Bird News from the Reserve Manager
By Kelly O'Reilly
May 9 – We have been seeing something unusual here at Bolsa Chica with regard to the Elegant Terns. These Terns have been flocking by the thousands on the Bolsa Basin mudflats since March but they have ignored North Tern Island where they typically nest. Although a few Caspian terns are around, they have not gone to North Tern Island either.
Peter Knapp reported seeing 500 Elegant Terns swarming over the Forster’s Terns nesting within Inner Bolsa Bay marsh. That same day, using the Bolsa Chica Land Trust’s Eco Cam from our office, we see even more gathering over the marsh with roughly 1,000 down on the marsh. It appears to us that the Elegant Terns may nest on the pickleweed in the marsh among the Forster’s Terns rather than use North Tern Island which is empty but for a couple of Canada Goose nests. This will be interesting to watch through the season.
In other news, we began California Least Tern monitoring this week and have found twelve nests thus far (Nest Site 1-north=2; South Tern Island=2; Nest Site 2=8). Canada Goose are increasing in numbers and are nesting on both tern islands in Bolsa Bay and nest site 1. I counted 16 Canada Goose on nest site 1 with at least two nests (likely more) and 4 Canada Goose on South Tern Island.
Black-necked Stilts and American Avocets are nesting throughout the Bolsa Chica, and we observed the first Avocet chicks the week of May 9.
May 24 – There appears to have been a decrease in the number of Elegant Tern nests and we suspect this may be due to tidal flooding. Given where the terns chose to lay their eggs, we anticipated that some of them would get flooded out during the recent high tides (during the full moon phase).
As for other nesting birds, here are the season totals to date for Least Terns and Snowy Plovers: California Least Tern: 72 nests (and more expected); 40 of those nests (56%) are on Nest Site 2 located within the Muted Tidal Basin. Western Snowy Plover: 49 nests and numerous broods. On May 20, CDFW staff counted 94 adult Plovers (53 males and 41 females).
An osprey pair has nested on top of the northernmost electrical pole on the oil operator’s Whipstock area. That is located just south of the southern end of the reserve. They have three pre-fledglings and we are very hopeful that all three of the young osprey will fledge. If they do, this will be the first successful osprey nesting event. I’m not aware of osprey successfully nesting at Bolsa Chica in the past.