A few days ago at Conejohela Flats, I was treated to my first Sanderling in Pennsylvania. Soon after we landed on the flats it was running around with a Whimbrel, similar to the Buff-breasted Sandpiper the day before.
I am used to seeing flocks of Sanderlings on the shore, chasing waves back and forth as they feed. It is quite another thing to watch one loafing around in the middle of PA on a muddy island, with no waves. The Sanderling seemed pretty content to stick around, lounging around all day in pretty much the same location.
The Sanderling was actually a bit difficult to digiscope. Most of my photos ended up nicely focused except for the head, which was always moving. It was in constant motion, foraging in the drier mud and pulling out worms. Its very sturdy bill enables it to probe in harder mud for prey. In a study of foraging flocks of Sanderlings in New Jersey, the Sanderlings spent 65% of their time actively searching for food and 35% probing, gleaning and pecking (Morton 1996).
Sanderlings have been known to live up to 13 years (Boates and McNeil 1984). Based on broad-scale surveys, the N.A. population of Sanderlings is roughly 300,000 individuals (Morrison et al. 2000). The number of Sanderlings along the Atlantic flyway is estimated to have decreased by 80% in the last 30 years. The biggest threats to Sanderlings are human disturbance, habitat loss and the associated loss of food.
1984. Longevity record for the Sanderling. J. Field Ornithol. 55: 485.
2000. Population estimates of Nearctic shorebirds. Waterbirds 23: 337–352.
1996. Effects of human disturbance on the behavior and energetics of nonbreeding Sanderlings. Ph.D. diss., Virginia Polytechnic Inst. and State Univ., Blacksburg.
The Nature Conservancy. Sanderling. http://www.nature.org/initiatives/programs/birds/sibley/animals/art5632.html. Accessed 9/7/08.