Posts Tagged ‘nest’

Exotic Brown-Headed Cowbirds Kill Native San Francisco Birds

Wednesday, July 16th, 2008

The bird on the left in this photo from Golden Gate Park is an adult that has adopted the baby Brown-Headed Cowbird on the right. The baby cowbird’s real mother is a brood parasite, so she doesn’t know how to build a nest of her own. She just lays eggs in existing nests and lets other parents do all the work. When the interloping egg hatches, the newborn cowbird succesfully competes against its nestmates.

The tricked parent bird doesn’t know the difference and works twice as hard to feed the baby cowbird. In this scene, the young cowbird receiving food is already bigger than its adoptive parent. 

Click to enlarge:

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These cowbirds were native to the Midwest, but some of them traveled to the bay area about 85 years ago. Cowbirds remain a threat to native species in the bay area and beyond.

Baby Heron vs Adult Gopher in the Trees Above Golden Gate Park

Friday, May 23rd, 2008

This didn’t end well for the gopher.

The parent bird, the tallest one, just hunted and killed a pocket gopher to bring back to the nest high above Stow Lake in Golden Gate Park. The middle chick (fledgling now?) scooped up the undigested rodent to the chagrin of its siblings.

You can see the outline of the gopher slowly sliding down the neck of the aptly named Great Blue Heron.

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Canon 600mm 4.0 IS with Canon 2x II extender.

The Great Blue Heron Watch is Once Again On in Golden Gate Park

Wednesday, April 16th, 2008

It’s that time of year again when giant herons return to their home island on Stow Lake in Golden Gate Park.

This particular domestic partnership is shown high atop a Monterey Cypress changing shifts as they take turns guarding their nest and hunting for seafood and pocket gophers. Mmmm, pocket gophers.

Come and watch them on Saturdays per this schedule from San Francisco Nature Education when people like naturalist Nancy DeStefanis can hep you to what’s going on and offer you a free close-up view of the avian activities.

See you there!

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