February 2010 home page


Birds Come for Christmas
Ed Mirsky | Hoska Drive | with Robert Patton, Coordinator for the Rancho Santa Fe area Audubon Christmas Bird Count


Buffelhead Ducks.  Photo Paul Haydu.

On 3 January 2010 the National Audubon Society conducted a Christmas Bird Count (CBC) in the Rancho Santa Fe area. The San Dieguito Lagoon is within the 15 mile radius of the survey.

The San Dieguito Lagoon survey was divided into two areas: The West survey area consisted of the lagoon between Highway 101 and interstate I-5 plus Crest Canyon. The East survey area consisted of the wetlands and adjacent upland habitats from I-5 to El Camino Real. Within the lagoon survey areas, species diversity increased from 46 in 2007, to 85 in 2008, to 102 in 2009. Similarly, the number of individual birds counted increased from 541 to in 2007, to 2506 in 2008, to 2613 in 2009 (this year’s CBC). These increases also correspond with significant increases in the numbers of participants (doubled each year) and with the area covered (in 2007, there was no access/coverage between I-5 and El Camino Real).

Mr. Patton is hesitant to make any broad generalizations from the data of such a brief “window” counts. He notes that generally speaking, in coastal southern California, converting an upland scrub habitat to a wetland habitat will increase species diversity, simply because there are more winter species of shorebirds and waterfowl than there are species using upland scrub and grassland habitat. Thus, statistically, many more samples are required to make any valid conclusions.

The numbers for all survey areas in the Rancho Santa Fe CBC were also encouraging. Robert Patton reports that 92 participants identified 191 species of birds within the survey area. The second highest number of species identified on the Rancho Santa Fe CBC in the last 28 years. The average number of species for this count over 28 years is 172 species, with a range of 145-193. Outstanding! But what does this mean for the newly revitalized San Dieguito Lagoon?

The CBC is only one measure of the importance of the lagoon and the success of the restoration project. All of the species of water fowl and shorebirds we have had in the past are still present, and the sandpipers and their relatives are increasing in number. Our lagoon remains a major food source for bids migrating along the Western Flyway, and it is a vital resource as a productive “fish hatchery.”



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