Friday, September 2, 2011

What loon is it?...Common, Yellow-billed or some hybrid?

Loon species, Quabbin Park, Sept 7,2007

Loon species, Quabbin Park, Sept 7, 2007

Loon species, Quabbin Park, Sept 7, 2007

I have been meaning to post about this bird for months and now I am finally getting around to it.  The story of the bird, the photo and the ID question have been floating around for quite some time and the initial date of the sighting is nearing the four year mark (originally found and photographed September 7, 2007). 
First a little background on the bird.  I came across a series of three images while reviewing old photos of loons and was immediately struck by the appearance of the bird. I have a vague recollection of seeing the bird but dismissing it at the time as a Common Loon with an ‘odd’ bill. The thought of an adult Yellow-billed Loon was not something I was expecting or even thought of as a possibility in Massachusetts in early September at the time. It was just not on my radar screen. Given what I knew of Yellow-billed Loons at the time I was expecting a much larger appearing bill then what I saw but further research now has shown me there is much overlap in bill size between Common Loon and Yellow-billed.  The bird was photographed from the end of the Gate 52 road within Quabbin Park. The weather at the time of observation appeared at least partially sunny with a temperature around 60 degrees F. I believe given the location and the size of the images I was 75-100 feet or so from the bird at the time the photos were taken. I was using a Nikon D50 with a focal length of 300mm at the time the photos were taken.  

Loon species, cropped photo, no other modifications

Loon species, cropped photo, no other modifications

I e-mailed several people whom I consider experts in the field to get their input on this and to try and talk me out of what I believed I was looking at in the photos.  These people included James Smith, Marshall Iliff, Jeremiah Trimble, Scott Surner, Tom Gagnon and a few biologists at Quabbin.  All of those who initially viewed the images have stated it indeed appeared to be a Yellow billed Loon and that the sighting should be submitted for review.  I shot many e-mails with attached photos back and forth to get further opinions on the bird.  Many other experts (those mentioned above plus David Sibley and others) weighed in on the bird and the came to the conclusion that it was indeed an odd Common Loon and not a Yellow-billed Loon.  The possibility of some type of hybrid was also mentioned (which would be even rarer than a pure YBLO).  I may indeed still submit the sighting to the Massachusetts Avian Records Committee for final, official review and to get the information out there that there is a potential ID pitfall regarding Common Loons vs. Yellow-billed Loons.

Some background on why the bird appears to be a Common Loon instead of a Yellow-billed Loon was included in an e-mail from Jeremiah Trimble and included the following:

"I am not sure I have gone into some reasoning why I came to the conclusion (along with many others) that your bird was in fact a Common Loon with an odd bill. One reason was seeing the images at the following links:

While these birds are not as extreme as your bird, I think you can see how they are tending towards it and may in fact be on their way to looking like your bird exactly. Other issues with you bird are the overall bill shape which I think is too short and thick and not as up-turned as a YBLO should show. The thick neck and head also point away from it. Also, the color, while suggestive on the bill, is not quite the clear bright color it should be."
(Jeremiah Trimble, personal correspondence)

Just for some additional background concerning Yellow-billed Loon sightings I have included an e-mail from Marshall Iliff which provided the following information.  This information was sent prior to the final conclusion that the bird was not a Yellow-billed Loon but I found the information interesting nonetheless.

1) The date is extraordinary. Although Yellow-billed Loons in California, Nebraska, and some other areas have summered, these are almost invariably first-summer or second-summer birds. Yours is clearly an adult and the date is remarkable for anywhere outside Alaska!!!

2) Although Yellow-billed Loons have turned up regularly in the Great Plains, Midwest, and Rocky Mountains states over the past 20 years (almost all Nov-Mar), the East Coast has fared very poorly. My impression is that inland loons have been on the rise in the interior of the country as reservoirs created in the last century have matured, become great fish areas, and as loons have gradually “discovered” that they are good wintering areas. Thus, I would attribute the increase in inland Pacific, Yellow-billed, Common, Red-throated, and even Arctic (now two Colorado records). Remember that the Great Plains and Midwest did not have many/any natural lakes until the last century: these are all created by dammed up rivers. Loons now wintering there have surely survived and propagated those inland wintering genes, which is why each year seems to have more inland loons.

3) As I said, the East Coast has been slow to catch up. There have been a lot of questionable or erroneous reports, but very few well-documented valid ones. I know of only 5 Yellow-billed Loon records east of the Midwest:

o Yellow-billed Loon 1 im.? Winter 1999 Hinckley Res., Oneida/Helkimier, NY (photos)

o Yellow-billed Loon 1 12/21/1997 thru 01/6/98 Oswego Harbor, Oswego, NY (photos)

o Yellow-billed Loon 1 early 1930 eastern Long Island, (specimen of mandible ONLY, AMNH skeletal collection 4005)

o Yellow-billed Loon 1 (May 2008, I think) Susquehanna River,

xxx CO., PA (well photographed)

o Yellow-billed Loon 1 date? Georgia, some inland reservoir

(widely seen and photographed)
- Not sure what became of this record:

o Yellow-billed Loon 1 basic im 12/??/1995 12 ?? 1995 "in the ocean along the southern coast", NC (LeGrand et al. 1997, Chat 61 (4))

Also some others from Tennessee, Kentucky…

Sorry for the lack of detail on the PA and GA record; both are recent and I do not have the specifics in my rarities database. The New York “mandible only” specimen has been questioned, but is generally accepted. Not sure of the NY Records Committee has addressed it.
(Marshall Iliff, personal correspondence)

In conclusion I'm not certain what the bird was but the overall consensus is that it a Common Loon with an odd bill or perhaps a hybrid of some sort.  A part of me is disappointed it was not a Yellow-billed Loon as it would be a first state record in a state with a long and distinguished ornithological history.  Another part of me is glad that I didn't miss out on a mega rarity at the time by dismissing the bird as nothing more than a Common Loon with a 'odd' bill.  In the end the entire episode has been a great learning for myself and perhaps others.  I wish to thank those that took the time to look at the photos and correspond with me regarding this bird and provide encouragement to get the info out there despite the time that had elapsed from the initial sighting.  I know I will miss some who assisted but I would like to thank James Smith, Marshall Iliff and Jeremiah Trimble.