Oh my God, Dowitchers! (1 Viewer)

These swimming Dowitchers were photographed in February at the Upper Newport Bay in Orange County, California. Before I post the full photo in the Gallery I would like to invite your comments on the ID. I didn't notice their call because there were so many birds around that I didn't know which sounds were coming from which birds.

I did some homework: in about 18 guides (some with photos, most with drawings) I measured the width of the head and the length of the bill of the Dowitchers, and then divided the headnumber by the billnumber. This gives a raw indication of what it could be: below about 0.55 down into the 0.40s would be a Long-billed, higher up to the 0.70s would be a Short-billed.

It is also said that every bird where the pale tailbars are wider than the dark ones can safely be said to be a Short-billed. And the Short-billed is more a coastal bird, while the Long-billed is more a freshwater bird.

My measurements on the photo give the figures 0.56 and 0.69 and the bars on the tail look like having more white. The birds are on a coastal mudflat area about 3 miles / 4.5 km from the coastline.

Combining all this I come to an ID of Short-billed Dowitcher. What do you think?

Peter

I agree with you - Short-Billed.

Fulmar,
Another good way if identifying Dowitchers is by the time of year they were seen. The LB and the SB migrate at different times (at least for the fall migration) so this can frequently be used to separate them.

Unfortunately for me, they both winter here so I can't use this except for the first month when the SB's arrive first.

Hi Peter,

Whilst I agree that they do look rather short billed I would have to go with Long Billed, mainly becuase they have unbarred tertials. The tertials as far as I know are the single best feature in identifying Dowitchers. Short Billed show very densely barred tertials in all plumages.

Watch Harry Hussey or Michael Frankis come along and say I'm wrong....

tom mckinney said:

Hi Peter,

Whilst I agree that they do look rather short billed I would have to go with Long Billed, mainly becuase they have unbarred tertials. The tertials as far as I know are the single best feature in identifying Dowitchers. Short Billed show very densely barred tertials in all plumages.

Watch Harry Hussey or Michael Frankis come along and say I'm wrong....

Click to expand...

No need to wait for them.. I can do that I make a point of only seeing juv Dowitchers...and even then I make them call.

Short-billed Dowitchers can have plain tertials.... in non breeding plumage. Thats why I only ever want to see Juvs! NOw I'm here I better take a look at them!

tom mckinney said:

Watch Harry Hussey or Michael Frankis come along and say I'm wrong....

Click to expand...

...or Jane Turner

Tom,

I had read about those differing tertials too, but I understood that it was only valid for juveniles?

Peter

Structurally these do not look hugely long-billed - but bill length is notoriously variable. Its probably safe to say there isn't a female Long-billed here! There is a believe something useful in wing-length in non-juv dowitchers - and I'd say the most right hand bird does appear to have wings beyond the tail tip... which would be a point to short-billed, though since the wings are held up, I'm not 100% confident I can rely on it. The bird in front appears to be shorter winged anyway

I can't see enough of the tail to make a judgement on the relative with of the black and white bars, most of the barring visible is upper and lower tail coverts... I'd expect a SB to have finer spotting on the utc.s.

So I guess my consulsion is that these are not safely identifiable

I've never seen Short Billed, but I've seen quite a few autumn/winter Long Billed in Britain.

I admit that the bills do look too short for a bog standard Long Billed, and if the tertials are not as clear cut as I thought, then I'll also go along with Short Billed.

You learn something new every day...

Fulmar,
I did a little more research on distribution and found two excellent articles on the California Department of Fish and Game website. Typically the SB does NOT winter in California EXCEPT in several specific locations, and Newport Bay is one of them where they are listed as abundant. So this would give a high probability to yours being SB.

Here are the links:
Short-billed and
Long-billed

Fulmar said:

I had read about those differing tertials too, but I understood that it was only valid for juveniles?

Click to expand...

You're right, in juv's Short-billed *always* have markings in the tertials, while the tertials of juv. Long-billed *always* are quite uni-colored except for the paler edge. The problem is that adult winter Short-billed have tertials similarly uni-colored. Wing versus tail is a often a relatively good feature, but, as this is somewhat variable in both species, not conclusive. Except if in hand, the only really good feature for seperating ad. winter Dowitchers, is pattern on tail. Something that at least I can't judge from the photos. As Jane said, bill lenght is notoriosly un-reliable. Only the two extremes are possible to differentiate; otherwise there is a great overlap between the two species. Of course the best is voice...

So, what am I saying? Well, to me the birds on the photos could be either...