It's Spring and the Herons are Nesting
Today I’ve got a guest post from Nancy DeStefanis, executive director of San Francisco Nature Education, aka the Heron Lady of Golden Gate Park. She offers this update on the Great Blue Herons at their namesake lake:
Great Blue Herons have returned to breed at the newly renamed Blue Heron Lake! San Francisco Nature Education successfully campaigned to rename the lake after the beautiful herons who have nested there for 31 years!
Three of the nests are located on a giant pine tree on the island opposite the boathouse. Another pair have reoccupied last year’s nest on the island near the waterfall in the healthy tree.
Currently, two pair are incubating eggs. Females lay two to five eggs and then both male and female take turns incubating the eggs. Generally, eggs hatch 26-30 days later. Parents take turns staying at the nest and keeping them warm at night for the first four weeks. Each parent forages for the chicks and regurgitates large fish, gophers, and small birds—even ducklings! —into the nest. At four weeks, both parents must spend all their time feeding the chicks every two hours or so.
At six weeks, chicks become full size- four feet, three inches!!!! At about 8 weeks, chicks begin flapping. Learning to fly involves branch hopping and many test flights. Even after the chicks learn to fly, they return to the nest to be fed by their parents. At twelve weeks, all the chicks go their own way- they do not stay together as a family. Their parents split up as well.
Great Blue Herons can live up to 15 years in the wild. However, first-year herons have a 50 percent mortality rate. If they can survive for two years, they can reproduce for a long time!
Every Saturday from April 13 through May 20, SFNE conducts the free program, Heron Watch, at the lake. Volunteers with high powered spotting scopes show the public the chicks and explain their behavior. The program is open from 10am to 1pm; donations are welcome; map with our location is on the SFNE website. SFNE also conducts family and adult field trips each Sat. from 10am -noon. To enroll in field trips, please sign up and prepay in advance. Visit sfnature.org for registration and more information. Or download the PDF below:
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