Waterbird Wednesday week 16: Pectoral and Sharp-tailed Sandpipers

Pectoral Sandpiper (Calidris melanotos) and Sharp-tailed Sandpiper (Calidris acuminata) are two very similar waders. Both are notable species, Pectoral Sandpiper being recorded many times each year in the UK (classed as a scarce migrant by the BOU) and Sharp-tailed Sandpiper having only 32 previous records. Compared to other Calidris sandpipers they are relatively upright, with long necks and long yellow legs. They have medium-length, pale based, slightly drooped bills and in flight show a white rump with a dark stripe through the middle, as seen in Dunlin. The upperparts are brownish, and the underparts are mainly white with a dark breast. Though they are mainly similar, there are subtle differences, as will be described in this post. Pectoral Sandpiper

Without doubt this is the more common of the two species, being recorded several times a year in the UK. Normally this species breeds in North America and NE Siberia, and is most commonly seen in the UK during it's autumn migration. In all plumages shows a relatively weak head pattern, with rather dull brown upperparts and an abrupt border between the breast streaks and white belly.

Juvenile

Juvenile birds are pretty similar to adults, with slightly more buffy tones to the upperparts and breast and two white 'V' marks on the back.

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Adult

In autumn, adult birds are moulting from summer to winter plumage. They have a far more consistent colouring to the upperparts, being a dull brown. The breast, neck and head are a far more dull brown to juveniles, and adult birds show a short 'split' supercilium where a white stripe goes up from the lores.

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Sharp-tailed Sandpiper

Overall a far more warm-toned bird to Pectoral Sandpiper. This species is far rarer in the UK, with only 32 records, and breeds in Eastern Siberia. The head pattern is far stronger, and appears to have dark markings on a pale base as oppose to light marks on a dark base. The cut-off point of the breast markings is far more diffuse, unlike the abrupt cut-off seen in Pectoral Sandpiper.

Juvenile

Juvenile Sharp-tailed Sandpipers do not have a streaked breast as seen in Pectoral Sandpiper. The breast is orange-buff, with streaks on the neck and flanks. The upperpart tones are far more orangey than in Pectoral Sandpiper.

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Adult

Adult birds have spots running down the sides of the belly, not seen in Pectoral Sandpiper. They are far warmer toned, particularly on the breast, with stronger head patterning.