25th-26th June
With all the complications that arose for the ID of our Semipalmated Sandpiper seen on Trolla over the past couple of days, we thought the bird warranted its own blog post highlighting the key ID features that we noted and that were pointed out to us during the identification of the bird.
Found by volunteer Bobbi Brander, a keen, sharp young birder from Lothian, initial views of the bird weren't great, but a lot of perseverance saw us obtain some decent photos over the two days the bird has so far been present. Photos used in this post are credited to Maddy Hine, George Gay, and Craig Forsyth.
Compared to the waders the bird was associating with, it was obviously much smaller and more diminutive. The bird was easy to pick put amongst the small wader flock based on size alone. The structure is also important to the ID. Compared to what would be expected of Little Stint, the bird is more compact with a less attenuated rear end. Overall it appears quite dumpy and long legged with limited rear-end attenuation.
The photos above show a thick set bill with a deep base and lateral thickening at the tip. The photo of the bird head on (top right) shows this feature more clearly, with the thick bill at the base tapering in the middle and then thickening again towards to tip. In Little Stint the bill would appear much slimmer with a fine tip, giving a more spikey billed appearance compared to the deep and heavy bill shown here.
A few flecks of flank streaking left over from the bird having moulted out of adult plumage are shown in the photos above. A Little Stint would show no such streaking. The shape of the streaking also helps rule out Western Sandpiper, which would show distinctive arrowhead shaped streaks across the breast and into the flanks.
Photos of the rear end of the bird show the bird to have a short primary projection with three primary tips visible beyond the tertials. Little Stint would show a longer primary projection.
The colour grabs from the photo above show the tertials to have pale fringes instead of rufous fringes. The centres of the tertials are blackish.
A relatively long hind claw helps rule out other dark legged stints such as Red-necked and Little.
Perhaps the most important feature which we were unable to obtain photos of until the morning after its original discovery is the palmations between the toes. The photos above which show the toes at slightly different angles demonstrate the toe webbing clearly.
1. Overall size and structure compared to accompanying waders
Compared to the waders the bird was associating with, it was obviously much smaller and more diminutive. The bird was easy to pick put amongst the small wader flock based on size alone. The structure is also important to the ID. Compared to what would be expected of Little Stint, the bird is more compact with a less attenuated rear end. Overall it appears quite dumpy and long legged with limited rear-end attenuation.
2.Bill size and structure
The photos above show a thick set bill with a deep base and lateral thickening at the tip. The photo of the bird head on (top right) shows this feature more clearly, with the thick bill at the base tapering in the middle and then thickening again towards to tip. In Little Stint the bill would appear much slimmer with a fine tip, giving a more spikey billed appearance compared to the deep and heavy bill shown here.
3.Scapulars
The scapulars pointed out with the red arrows are winter-type; grey with a black shaft streak. The scapulars pointed out with the yellow arrows are summer-type, with large, broad, elongated black centres. The scapulars pointed out with the purple arrow shows summer-type scapulars with asymmetrically placed and contrasting oval shaped marks at base. Little Stint would not show scapular patterns such as this.
4.Flank streaking
A few flecks of flank streaking left over from the bird having moulted out of adult plumage are shown in the photos above. A Little Stint would show no such streaking. The shape of the streaking also helps rule out Western Sandpiper, which would show distinctive arrowhead shaped streaks across the breast and into the flanks.
5.Primary projection beyond the tertials
6.Tertial centres and fringes
The colour grabs from the photo above show the tertials to have pale fringes instead of rufous fringes. The centres of the tertials are blackish.
7.Long hind-claw
A relatively long hind claw helps rule out other dark legged stints such as Red-necked and Little.
8.Palmations
Perhaps the most important feature which we were unable to obtain photos of until the morning after its original discovery is the palmations between the toes. The photos above which show the toes at slightly different angles demonstrate the toe webbing clearly.
All the features highlighted above helped us come to the conclusive ID of Semipalmated Sandpiper. A difficult ID but an overall satisfying one!
Many thanks to all those who aided with the ID.
Comments