Chapters 1 - U.S. Fish and Wildlife Service

Refuge Resources
between 1969 and 1972; another fill site in Huntington Harbour was also used between 1970 and
1972 (Collins 2007). Terns began nesting on NASA Island in 1979 and by 1998, approximately 165
breeding pairs were observed using the site.
The recovery strategies included in the California Least Tern Recovery Plan that are specific to
the NASA Island nesting site in Anaheim Bay include:
Preserve and manage existing nesting colonies, such as the one at NASA Island;
Develop and implement management plans to construct and manage new nesting sites
in protected areas including Anaheim Bay;
Protect and manage adequate feeding habitat for nesting colonies;
Monitor the least tern population to determine status, distribution, and progress of
management during the breeding season;
Conduct research to obtain necessary information for tern management (e.g., effects of
environmental pollutants, factors affecting choice of roosting, loafing, and feeding
areas used during breeding and post-breeding seasons, causes of colony disruption and
site abandonment, methods for enhancing nesting sites in existing colonies); and
Develop and implement a conservation education program.
The NASA Island nesting site has been monitored annually since 1998. Monitoring results for this
nesting site are provided in Table 4-8.
Table 4-8
California Least Tern Nesting Results for Seal Beach NWR
Year Estimated Number of Nests Estimated Estimated
Number of
Number of Fledgling per Pair
Breeding Pairs
Fledglings
Ratio
1987 1 69 n/a 97 – 109 1.4 – 1.6
1988 1
82 n/a 65 0.79
1989 1 97 97 109 1.1
1993 2
198 201 * *
1998 3
165 165 94 – 104 0.57 – 0.63
2000 4 107 107 180 1.68
2003 5 30 30 0 0
2004 5 206 206 73 0.38
2005 5 130 145 87 0.66
2006 5 170 186 78 0.47
2007 6
165 166 12 0.04
2008 7
166 - 200 206 44 .22 – .27
2009 8
168-177 177 80 0.45 - 0.48
2010 9 260 265 32 0.12
* Data for these two categories were considered substantially over estimated based on the
methodology used to determine total fledglings and therefore is not included on the table.
Source: 1 (USFWS 1990), 2 (Caffrey 1994), 3 (Keane 1999), 4 (Patton 2002), 5 (Collins 2007), 6 (Marschalek 2008),
7 (Marschalek 2009), 8 (Marschalek 2010), 9 (per comm. Marschalek 11/17/10)
The number of breeding pairs and the number of fledglings at NASA Island fluctuate in some
years as a result of various factors including food supply and predation. In 2003, the area
Draft Comprehensive Conservation Plan/Environmental Assessment 4-61