Bird migration and nesting patterns

We almost always assume everything will be the same. That is not true for humans or birds.

Climate change in California is affecting birds more so than people. Thirty percent of California forests have burned in the last decade. This does not include the loss of plants due to erosion, which provided food and shelter. During migration, most birds live off the land. They consume fruit and water. Plants lost to fire may take years to repopulate and provide this food.

This year there seems to be a reduction in swallows numbers. Part of this may be due to the spring’s cold weather. Insects won’t show until the weather warms. Cold prevents insects from hatching, except for mosquitoes.

No robins nested in March as in prior years. Neotropical species like black headed grosbeak may be late. Swainson’s thrush migrates at night but sleeps at night. Some birds feed on the go, like swallows. They move only a limited distance each day.

Others, like swallows, must have constant sources of insects, requiring hundreds of calories just to fly. When arriving at their nesting grounds, they must have good body reserves to lay eggs and care for their young. After arriving, the weather must be conducive to supply food for both the adults and their nestlings.

The nesting season varies with each swallow species. Barn swallows are the winner, sometimes laying four clutches in a nesting season. The newly fledged young may help feed newly hatched chicks. I have seen young birds with parents going south on Thanksgiving Day. Tree swallows may abandon their nest the minute cold weather sets in and return to renest when food is available. They rarely nest more than twice. Violet-green swallows usually nest only once. Bank swallows only nest on cliffs. Rough-winged swallows only nest once.

This summer keep an eye out for flocks of white pelicans. They nest on islands in saltwater areas and feed as a group on large schools of smelt and herring. Mostly they surround schools, chasing the fish into tight groups. They open their bills together in a collective attempt to scoop up these fish. They then fly off to their nesting areas.

I had heard last year nests were discovered on an island in Padilla Bay. I also heard that the nests were wantonly destroyed. Someone doesn’t like pelicans.

The local snow goose population’s summer nesting is on Wrangel Island off Russia’s northeastern coast. It is now a haul-out spot for outbound polar bears. Last year over 1,000 bears were stranded here and spent the summer and fall without food. Some surely starved to death.