Hatching strategies – when and why?

Hatching strategies – when and why?

By Daryl Anne Goldman

It’s breeding season — an opportunity for birders to watch courtship rituals, nest building, eggs hatching, and parents caring for their chicks. It’s fascinating how much diversity there is among species in the number of eggs in a clutch, what the newly hatched chicks look like, and how dependent or mobile chicks are after hatching.

Did you ever wonder why the eggs of songbirds and owls hatch up to several days apart, while a clutch of duck eggs hatches within a few hours of each other? Why do duck eggs hatch within four hours when they are laid over the course of several days?  These questions got me wondering about the parental contributions to this process, and whether the embryos do anything to directly influence this.

With a little research I learned that here are two types of hatching strategies — asynchronous and synchronous.

Asynchronous hatching

Asynchronous hatching is when the eggs of a clutch hatch over a period of a few days.  The time between the first and last egg hatching can be as much as 14 days, as with the Barn Owl.   With this hatching strategy, incubation usually starts before the later eggs are laid.  There is a higher rate of mortality with this hatching strategy, and the last chick is usually not expected to survive and is more of an insurance policy against the loss of the first offspring.   It’s much like the British monarchy: You need an heir and a spare.  In some species the firstborn, stronger chicks or even the parents may push the weaker, last born chicks out of the nest.

Asynchronous hatching, by Maja Dumont

What are the parental contributions to asynchronous hatching? The female deposits differing amounts of hormones, immunoglobulins, and antioxidants in the yolk, albumen, and shells of the eggs she lays, which then affects the survival of each hatchling.  For instance, in some species yolk antioxidant and immunoglobulin concentrations may decrease across laying order, thus handicapping the immune system of the last hatched chicks. However, in the same species, yolk testosterone concentrations may increase with laying order, which may compensate for poorer immune function by helping accelerate growth and food begging rates.

Does the embryo have a role? There is some research showing that bird embryos can actively modify the action of the hormones deposited in the yolk, and use maternal steroids to benefit their own fitness.…

Centennial exhibit comes to Oakland

Centennial exhibit comes to Oakland

By Ilana DeBare
On the road again… to Oakland!
After a month’s hiatus for Birdathon, Golden Gate Bird Alliance’s traveling Centennial exhibit has returned to public view, now at Oakland’s City Hall complex.
The main Centennial exhibit of 14 colorful panels is open during business hours in the lobby of the city’s Dalziel Building until July 7.  In addition, we have a photo exhibit of Oakland and Alameda wildlife on the third floor of City Hall, just outside the City Council Chambers.
If you haven’t had a chance to view the exhibit yet, come by and bring a friend! You can expand your visit into a full morning or afternoon outing by adding a mini-field trip — strolling over to the nesting colony of Black-crowned Night-Herons and Snowy Egrets just a few blocks away.
The Centennial exhibit in the Dalziel Building lobby / Photo by Ilana DeBare
Passerby views the Centennial exhibit. Photo by Ilana DeBare
Snowy Egrets nesting in street trees, just a few blocks from City Hall / Photo by Ilana DeBare
Although the bulk of breeding season is past, you should still be able to see nesting herons and egrets — some with a second clutch if they lost their first — through the middle of June. Golden Gate Bird Alliance volunteers have been monitoring the trees for fallen young herons, and we are partnering with Oakland Zoo and International Bird Rescue to retrieve, heal, and release the injured juveniles.
Then round out your visit to the Centennial exhibit and the heron colony with lunch downtown! See below for some good Oakland eateries near City Hall and the rookery.
It’s fitting that the Centennial exhibit find a roost at City Hall. Golden Gate Bird Alliance has a long history with Oakland residents and wildlife, including:

  • GGBA member and conservation chair Paul Covel served as the City of Oakland’s first paid naturalist from 1947 to 1972. He introduced thousands of children and adults to the wildlife of Lake Merritt and the Oakland Hills, established a refuge for injured birds at Lake Merritt, and marshaled support to build the Rotary Nature Center there.
  • GGBA fought long and hard to preserve wetlands along San Leandro Bay, an area that today includes the city’s beloved Martin Luther King Jr. Regional Shoreline. Thanks to a GGBA lawsuit in the 1980s, 73 acres of wildlife-rich marsh there were saved from development and turned into parkland.
Birdathon 2017 – it’s a wrap!

Birdathon 2017 – it’s a wrap!

By Ilana DeBare

Golden Gate Bird Alliance just wrapped up another successful Birdathon — great trips, great birds, and a great deal of money raised to protect Bay Area wildlife.

Birdathon 2017 culminated with a festive garden party on Saturday, May 13, where we announced winners of the birding and fundraising prizes, as well as the local heroes being honored with our annual Elsie Roemer Conservation Award and Paul Covel Education Award.

About 265 people took part in Birdathon events, which ranged from Big Six Hour trips to behind-the-scenes tours of California Academy of Sciences, International Bird Rescue, and Pixar, where attendees met the director of Piper, the Oscar-winning animated short about a young sandpiper. (It turns out the director is a fan of our Osprey nest cam and watches it over breakfast!)

Behind the Gates trip to Hayward Shoreline Released a rehabilitated cormorant during the Behind the Scenes at IBR trip / Photo by Marjorie Powell Tasting gourmet chocolates during our first-ever Birds & Chocolate trip / Photo by Leonard Stanton

Fifty inspired fundraisers spread the word about Audubon to their friends and family: Four raised over $2,000 each, and ten raised $1,000!

In total, our generous donors and fundraisers generated over $57,000 — close to our goal of $60,000. (There’s still time to help us reach that goal: Click here to make a tax-deductible contribution to Birdathon.)

And now… drumroll please… our award winners:

Elsie Roemer Conservation Award

Our top conservation honor — named after the Alameda activist and GGBA member who led numerous fights to protect East Bay shoreline habitat in the 1960s and 70s — went to Tony Brake. Tony, a longtime volunteer with Golden Gate Raptor Observatory, has been an outstanding leader of citizen science efforts to understand the population of nesting Ospreys along San Francisco Bay. He was also an invaluable help in launching the Bay Area’s first Osprey nest cam this spring.

 

Tony Brake receives the Elsie Roemer Conservation Award from GGBA Executive Director Cindy Margulis.

Paul Covel Education Award

Named after the GGBA leader who introduced thousands of East Bay residents to nature as Oakland’s first city naturalist, this award went to Eddie Bartley, Jack Dumbacher, and Bob Lewis — founders and instructors of the Master Birding class that we’ve co-sponsored with California Academy of Sciences for four years. About 80 local birders deepened their birding skills, ornithological knowledge, and conservation leadership through the intense year-long class.…

Congratulations, it’s an Osprey chick!

Congratulations, it’s an Osprey chick!

By Ilana DeBare
Mother’s Day came early on top of the Whirley Crane — with the Osprey pair at the center of our live nest cam hatching their first chick early Friday morning!
Rosie, the mother, was on the nest in the early morning hours as the first of two eggs hatched over a period of about nine hours. When the chick had pecked its way partly out of the shell, she picked up the discarded top half of the shell and tossed it out of the nest.
What was at first only visible as a pink ball hidden deep with in the nest became a limp, squirmy creature… and then an active chick, holding up its head and begging for food. Richmond, the father, flew in with a fish and took part in the first feeding.
Here’s a video clip of the family shortly after hatching:

And here are two photos of the chick during its first feeding, around 12:30 p.m. on Friday:
Chick calls for food.
Chick receives bits of fish from one parent while the other stands watch. Note the speckled second egg to its left.
Golden Gate Bird Alliance launched the live nest cam of the Osprey nest at the end of March. Since then, over 24,000 have visited the nest cam web site at sfbayospreys.org to watch the pair incubate their eggs and prepare to raise a family.
Rosie and Richmond’s first egg was laid on April 1st. Rosie initially laid three eggs, but she removed one from the nest on May 1 after it developed a crack and was no longer viable.
The young Ospreys will spend 50 to 55 days in the nest before they fledge. Both parents will take turns feeding them and attending the nest to warm the chicks and protect them from predators such as eagles and ravens. The biggest potential threats to nestling Ospreys are predation, exposure, and lack of food.
“Rosie and Richmond so far have been terrific parents,” said Cindy Margulis, Executive Director of Golden gate Audubon “They kept the eggs consistently covered and warm, fought off interloping birds, and rebuilt part of the nest when it was damaged during heavy winds. We’re hoping they will be just as good a team when it comes to feeding and tending their chicks.”
While a successful hatch of Osprey eggs may seem routine, that has not always been the case.…

Top ten reasons to be a citizen-advocate

Top ten reasons to be a citizen-advocate

Audubon members are great at being citizen-scientists!  No one lets their lack of a PhD stop them from contributing to the understanding of birds through Christmas Bird Counts, breeding bird surveys, and other field work.

But protecting the birds we love takes more than citizen-scientists. We also need citizen-advocates… people who care about California wildlife and are willing to convey that passion to government policymakers.

Audubon California will hold its third annual Advocacy Day in Sacramento on Thursday, June 8, 2017. We need some people to take part representing the Bay Area! No prior political experience necessary — only a love of birds and wildlife.

Advocacy Day is fun, fascinating, and empowering. You’ll come away with a firsthand understanding of how our legislature works and how your voice can have a real impact. Golden Gate Bird Alliance member Chris Winn took part last year. Here are his Top Ten reasons to become a citizen-advocate:

1.  The Capitol is a beautiful building, especially when the surrounding gardens are in bloom as they are in June.

2.  I don’t think of the Capitol as “their” building but instead think of it as “our” building.

3.  The State Senators, Assemblypersons, and staff people I speak to always make me feel at ease.

Audubon members met with East Bay Assemblyman Tony Thurmond in 2016

4.  Important bills are up for consideration each year, especially this year when California is trying to bolster our environmental standards against federal rollbacks.

5.  I like to show newcomers the older, historic side of the building especially the contrasting portraits of Governors Jerry Brown and Arnold Schwarzenegger.

The famous portrait of Gov. Jerry Brown from his first terms in the late 1970s-early 1980s / Photo by Chris Winn

6.  I found a perfect hidden coffee shop, one block from the Capitol and I’m willing to share!

7.  The orientation meeting before going into the Capitol is informative and answers all my questions.

8.  There are always enough folks so that nobody sees a legislator/staffer alone, but is usually sent in with someone fairly expert at the pieces of legislation under consideration.

9.  There is usually a little after-party somewhere to meet new friends and compare notes.

10.  I like birds!

Sign up now! California birds need your voice. See audubon.org/get-involved/2017-audubon-california-advocacy-day for details, the day’s schedule, and registration. And email us if you want to find out Chris’s secret coffee shop.