Subarctic, alpine nesting by Baird's Sandpipers Calidris bairdii

Subarctic, alpine nesting by Baird's Sandpipers Calidris bairdii.Wader Study Group Bull.104: 39-50.Baird's Sandpipers Calidris bairdii were found nesting in alpine habitat in southwestern Alaska (60ø48'N, 154ø00'W), almost 250 km from the nearest known breeding site, and studied over three consecutive seasons, 1997-1999.The first birds arrived during the second week of May each spring with peak numbers recorded the third week of May.Most nests and newly hatched broods were found on sparsely vegetated dwarf shrublichen mat tundra on level or gently sloping areas throughout the alpine zone between 980 and 1400 m above sea level.Most eggs hatched during the third week of June and independent young were noted during the second and third weeks of July.Both parents initially tended broods, but only the male remained after chicks were about four days of age.During early brood-rearing, adults began to move chicks, often to higher elevations and over distances of several hundred metres.Throughout the area the density of nesting birds was about 0.2 pairs/km 2 with up to 0.9 pairs/km 2 found on southerly exposures of the north study slope.A summary of available information revealed the global nesting distribution of bairdii to be strongly associated with disturbed landscapes, especially montane areas affected by glaciation, suggesting the breeding range is likely to be much more extensive than currently known, especially in areas of Alaska, the Yukon, and possibly Chukotka. of Alaska, Canada, and the Russian Far-East (Chukotski Peninsula), and even into subarctic portions of Beringia, where it is largely restricted to the alpine zone of several mountain groups (Brandt 1943, Gabrielson & Lincoln 1959, Portenko 1972, Cramp & Simmons 1983, Godfrey 1986, AOU 1998).Knowledge of the species' breeding biology, however, comes almost entirely from the high-Arctic portion of its range (e.g., Drury 1961, Parmelee et al. 1967, Reid & Montgomerie 1985, Moskoff & Montgomerie 2002), the exception being Irving's (1960) study from the central Brooks Range of Alaska.While studying nesting Surfbirds Aphriza virgata and Wandering Tattlers Heteroscelus incanus, we found Baird's Sandpipers to be a regular breeder in subarctic, alpine habitats of the southern Alaska Range, considerably south of the species' nearest reported breeding site (AOU 1998; D. Gibson pers.comm.).Here we present information on several aspects of the breeding ecology of this southern assemblage of C. bairdii and compare our findings with those from other nesting areas throughout the high Nearctic.763 m a.s.1.(above sea level) and is one of a series of glacially-formed, east-west oriented lakes whose moderateto steep-sloping valley walls include remnants of the most recent series of recessional Late Wisconsin glacial moraines (Fritschen 1995).From the surface of Turquoise Lake these stair-step moraine terraces rise an additional 240-640 m onto gently rounded plateaus (Fig. 2).Dwarf shrub-lichen mat tundra dominates the landcover of the area and is characterized by dwarf shrubs, lichens, and herbs and non-vegetated substrates including scattered boulders, stones, and patches of unvegetated gravel and clay (Kessel 1979).Dense stands of Betula nana and sometimes Ledurn palustre up to 0.5 m high are common at the bottom and lower (up to 900 m a.s.1.)slopes of the basin; most drainages and wet areas at the base of terraces are lined with willows (Salix spp.), some 1-to 4-m tall in the most prominent drainages.The driest places, usually crests of moraines and edges of terraces, are covered with mat-and cushionforming plants, dwarf willows, sedges and forbs (see Results).At higher elevations (900-1,200 m a.s.1.)areas of tundra and bare ground occur in patches with bare ground comprising about 40% of the surface; however, tundra becomes more sparsely vegetated and bare ground more gravelly with increasing elevation (Fig. 2).At all elevations boulders and rock fields are common.METHODS STUDY AREA Our study site (see Gill et al. 1999) was the Turquoise Lake basin (about 160 km 2) on the west slope of the Neacola Mountains (60ø48'N, 154ø00'W) of southwestern Alaska (Fig. 1).The 8-km-long by 2.5-km-wide lake is located We were present at the study site 7 May-18 July 1997, 6 May-16 July 1998 and 4 May-16 July 1999.The main study area encompassed the upper north-and south-facing slopes and plateaus of the Turquoise Lake basin, which we visited almost daily from our camp along the northwest shore of the lake (Fig. 1).Adjacent areas, extending north 5 km to Trail 39

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