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Notice to campers staying at Coast Campground:
The Coast Trail between the Hostel and Coast Campground is closed weekdays while salvage operators attempt to remove a wrecked boat from Santa Maria Beach. The potable water sources at Coast Campground have been shut off. More »
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2012 Harbor Seal Pupping Season Closures
From March 1 through June 30, an annual closure of Drakes Estero and certain beaches of Tomales Bay is implemented to protect harbor seals during the pupping season. Please avoid disturbing seals to ensure a successful pupping season. More »
Giacomini Wetland Restoration Project: Restoration: Giacomini Wetlands: A Haven for Ducks: Year Three
Figure 1. Total numbers of waterbirds (waterfowl, shorebirds, and other birds on survey dates in each survey month for the past three winter fall, winter, and spring seasons. Source: Avocet Research Associates. During Year Three, numbers of waterbirds--particularly waterfowl--continued its seemingly incredible upward climb. Number of birds observed during all ARA surveys practically doubled from 17,507 in Year Two to 34,077 in Year Three (ARA 2011). As with previous years, abundance peaked in December, with a new high of 11,488 recorded on December 9, 2010 (ibid). Species richness also continued to rise from 63 in Year Two to 78 in Year Three (ibid). Average number of birds per survey climbed modestly from 2,917.8 in 2009-2010 to 3,407.7 in 2010-2011, which again suggests that some of the increase is related to survey frequency, which again increased from six in Year Two to 10 in Year Three, with assistance from ACR's shorebird surveys (ibid). Similar to Year One, waterbird composition was again dominated by waterfowl, representing 93.8% of all individuals observed (ibid). American wigeon also again represented the dominant species, accounting for 29.5% of all waterbirds (ibid). Peak densities of this species also jumped dramatically in Year Three from 7.5 and 5.7 birds per hectare in 2008-2009 and 2009-2010, respectively, to 18.1 in 2010-2011 (ibid). Similar dramatic increases in peak densities were also observed for Northern pintail--from 4.2 in Year Two to 11.5 in Year Three (ibid). The December 17, 2010, survey, in fact, marked high points in terms of numbers for several species, including American wigeon (4,127); Green-winged teal (1,408); Northern pintail (2,613); and American coot (1,224; ibid). 
A flock of buffleheads in restored wetlands in winter 2009-2010. While peak pre-restoration densities are not readily available in the U.S. Geological Survey monitoring effort that was conducted prior to restoration to evaluate bird use of the unrestored dairy ranch, some conclusions about the effect of restoration can be made regarding mean densities of certain species (ARA 2011). Prior to restoration, dabblers such as American coot, American wigeon, and Northern pintail had the highest mean density per hectare of 6 per ha in the East Pasture (after American blackbirds; ARA 2011). Averaged for the entire Project Area, dabbler density dropped slightly to 4 birds/ha (ibid). In Year Three post-restoration, the same suite of six dabbling duck species--American wigeon, Gadwall, Green winged-teal, Northern pintail, Northern shoveler and Mallard--averaged 12.8 birds/hectare, an increase of 320% (ibid). The largest change occurred for Gadwall, which increased 21.4% relative to pre-restoration densities (ibid). Between Years Two and Three, abundances jumped for several dabbler species, including American wigeon, Green winged-teal, and Northern pintail, while those of others such as Gadwall and Northern shoveler and the one common diving duck, Bufflehead, remained relatively constant (ibid). Interestingly, the mean abundances of dabbling ducks at the newly restored wetlands in Years Two and Three greatly exceed any of the mean values reported by Kelly and Tappen in 1998 for all of Tomales Bay (ibid). Some of the new noteworthy additions to the restored wetlands during Year Three included Redhead, Eared grebe, Clark's grebe, Lesser yellowlegs, and Heerman's gull (ibid). Two species also "flew over" the site, but did not drop in--Surf scoter and Wandering tattler (ibid). A rare Yellow rail was also apparently detected in the newly restored West Pasture near Inverness Park during the Christmas bird count (K. Hansen, T. Easterla in ARA 2011). This species has been observed in the Undiked Marsh north of Giacomini in previous years, but never within the former dairy site (ibid). 
Figure 2. Numbers of shorebirds documented in southern Tomales Bay by Audubon Canyon Ranch. The shorebird situation continues to puzzle. After a lackluster start in 2008-2009, waders appeared in 2009-2010 to have "found" the newly restored wetlands, with numbers increasing dramatically in Year Two. Numbers remained high even through fall and early winter of Year Three (Kelly and Condeso 2011; Figure 2 [482 KB PDF]), but in mid- and late- winter and spring, wader abundance plummeted relative to the previous year (ARA 2011, Kelly and Condeso 2011). For all ARA surveys combined in Year Three, waders represented only 5.7% of the waterbird community, compared to an average of 27.1% during Year Two (ARA 2011). Waders averaged 327.3 individuals/survey in Year Three, compared to 780.7 individuals/survey in Year Two (ARA 2011). On at least one count date in Year Three (11/12/10), shorebirds did account for 20.5% of all waterbirds observed (ARA 2011). This peak number illustrates one of the confounding variables of any biological or environmental monitoring efforts: surveys or sampling may not always catch peak abundance or concentrations. Most of ARA's survey effort was concentrated in mid- to late winter and spring, so, therefore, averages were skewed by the scarcity of waders during that period. However, this phenomenon was not relegated strictly to Giacomini. Reduced abundances of shorebirds occurred throughout Tomales Bay in late winter and spring of 2010-2011 (Kelly and Condeso 2011). Some of this may be due again to increased precipitation during those periods, as discussed earlier: The decline in numbers corresponds closely to the onset of rainy season (Figure 3 [118 KB PDF]). 
Figure 3. Waterfowl and wader numbers in Year 3, with strong declines in January 2011. Source: ARA. Despite reduced shorebird numbers overall, some species continue to persist at the newly restored wetlands, including Greater yellowlegs, which had a peak abundance in Year Three of 82 individuals, roughly equivalent to Year Two (79 individuals; ARA 2011), although ACR surveys suggested a stronger decrease relative to Year Two (Kelly and Condeso 2011). Greater yellowlegs have always visited southern Tomales Bay in high numbers, leading some birders to consider it "magic" for this long-legged species (Kelly and Condeso 2011). Western sandpiper occurred in incredibly high numbers during Fall 2010 (mean of >800): juvenile fall migrant often determine wintering areas for future years (Kelly and Condeso 2011). Least sandpipers also returned in early winter of Year Three in roughly equivalent numbers to the prior year (Kelly and Condeso 2011). Wilson's snipe was one of the few species that remained relatively common in Year Three during both early winter and late winter surveys (Kelly and Condeso 2011). This species has always been attracted to the seasonally inundated or saturated grassy margins of the Project Area (Kelly and Condeso 2011). Conversely, numbers of species such as Dunlin (the most common shorebird in Tomales Bay), Black-bellied plovers, Dunlin, and Dowitchers fell dramatically during Year Three.
Giacomini Wetlands: A Haven for Ducks restoration includes: |
Did You Know?
So many California red-legged frogs were caught for consumption in the late 1800's that their numbers declined throughout California. So bullfrogs were imported from the east to help meet the demand. But bullfrogs are voracious predators and helped drive the red-legged frog population lower yet. More...