[EBB Sightings] Scaups: oiled or not oiled?

	<47520E2C.8020408 at comcast.net>

All, 

Sorry, I've been away tending to a family emergency.  In general, oiled birds will have a "wet dog" look with feathers wetted and clumped together.  Sometimes it's hard to see black oil (in the case of dark-plumaged birds like cormorants, etc.) or, if it's diesel or a light gasoline, the oil will be nearly clear in color, and thus hard to see even on a white bird.  Nevertheless, the bird will not have plumage that is pristine and dry or fluffy.  Feathers will be out of place and appear wet and matted.  Sometimes black oil will also leave a brownish-yellow wash on white feathers.  

The other key thing to look for is unusual behavior that is associated with hypothermia and starvation.  Even a spot of oil the size of a dime or a pencil line across the breath can destroy the bird's ability to keep warm in cold water.  Like a hole in a wetsuit, the water can penetrate and then spread against the skin, chilling the entire bird.  If the bird is dependent upon diving for food (e.g. diving ducks, grebes, loons, alcids), they will cease feeding and quickly succumb.  Due to their metabolism, they can lose up to 1/3 of the body weight in two days if they are not feeding (see Oka, N. and M. Okuyama. 2000. Nutritional status of dead oiled rhinoceros auklets (Cerorhinca monocerata) in the Southern Japan Sea. Marine Pollution Bulletin 40(4): 340-347. )
Such birds will stand out to the observer, usually because they are either constantly preening, swimming listlessly near shore with minimal avoidance reaction to humans, or (most obviously) are onshore.  For example, any grebe or loon seen on shore in the Bay Area is almost certainly oiled.  On some of these birds, you might be hard pressed to see the oil.  For example, I saw an obviously hypothermic (visibly shivering) LESC perched on the rip-rap all alone, but the plumage looked flawless, dry, etc.  Upon further investigation, I realized the vent was oiled, but this was hard to see at first.  Often, only the vent is oiled.  

Note that species that can forage out of water (e.g. gulls) can survive oiling much longer. 

all for now, 






Steve Hampton
________________
Resource Economist
Office of Spill Prevention and Response
California Dept of Fish and Game
PO Box 944209
Sacramento, CA 94244-2090
-----------------------------------
(916) 323-4724 phone
(916) 324-8829 fax

>>> Glen Tepke  12/1/2007 5:45 PM >>>
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

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