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The Great Migration: Fall 2018

Updated: Oct 21, 2019

As the Earth’s axis tilts away from the sun it causes our seasons to change. Autumn brings colder temperatures, crisp breezes, and hopefully first rains. Fish, insects, birds, and mammals instinctually know its time to migrate. This doesn’t just happen in California, they make an invisible criss cross pattern of lines around our planet. Fall is here, and the Great Migration is taking place. Something that has happened on our beautiful living planet for millions of years. We put together some local creature migration facts and viewing information so you can get out and get you some Nature!

Monterey Bay's Humpback Whales

Megaptera novaeangliae is a marine mammal that can grow to 62 feet, and weigh 53 tons.

Humpback Whales migrate annually thousands of miles from their winter calving and mating areas off the coast of Mexico to their summer and fall feeding areas off the coast of California and Oregon.

Migration Patterns

Humpback Whales occur in Monterey Bay from late April to December. During this period the whales are here to feed on anchovies, sardines, and krill. Humpbacks work as a team when hunting for schooling fish. In Monterey Bay they lunge feed and off the Coast of British Columbia and Alaska they can be seen bubble-net feeding. Once underwater, several humpbacks encircle the fish with a "bubble net"—making the fish believe they are trapped in a net of bubbles.

Humpbacks have the most beautiful, complex call of all whale species - it can carry for miles.

San Jose's Chinook Salmon

The King salmon begin their migration from the Pacific Ocean and into the Sacramento and San Joaquin Rivers and their tributaries annually during the fall

Here in San Jose Chinook salmon, the behemoths of our local freshwater rivers and creeks, begin their migration from the Pacific Ocean underneath the Golden Gate Bridge, through Alviso and into the Guadalupe River annually beginning in August and finishing around the end of November.

Chinook salmon hen on redd bed Guadalupe River credit: Tejeda

The actual number is unknown, although Valley Water has the ability to capture photos as salmonidae migrate up and down stream. The largest species in the Pacific salmon genus Oncorhynchus adult fish range in size from 24 to 36 inches but may be up to 58 inches; they average 10 to 50 pounds but may reach 130 pounds in Alaska.

You can view Chinook on the Guadalupe River in downtown San Jose around this time by looking off bridges. You can walk the Guadalupe River Trail or Los Gatos Creek Trail while looking for wakes in the water caused as the female builds the redd bed (nest).

Sacramento River winter-run Chinook are listed as endangered under the Endangered Species Act by the National Oceanic and Atmospheric Administration, the California Coast population is listed as threatened.

Guadalupe River credit: Tejeda

Get involved, make a difference! Click here to register for our next National River Cleanup Day and Coastal Cleanup Day event.

Santa Cruz's Monarch Butterfly

These “king” of butterfly beauties arrive in September and fill the surrounding trees like ornaments on a Christmas tree.

We’re west of the Rockies so our population migrates to the Coast of California and southwest to Mexico. Their migration is the greatest natural phenomena in the insect world! Just like salmon they make their way hundreds or thousands of miles using only natural instinct.

Only monarchs born in late summer or early fall make the migration, and they make only one round trip. By the time next year's winter migration begins, several summer generations will have lived and died, and it will be last year's migrators' great grandchildren that make the trip. Yet somehow these new generations know the way and follow the same routes their ancestors took—sometimes even returning to the same tree.

You can view them at Natural Bridges Monarch Butterfly Natural Preserve

Natural Bridges

Overall monarchs have declined by more than 80 percent over the past two decades.

In 2014, United States Fish & Wildlife Service petitioned to protect the monarch butterfly under the Endangered Species Act.

The Central Valley's Sand Hill Cranes

There have been fossils found of these pterodactyls of the sky dating back 2.5 million years. They even have a prehistoric sounding call as they circle from high above scanning the area for predators before landing in an agricultural field. During migration the family units group together with other families and nonbreeders, forming loose roosting and feeding flocks. They are one of North America's largest Crane with a wing span of 7 feet and standing 4-feet tall.

The Sandhill Crane is well known for its courtship dance! Facing each other, members of a pair leap into the air with wings extended and feet thrown forward. Then they bow to each other and repeat the performance, uttering loud croaking calls. Courting birds also run about with their wings outstretched and toss tufts of grass in the air.

Their range in the Pacific Flyway is from Siberia and Alaska to California's Central Valley.

You can view them by doing the Sandhill Crane Wetland Tour at the Woodbridge Ecological Reserve

The Central Valley population of Greater Sandhill Cranes remains low, with recovery of the population hindered by the lack of habitat restoration and farmland management that could greatly benefit this population. The good news is that their population is up from 150 - 200 pairs in California and Oregon to an estimated 465 breeding pairs in California in 2000.

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