After a very busy week I can only imagine that it is appropriate to begin the weekend raptor style.  So let’s get started a little early with a few portraits I’ve captured during my travels.

Osprey

Bald Eagle

Red Shouldered Hawk

Golden Eagle

Turkey Vulture

Harris's Hawk

Preface:  As the burrowing owl activities continue behind the scenes, I thought I’d lighten the mood just a little and share what nature does right as opposed to what we are doing wrong.  More Antioch burrowing owl information to come.

Watching raptors never gets old.  And for 9 years it has been a ‘who can spot the hawk?’ game as we cross the bridge that separates the far reaches of the east S.F. Bay Area from the rest of my world.  It is a trek that we happen to find ourselves on somewhat frequently as we attempt to satisfy family get-together obligations and trips to wildlife preserves for instance.  It is a corridor of farmland and pastures that is intertwined with the delta system and divided by thousands of fence posts sufficiently deteriorated to complement the rustic scene. 

There are a few places to park and escape the confines of a vehicle, numerous areas to stop that perhaps straddle legal code, miles and miles of mostly empty roadway conducive to middle of the street pauses, and plenty of opportunities to miss a great photograph or capture a winning shot.  It is never a dull trip.

Although the birding is quite varied, the most prominent feature of this secret landscape are the raptors.  Balancing on a leaning fence post, observing from telephone poles, sitting idle on the ground, and posing on the limb of a tree are all common scenarios whether the sun is shining or the fog is masking long distance visibility.

So enjoy a few of the many raptors we encountered on our last drive, see if you can identify them, and thanks for all the recent support with my struggle to protect burrowing owls.

I missed the Wordless Wednesday boat yesterday as I was enveloped in the details of a burrowing owl relocation plan that I recently received from the city.  So here’s the photo and enough words already…

Photo: Carlos Sanz

Manipulating egg quality and brood mates  is a strategy that is not uncommon for birds.  In fact, this is an important tactic in the survival of species when food is scarce and territories are poor.  The idea is that deteriorating environmental conditions will drive parents to invest more resources in the sex that maximizes their fitness, also called the cheaper sex.  And when environmental conditions once again become favorable, the sex ratio of males to females will eventually return to a state of equilibrium.

But when genetic predisposition for altering the sex ratio of a population is combined with an age bias and a small existing population, extinction risk creeps into the picture.  And a species that fits this bill is the Spanish Imperial Eagle.

The very rare Spanish Imperial Eagle has a population hovering around 200 breeding pairs (split into three subpopulations with relatively little interchange), which is a phenomenal recovery from the only 30 pairs that remained in the 1960s.  It is a non-migratory raptor that can approach a weight of 8 pounds, has a low reproductive rate, a lifespan of approximately 22 years in the wild, and of special note an immaturity period of 4-5 years.  According to a study in the Journal of Conservation Biology, since breeding age is a factor of density in this case, when the population of Imperial Eagles declines below capacity level the number of immature breeders increases.  And with a species harboring an age bias, an increase in immature breeding individuals resulted in a higher production of male offspring, which just so happens to be the cheaper sex for Imperial Eagles.

Photo: Antonio Lucio Carrasco Gómez

“Our findings show that fledgling sex ratio could be biased at the population level, and that bias toward the cheaper sex (males for Imperial Eagles) could be related to parental age. Because the mean age of breeders is density-dependent in Spanish Imperial Eagles, sex ratio ultimately may be related to population density.”

Thus, Spanish Imperial Eagles are finding themselves potentially embroiled in a vicious circle as the relatively low numbers in each of the three subpopulations are causing a decrease in the first breeding age and driving increases in male offspring.  Both of which are increasing the extinction risk as sex ratios are skewed from equilibrium. The authors found that when the number of males reached a level of 72% of the population (as opposed to 50% at equilibrium), the average time to extinction was reduced by almost 43%.

FERRER, M., NEWTON, I., & PANDOLFI, M. (2009). Small Populations and Offspring Sex-Ratio Deviations in Eagles Conservation Biology, 23 (4), 1017-1025 DOI: 10.1111/j.1523-1739.2009.01215.x

My last few postings about a local band of burrowing owls was more about the trial and tribulations of their lives in a habitat continually being squeezed by urban development.  Whether under threat of a housing development or a community center, the tone was less than upbeat as I waded through red tape and alternating project managers in an ongoing plight to ensure their survival.

And with that said I had not actually planned to breach the burrowing owl topic so soon, but I came across a video that is nothing more than a feel good burrowing owl moment.  So, sit back and take a close-up look at a burrow in Washington state that is home to 12 successfully reared owlets.

By the way, glad to see the parents are ever so attentive as a predator soars above their heads!

Kevin Cole from Pacific Coast, USA

As I returned from a 2.5 week hiatus, I read a post at GreenSpot-On entitled “Ode to My Sister, Rescuers and Other Rehabbers!”  For the few of you who have been following JournOwl since its inception, you are quite aware that the origins lie within a daily log of my time as an intern at the Lindsay Wildlife Museum.  Well that time has passed, but the GreenSpot-On post got me reminiscing about my first time witnessing the release of a rehabilitated raptor.

I imagine that since there are just about 6,000 native California wild animals that are treated by the museum/hospital each year, this is definitely not the only day a bird was successfully rehabilitated and released.  I can certainly understand that the hospital is not going to release most patients in the heavily populated adjacent park, but local birds that, with the assistance of East Bay do-gooders, who find their way to the hospital are occasionally publically released as a token of appreciation for community support.  A karmic reward if you will.

While I was preparing the visually impaired acorn woodpecker’s diet, a call emanated from the front desk alerting the entire staff as well as museum patrons of the release of a Cooper’s hawk in the park.  In one fell swoop, the chaotic flow of peoples from exhibit to exhibit organized in linear fashion as if Kindergarten was suddenly in fashion.  Making our way to the grassy knoll (yes, I was recently exposed to a JFK documentary and hence the reference), we awaited the much hyped release of a once injured raptor.  And we waited and waited.

Finally, the hospital group appeared with the eager patient and situated the cardboard carrier on a cement platform.  Ushering the crowds to a safe distance, the crew opened the box at the exact moment the Cooper’s hawk extended her wings and shot into a heavily needled pine tree.  It was akin to a jack in the box explosion that resulted in the disappearance of jack himself.  Yes, just as with many things in life, the hype was more than the event itself, especially since the hawk was well hidden within the tree. Of course we all hoped for a grand exit, a circling flight pattern overhead and a graceful voyage out of sight that would lend itself to water cooler talk on Monday morning, but what we got was anticlimactic as far as movie fanatics are concerned. 

HOWEVER, for wildlife lovers it was definitely a moment of Zen in which the kinship between human and nature afforded the aforementioned Cooper’s hawk a second chance at life in Contra Costa County, CA.

As a point of interest, GreenSpot-On has a regular post called Wildlife Q&A so check out their blog for additional details:

As someone who has done wildlife rehabbing, JRouse has worked with many different types of animals. She would like to give children and adults the opportunity to ask her questions about the animals she has helped.

http://www.greenspoton.blogspot.com/

Photo credit: Kevin Cole from Pacific Coast, USA

On June 8, 2009 the FWS released the following:

Jesse Barresse of Hudson was sentenced in U.S. District Court in Tampa today for intentionally shooting and killing a bald eagle, while he was illegally duck hunting in Ruskin on January 13, 2008.   Barresse received six months in federal prison, followed by a year of supervised release. He also must pay $500 in restitution to the North American Wetlands Conservation Fund and $25 in court fees.

This rides on the heels of a couple of other shootings involving California condors and begs the question: What’s wrong with people?

There are no words for complete stupidity and I only wish a maximum sentence had been handed down.

Read the press release:  Eagle Shooter Sentenced in Tampa, Florida

If you have ever driven by a landfill it becomes quite apparent that it is not a biological wasteland.  As tractors move an endless supply of debris about the land, the skies are littered with flocks of birds capitalizing on the smorgasbord of human consumption.  It is disturbing to see wildlife integrate a daily trip to the dump as a means of survival, but the landscape ultimately undergoes a transformation as garbage is covered by earth and grasses.  A seemingly semi-pristine environment now appears on the horizon with the exception of methane burners emerging from the treeless area and representing the only evidence of meddling.

As the flock of gulls migrate with the bulldozers, a host of other species move in to fill the niche.  Not surprisingly, the influx of rodents drives an increase in raptors that utilize the tall methane burners as perches for spotting prey.  A topic that I had not been aware of prior to a recent AP article on May 24, 2009, these landfill methane burners intermittently ignite and are scorching and killing perched hawks and owls.

“The methane burners have an igniter which causes a sudden flame flare that can scorch or even kill anything perched on top, flying over, or located inside the stack.”

“Typically, closed landfills are low traffic areas, so only a small percentage of burned raptors are rescued.  It is believed that most injured raptors die due to starvation or predation after burn injuries have been sustained.”

Wildlife Rehabilitation Bulletin, Raptor Burns from landfill Methane Burners, Gary Siftar, 2008

A number of remediation ideas are being discussed by wildlife rehabilitators and conservationists to prevent perching, but what I found interesting, as pointed out by the AP, is that the New York State Association for Solid Waste Management and the Federation of New York Solid Waste Associations have joined forces with the National Audubon Society to help curb the problem.  It is definitely a positive note that I hope is not just limited to lip service but becomes an adopted practice at landfills nationwide.

Links of interest:

The Birdchaser – More Methane Burned Hawks in Oklahoma

Audubon Birdscapes – Making Landfill Methane Burners Safe for Raptors

AP, May 24, 2009 – Landfill methane towers scorch perched hawks