Tag Archives: bird

Craniac Country: Nebraska’s Sandhill Crane Migration

Two girls in a jeep rumble around the country roads of Nebraska to check out the spring sandhill crane migration and can’t believe their eyes. Be careful. Watching this might make you a craniac.


Could a proposed EU ban on discarding bycatch threaten seabirds?

Northern gannet picture taken at bird colony of Helgoland, North sea, German Bight, May 2002. (Photo/ Michael Haferkamp)

You know the scene. A commercial fisherman hoists a net roiling with flip-flopping fish. Clouds of seabirds swarm and fill the air with a greedy squawking, their beaks hungry for unwanted catch.

That raucous chorus may get a little quieter soon as birds are forced to seek their feast elsewhere. In a move aimed at curbing the devastating environmental consequences tied to commercial fishing, the European Union looks to consider new restrictions that would ban the discard of unwanted fish. The rule could be a win for fisheries conservation, but in a twist of good intentions, could also risks endangering the gannet, a seabird that thrives on bycatch tossed overboard.

Fisheries have dealt more than one blow to seabird populations as birds compete for resources or risk becoming ensnared in equipment. One of the few successful species, the gannet, has adapted to exploit the leftovers of commercial fisheries, swooping in on fish and other creatures thrown aside and left behind.

Dr. Keith Hamer, a researcher with Leeds’ Faculty of Biological Sciences is leading a team of researchers that will study the gannet and assess the possible consequences of imparting a ban on discarding unwanted catch. “Although discards should be stopped to protect marine biodiversity, research is needed on the impact of a ban, so policy makers can understand the best way to implement it,” said Hamer in a press release.

The study will especially look to better understand how gannets rely on bycatch for raising chicks. Past research indicates that breeding pairs may prefer different menus with some birds relying mostly on discards from fishing boats and others seeking out sand eels or diving for mackerel and herring. “We think gannets have different aptitudes and specialities and for some, that skill might be finding and following fishing boats,” said Hamer.

So if gannets feel like they’re being watched, they’re not so far off. Researchers plan to catch and tag breeding pairs from 12 colonies throughout the United Kingdom. Hamer along with scientists Stephen Votier of the Marine Biology & Ecology Research Centre at the University of Plymouth, and Stuart Bearhop, with the University of Exeter, will keep tabs on the birds’ locations, diving patterns, diet and nests.

“Although the long-term benefits of a ban will be positive, we need to accurately predict short-term impacts as well,” said Hamer. “If gannets have specialised to the extent we believe, rather than cut off a crucial food source overnight, a gradual phasing in of the ban would allow them time to retrain to find food elsewhere.”

Hopefully this thinking ahead will help prevent a new conservation crisis from cropping up even as the EU takes steps to solve another.


Migratory birds prefer organic

Going organic isn’t just a popular choice for eco-savvy dieters, turns out migratory birds like it too. A new study out of Lund University in Sweden shows that migrating birds lean towards green when it comes to large-scale monoculture farms, with higher abundances and diversity of birds choosing to stop at organic farms than conventional ones. The findings offer new crops for thought when it comes to managing agriculture for wildlife well-being.

The idea that organic farming is good for wildlife is nothing new. Farming practices that hit overdrive and heavy pesticide use have been linked to drops in wildlife populations. But previous studies focused largely on bugs or resident bird populations. Juliana Dänhardt and Martin Green of Lund University decided to take the research a step further, focusing on migratory bird species.

Migratory birds get hit with a double whammy when dealing with environmental stress. They contend with a lot of the same environmental pressures as resident birds, but enjoy the added baggage that comes from moving into a temporary living situation. These visitors tend to show up at tilling time to an unfamiliar landscape and must fuel up in a hurry before embarking on the next leg of their journey.

Dänhardt and Green wanted to see if organic farming and more diverse cropland would helped alleviate some of these pressures. In 2005, they and their team selected a dozen pairs of farms in Falsterbo, Sweden, one of the richest agricultural regions of the country. The pairs were set up to compare organic versus conventional and diverse versus simple crop farms. During the fall migratory season, they conducted bird surveys to see what happened. Dänhardt and her colleagues found the relationship between birds and farm preference to be a complicated one.

The strength of bird populations was all over the show. Some types of birds did prefer diverse organic farmland, while others were less discerning. And certain species, such as geese and golden plovers, showed a penchant for wide-open monoculture fields. But one overarching trend did emerge from the complexity. Turns out, birds that chose the wide-open fields also preferred the organic version.

At the moment, ag trends in Sweden lean towards encouraging crop diversity as a way to bolster wildlife populations, but this study indicates that supporting organic or low-impact farming practices on large-scale monoculture farms could be another method for helping out those hard-flying, fast-eating, stressed out migratory birds.

The study is published in the online early edition of the journal Oikos.


Greater sage grouse worth endangered species listing, but other species come first

There’s only so much room on the endangered species list, and greater sage grouse will have to wait in line a little longer to receive protection. A report released today by the U.S. Fish and Wildlife Service declares that the bird is heading towards extinction and warrants listing, but does not take priority for designation as about 250 other species are in more immediate danger.

The announcement serves notice to land managers and the energy industry to bulk up conservation efforts for the grouse, but these efforts will take place without the backing power of listing under the federal Endangered Species Act.

“Voluntary conservation efforts on private lands, when combined with successful state and federal strategies, hold the key to the long-term survival of the greater sage-grouse,” said Assistant Secretary of the Interior for Fish and Wildlife and Parks Tom Strickland in a press release.

Across the West, greater sage grouse populations dwindled to about 56 percent of their former range. In places like Wyoming’s Red Desert, key habitat for the grouse and an energy development hotspot, populations dropped 90 percent in the last 50 years, according to Lorraine Keith, public affairs officer with the Rock Springs office of the Bureau of Land Management. This 90 percent drop isn’t just because of energy development, the decline started before the energy boom, said Keith. But if the trends of the last 50 years continue, many populations will disappear in the next 30 to 100 years, according to the U.S. Fish and Wildlife Service.

The downside of the ruling is that precluding the grouse from listing relies on industry and state agencies to take the necessary management steps to stop the bird’s decline, a practice which so far has left sage grouse shaking in their leks. But the ruling does make conservation efforts for the bird a priority, especially if industry would like development to continue in the West.

“The sage grouse’s decline reflects the extent to which open land in the West has been developed in the last century,” said Secretary of the Interior Ken Salazar in a press release. “This development has provided important benefits, but we must find common-sense ways of protecting, restoring, and reconnecting the Western lands that are most important to the species’ survival while responsibly developing much-needed energy resources. Voluntary conservation agreements, federal financial and technical assistance and other partnership incentives can play a key role in this effort.”

Though not listed this time, the federal government has their eye on greater sage grouse. U.S. Fish and Wildlife Service is adding the greater sage grouse to the endangered species candidate list and will undertake annual reviews of the bird in an effort to make sure it doesn’t slip over the edge to extinction.

While not a perfect outcome for the conservation community, the ruling gives them hope for the bird. “Up to this point we’ve seen plans that predict continued sage grouse declines,” said Erik Molvar, wildlife biologist with the Biodiversity Conservation Alliance, “but hopefully this decision will be the wake-up call that’s needed to turn things around and compel corporate interests like the oil industry to start using advanced technologies to achieve major reductions in impacts on the sage grouse, other wildlife, and the American West as a whole.”


Dosed: Livestock scavenging vultures consume cocktail of veterinary drugs

A griffon vulture soars through canyons of the Douro River in Portugal. (Photo/Morgan E. Heim)

Griffon, their name conjures images of legend and mythology, but in the skies above Spain and Portugal, thousands of real life griffon vultures survey the earth looking for their next meal. And to a griffon, nothing says “yummy” quite like a fresh pile of pork carcasses – well, maybe sheep.

Don’t knock it. They are one of nature’s best cleaner-uppers. But it turns out that griffon vultures and at least two other vulture species are ingesting something not on their carrion menu, drugs and lots of them.

Vulture numbers have soared in Europe since the 1980s, thanks in part to the common practice of carcass dumping of dead livestock, also called muladares, which provide vultures with a ready and reliable supply of chow. But in cattle, drugs abound. And lunch at a muladar promises a chemical cocktail of veterinary medicine as well as protein.

A griffon vulture soars in the skies above the Douro River in northeastern Portugal. (Photo/Morgan E. Heim)

A new study by Guillermo Blanco with Museo Nacional de Ciencias Naturales in Madrid showed that the proportion of vulture nestlings testing positive for antibiotics rose from 0 percent in 2001 to 70 percent in 2006, and now scientists are seeing a triple threat. Blanco found griffon, Egyptian and cinereous vultures, contained combinations of antibiotics, anti-parasitics and non-steroid anti-inflammatory drugs, such as aspirin, in their system, a never before seen combination in a wild animal, according to the researchers.

Scientists are still studying what this chemical cocktail could spell for the vulture, and the three species did show variance in the amounts and types of drugs found in their systems, possibly due to the differences in how they feed. But Blanco and his colleagues do mention possible reasons for why and how the drugs are building up in the birds’ bodies.

Vultures typically split mealtimes between muladares and “vulture restaurants,” scavenging from the carcasses of free-ranging livestock. Drugs abound in both food sources, but reside in much greater concentrations and types in the bodies of farm-raised cattle – farm-raised livestock require more drugs due to their compact living quarters. Recent European Union regulations aimed at curbing the spread of mad cow disease made it illegal to abandon carcasses of free-roaming cattle in the countryside. As an unintended consequence of the rule, this practice eliminated one key source of food for the vulture, concentrating food in the veterinary drug-laden muladares. The regulation has also been reputed to be a probable contributor to the vulture’s decline since 2003.

Side-effects could include increased disease, due to exposure to immuno-suppressants, changing delicate bacterial communities in the vulture’s system and a rise of infection or transmission at feeding sites.

One remedy would be to allow for carcass abandonment to resume according to the study. “There is no evidence of BSE [mad cow] transmission risk due to the abandonment of unstabled livestock carcasses in the countryside,” wrote the study authors. “Therefore, this traditional practice in the Mediterranean regions should be legally permitted in order to increase availability, dispersion and quality of food for scavengers.”

You can read more about Blanco and his colleagues’ findings in the December 2009 issue of the journal Animal Conservation.


The high fidelity of alligator love

Two American Alligators (Photo/Matthew Field)

Two American Alligators (Photo/Matthew Field)

Oh alligator love, it’s not as fickle as you might think. Get on a gator’s good side and you may just have found a friend for life, if you’re another alligator of course.

In a study that combines field science with molecular biology, researchers from the Savannah River Ecology Laboratory found that alligators were surprisingly loyal partners and akin to birds in their mating habits. The discovery offers new insights into evolutionary links and behavior of crocodilians, birds and dinosaurs – and certainly, at least where one science writer is concerned, proving there is a lot more going on behind those alligator eyes than a cold reptilian stare.

Researchers trapped and re-trapped alligators at Louisiana’s Rockefeller Wildlife Refuge, 76,000 acres of alligator dream real estate bordering the Gulf of Mexico. “Given how incredibly open and dense the alligator population is at RWR, we didn’t expect to find fidelity,” said researcher Stacey Lance. “I don’t think any of us expected that the same pair of alligators that bred together in 1997 would still be breeding together in 2005 and may still be producing nests together to this day.”

Crocodilians have already proven to be more invested in the care of their offspring than most other reptiles, actively nurturing young and defending nests. Crocodiles are even known as considerate egg-layers. As a female drops the egg, she will blindly catch it with a hind leg before it hits the ground and gently place it in the nest. But up until now alligators were thought to be polygamous, mating with several different partners and leading to many fathers for a single nest.

After ten years of following alligators at the refuge, scientists Lance, Travis Glenn, Ruth Elsey and Tracey Tuberville discovered that 70 percent of female alligators stick with who they like. Even if they have multiple partners, the same bachelors get picked year after year, regardless of whether females encounter a new slew of potential suitors.

The study marks the first time fidelity has been observed in any crocodilian species. “In this study, by combining molecular techniques with field studies, we were able to figure something out about a species that we never would have known otherwise,” said Lance. “Hopefully future studies will also lead to some unexpected and equally fascinating results.”

Results of the study were published in the October 7 issue of Molecular Ecology.


Monarch flycatchers: Catching the moment one bird species becomes two

Plumage variations of the monarch flycatcher. (Photo/Courtesy J. Albert Uy)

Plumage variations of the monarch flycatcher. (Photo/Courtesy J. Albert Uy)

How do you measure the instant one species becomes two? Well, in the Solomon Islands, biologist J. Albert Uy is trying to pick a fight with monarch flycatchers to find the answer. The fight’s tipping point has to do with a bunch of feathers, a change in plumage colors that is allowing scientists to capture a snapshot of evolution in action.

A territorial flycatcher (Monarcha castaneiventris castaneiventris) aggressively responding to a taxidermy mount during our mount presentation experiment. We used mount presentation and song playback experiments to test if divergent plumage color and song are used in species recognition between sister taxa (described in Uy et al. 2009). (Photo/Courtesy J. Albert Uy)

A territorial flycatcher (Monarcha castaneiventris castaneiventris) aggressively responding to a taxidermy mount during our mount presentation experiment. (Photo/Courtesy J. Albert Uy)

Flycatcher males are territorial and will launch an avian smackdown towards perceived rivals trespassing on their turf. But a flip of a single gene is turning the monarch flycatcher into a bird of a different color, and in the process changing the social dynamics of rival birds.

It seems that though they are technically still the same species, the black-feathered flycatcher didn’t get the memo about their chestnut-bellied kin, and vice versa. Uy tested this by invading flycatcher territory with dummy birds. What he’s found is that the two don’t see each other as rivals, and are therefore probably more interested in mating with their like-feathered counterparts.

At least in the case of the monarch flycatcher, this single gene and spot of color heralds the birth of an entire new species.

J. Albert Uy (Photo/ C. Low, courtesy J. Albert Uy)

J. Albert Uy (Photo/ C. Low, courtesy J. Albert Uy)

We often hear about species being lost, but rarely do we learn of one being created. Uy’s work provides a glimpse of the “fork in the evolutionary road” as it happens in real-time, and what that could mean for our understanding of bird life.

Uy’s work appears in the current edition of American Naturalist, and you can read more about monarch flycatchers in the 2005 New York Times article, “In Give and Take of Evolution, a Surprising Contribution from Islands.”


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