野天鹅
今天下工地，刚下了高速驶入小镇，离家30分钟左右的路程，海湾湿地公园的水面上，一只白天鹅竟出现在我的眼前，梦境一般！手机咔嚓一下，做个纪录。
北美洲的野天鹅候迁。园庭的白天鹅 （Mute Swan），它们是当年欧洲移民从欧洲带过来的。白天鹅它们不候迁，守护家园。
见链接 https://www.allaboutbirds.org/guide/Mute_Swan/overview
抄一段：
Wild Swans, there are three main species of swan found in North America:
- Trumpeter swan – The largest swan species native to North America. They are all white with a black bill and can reach over 4 feet long with a wing span over 6 feet. They are named for their loud, brassy vocalizations. Trumpeter swans breed in Alaska and Canada and migrate south for the winter.
- Tundra swan – Slightly smaller than trumpeter swans but still a large, all-white swan with a black bill. They breed in the Arctic tundra and migrate south along the Pacific coast for winter. They are also known as whistling swans due to their musical calls.
- Mute swan – A Eurasian species introduced to North America. They can be distinguished from native swans by their orange bill with a black base. Mute swans are now considered an invasive species in parts of the U.S. due to their aggressive behavior towards native waterfowl.
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Tundra Swans in California
Every winter, tundra swans make an incredible journey from their Arctic breeding grounds to wintering sites along the Pacific coast. There are estimated to be over 100,000 tundra swans in the Western Flyway population that migrates down the west coast of North America.
In California, tundra swans typically start arriving in late October and stay until early April. They spend the winter months feeding in shallow wetlands and estuaries. Prime spots to see concentrations of wintering tundra swans in California include:
- Suisun Marsh – Part of San Francisco Bay, north of Sacramento
- San Pablo Bay – Part of San Francisco Bay, north of Oakland
- Humboldt Bay – Coastal bay in northern California
- Crescent City Marsh – Coastal wetland near Oregon border
- Lake Earl – Coastal lagoon in Del Norte County
- Sacramento Valley wildlife refuges – Networks of wetlands including Gray Lodge and Colusa National Wildlife Refuges