ID please!

[Scott Grant]

shot this past weekend on the west coast of Newfoundland, Canada.

Thanks in advance!

SG

[John Chardine]

White-rumped Sandpipers are quite frequent this time of year in Newfoundland. Shorebird experts please chime in!

[Wayne Richardson]

We can say with certainty that this is a juvenile Calidris sandpiper & a jizz that indicates a small bird. There are 4 black-legged ‘peeps’ in N America & 3 can be eliminated on negative ID features as follows:

Western: No obvious rufous fringing of the scapulars contrasting with plain greyish wing coverts. In addition, this bird doesn’t look large headed, long-billed or ‘front-heavy’.
Bairds: Largest of the ‘peeps’ with a very buff & scaly appearance. It is very long-winged with tips extending well beyond tail. A relatively long straight fine-tipped bill.
White-rumped: Features are pretty much as Bairds in structure, but with relatively shorter legs. They have a medium length fine-tipped bill with pinkish base to lower mandible. Note youngsters don’t leave breeding grounds until mid or late September.
So by this process you are left with Semipalmated. IMO there is nothing in the structure or feather details that is unusual for this species.
Both black-legged Stints (Little & Red-necked) were also considered, but this bird doesn’t have any of their ID features.
Cheers: Wayne
PS: A very nice capture & the water colours are particularly attractive.

[John Chardine]

Wayne- I seem to remember an ID feature with the White-rump being something to do with the relative length of the wing and tail. You didn't mention this. Is my memory failing me?!

[Wayne Richardson]

Wayne- I seem to remember an ID feature with the White-rump being something to do with the relative length of the wing and tail. You didn't mention this. Is my memory failing me?!

Hi John

You are correct about the wing/tail ratio being diagnostic on WRS. The wing tips (like BS) extend well past the tail & perhaps I didn't make it clear in my summary. On this particular bird the wing tips fall level & is consistent with SPS. Note also that there is little contrast between the wing coverts & mantle feathers, good for SPS, but not WRS which is similar to WS in this respect.

An additional WRS ID feature is the strongly streaked breast that demarcates sharply with the pale belly, i.e. very much like Pectoral Sandpiper.

Cheers: Wayne

[Scott Grant]

:D this place is just a wealth of knowledge! thanks John and Wayne! you're both fantastic! :D

[John Chardine]

Thanks Wayne. It's a bit ironic that over the past three weeks I've been seeing upwards of 100,000 Semipalmated Sandpipers migrating through our area but did not immediately recognise this bird! In our area they occur in huge flocks and I don't get a chance to focus on one bird.

Hi John

You are correct about the wing/tail ratio being diagnostic on WRS. The wing tips (like BS) extend well past the tail & perhaps I didn't make it clear in my summary. On this particular bird the wing tips fall level & is consistent with SPS. Note also that there is little contrast between the wing coverts & mantle feathers, good for SPS, but not WRS which is similar to WS in this respect.

An additional WRS ID feature is the strongly streaked breast that demarcates sharply with the pale belly, i.e. very much like Pectoral Sandpiper.

Cheers: Wayne

[Arthur Morris]

Hey John, What are the peak dates on the St. Mary's birds?

[John Chardine]

Artie- Based on this year, the best time to be here for the semis is the second week of August. They can be found anywhere along the shore at Johnson's Mills and also at Hopewell Cape, Mary's Point or Evangeline Beach in the upper Bay of Fundy.

[Arthur Morris]

Thanks John, The reason that I asked is that by the second week of August the great likelihood, based on the timing of migration, is that the great majority of semis at that time would be juveniles, probably about 90%. In NYC where I did the count for Manomet for about 8 seasons, the peak of adult Semipalmated Sandpiper migration was the last ten days of July.

Thus, it is very likely that 90% of the birds you were seeing looked just like the bird in this post. Sometimes you cannot see the forest for the trees!

[John Chardine]

Correct Artie. We get females first, followed by males, then juvis. We can sex the birds with bill and wing measurements and as you have pointed out many times, the juvenile plumage is quite different. Over the years that we have been monitoring birds at Dorchester Cape we have seen birds getting later and later over the period. This may have to do with climate change and the fact that the birds do not need to leave the Arctic so soon. Anyway this is all to say that the large concentrations of birds that now occur in August are likely adults with the juvis trickling through later in the month. Some years we don't see many at all which may be a function of poor breeding success those years.

[Arthur Morris]

Thaks for the info. It would be really interesting if the trends at JBWR have changed...