Baird's sandpiper

Calidris bairdii is a shorebird of the family Scolopacidae; WoRMS accepts the name with the authority Coues (1861) ^[1]. In Peru it is recorded as a Nearctic migrant on the San Andrés beaches, in Pisco ^[2]. It is a long-distance migrant, and in spring it crosses the Great Plains of North America ^[3]. The IUCN lists it as Least Concern ^[4].

It is a long-distance migrant: the migration distance index between its breeding and wintering areas is 16.7 (in thousands of km), close to that of Calidris fuscicollis (17.2) and somewhat higher than that of Calidris himantopus (15.0) ^[3].

In Peru, a bird inventory of the seashore at San Andrés, in the district of San Andrés, bordered on the south by Paracas and its national reserve, in Pisco province, classes it as a Nearctic migrant and assigns it to the sandy beaches and to the stony and rocky ones ^[2].

In the model of spring migration through the Great Plains, the authors place it among the shorebirds with a more easterly distribution, mostly long-distance migrants ^[3].

Among the early migrants of the Great Plains, this species begins its northbound flights before April ^[3].

In a review of Arctic studies, Saalfeld and Lanctot list it among the early-laying, conservative species, as on Bylot Island, in Canada. They also cite that, at sites in northeast Greenland and on Herschel Island, species of this type, this one among them, advanced their laying dates by 0.4 to 1.0 days per year ^[5].

For spring migration, the source assigns it foraging in shallow water up to 5 cm deep on wet ground ^[3].

Migratory shorebirds depend on wetland complexes, and about half of the Great Plains region studied has been converted to agriculture, mostly in the east ^[3].

The IUCN lists it as Least Concern ^[4]. According to the Great Plains study, its population trend is unknown ^[3].

In the eastern Canadian Arctic (Rasmussen lowlands and Foxe Basin), the species' occupancy in the surveyed plots fell from 6.2 % in 1994-1997 to 0 % in 2019. The authors count it among the colder-breeding species, with a temperature index of 1.2 °C, and note it may have been seen less because its range shifted northward ^[6].

A climate model for the Great Plains projects, as an average over five models and the spring-migration dates, an increase of 0.029 in its probability of occurrence between 1981-2010 and 2041-2070 ^[3].

On the San Andrés beaches, in Pisco, two surveys carried out in January 2023 and December 2024 added up to 12 individuals, an average of 1.5 per day ^[2]. It was a scarce presence compared with other shorebirds at the same site, for example Calidris alba, with 1,179 individuals ^[2].