Bald Eagle grasping Pacific Sand Lances on May 20, 2009. Photo: David Ellis

The two ornithologists had just visited a Peregrine Falcon (Falco peregrinus) eyrie and were motoring their way to another one. As their inflatable boat rose and fell in heavy swells along the northern Queen Charlotte Islands off Canada’s western coast they saw a flock of whirling Bald Eagles (Haliaeetus leucocephalus).

By Rex Graham

David H. Ellis, Ph.D., of the Institute for Raptor Studies,  and R. Wayne Nelson, Ph.D., had seen plenty of Bald Eagles up here before, but the frenzied way the eagles were hitting the Pacific Ocean’s surface was highly unusual. They detoured for a closer look at an event few scientists have ever witnessed.

“We were making our way  through a narrow straight when we saw the circling Eagles,” recalled Ellis. “I said, ‘Wayne we’ve got to get out there.’ He was at the helm, simply trying to keep both of us alive.”

Ellis and Nelson not only survived, but they saw a record number of fish taken in a single Bald Eagle feeding frenzy. “Many people had seen such feeding frenzies from afar, but no scientist had previously been close enough to document eagles catching 10-15 fish at a pass,” said Ellis.

Onlooking Auklets

Rhinoceros Auklets feed frequently at "bait balls" of Pacific Sand Lances. Photo courtesy of Langara Fishing Adventures

Ellis and Nelson were impressed by the utter improbability of so many fish being caught and eaten so fast by Bald Eagles – all within a few meters of human observers.

“It looked like the Bald Eagles had shown up at McDonalds and were grabbing fistfuls of French fries,” Ellis said. “I took photo after photo, but the camera’s batteries wore down. There were so many fish being taken so fast by so many Eagles, I just couldn’t take it all in. As the camera batteries were recovering between shots, I instinctively began counting; one-thousand-one, one-thousand-two, one-thousand-three.”

Ellis and Nelson estimated that the Bald Eagles “slapped” at the bait ball about every four seconds. The ornithologists’ first-of-its-kind scientific report of an estimated 2,500 individual fish taken in a 18 minutes on May 20, 2009 was published in a 2010 issue of the Journal of Raptor Research. But Ellis and Nelson are still shaking their heads over the novelty of their observations.

Also watching that day from a discrete distance were Glaucous-winged Gulls (Larus glaucescens), Rhinoceros Auklets (Cerorhinca monocerata), Herring Gulls (Larus argentatus), Black-legged Kittiwakes (Rissa tridactyla) and the occasional Common Murre (Uria aalge).

As 21 Bald Eagles repeatedly grabbed fistfuls of French-fry-sized Pacific Sand Lances (Ammodytes hexapterus), all the onlookers were treated to another, more sublime treat – a glittering shower of fish-scales, with the occasional plop of a whole Sand Lance.

“I have swum with manatees and been hit in the back by a Peregrine, a Prairie Falcon (Falco mexicanus) and a Zone-tailed Hawk (Buteo albonotatus), but that was one of the most amazing wildlife experiences I’ve ever seen,” said Ellis in a telephone interview.

Bait-ball banquet

They noted in their report that nothing close to such a mass fish capture had ever been reported in “the extensive Bald Eagle literature.”

Bald Eagle grabbing Pacific San Lances on July 11, 2008. Photo: Dave Chandler

Comment: “Pretty amazing the numbers of small fish these bald eagles are able to grab at any one time, yet their powerful, almost unbelievable grip coupled with the rough, spiculed surface of their foot pads, seems to be working pretty efficiently here,” said Teryl G. Grubb, a scientist at the Rocky Mountain Research Station in Flagstaff, Ariz.

Bald Eagle carrying Pacific Sand Lances on June 14, 2009. Photo: Dave Car

Comment: “Like Ellis’ lead photo in this series, it appears these adults are about to ‘eat on the wing,’” said Grubb. “Works out well when prey that small would likely be dropped if the Eagle landed, and even better when they’re out to sea and have no choice. Eating on run also allows quick returns for seconds.“

Bald Eagle flying away with Pacific San Lances on June 2, 2010. Photo: Mike Larkin

Comment: “I suspect this eagle is gaining lift by flying close to the water surface like a Brown Pelican, taking advantage of any extra air currents and updrafts, to regain elevation,” said Grubb. “Bald eagles typically do more soaring than active flying: they’re masters of utilizing even the smallest of air currents to their advantage.“

Three Bald Eagles take turns grabbing Sand Lances on July 7, 2011. Photo: Dave Car

Comment: “Group foraging is not all that unusual,” said Grubb. “Sometimes it’s competitive and sometimes there is some obvious group cooperation where several eagles will fly over, one after another, keeping say a diving duck down, till when the poor duck comes to surface for air, the next eagle can grab it.”

Bald Eagles attract a lot of attention no matter what they do. After all, the photogenic predator is a national symbol. A white head, fierce eyes and lethally curved beak adorn the official Great Seal of the United States. Its toes are covered with knobby spicules and tipped by sharp talons. The presidential seal shows an Eagle grasping a 13-leaf olive branch with one foot and 13 arrows in the other, but Bald Eagles have evolved to grab and hold slippery fish.

Bald eagles are one of eight species of sea eagles (Genus Haliaeetus), and as such feed primarily on fish. However, they are incredibly opportunistic and are known to take cats, ground squirrels and rats. Ornithologists have documented them killing White-tailed Deer (Odicolens virginianus) fawns, taking Trumpeter Swans (Cygnus buccinator) and seabird eggs and chicks. They scavenge dead Harbor Seal (Phoca vitulina) pups on the beach when fresh meat is scarce, or feed on live ones.

Needlefish not on menu?

But in all the previously documented 2,000 total fish eaten by Bald Eagles, not a single Sand Lance was listed on the menu.

Ellis and Nelson had no reason to doubt what they had seen that windy afternoon in 2009. They were convinced that mass fish captures may be common. But they needed more observations to be sure.

Another opportunity came two weeks later in the same area. The ornithologists followed a Bald Eagle from shore to another bait ball that quickly attracted 13 additional Eagles.

“Somehow, often thought from their keen eyesight in association with subtle variations in flight behaviors, Eagles seem to be able to key on each other from great distances to ‘communicate’ exceptional foraging opportunities like these Sand Lance balls,” said Teryl G. Grubb, a scientist at the Rocky Mountain Research Station in Flagstaff, Ariz.

But this time the birds circling about 1 km from shore came up empty-footed after four attempts to grab Sand Lances. Rather than waste their energy, the Eagles flew back to shore.

“We then motored very close to this pod of fish and saw that it consisted of much smaller fish than we’d seen earlier,” Ellis said. Something else was different: the smaller Sand Lances were clustered in a narrow serpentine line at the water’s surface rather than in a dense ball of full-sized adults.

Boiling panic of fish

Humpback Whales feeding on Pacific Herring on June 29, 2004. Photo courtesy of Langara Fishing Adventures

Pacific Sand Lances, also called Needlefish, along the Coast of Washington, British Columbia and Alaska are also favorites of Salmon, Humpback Whales (Megaptera novaeangliae) and diving birds such as Rhinoceros Auklets.

Huge schools of Sand Lances are found in areas with sandy bottoms. If Sand Lances can’t escape by burrowing into the sand, they swim to the surface in dense masses. Sections of the ocean’s surface can turn into a boiling panic of fingerlings.

Ellis and Nelson, both retired, are convinced that “under the right conditions,” Bald Eagles in the Pacific Northwest are harvesting  thousands of Sand Lances or more in binges similar to the one they witnessed on May 20, 2009.

Indeed, photos provided by Langara Fishing Adventures that were taken in the same vicinity by the company’s clients before and after the observations of Ellis and Nelson show Bald Eagles feasting on Sand Lances.

“From afar, I’ve seen the Eagles fly out to the bait balls,” said Mike Randall, marketing manager of Langara Fishing Adventures, a sport-fishing company on Langara Island, British Columbia, Canada. “Some of the people on our trips have provided photos of Bald Eagles and other birds feeding on Herring and Needlefish.”

A variety of gull species take advantage of a Sand Lance "bait ball" on July 24, 2011, off Canada’s northern Queen Charlotte Islands. Photo courtesy of Langara Fishing Adventures

The fish-rich Pacific about 500 km south of Juneau, Alaska, attracts salmon, Humpback Whales, Dolphins, Porpoises, gulls and diving birds. Some of the predators corral large schools of Sand Lances and Pacific Herring (Clupea pallasii) at the water’s surface. If Ellis and Nelson are right, Bald Eagles routinely join the feast.

Eagles, DDT and lead

Egg-shell thinning caused by pesticides such as DDT and Dieldrin decimated Bald Eagles and other apex avian predators in the lower-48 states in the 1960s and 1970s. Swiss chemist Paul Hermann Müller won a Nobel Prize in 1948 for discovering the pesticide’s high efficiency against arthropods, and Rachel Carson’s 1962 book “Silent Spring” led to the banning of it in most places. Carson’s vision went beyond DDT by questioned the wisdom of releasing large amounts of any environmentally devastating chemical without fully understanding the effects on ecology or human health.

Ornithologist David Ellis

Eagles in Alaska and Western Canada were mostly unaffected by DDT, but to understand Eagles’ diet elsewhere, researchers have measured the concentration of DDT and other environmental contaminants in the remains of prey under their nests,as well as from blood and feather samples collected during banding operations.

With DDT fading from the environment, annual Bald Eagle surveys in many parts of the United States such as in the Pacific Northwest (Oregon and Washington), Great Lakes region (Michigan, Minnesota), Arizona, New York, Florida and other states have documented soaring numbers of breeding pairs. But Bald Eagles aren’t out of the environmental woods in the Lower 48.

“With an ever increasing human population, especially along marine and aquatic shorelines, habitat loss is one of the greatest threats to bald eagles,” said Grubb. “Other contaminants such as PCBs and mercury remain pervasive in the environment. Collisions with vehicles, power poles, and transmission lines continue, as do electrocutions. And now a new threat is appearing on the landscape – wind farms, with giant turbine blades that are already documented to be killing a disturbing number of golden eagles. Sadly, direct persecution in the form of shooting, poisoning, and trapping, is further exacerbated by secondary lead poisoning.”

Bullet fragments in rifle-killed deer carrion are blamed for lead poisoning and death in Bald Eagles, Golden Eagles (Aquila chrysaetos), California condors (Gymnogyps californianus), and other avian scavengers. Recent research has shown that a single bullet will produce a “spray” of thousands of microscopic fragments from a single bullet impact.
Researchers with The Peregrine Fund in Boise, Idaho and Washington State University in Pullman warn that such exposure to lead from bullets and shotgun pellets poses a danger to all avian scavengers.

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A multi-agency report on the state of birds in the San Francisco Bay area paints a mixed picture, with most bird species doing well after decades of investments in habitat restoration, but many are vulnerable to rising sea levels, extreme-weather events, non-native predators and other threats.

The analysis was based on years of monitoring efforts by a variety of organizations, including the Point Reyes Bird Observatory, San Francisco Bay Bird Observatory, Audubon Canyon Ranch, the California Coastal Conservancy, U.S. Geological Survey and the U.S. Fish and Wildlife Service.

Key findings from the report include:

The report was inspired by the United State’s first-ever State of the Birds Report released in 2009.

“Our hope is that this detailed report with dozens of science-based recommendations will inspire action to benefit birds as well as fisheries, water quality, flood control and our communities,”  said Beth Huning, coordinator of the San Francisco Bay Joint Venture.

Tidal Flats

Tidal flats. Photo: Philip Bouchard

One of the common species, the Western Sandpiper, has declined bay-wide, but the Least Sandpiper and Willet have increased greatly. Photo: San Francisco Bay Subtidal Goals Project

Managed Ponds

Photo: Beth Huning

The San Francisco Bay area has about 1,380 breeding pairs of American Avocets. Photo: Tom Grey

Commercial salt ponds were constructed around the edge of San Francisco Bay beginning in the mid 1800s. Many former salt production ponds in San Francisco Bay have recently transitioned to public ownership and are being restored and managed for wildlife. These shallow ponds now provide habitat for hundreds of nesting terns, gulls, and shorebirds, and roosting and feeding habitat for hundreds of thousands of migrating and wintering shorebirds and ducks.

Tidal Marsh

Photo: Sonoma Land Trust

Restoration of artificial ponds once used for salt production will create new habitat for Common Yellowthroats, Clapper Rails and other marsh-dwelling birds. Photo: Tom Grey

Subtidal Habitat

Fewer herring along the Pacific Coast is bad news for scoters and scaup, which feed on them throughout the winter. Photo: Mike Baird

Human-created Habitats

Alcatraz Island. Photo: Anonymous

Photo: .Len Blumin

But seabirds are long-lived birds. Their populations can withstand occasional years of poor reproduction or reduced reproductive
effort. Because of this, evaluating the status of a nesting colony is done by looking at the reproductive success or breeding population size.

Upland Habitats

Upland habitat.Photo: Caroline Hardter

Coastal scrub-chaparral and grassland birds are declining, coastal scrub by 27% and grassland by over 45%. Photo: Tom Grey

The loss and degradation of habitat is mostly to blame, trends that also are reported the National State of the Birds Report, 2009.

Upland bird species are hurt when open space is converted to housing or intensive agriculture. They also have declined due to invasions of native species (such as Douglas fir), and non-native species (such as broom), and lack of ecological disturbances such as fire.
 

Download full report

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Two whooping cranes — the most endangered of all of the world’s crane species — have been shot and killed near the Jennings, Louisiana, according to the he Louisiana Department of Wildlife and Fisheries (LDWF). Agents have identified two juveniles for their alleged role in the illegal shooting of the cranes, which were part of a non-migratory, experimental population in Jefferson Davis Parish.

According to an eyewitness account, two juveniles stopped on Lyons Road between Mouton and Guidry roads south of Jennings at 3:30 p.m. on Oct. 9, and shot from their truck, killing the whooping cranes.

Adam Einck, spokesman for the LDWF’s enforcement division, told the Associated Press that two boys, ages 16 and 13, have been told they are suspects based on witness’s description of a truck and other information.

In this video, Patuxent Scientist John B. French describes the contribution of the Crane program at the Patuxent Wildlife Research Center to the restoration of a migratory flock of whooping cranes in the eastern United States.
Videographer: Hannah Hamilton (USGS)

“Losing two cranes, especially in such a thoughtless manner, is a huge setback in the department’s efforts to re-establish a whooping crane population in Louisiana,” said LDWF Secretary Robert Barham. “We take this careless crime very seriously.”

LDWF received 10 whooping cranes (Grus americana)

Photo by Geoff Gallice

Only five of the cranes are still alive. LDWF spokesman Bo Boehringer said in an email to the Associated Press that one bird disappeared in June around St. Martinville and is presumed dead. Another flew about 80 miles to Morganza, where evidence indicates a predator ate it, and another bird with a lung infection was euthanized. Satellite transmitters have located four recently and one is currently unaccounted for, Boehringer said.

This re-introduced population, which will be joined by other cranes in the future, marked the first presence of whooping cranes in the wild in Louisiana since 1950.

LDWF is working cooperatively with the U.S. Fish and Wildlife Service (USFWS), USGS, the International Crane Foundation and the Louisiana Cooperative Fish and Wildlife Research Unit to bring the species back to Louisiana. This non-migratory flock of whooping cranes is designated as a non-essential, experimental population and is protected under state law and the Migratory Bird Treaty Act.

“This is a profound setback to the many people and organizations who have worked so hard to bring this magnificent bird back to Louisiana,” said Cindy Dohner, Southeast Regional Director for the U.S. Fish and Wildlife Service.

Whooping cranes were first added to the federal status of an endangered species on March 11, 1967. The reintroduction at White Lake WCA is part of an ongoing recovery effort coordinated by the USFWS.

Whooping cranes are monogamous and generally mate for life, once they have reached sexual maturity at 3-5 years of age. Photo: Ryan Hagerty

Historically, both a resident and migratory population of whooping cranes were present in Louisiana through the early 1940s. Whooping cranes inhabited the marshes and ridges of the state’s southwest Chenier Coastal Plain, as well as the uplands of prairie terrace habitat to the north. Within this area, whooping cranes used three major habitats: tall grass prairie, freshwater marsh, and brackish/salt marsh. The Louisiana crane population was not able to withstand the pressure of human encroachment, primarily the conversion of nesting habitat to agricultural acreage, as well as hunting and specimen collection, which also occurred across North America. The last bird in southwest Louisiana was removed to a sanctuary in 1950.

The only self-sustaining wild population of whooping cranes migrates between Wood Buffalo National Park in the Northwest Territories of Canada and Aransas National Wildlife Refuge in Texas. Like those in the eastern migratory population, it remains vulnerable to extinction from continued loss of habitat or natural or man-made catastrophes. Multiple efforts are underway to reduce this risk and bring this bird further along its path to recovery. This includes increasing populations in the wild, ongoing efforts to establish a migratory population in the eastern United States, and establishing a resident population in Louisiana.

There are about 570 whooping cranes left in the world, including only 400 in the wild. About 100 cranes are in the eastern migratory population.

For the 11th time in as many years, ultralight-led captive reared whooping cranes are learning their migration route to wintering sites in St. Marks National Wildlife Refuge and Chassahowitzka National Wildlife Refuge. Ten young whooping cranes began their journey on Oct. 9, 2011.

RELATED LINKS:

Whooping Crane Eastern Partnership
Whooping Cranes at Aransas National Wildlife Refuge

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Tony Ball

Commercial development is Thailand’s cancer. It is spreading mindlessly toward national parks and wilderness areas, eating away the beauty and tranquility of this lovely country.

I have enjoyed hundreds of species of birds in Thailand for 22 years and grown to love this country. My two decades of fond memories makes the commercial metastasis so painful to witness. Like me, the average Thai citizen feels powerless.

Conventional tourism is partly to blame. The Thai government’s encouragement of tourism is founded on exploiting its natural areas rather than preserving them. I’ve seen no evidence that the 200-baht entry fees that foreigners pay are being used to maintain Thai parks.

Parts of Thailand, like the mountains in the north, are still relatively intact and beautiful, but only because they are so remote.

I recommend that Thailand make these three changes:

• Stop all development that encroaches on national parks.

• Ban slash-and-burn practices and enforce the prohibition. Human deaths from respiratory effects of smoke spike during a two-month winter burning period. The burn-offs must be stopped on agricultural, municipal and military lands and in construction zones under development.

Air pollution at Huay Tung Tao in March 2007.

• Reduce vehicle emissions. The laws on the books that govern this environmental problem should be phased in over time to ease the transition to cleaner vehicles and fuels.

This photos shows smog/polution at Huay Tung Tao in March 2007. A great deal of the smoke pollution is blown to Thailand from Burma, Laos and as far away as Indonesia.

Huay Tung Tao, a 2.6-km circumference reservoir on land owned by the military is an example of malignant, mindless deforestation here. Over the past 8-9 years I have documented the birds in this resort area. In the early years it was very productive bird-wise. But then the military began to slash-and-burn the area and prune the lakeside vegetation to the ground.

During one breeding season, all the growth around the lake was chopped, including the thorny mimosa, which was a sanctuary for the smaller birds. I found broken eggs and dead nestlings.

A paintball area was added. All terrain vehicles were introduced, and most of the birds left. The checklist of birds I documented over the years in this area is misleading because many species have disappeared or remain in greatly reduced numbers.

I have played my part in that process by introducing schoolchildren and kids from the villages to the birds that are still in the area. Some of them now enjoy birding as adults.

Indeed, more Thais are taking a greater interest in birding, which is needed to slow the cancer of devastation and then stop it.

RELATED LINK:
A Birdwatcher’s Diary (Thailand)

A male Least Bell’s Vireo (left) building a nest in May 2010 with a female White-eyed Vireo (right) at the San Luis Rey River in California.Photo: Lisa D. Allen

By Rex Graham

His mate was a female White-eyed Vireo (V. griseus). The female soon laid four eggs, and the pair successfully raised and fledged four nestlings. It was the first documented case of interspecific breeding involving the two Vireo species.

Melissa Blundell, a graduate student in animal behavior at UC Davis, and Barbara Kus, a distinguished research ecologist with the U.S. Geological Survey (USGS), reported in the September issue of the Wilson Journal of Ornithology the first interspecific mating of the two vireo species.

Blundell and Kus mist-netted the female White-eyed Vireo, but not the male Least Bell’s Vireo in order to minimize disturbance at the nest.

Melissa Blundell, graduate student at UC Davis,

They also examined the four chicks and collected DNA samples from them and the mother. “We collected a pin feather sample from each nestling and a blood sample from the female via a toenail clip,” they wrote in the Wilson Journal. “This genetic material is currently being analyzed for further evidence of this interspecific breeding occurrence.”

The nest was empty by June 14. Two fledglings were heard calling nearby. Blundell and Kus visited the nesting area three more times and searched unsuccessfully for a second nesting attempt.

The female White-eyed Vireo vanished, but Blundell observed one of the banded fledglings with the male Least Bell’s Vireo on June 27. The fledgling resembled a Least Bell’s Vireo fledgling in appearance with a white underbelly, gray crown, back and primaries, and black eyes.

Blundell and Kus hope to observe members of the unusual Vireo family in the future.

Kus is a well known Vireo expert who knows their breeding habits as well as anybody. After she graduated with a Ph.D. from UC Davis in 1985, she began working for the USGS’s Western Ecological Research Center, and has also been associated with the Department of Biology at San Diego State University. She has published more than 25 scientific papers on Neotropical migratory birds in restored woodlands, and she has developed a special expertise on the Least Bell’s Vireo.

Barbara Kus Kus is a well known expert on California's Vireos.

Kus and Blundell are now members of a small group of people who have personally witnessed an interspecific Vireo mating. One of the first such recorded observations was made on May 26, 1958, by Doris Hauser. She saw a male Yellow-throated Vireo (V. flavifrons) display a few inches from its nest in a post oak in her front yard at 309 Sylvan Road in Fayetteville, N.C. Hauser watched the male mate twice there with a wing-fluttering female Solitary Vireo (V. solitaries).

Other hybridizations among Vireo species have been reported*:

V. altiloquus and V. olivaceus
V. cassinii and V. plumbeus
V. flavifrons and V, solitaries
V. olivaceus and V. altiloquus
V. olivaceus and V. philadelphicus
V. philadelphicus and V. olivaceus
V. plumbeus and V. cassinii
V. solitaries and V. cassinii
(*Source: bird-hybrids.com)

Actually, hybridization in birds is well known. About one in 10 species is known to hybridize: as many as 895 species of birds are known to have bred in nature with another species and produced hybrid offspring, out of a world total of 9,672 species, according to Princeton University’s Peter and Rosemary Grant, legendary evolutionary biologists who studied the finches of the Galapagos island of Daphne Major for four decades.

Order	Species	Species hybridizing	Species hybridizing
	number	number	percent
Struthioniformes Photo: Lip Kee Yap	10	0	0
Tinamiformes Photo.Marcos Massarioli	47	0	0
Craciformes Photo: Dario Sanches	69	2	2.9
Galliformes Photo: JJ Harrison	214	46	21.5
Anseriformes Photo: Kitkatcrazy	161	67	41.6
Turniciformes	17	0	0
Piciformes Photo: Alan Vernon	355	48	13.5
Galbuliformes Photo: Brian Gratwicke	51	2	3.9
Bucerotiformes Photo: Lip Kee Yap	56	0	0
Upupiformes Photo: Alan Manson	10	0	0
Trogoniformes Photo: Matt MacGillivray	39	0	0
Coraciformes Photo: Piotr Kuczynski	152	8	5.3
Coliiformes Photo: Alois Staudacher	6	2	16.7
Cuculiformes Photo. Mark A. Wilson	143	4	2.8
Psittaciformes Photo. Louise Docker.	358	27	7.5
Apodiformes Photo. Jakub Stanco	103	0	0
Trochiliformes Photo. Michelle aka Mitternacht90	319	61	19.1
Musophagiformes Photoz; Chrumps	23	0	0
Strigiformes Photo: Dori	291	2	0.7
Columbiformes Photo. 4028mdk09	313	10	3.2
Gruiformes Photo. Marek Velechovsky	196	17	8.7
Ciconiiformes Photo. Dick Daniels	1,027	139	13.5
Passeriformes Photo. Donna Dewhurst	5,712	460	8.0
TOTAL	9,672	895	9.2

The Grants reported in Science magazine that 460 of the 5,712 species of Passeriformes have hybridized, but the true global incidence of bird hybridization is likely to be higher than 10 percent.

The Grants banded almost every bird on Daphne Major for years and documented the fitness of hybrid birds, finding that in many combinations of species, hybrid offspring survived better than their related-species contemporaries. They speculated that hybrids may be better able to deal with the exigencies of the environment better than parental species phenotypes.

“Hybrids, as well as surviving well, breed well; they are fertile as well as viable,” the Grants reported. However, genetic incompatibilities between hybridizing species sometimes appear in subsequent generations.

Least Bell's Vireo

The Least Bell’s Vireo it is an endangered species that breeds from northern Baja California, Mexico north to San Diego County in Southern California along the San Luis Rey and Santa Margarita rivers.

The White-eyed Vireo breeds in eastern North American from Florida and Massachusetts on the east through Illinois on the west. There have been only 67 confirmed sightings of a White-eyed Vireo in California between 1969 and 2009, according to Blundell and Kus.

Such small populations of a Vireo species such as the Least Bell’s might be expected to result in “inbreeding depression,” the reduced fitness that results when more deleterious traits become manifest. Kus and Blundell’s hybrid Vireos could provide insight into what the future may hold for the Least Bell’s.

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Nocturnal predators and full moons are deadly combinations for many mammals. No wonder rabbits, deer mice and even bats exhibit “lunar phobia,” becoming less active and more vigilant as moonlight intensity increases. They tend to spend moonlit nights in thickets and other safer areas even if there is less food to eat there.

Full moons also have a profound effect on Europe’s largest owl, the Eagle Owl (Bubo bubo). Nesting males hoot more frequently and flash a white badge on their throats. But ornithologists couldn’t observe what else moon-crazed eagle owls were up to.

Sound recording of copulating eagle owls

New answers, more questions

Now, radio tagging and other sensor technologies are providing answers – and raising tantalizing new questions about the roll moonlight plays in the evolution of both predator and prey.

Conservation biologist Dr. Vincenzo Penteriani fitted 71 Eagle Owls with 30-gram backpacks containing radio tags and body-posture sensors. Penteriani worked with other conservation biologists Anna Kuparinen at the University of Helsinki, Maria del Mar Delgado and Rui Lourenço, both at Estación Biológica de Doñana and the University of Helsinki, and Letizia Campioni at Estación Biológica de Doñana. The team followed the owls’ nightly movements and activities from 2003 to 2010 in the Sierra Morena of southern Spain.

The researchers wondered how Eagle Owls had enough time for so much hooting and territorial posturing on intensely moonlit nights and also hunting harder-to-find rabbits and rats.

This direct attack by an Eagle Owl on a video camera reveals what to many rabbits is a lethal encounter.

“I was very intrigued by the idea that the less reflective tails of unhealthy individual rabbits might lead Eagle Owls to target them during moonlit nights,” Penteriani said. “We hypothesized that the eagle owl’s preference for substandard individuals could be due to the easier detection of slightly duller rabbit tails.”

Complex trade-off for eagle owls

Describing results of eight years of observing owls from sunset to dawn, Penteriani reported in Animal Behaviour that the response of a predator like the Eagle Owl to moon phases may represent a complex trade-off. Breeding adults may need to carefully balance the difficulty of overcoming anti-predator strategies of its prey, mostly rabbits (Oryctolagus cuniculus) and rats (Rattus rattus and R. norvegicus), with owls’ need to feed themselves and their young as well as advertise their home territory.

“Modern technology such as radio-tagging represents one of our best tools to discover nightlife,” Penteriani said. “Each night we focused on one individual.

A mercury posture sensor allowed his team to discriminate different behaviours by changes in the radio signal of the transmitters. “After more than 700 nights of continuous radio-tracking of more than 100 owls, we were easily able to discriminate between hunting, vocal displays, feeding young, roosting and other behaviours,” he said.

These are the highlights of his long-term study:

–Non-breeding, dispersed owls weren’t affected by the lunar cycle.

–Breeding Eagle Owls traveled longer distances at greater speed and also increased the number of flights per night, increasing in phase with the intensity of lunar light.

–Owls move much less at the time of a new moon.

–Non-breeding dispersed owls were not affected by the lunar cycle.

–Younger owls flew farther and faster than older owls.

–Female owls moved less than males, presumably so they could remain closer to the nest while males could range father to hoot and make territorial displays.

–Owls moved more frequently when hunting in denser habitats such as forests.

–Owls living in home ranges with few rabbits relied much more on rats and other smaller prey, which required them to devote more time and energy to hunting.

–Dark nights are more silent nights — owls use lunar light to increase the effectiveness of their territorial communication.

Owls and rabbit tails

“We also measured the reflectance of the tails of individual rabbits and found that those with duller tails were more likely to be taken by Eagle Owls,” Penteriani said. “These preyed rabbits were the substandard individuals of the whole population. In fact, the higher survival of rabbits in prime condition is consistent with previous studies on the relationship between viability and secondary sexual characters.”

Since Eagle Owls have evolved with rabbits, the suggestion that their predatory behavior is guided by visual cues is in agreement with the hypothesis that bright coloration may signal an unprofitable hunt.

“More fit individual rabbits may be signaling their greater ability to avoid predators compared to less fit, duller ones,” Penteriani said. “We may be dealing with a mechanism that has evolved in predators, which also plays role in rabbit sexual selection.”

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Birds collected after colliding with buildings in Toronto, Canada.

By Rex Graham
BirdsNews.com

The San Francisco Planning Commission by a 5-1 vote on July 14 approved new Bird Safe Building Standards. The San Francisco Board of Supervisors is expected to consider at its August or September meeting the new standards, which were supported by the American Bird Conservancy and Golden Gate Audubon.

“Bird deaths from building strikes, one of the main causes of bird mortality in the U.S., can often be prevented with reasonable, affordable measures,” said Mark Welther, executive director of Golden Gate Audubon.

“This is a very forward-thinking and wildlife-friendly approach to prevent the death of up to 1 billion birds each year in building collisions nationwide,” said Dr. Christine Sheppard, manager of ABC’s Bird Collisions Campaign.

U.S. Congressman Mike Quigley (D-IL) has introduced legislation (HR 4797) that calls for each public building constructed, acquired, or altered by the General Services Administration to incorporate, to the maximum extent possible, bird-safe building materials and design features. The legislation would require GSA to take similar actions on existing buildings, where practicable.  The terms “bird-safe building materials and design features” are defined through reference to several publications addressing those topics.

The push to make buildings greener has ironically increased bird mortality because it has promoted greater use of glass for energy conservation.

Reduction of bird strikes with new buildings can be achieved with fritting – the placement of ceramic lines or dots on glass. Fritting is used to reduce heating and air conditioning costs by lowering heat gain in window, and when applied in particular patterns, increases the visibility of the window to birds.  While reducing the likelihood of bird impacts, there is little effect on the transparency of the glass from the inside.

The Planning Commission voted on a 38-page “Standards for Bird Safe Buildings,” which included sections on safer windows, night lighting, and the construction of wind turbines in the urban environment.

Light pollution can confound birds’ ability to navigate by the stars during migration.  Lighted buildings can attract birds, resulting in their exhaustion, injury, or death.  The guidelines would reduce unnecessary interior and exterior lighting during bird migratory seasons.

The guidelines split parts of San Francisco into “Blue” and “Green” zones, depending on the degree of risk new projects in those areas may pose to birds.  Compliance with the guidelines will be mandatory in Blue Zones, which are located near bird nesting and feeding sites, in fog-prone areas, along migration paths and resting areas, or in districts that are zoned to allow tall buildings.  In lower-risk Green Zones, the guidelines will be voluntary.

Birds and Collisions

On July 12, ornithologist Dr. Colin Miskelly received a phone call with mind-boggling implications. A Department of Conservation colleague reported that Broad-billed Prions, which spend their lives at sea, had been blown over the Tararua Range of New Zealand’s North Island.

And then reports of massive prion fatalities on New Zealand’s western coast began arriving.

Since 1986, hundreds of volunteers patrolling about 3,700 km of New Zealand coastline have documented up to 14,462 dead petrels, shearwaters, penguins and other seabirds in single “wrecks” due to sudden disappearance of food or bad weather. But Miskelly, Curator of Terrestrial Vertebrates at Te Papa Museum of New Zealand, suspected the July wreck may reach 350,000 birds.

“The true scale of the event was massive,” said Dr. Phil Battley, senior lecturer in zoology at Massey University, Palmerston North, New Zealand, at the time. “People found 400 to 500 birds per km most places they look along the North Island, and that’s just the ones on the surface that were not covered by sand.”

Phil Battley

As anecdotal reports and careful counts are compiled and ornithologists analyze the increasingly gruesome statistics, the estimated death toll rises.

“Far more prions were killed in July than during the total history of seabird wrecks recorded over 37 years by the Ornithological Society of New Zealand’s Beach Patrol Scheme,” said Miskelly. “Details are still being collected and collated, but large numbers have been found between Dargaville to Okarito, which are 900 km apart. In places, over 400 birds were stranded per kilometre of coast, and more were blown inland.”

Colin Miskelly

Small numbers of other species of storm-pummelled birds also were found dead. Survivors included Salvin’s Prion (Pachyptila salvini), Antarctic Prion (Pachyptila desolata), and Slender-billed Prion (Pachyptila belcheri).

Miskelly, Battley and other scientists agreed that roughly 90% of all dead and exhausted birds were Broad-billed Prions (Pachyptila vittata). “The largest previous wreck of Broad-billed Prions was about 1,400 birds,” said Miskelly. “But the 2011 wreck is likely to be 250 times larger.”

Blown in the winds

Beginning about July 6 and continuing for a week, relentless winds blew north from Antarctica toward Australia then bent east toward New Zealand, eventually sweeping Broad-billed Prions (Pachyptila vittata) toward New Zealand’s west coast. Thousands of the gray seabirds with a wingspan up to 66 centimetres, weighing about 200 grams were grounded in what Miskelly, Battley and other New Zealand scientists consider to be the largest avian wreck on record for any bird species in New Zealand.

Bird rescue centres swamped

Concerned residents rescued dozens, and then hundreds of exhausted and cold prions. People carried dozens of birds in boxes, dog crates or other containers to Massey University’s Wildlife Health Centre, or local vets and bird rescue centres. The unprecedented numbers of birds being handed in alive signalled that the wreck was huge. “The Massey vets had received 270 prions by July 12, but Kapiti SPCA (in Waikanae, NZ) received more than 500, including 400 in one day,” Battley said.

About 200 Broad-billed Prions were taken to the Anexa Raglan Vet Clinic in Raglan, NZ. “Keeping these birds alive has been such a challenge. Department of Conservation people and other birders told us that they would probably all die but we were hoping to prove them wrong,” said Moana Robb, junior veterinary nurse at the Raglan clinic. “It’s been really disheartening and quite gutting that we are down to our last two out of about 200.”

Media reports included accounts of hundreds of birds found dead on beaches, or simply sitting on land, still alive but unable to fly out to sea to eat.

Pukerua Bay resident Jaroslav Benc told The Dominion Post that he saw dead birds littering the beach.

Jared Smith, a writer with the Taranaki Daily News, said New Plymouth’s Department of Conservation offices looked like “a casualty ward for seabirds as a steady stream of victims poured in this week.”

“By 9 p.m. tonight (July 14) when we went home, we had admitted 549 prions,” said Dr. Brett Gartrell, director of the New Zealand Wildlife Health Centre at Massey University.”The birds are coming in with starvation, anaemia, hypothermia and dehydration. About 100 of these died in care. Another 100 were dead on arrival. Wellington Zoo has over 600, Hamilton rehabilitators have about 100.”

The first release of the strongest rescued prions from Massey University began on July 15.

Life and death on the winds

“Prions are a group of six small, closely-related seabirds that are hugely abundant in southern oceans,” Miskelly said. “They are petrels, and like most petrels, typically breed in enormous colonies on remote islands free of introduced predators.”

Like all petrels, prions live at sea, coming to land only so that females of nesting pairs can lay a single egg in a burrow nest and feed their young.

The three prion species with the widest bills, including the Broad-billed, use comb-like structures along the edge of the upper mandible to filter tiny crustaceans and other small animals and their eggs from seawater. Prions seek out the food bounty of ocean upwellings.

Miskelly, an expert on prion behavior, said prions are usually unfazed by strong winds, and actually use them to fly long distances with ease. But for more than a week in July, gale-force winds continually pushed locally breeding prions eastward toward danger: land.

Reports by MetService, an international weather forecasting service, said fast-moving showers and thunderstorms pummelled New Zealand on July 9, with damaging winds on the Kapiti Coast blowing 70 to 90 km per hour. A tornado reported by eye witnesses was associated with a strong thunderstorm east of Waikanae at 4 p.m. on July 9.

As New Zealand’s western shore loomed closer, prions began to struggle to avoid it. Eventually, they were driven ashore in exhausted waves in the tens of thousands, possibly hundreds of thousands.

Dead seabirds found on New Zealand beaches in 1998

The area in northeastern Alberta includes a surface-mineable area containing facilities, mine pits and toxic tailings ponds. Scientists estimate the avian mortality at the ponds to be 458 to 5,029 birds annually.

The only self-sustaining wild population of whooping cranes in the world breeds in Wood Buffalo National Park in the Northwest Territories and northern Alberta. That group consisted of only 270 birds in 2008.

Rapid development of oil sands

“There is little evidence that the governments of Alberta and Canada have adequately considered whooping cranes in the approval of industrial developments in Alberta’s oil sands region,” said author Peter Lee, executive director of GFWC. “The rapid pace and large scale of Alberta’s oil sands industrial developments within the flight path of migrating whooping cranes raises the concern that damage may already be done.”

Lee said the Kearl Lake and Jocelyn North Mine oil sands projects are two recent examples of major project approvals where whooping cranes were given only cursory, inadequate treatment in the environmental impacts assessments and joint panel decisions.

Toxic tailings ponds

At tailings ponds, cranes can ingest toxins or risk oiling, which can kill birds or reduced their ability to migrate successfully. There are other risks due to air pollution, power lines, declining water quality and contamination of the food web contaminants.

However there is a lack of sufficient credible scientific monitoring of the bird’s migration, landing, and mortality.

Canada’s Committee on the Status of Endangered Wildlife in Canada designated whooping cranes as endangered in 2000, and the species is currently listed as Endangered on Schedule 1 of Canada’s Species at Risk Act.

The species is protected in Canada under the Migratory Birds Convention Act, National Parks Act, Canada Wildlife Act, and Species at Risk Act, as well as by provincial and territorial wildlife acts.

In Alberta, the whooping crane is currently ranked ‘At Risk,’ meaning the species is in danger of local extinction. The Alberta Wildlife Act lists the whooping crane as endangered. It is protected in the United States by the Migratory Bird Treaty Act and the Endangered Species Act.
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