Found Birds

In Banding Research on July 6, 2015 at 8:03 pm

I do not agree with the Darwinian view that when Peregrine Falcons fledge badly, that they are deficient. Or that those originating at poorly located eyries (bridges, cranes, etc.) are the progeny of genetically deficient parents who are unable to choose a safe nest site. This fatalistic viewpoint holds that these falcons are better left for nature to take its course. My view is that the Peregrine Falcon is a precious resource that should not be squandered by narrow thinking and that if we can pick them up and give them a second chance, we should.

We band birds with the glimmer of hope that someone, somewhere might see them again. But most banded birds never are. The many Peregrine Falcon observers in the San Francisco Bay Area increase my chances. Bands give me an opportunity to learn more about dispersal distance and direction, nest site tenacity, and, the longevity of Bay Area Peregrines.

Today, I have information on one banded female falcon that is worth sharing. She fledged poorly and probably would have expired had a Good Samaritan not picked her up and given her a second chance. Her story is a good example of a falcon that is clearly not genetically deficient–just unlucky on her first attempt at flying.

It is important to note that fledging falcons are inherently clumsy. Having never stuck a landing in their short lives they are uncoordinated at braking before a landing and then grasping and balancing upon a perch. The bird in our example fledged from a nest box situated on a 250-foot high catwalk encircling one of two smokestacks at the Moss Landing Power Plant. Peregrines had attempted to nest at the power plant for years, probably because it overlooked abundant foraging habitat at Elkhorn Slough. But this attractive site near the midpoint of the Monterey Bay shoreline offered no nesting substrate on the one structure near the slough. Plant workers added a tray of gravel and the grateful Peregrines moved right in.

When our falcon tested her wings for the first time she missed attempts at perching and fluttered to the ground where she was immediately set upon by gulls. It was July 2nd, 2012.

A power plant worker saw the melee and scooped the young Peregrine into a cardboard box. A young woman living nearby heard about the capture through the wildlife network and drove immediately to the power plant and offered to take the bird to her veterinarian father for evaluation. The young woman is Sierra Roush and her father is Jim Roush, founder of the UC Santa Cruz Predatory Bird Research Group. (Jim thinks the bird should be now be known as “Sierra!”)

Dr. Roush declared the bird fit for release and I banded her with the VID band, 23/R. I released her the next day on a large flat roof near the power plant smokestack where the resident pair could resume their parental duties. That would be the end of the story except for a photograph taken yesterday by an exceptional peregrine watcher–Cleve Nash.

People like me who band Peregrines, are so grateful for people like Cleve who search for Peregrines and then report their whereabouts. These patient observers wait hours, days, weeks, and sometimes months, for a falcon to stretch a wing and a leg at a time and place where they can see–and perhaps photograph–its banded leg.

Three years and two days after she was banded and released at Moss Landing, Cleve verified that 23/R was the nesting female at one of the world’s most famous Peregrine Falcon eyries–the north side of Morro Rock at Morro Bay, California. She produced 3 young in 2015. When I relayed her story to Cleve he said, “maybe the stacks at the Morro Bay Power Plant looked like home to her.”

23/R had some bad luck on her first flight but has proven that she is in no way deficient by taking over the iconic nesting territory at Morro Rock as a three year old.

Here is Cleve’s photograph:

7-5-15 5351

7-5-15 5351a



In Uncategorized on July 7, 2014 at 1:27 pm

Espie and her brother Hiko fledged from the San Jose City Hall nest in 2007–Clara’s founding year in her territory. Hiko settled at the Fruitvale Avenue Bridge territory and Espie, the East Span of the San Francisco-Oakland Bay Bridge. 

The East Span territory has been used in the post-DDT era since 1983 when a blue-banded pair (peregrines released by SCPBRG) appeared. The male had been fostered into a Napa County eyrie and the female cross-fostered into a San Luis Obispo County prairie falcon eyrie. The female was shot near the nest and while peregrines were seen on the span for several years, breeding was not documented until 1990.

The peregrines preferred a nest site that was a little alcove in “E-2” the second tower east of Yerba Buena Island about thirty feet below the eastbound roadbed. This north-facing metal box contained enough dirt, gravel, and road debris to support incubation and nesting attempts were made in many of the years after 1990. 

Our observers documented all manner of calamity when the young attempted fledging. Peregrines are clumsy at landing during their first few days on the wing and the East Span of the Bay Bridge offers scant perching structure to a young peregrine. Sometimes they were carried upward on the strong wind out of the north and then clambered for a perch alongside the roadbed and were squashed by a speeding vehicle. Other times they were set upon by gulls and driven into the sea where they drowned.

A unique agreement was reached whereby the young could be moved to a safer fledging environment during seismic retrofitting construction following the 1989 earthquake. We moved young from the bridge for years. The agreement allowed construction to go forward where a state-endangered species was nesting and it was very good for the birds because their young had a 95% chance of drowning if left in place. When the seismic retrofit construction was complete and state-endangered status removed (2009) the agreement to move young expired. 

Today, lands immediately adjacent to the San Francisco Bay probably have more peregrine falcon territories than at any time in history. Their speedy recovery from near-extinction in our state is due first to stopping the use of DDT and then to recovery activities. But the Bay Area population density can only be explained by the appearance of modern structures offering nest ledges on bridges, buildings, and cranes, and the presence of a booming non-native rock dove (pigeon) population. Nest sites average less than 5 miles distance between them in some parts of the Bay Area and this year a sample of 12 nests yielded an average 3.0 young per nest that were at least 25 days of age. 

The peregrine falcon population is robust but I do not think that is a good reason to look the other way when a recent candidate for extinction will very likely fledge its young into the sea. We brought them back from extinction. We put up the nesting habitat. And, we introduced the abundant food source that now sustains them. I think we bear some responsibility to give them a chance at safe fledging and I have fought that fight for years. But what we (those of us who love peregrines) are up against is an agency-wide wildlife non-intervention policy. That policy, coupled with a species that is now abundant, makes it very difficult for us to gain an exemption.

An additional caveat making it especially hard to do the right thing for bridge-nesting peregrines is this: The State Department of Fish and Wildlife established a policy whereby peregrines may not be hacked (released) less than 50 miles from the coast (a protection for snowy plovers & California least terns–a decision based on emotion and not science in my opinion) or, in the habitat of the greater sage grouse. With this policy the State has pretty much eliminated suitable habitat for peregrine releases. Thanks to an accommodation by colleagues at UC Davis, I was able to gain approval for a release site at one of their off-campus animal facilities that was useful for early season peregrine fledging, and I used that site successfully last year.

The end of the story about Espie and her young is this: The old East Span is being dismantled this year so the agencies changed their mind about non-intervention and agreed to allow me to move Espie’s young. But, in a particularly bone-headed move, CalTrans sealed off the favored E-2 nest site in mid-February thus throwing off the breeding cycle. A little later the pair appeared to be making an attempt to nest on a corner gusset plate that anchors a girder to a tower, and finally, quite late in the breeding season, they settled in a cavity low on the E-8 tower. 

Knowing that temperatures would be exceeding 100 in Davis by the time the young were ready to fledge (it is forecast to be 101 today) I cancelled plans to have any part of their translocation. Putting peregrines inside of a box on the top of a roof in 100 plus degree heat just might be worse than fledging from the Bay Bridge. What I do know is that a peregrine tortured with enclosure in a hot box for a week would probably never return to the box for food and quickly starve. It was frustrating to be able to take them but unable to release them in a manner that was up to our standards. Their chances on the bridge? Probably not good either. An industrial area to the south may offer them a perch. A short distance to the north is the speeding traffic of the new east span which is certainly lethal. And then there are the gulls. 

Observers may ride a bicycle or walk out the bike path on the new East Span to view the birds on E-8 (count 8 towers from the island). Some folks report getting quite close to Espie and her mate while they are perched on the new span. The young should be fledging any day now. Personally, I do not want to witness the calamity.

(Post Script: We withheld information about the E-2 nest location because the area was closed due to bridge construction activity).

Central Asian Falconry

In Falconry Observations on April 22, 2014 at 3:43 pm

An image from Dennis Keen's Central Asian Falconry website.

An image from Dennis Keen’s Central Asian Falconry website.

I write today to share an extraordinary resource about the practice of Kazakh falconry that has been researched, written, photographed, and most importantly lived, by the former UC Santa Cruz student, Dennis Keen. Dennis is in his fifth year of studies in Central Asia. He is a Fulbright Scholar and has completed a Stanford Master’s degree. His website is a collection of his current observations of culture plus historic knowledge of the ancient art of falconry including interviews with an elderly Kazakh falconer who is the repository for generations of falconry knowledge. It is a fascinating read for anyone with a curiosity about lands and cultures beyond our own and especially about those who have hunted with goshawks, falcons and eagles over millennia.

You may learn more about the work of Dennis Keen here:

Borrowed from the website: Central Asian Falconry, by Dennis Keen

Borrowed from the website: Central Asian Falconry, by Dennis Keen