Circumstances: This juvenile was originally found at a high tide roost 31 October 2019 by Sharon Jue. I swung by Emeryville Marina after a meeting at Golden Gate Audubon this afternoon. Met Mark Rauzon who found the bird roosting in the usual place, the rip-rap on the south side of Powell. This is a rarity in California and it appears to be the fifth Alameda County record.
Description: Small godwit, boldly patterned above. Wing coverts and mantle with strong pale notches on edges. Buff wash across chest. Lacked expected dark cap. Supercilium not obvious, rather faint. Long primary projection. Long pink-based bill, slightly upturned. Lacks overall cinnamon color of adjacent Marbled Godwits. Tail and rump white with dark transverse bars. Back mottled gray and white. Underparts white with fine gray flank streaks. Based on long bill, I believe this was likely a female.
Discussion: Most Bar-tailed Godwits occurring in North America are of this large dark-backed race, L. l. baueri which breeds in Alaska. Studies of radio-tracked birds found this population undergoes the longest known non-stop migration of any bird. Apparently they take advantage of major pressure ridges to sling-shot across the Pacific, covering distances of up to 11,000 km (7,200 statute miles) in nine days (Gill et al 2009). They lose up to half their body weight during these marathon non-stop migrations. Sadly, the future of these extraordinary migrants has been imperiled by reclamation projects in the Yellow Sea destroying key migration staging areas for shorebirds in East Asia. This godwit's conservation status was upgraded from "least concern" in 2012 to "near threatened" in 2015 by IUCN as their population continues to plummet.
Digiscoped with Panasonic DMC-LX5 | Nikon FieldScope 3 | 30X WA | hand-held (no adapter).
References:
BirdLife International 2017. Limosa lapponica (amended version of 2016 assessment). The IUCN Red List of Threatened Species 2017: e.T22693158A111221714. http://dx.doi.org/10.2305/IUCN.UK.2017-1.RLTS.T22693158A111221714.en. Downloaded on 05 November 2019.
Gerard Hutching, 'Wading birds - Bar-tailed godwits', Te Ara - the Encyclopedia of New Zealand,
http://www.TeAra.govt.nz/en/wading-birds/page-7 (accessed 26 March 2017)
Gill, R.E.; Tibbitts, T.L.; Douglas, D.C.; Handel, C.M.; Mulcahy, D.M.; Gottschalck, J.C.; Warnock, N.; McCaffery, B.J.; Battley, P.F.; Piersma, T. (2009). "Extreme endurance flights by landbirds crossing the Pacific Ocean: ecological corridor rather than barrier?" Proceedings of the Royal Society B. 276 (1656): 447–457. https://doi.org/10.1098/rspb.2008.1142.
McCaffery, Brian J. and Robert E. Gill. (2001). Bar-tailed Godwit (Limosa lapponica), The Birds of North America (P. G. Rodewald, Ed.). Ithaca: Cornell Lab of Ornithology; Retrieved from the Birds of North America: https://birdsna.org/Species-Account/bna/species/batgod DOI: 10.2173/bna.581
Piersma, T., Lok, T., Chen, Y., Hassell, C. J., Yang, H.-Y., Boyle, A., Slaymaker, M., Chan, Y.-C., Melville, D. S., Zhang, Z.-W. and Ma, Z. (2016), Simultaneous declines in summer survival of three shorebird species signals a flyway at risk. J Appl Ecol, 53: 479–490. https://doi.org/10.1111/1365-2664.12582
Van Gils, J., Wiersma, P., Sharpe, C.J. & Boesman, P. (2017). Bar-tailed Godwit (Limosa lapponica). In: del Hoyo, J., Elliott, A., Sargatal, J., Christie, D.A. & de Juana, E. (eds.). Handbook of the Birds of the World Alive. Lynx Edicions, Barcelona. (retrieved from http://www.hbw.com/node/53890 on 26 March 2017).
Woodley, K. 2013. Bar-tailed godwit in Miskelly, C.M. (ed.) New Zealand Birds Online. www.nzbirdsonline.org.nz