Field Journal Entry 5
Date & Location
October 4, 2023
Rodeo Lagoon | 37°49’49.8″N 122°31’58.6″W | 137 ft
Site Description
Rodeo Lagoon is a long, narrow coastal lagoon in the Marin Headlands of southern Marin County. It is in a complex area, and its shape is affected by sea level rise, tectonic activity, and erosion. It is a coastal wetland with open water, mudflats, and salt marsh. It is relatively shallow and surrounded by hillsides covered in coastal chaparral and grassland. The lagoon provides habitat for many bird species, including waterbirds, seabirds, and shorebirds. Some key bird species include cormorants, great egrets, great blue herons, and brown pelicans.
Species Account
Red-necked Phalarope | Phalaropus lobatus
The Red-necked Phalarope is a small migratory bird that breeds in the Arctic and winters in temperate and subtropical oceans in the Northern Hemisphere. They are about 20 cm long with a wingspan of about 40 cm. They have a distinctive black and white plumage, with both males and females having a white belly and undertail and black back and wings. Males have a red neck and breast during the breeding season, while females and non-breeding males are gray.
We saw this bird in the lagoon from a distance, and it was difficult to tell whether it was male or female. Red-necked phalaropes are pelagic birds, meaning that they spend most of their lives at sea. They are skilled swimmers and divers and eat small crustaceans, insects, and other invertebrates. Red-necked phalaropes have a promiscuous mating system, meaning that males and females mate with multiple partners. The female is responsible for all aspects of parental care, including nest building, incubation, and chick rearing.
Narrative
At around 8:10 am, we started walking to the cars but one of the cars had trouble starting the engine so Dr. Paul went to go get keys for another car. Then, we started driving at 8:20 am and got to Rodeo Lagoon around 8:50 am and birded for about 3 hours. At first, we started walking behind a building to try to see some birds, however a lot of them were flying around very quickly so it was difficult to identify them by eye but luckily, we had Merlin to help us out. After wandering around the area for a bit, we started walking around the lagoon, to the beach and back to where we first started. While walking back, we saw three cute river otters swimming in the lagoon!
Sources
¹ Red-necked phalarope – ebird. https://ebird.org/species/renpha
² Red-necked phalarope overview, all about birds, Cornell Lab of Ornithology. Overview, All About Birds, Cornell Lab of Ornithology. https://www.allaboutbirds.org/guide/Red-necked_Phalarope/overview
³ Rodeo Lagoon/Valley. Golden Gate National Parks Conservancy. (2019, May 15). https://www.parksconservancy.org/parks/rodeo-lagoon-valley
