks, breast
> or elsewhere. Since this is an uncommon plumage variation in males, I
> believe we should log it because some of the time it will be oil. On
> females, irregular black patches should be oil in all cases. 
>  
> 4. A preening bird rolls on its side and the breast shows brown patches
> (males), black patches, or black streaks. 
>  
> The last two criteria are much easier to see on males than females. If you
> have any tricks for spotting oiled females, please forward. The only
> female-specific criterion I can think of is if the white face patches are
> blackened. 
>  
> Excessive preening is frequently cited as something to look for. I have no
> experience observing how often healthy scaups preen, and so have no way to
> objectively identify excessive preening. Hence, I have not included it as a
> criterion.  
>  
> What are your thoughts on these criteria? What would you add or subtract?
> Are the criteria too restrictive or not restrictive enough?  There are some
> very experienced birders on this listserv. Let's hear your thoughts. I
> volunteer to watch the thread and roll-up the responses. 
>  
> Making sure the data we are forwarding is accurate and consistent is crucial
> to accurately assessing the wildlife impact of the spill. 
> 
> Steve Hampton: Since you're one of the key users of this data, please let us
> know your thoughts. Your suggestions are particularly important. 
>  
> Harv Wilson