Baird's Sandpiper
Calidris bairdii
Adults have black legs and a short, straight, thin dark bill. They are dark brown on top and mainly white underneath with a black patch on the rump. The head and breast are light brown with dark streaks. In winter plumage, this species is paler brownish grey above. This bird can be difficult to distinguish from other similar tiny shorebirds; these are known collectively as "peeps" or "stints". One of the best identification features is the long wings, which extend beyond the tail when the bird is on the ground.
ID text from Wikipedia, CC BY-SA 4.0
Curlew Sandpiper
Calidris ferruginea
The curlew sandpiper is a small wader 18–23 cm in length and weighing 44–117 g. It has a wingspan of 38–46 cm, a bill length of 32–44 mm, and a tarsus (the bone between the "knee" and the "ankle") length of 26–34 mm. It has a black bill, dark brown irises, and dark grey to black feet. All plumages have a large white patch on the rump, occasionally barred with red in some adults, and in flight show a distinctive white stripe going across the wing. Like most waders, the curlew sandpiper has seasonal plumages and moults yearly, shedding its old feathers and growing new ones. Voice: Only the male sings. Each song lasts for 10–15 seconds and consists of several parts, starting with several introductory notes, followed by multiple trilled doublets, a four-part phrase, and several drawn-out whine calls. Both genders vocalise calls. The alarm call is a whik, whik, whik repeated or wik-ki-ki-ki...
ID text from Wikipedia, CC BY-SA 4.0
Where you might meet both
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