2008 Annual Monitoring Report (pdf 10.9MB) - Bolsa Chica ...
2008 Annual Monitoring Report (pdf 10.9MB) - Bolsa Chica ...
2008 Annual Monitoring Report (pdf 10.9MB) - Bolsa Chica ...
You also want an ePaper? Increase the reach of your titles
YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.
<strong>Bolsa</strong> <strong>Chica</strong> Lowlands Restoration <strong>Monitoring</strong><br />
<strong>2008</strong> <strong>Annual</strong> <strong>Report</strong><br />
about half as many territories as in 2007. Zone 36 at the eastern end of the site is normally wet all<br />
year; but in <strong>2008</strong>, this zone dried out and was apparently not as suitable for the sparrow. It supported<br />
19 territories in 2007 and only 2 in <strong>2008</strong>. All other zones in the FFTB decreased by small numbers<br />
between 2007 and <strong>2008</strong>.<br />
The counts in the MTB were the most variable, ranging from counts of 45 territories in April to 72<br />
territories in May, while having had a count of 117 territories in 2007. The west MTB (Figure 0-1)<br />
was opened to tidal influence from the FTB on March 5, <strong>2008</strong>, which inundated much of the<br />
pickleweed growing at low elevations (in Zones 50, 66, and 49). In conjunction with rainfall, tidal<br />
waters flowing from the west to the central basin resulted in inundation of some low pickleweed in the<br />
central MTB as well (Zones 48 and some of 46). Belding’s Savannah sparrow were regularly<br />
observed defending territories that were inundated.<br />
Zones 41, 45, and 46 decreased from the 2007 counts by a minimum of 17 (63%), 14 (56%), and 9<br />
(45%) territories respectively. These zones are normally dry and covered in pickleweed and remained<br />
unchanged between the 2007 and <strong>2008</strong> breeding season.<br />
Using the area of undisturbed salt marsh available and the maximum number of territories recorded per<br />
cell over both surveys within Zones 2-29, the average territory size was estimated to be 1,836m 2 ,<br />
ranging from 693 m 2 in Cell 26 to 3,714m 2 in Cell 9. This is a very course calculation and does not<br />
take into account the observed patchy distribution of the birds in the marsh or the considerable areas of<br />
what appeared to be suitable habitat that remained unoccupied.<br />
Table 1-21. Belding’s Savannah sparrow territories at <strong>Bolsa</strong> <strong>Chica</strong> in 2007 and <strong>2008</strong><br />
Zone<br />
# of Territories # of Territories # of Territories Salt Marsh<br />
April 2007 April <strong>2008</strong> May <strong>2008</strong> Available (ha)<br />
Full Tidal Basin n/a 5 10 5.0<br />
Future Full Tidal Basin 143 72 76 25.3<br />
Muted Tidal Basins 118 45 72 44.5<br />
Seasonal Ponds 90 53 47 11.6<br />
Pocket Marsh n/a 2 3 4.6<br />
Total 351 177 208 91.0<br />
n/a = not counted during 2007<br />
Discussion<br />
The count of Belding’s Savannah sparrow territories in <strong>2008</strong> was considerably lower than in 2007, but<br />
comparable to the counts (201 territories) in the 2006 annual survey conducted by CDFG (Zembal et<br />
al., 2006) within a similar area of <strong>Bolsa</strong> <strong>Chica</strong>. The 2007 increase may have resulted from a<br />
movement of birds out of the newly created FTB. Prior to inundation the area of the new FTB<br />
supported pickleweed-dominated salt marsh where Belding’s Savannah sparrow regularly nested and<br />
foraged. When the FTB was excavated and later opened to the ocean in August 2006, much of the<br />
pickleweed in that area was lost, which may have forced the sparrows to move the following year<br />
(2007) to more suitable habitat in the salt marsh and salt panne areas of the FFTB, MTBs, and in<br />
particular the Seasonal Ponds.<br />
Merkel & Associates, Inc. 90