2008 Annual Monitoring Report (pdf 10.9MB) - Bolsa Chica ...

Bolsa Chica Lowlands Restoration Monitoring
2008 Annual Report
(3.3%), American wigeon (Anas americana) (2.6%), ruddy duck (Oxyura jamaicensis) (2.3%),
Belding’s Savannah sparrow (2.1 %), and marbled godwit (Limosa fedoa) (2.1%).
The most abundant bird guild was shorebirds in all survey periods except June (3,567 individuals in
February, 5,028 individuals in April, 7,059 individuals in August, 6,773 individuals in October, and
4,407 individuals in December) (Figure 1-17). Shorebirds made up an average of 53.8% of all birds
observed, with a high of 77% in October 2008. During June the number of shorebirds dropped to 656
individuals and represented only 17.2% of the birds present.
Number of birds
8,000
7,000
6,000
5,000
4,000
3,000
Jan 2008
Apr 2008
Jun 2008
Aug 2008
Oct 2008
Dec 2008
Mean- all 2008 surveys
2,000
1,000
0
Aerial Fish
Foragers
Coots and
Rails
Dabbling
Ducks/
Geese
Diving Ducks/
Grebes/
Cormorants
Gulls Herons Raptors Shorebirds Upland
Birds
Figure 1-17. Avian abundance by guild at Bolsa Chica during 2008 surveys
The most numerous shorebird species in 2008 was the western sandpiper with its highest numbers
during August (4,867 individuals and 51.8% of all species), October (3,735 individuals, 42.4%) and
April (2,723 individuals, 27.8%). There were low counts in December (1,342 individuals), February
(630 individuals), and almost no western sandpipers in June (8 individuals). Other abundant
shorebirds included black-bellied plover, dowitcher, marbled godwit, semipalmated plover
(Charadrius semipalmatus), black-necked stilt (Himantopus himantopus), killdeer (Charadrius
vociferous), and willet (Tringa semipalmata) in that order. In June, when most of the shorebirds were
absent, the black-necked stilt was the most common shorebird. This is one of several shorebirds that
nest at Bolsa Chica. The snowy plover is the only listed shorebird observed at Bolsa Chica and our
count of 49 individuals in April was almost identical to the 50 adults observed on a focused count for
this species in May.
The second most abundant guild was dabbling ducks/geese which had high counts in December (2,721
individuals), February (2,125 individuals), and April (1,151 individuals) and remained present year
round in smaller numbers. The most abundant of the dabbling ducks were northern shoveler,
American wigeon, and northern pintail (Anas acuta). American wigeon and northern pintail were
absent during the June and August surveys and present in only very small numbers during the February
Merkel & Associates, Inc. 80