San Juan Channel Seabird Abundance Patterns of Fall
Abstract
Seabirds are an important component of many marine ecosystems, but are in decline in
many parts of the world. While some studies have shown that Salish Sea seabirds are
declining, PEF has found no evidence of this decline. I attempted to characterize the
seabird community of fall 2013, as well as try to establish whether or not tidal influences
have been biasing our data collection. I used strip transect survey methods to analyze
the seabird community of 2013 and compare it to previous years, and looked at three
tidal metrics (tidal current speed, tidal current direction, and maximum tidal exchange) to
determine whether or not PEF has a sampling bias in regards to tides. The abundance
of seabirds in 2013 was relatively low, but not anomalously so, and the community
composition for this year is consistent with that of past years. Furthermore, analyses of
the tidal metrics yielded no evidence of sampling bias. Therefore, it is likely that the
interannual patterns observed by PEF in the past are real and are possibly due to global
climate patterns.