Spring in the Northern Hemisphere invites birds to large river deltas & lakes. El Niño brings the warmer season sooner this year. Some of the large rivers in the Northern Hemisphere are important breeding/ feeding grounds for birds and other pollinators.
North America
Bald eagle main destinations are the Columbia River, Snake River, Sacramento River, Yellowstone River. In the Pacific Ocean, the Monterey Bay is the most important breeding and feeding ground for pelagic seabirds and marine communities. Although, this area is dry, Monterey Bay receives cold water from the canyon that brings rich nutrients in the water of the Pacific Ocean and river deltas in California. That’s why the upwelling in California Pacific Ocean is colder than that of Seattle Pacific Ocean.
Spring time in the North Pacific welcomes California Condors, and they are scheduled to clean rivers and streams, remove carcasses in order to keep marshes and meadows clean for pollinators. They are extremely Bio, pesticides free. They fly very high over the Sierra Nevada.
North American Owls, in the Olympic Peninsula are the guardians in the Snake River and removed debris that overwhelmed the marshes and meadows thus clean passage of sockeyes.

Yellow warblers have become very rare, and can be seen at Cape May marshes and meadows. Warblers travel in North Eastern states, and Canada. Winter season has been very harsh with extreme cold from La Niña.

Europe large river, Denube Delta is home to Dalmation Pelicans, their number are getting smaller every year from flood melting glazier, and pollution. This river goes/ interconnects across all European countries, and many birds find their way through Denube and other rivers across Europe.