By Ilana DeBare
What a difference three years makes!
In spring 2014, Oakland post office officials thoughtlessly decided to cut foliage in the Bay Area’s largest heron rookery at the height of nesting season — destroying nests and leaving young birds injured and homeless.
This week, the City of Oakland had to remove a hazardous tree in that same rookery. But city staff partnered with Golden Gate Bird Alliance and International Bird Rescue in a humane, well-planned initiative to ensure that birds, eggs, and nests were protected.
THANK YOU to Oakland city staff — especially the folks in Animal Control; the Creeks, Watershed & Stormwater division; Tree Services; Traffic Control and Maintenance; and Drainage Maintenance!
Young night-heron in tree slated for removal / Photo by Ilana DeBare
Here’s the full story:
Over the past decade or so, the leafy ficus trees lining the streets near Alice and 13th Streets became home to the Bay Area’s largest nesting colony of Black-crowned Night-Herons and Snowy Egrets. Over 150 pairs of birds nest and raise young in the thick canopy, foraging for fish and other prey at nearby Lake Merritt and the Oakland Estuary.
The colony received little public attention until the disastrous tree trimming incident in 2014, which made national headlines.
In the wake of the trimming debacle, Golden Gate Bird Alliance launched a multi-year campaign to protect and educate the public about these dramatic-looking birds.
The problem went deeper than thoughtless tree trimming. The street trees are a dangerous nesting site: Young, not-yet-fledged birds that fall from the branches face broken bones on the hard concrete and deadly automobile traffic.
In 2015, we mounted an educational campaign with volunteer docents leading tours of the rookery, multi-lingual posters in nearby storefronts, a bilingual brochure on bird-friendly tree care, and a chalk art “flash mob” creating sidewalk art about the herons.
In 2016, we created a three-way rescue partnership with Oakland Zoo and International Bird Rescue. GGBA volunteers monitored the area for fallen birds; Oakland Zoo technicians provided speedy rescue and triage; then IBR provided long-term rehab and release into more suitable wild habitat along the Bay.
This year we continued that partnership. And two weeks ago, when one of the large rookery trees suddenly split in half and fell, GGBA, Oakland Zoo, and IBR all joined Oakland city staff in an emergency effort to rescue young birds from the fallen jungle of branches and leaves.…

By Eric Schroeder
As a horse owner dependent upon a trailer to get into our local parks in the spring, I am vigilant about the trailer’s readiness. My trailer lives at Hossmoor, a 138-acre horse property where I’ve seen over fifty species of birds. It’s also just an eight-minute drive from Briones Regional Park—an excellent place to ride and to bird year-round.
But this spring my horse had been injured and I let down my guard. Walking by the trailer in April,, I noticed that what we trailer owners fear most had happened—a Brewer’s Blackbird was sitting on a nest she had built on the spare battery compartment under the gooseneck of my trailer.
I thought to myself that if she hadn’t yet laid any eggs, I could remove the nest—maybe put it on somebody else’s trailer that wasn’t in use. I approached, the bird flew the nest, and I poked my head in. Four eggs.
Why my trailer? There were 25 other trailers that bird could have chosen! I realized immediately I wouldn’t be using the trailer for a while, even when my horse was sound again. But just how long would that be? On the west coast where Brewer’s Blackbirds are non-migratory, they start pairing up as early as the third week in January and all birds are paired by the second week in February. (I realize now that I should have been checking my trailer earlier—and regularly!—since females built the nests over a nine-day period.)
The nest on the trailer. Photo by Eric Schroeder
Generally, eastern populations of Brewer’s Blackbirds tend to nest on the ground, while western populations built nests in a wide variety of locations—in bushes, in vegetation over water, in vegetable crops, and on available trailer perches. Nests built above ground tend to be built from twigs and weed stems with the rougher outer construction giving way to finer materials around the bowl. Bowls are often lined with horsehair—lots of that where my blackbirds live!
Blackbird nest lining, including horse hair. Photo by Eric Schroeder
Brewer’s Blackbirds are synchronous nesters, meaning that nest building for an entire colony starts at the same time. (If I had been paying closer attention to the blackbirds as a whole population, this wouldn’t have happened!) I discovered the eggs in early April but I didn’t have any idea how long they had been there (or when I might use my trailer again).…

By Maureen Lahiff

On a Golden Gate Bird Alliance trip in late March, an early adventure as part of Birdathon 2017, we had a long, full day of birding on Saturday and a wonderful morning on Sunday. We visited a number of areas around Susanville (Lassen County), and then caravanned to Honey Lake, Jack’s Valley, and Eagle Lake. We saw almost 90 species, including wintering geese, ducks, and other water birds; six hawks and both Golden and Bald Eagles; and sagebrush obligates. But we were there for one primary reason — the privilege of witnessing Greater Sage-Grouse (Centrocercus urophasianus) on a lek.

Greater Sage-Grouse mate on leks

Male Greater Sage-Grouse gather on open areas called leks to strut, dance, and sound off. They raise and fan their spiky tails, show off magnificent white ruffs, inflate bright yellow throat sacs, and make a sequence of distinct sounds, ending with a popping sound as they rapidly deflate their throat sacs, which can hold up to a liter of air. Males competitively display at dawn for up to three or four hours. They typically defend small patches of territory on the lek, just a few yards in diameter, very close to each other. Threat displays between males with lowered heads are common, but among Greater Sage-Grouse, charges and wing-battering seldom lead to injury.

Females choose which male to mate with based on male displays. Researchers have not completely sorted out the science of lekking behavior: Do the females come because the males have gathered and it’s an efficient way to compare them and select mates, or do the females gather and the males follow? What traits are the females looking for? Endurance? Other characteristics that define “fitness?” The male’s only contribution is genetic; the females incubate and raise the precocial chicks.

View of the distant lek by Chris Wills. It took three days in a blind to get this picture of a male Greater Sage Grouse. / Photo by Bob Lewis, not from the recent GGBA trip. Male Greater Sage-Grouse performs his courtship display for a female / Photo by Jeanne Stafford (USFWS), not on the GGBA trip

There are also a lot of evolutionary puzzles, as most of the females mate with a few dominant males.

However it works, birds are faithful to lekking sites generation after generation.

An Aldo Leopold morning

I would describe my lek experience early Saturday as an “Aldo Leopold morning.”…

By Miya Lucas

In the spring and summer, the song of the California Thrasher always puts a smile on my face.  The rapid pulsing, throbbing beat within a continuous melody reminds me of a rhythmic rap song. Often lasting three to five minutes, it’s one of the more varied and complex bird songs and lacks a characteristic, repeated phrase that is easily identified with that bird.

The Cal Thrasher belongs to the Mimidae song bird family. “Mimid” means mimic in Latin, and other Mimidae include our familiar Northern Mockingbird and the Gray Catbird of the East Coast. Although the Cal Thrasher mimics a wide range of species including American Robin, House Finch, and Northern Flicker, mostly it’s known for its own complex song.  One study found 2,807 phrases in a single Cal Thrasher song! Some phrases are repeated like the chorus in your favorite pop song, while others are used only once.

Although you can hear California Thrashers year round, spring and summer are when they’re most vocal.  Even when they sing, it can be hard to spot them. They tend to perch on the middle or side branches of shrubs and trees rather than the top, and their brown heads, wings, and tails camouflage well in the undergrowth.

California Thrasher singing by Miya Lucas

Both female and male thrashers sing. Their songs are usually used for announcing and protecting territory, and mostly sung by the males.  However, if a male bird is clashing with another male who is encroaching into his territory, the female will “stand guard” and start singing until the male returns.  Once the male returns, the female often stands down and stop singing.

Cal Thrashers mate for life, and both male and female help raise the young.  If they have a second clutch, the female typically leaves the first brood while the male stays and continues to feed the chicks.

Males and females look similar. Juveniles have more yellow bordering their underwings than the adults.  The adults have darker bills, while the juveniles’ are brownish. Juveniles’ feet are also more brown, while the adults have dark gray to black feet.

The California Thrasher’s most distinctive visual feature is its long, decurved bill, which it uses to mow through grass or leaves like a farmer using a scythe.  This foraging behavior may be the source of its name – thrashing through leaves and mulch to find insects, spiders, berries, and seeds.…