Providing wintering habitat for canvasbacks was one of the reasons why San Pablo Bay National Wildlife Refuge was established. Historically, more than 50% of canvasbacks surveyed in the estuary were located in the North Bay.
The canvasback is one of the largest and fastest flying ducks in North America. In flight, the male exhibits the most white of any duck and is very distinct with its “canvas” colored back, chestnut-red head, elongated black bill, and blood-red eyes. The female has the same elongated bill, but its head is buffy with brown eyes, and its body is brown. For the past 25 years, the continental population of canvasbacks has fluctuated around 580,000 individuals, with 25% of that population in the Pacific Flyway. San Francisco Bay estuary has historically supported the largest wintering numbers in the flyway.
This excerpt is taken from “Tracking Canvasbacks Across Seasons” written by Kammie Kruse and John Takekawa in 1998.
Source: USFWS Website
Canvasbacks observed in San Pablo Bay by the Spanish explorer Jose Canizares in 1775
https://baynature.org/article/canvasback/
Canvasback connects ‘sister refuges’ in AK, CA
https://wildlife.org/canvasback-connects-sister-refuges-in-ak-ca/
Additional Canvasback research by Kammie Kruse
https://www.researchgate.net/scientific-contributions/Kammie-L-Kruse-2001949455
