Abstract
Seabirds have often been proposed as environmental indicators. Beached bird
data may provide an additional data source and such data is efficacious because
it can reliably be collected by volunteers. In addition to anthropogenic factors,
such as oil spills, changes in the ocean-atmosphere can affect carcass beaching
rate in 3 non-exclusive ways: (1) direct mortality following storms, (2) mortality
via bottom-up food web processes, and (3) increase in carcass delivery due to
shifts in surface water movement. We used data from 3 volunteer-based beached
bird data sets collected within the California Current System (CCS) to (1) examine
the level of response to anomalous ocean conditions in 2005 and (2) explore the
degree to which long-term beaching patterns could be explained by one or more
of our proposed mechanisms. In 2005, anomalous die-offs of Cassin's Auklet
Ptychorhamphus aleuticus and the Rhinoceros Auklet Cerorhinca monocerata
occurred in the winter in Monterey. By spring, anomalous die-offs of Brandt's
Cormorant Phalacrocorax pencillatus and the Common Murre Uria aalge occurred
throughout the CCS. Over the longer term, increases in beaching were associated
with changes in the timing and intensity of upwelling and, secondarily, with zonal
winds aloft - a potential proxy of shifts in pelagic community composition. These
results suggest that a bottom-up food web mechanism best explains seabird
beaching, at least in the spring. Correlations of local measures of storminess to
seabird beaching rates were weak to non-existent . Correlations were much
stronger at the California site (8yr) and weaker at the Oregon site (26yr).
Collectively, these data suggest that relationships between ocean physics and
beached bird response may be site specific and/or may reflect choices live birds
make vis-à-vis non-breeding distribution.
Keywords:
Upwelling,
Seabird,
Common murre,
Brandt's cormorant,
Cassin's auklet,
Rhinoceros auklet
http://dx.doi.org/10.3354/meps07077
Notes
Local copy
Internal Links
- Common Guillemot (Uria aalge)
- Brandt's Cormorant (Phalacrocorax pencillatus)
- Cassin's Auklet (Ptychorhamphus aleuticus)
- Rhinoceros Auklet (Cerorhinca monocerata)
- beached bird survey (BBS)
- upwelling
- mortality
- physical forcing
- seabird wrecks
Parrish, J.K.,
Bond, N.,
Nevins, H.,
Mantua, N.,
Loeffel, R.,
Peterson, W.T.,
Harvey, J.T.,
- California Current
- Marine Ecology Progress Series
Links to this page
- Parrish JK, Bond N, Nevins H, Mantua N, Loeffel R, Peterson WT & Harvey JT
(2007) "Beached birds and physical forcing in the California Current System"
Mar Ecol Prog Ser 352: 275-288
[Notes]
http://dx.doi.org/10.3354/meps07077
Parrish et al (2007)
External Links
