Monthly Archives: June 2017

Towards seabird-safe fisheries, global efforts and solutions

wandering_alba.jpg(Stephanie Winnard & Berry Mulligan 29 June 2017)
The RSPB and BirdLife International have produced a new publication that presents some of the remarkable efforts fisheries have made on a global scale to tackle seabird bycatch.

Seabirds are one of the most threatened groups of animals in the world, with many species in decline to due being incidentally killed in fisheries.

They are caught and drowned on baited longline hooks and in nets, and are killed by collisions with trawl cables. It’s estimated over 100,000 albatross meet this grisly fate every year.

However this doesn’t have to be the case. Simple and inexpensive measures already exist that can be highly effective in preventing seabird deaths, and others are still in experimental stages but have shown great promise.

Some fisheries have already reduced deaths by over 80%, demonstrating the scale of potential success.

The RSPB and BirdLife International have produced a new publication that presents some of the remarkable efforts fisheries have made on a global scale to tackle this problem; from saving turtles in Peru to Black-browed Albatross in Namibia.

These stories demonstrate that collaboration between fishers, scientists and decision makers can lead to practical solutions that will ultimately turn the tide for many of these seabird species.

This booklet is a resource for the fishing industry to inform them of the measures they can take to avoid seabird deaths, and to inspire them to take action to improve the sustainability of global fisheries.

It would not have been possible to create this resource without the generous support of the David and Lucile Packard Foundation.

New parrot species discovered in Mexico

Blue-winged Amazon(Matt Mendenhall 27 June 2017; Photo Tony Silva)

Ornithologists have announced the discovery of an apparent new species of parrot in a remote part of Mexico’s Yucatán Peninsula. They’re calling it the Blue-winged Amazon because the tips of its wing feathers are bluish green. (Its Spanish name is Loro de alas azules.)

It will be up to the American Ornithological Society’s North and Middle American Classification Committee to decide whether to accept the parrot as a new species.

The authors of a paper describing the species propose that its scientific name be Amazona gomezgarzai. The Amazona genus includes about 30 other species native to the Americas, and the specific name, gomezgarzai, honors Miguel A. Gómez Garza, the man who first came across the birds and recognized that their colors differed from other known species. Gómez Garza is a wildlife veterinarian and the author of Loros de Mexico, a 2014 book about the parrots of Mexico.

He spotted the birds in early 2014 south of the town of Becanchén, which is about in the middle of the peninsula. The new parrot occupies a similar area in the Yucatán as the Yucatán Amazon (A. xantholora) and the White-fronted Amazon (A. albifrons), but it does not hybridize with them.

A distinctive feature of the new taxon is its call, which is loud, sharp, short, repetitive, and monotonous; one particular vocalization is more reminiscent of an accipiter than of any known parrot. The duration of syllables is much longer than in other Amazon parrot species. In flight, the call is a loud, short, sharp, and repetitive yak-yak-yak. While perched, the call is mellow and prolonged.

This species lives in small flocks of less than 12 individuals. Pairs and their offspring have a tendency to remain together and are discernible in groups. Like all members of the genus Amazona, this parrot is an herbivore. Its diet consists of seeds, fruits, flowers, and leaves obtained in the tree canopy.

An analysis of mitochondrial DNA genes indicates that the Blue-winged Amazon has evolved only recently, about 120,000 years ago, from the White-fronted Amazon.

The paper describing the species says it occurs in an area of roughly 100 square kilometers (39 square miles) centered south of Becanchén. “No part of the range is presently protected in any form,” the authors write. “Very little is known about this parrot’s biology. There is no conservation program currently in effect to preserve this parrot, but its long-term existence impinges on the local communities and making them aware of this parrot’s value as a result of its uniqueness, its potential as a bird watching attraction, and the fact that it is present only locally. Its small range and rarity should make its conservation a priority.”

 

The trouble with being a handsome bird

(SD, Monash University 28 June 2017; Photo Kaspar Delhey)

Male birds often use brightly colored plumage to be attractive to females. However, such eye-catching trimmings may also attract unwanted attention from predators. Now, a new study led by Monash University has found that showy males indeed perceive themselves to be at a greater risk of predation.

The study’s lead author, PhD student Alex McQueen, from the School of Biological Sciences, studied risk-taking behaviour in Australia’s favourite bird, the superb fairy wren, also known as the blue wren. Every year, male wrens change their color from dull brown to a stunning combination of brilliant azure blue, with contrasting dark-blue and black plumage.

This annual color change makes them a useful study species for measuring the risk of being brightly colored, as the behaviour of the same individual bird can be compared while he is in different colors.

As part of this study, published in the Royal Society Journal Proceedings B, researchers snuck up on unsuspecting fairy-wrens. They then broadcast fairy-wren alarm calls from portable speakers, and observed the behaviour of the birds.

“When birds hear such alarm calls, it tells them there might be a predator nearby,” says Alex. “Whether they ignore the alarm or flee to cover, and the amount of time taken to re-appear from cover, tells us how high they perceive their predation risk to be.

“We found that fairy-wrens were more cautious while they were bright blue: they fled more often in response to alarm calls, and took longer to re-emerge from hiding. They also spent more time in cover, and more time scanning their surroundings.”

Alex’s supervisor, Associate Professor Anne Peters said an interesting observation was that brown fairy-wrens appeared to take advantage of the risks faced by blue males.

Fairy-wrens go about in social groups, often made up of individuals in different plumage colors.

“When a blue male was nearby, fairy-wrens spent less time hiding in cover after fleeing in response to alarm calls, and devoted less time to keeping a look-out,” Associate Professor Peters said.

“This could be because the dull brown wrens view blue males as a colorful decoy that reduces their own risk, or because blue males are more vigilant, allowing the brown wrens to drop their guard.”

The study, which was done in collaboration with Professor Rob Magrath from the Australian National University (ANU), shows that fairy-wrens perceive themselves to be at higher risk when they display their bright blue plumage, and adjust their behaviour accordingly.

Birds’ feathers reveal their winter diet

(AOS 21 June 2017; Photo RM Jensen)
Influences outside the breeding season can matter a lot for the population health of migratory birds, but it’s tough to track what happens once species scatter across South America for the winter months. A study from The Condor: Ornithological Applications tries a new approach for determining what declining migratory grassland birds called Bobolinks eat after they head south for the winter—analyzing the carbon compounds in their plumage, which are determined by the types of plants the birds consume while growing their feathers during their winter molt.

Thanks to a quirk of photosynthesis, rice contains a different ratio of carbon isotopes than most of the native grasses in South America where Bobolinks winter. Rosalind Renfrew of the Vermont Center for Ecostudies and her colleagues took advantage of this, collecting feather samples from wintering Bobolinks in a rice-producing region and a grassland region and from breeding Bobolinks in North America. When they analyzed the feathers’ isotopes ratios, the results from South America confirmed that isotopes in Bobolinks’ feathers reflected the differences in their diets between regions with and without rice production. The samples taken in North America showed that the winter diet of most individuals was weighted more toward non-rice material, but that rice consumption was highest late in the winter, when rice is nearing harvest and the birds are preparing for their northbound migration.

Rice could be beneficial by providing the birds with needed calories as they prepare for their journey north, but it could also increase Bobolinks’ exposure to pesticides and threats from farmers who see them as pests. According to Renfrew and her colleagues, maintaining native grasslands, encouraging integrated pest management programs to reduce toxic pesticide applications, and compensating farmers for crops lost to feeding birds all would be helpful.

“The time spent coordinating the field work for this study may well have been greater than the time spent collecting the data,” says Renfrew. “It was truly a team effort, and the assistance we received from our partners was absolutely essential, especially in South America. Aves Argentinas and the Museo de Historia Natural de Noel Kempff Mercado provided priceless logistical support, and this study could not have happened without them. Some of the same partners have provided input on a Bobolink Conservation Plan that lays out actions to address threats to grassland birds in North and South America, based on results from this and other studies.”

“As Bobolink populations continue to decline, Renfrew and her colleagues use state-of-the-art isotope analysis techniques to assess the Bobolink’s diet on its South American wintering grounds,” according to John McCracken of Bird Studies Canada, an expert on grassland bird conservation who was not involved with the study. “The authors conclude that rice may have negative effects on Bobolinks, owing to its relatively low nutritional quality and from exposure to insecticides.

How we’re saving the kings of the ocean

wandering_albatross.jpg(Stephanie Winnard 22 June 2017)

It has been another busy year for the Albatross Task Force, and our teams have made good progress in reducing the bycatch of vulnerable seabirds in some of the world’s most deadly fisheries

Albatrosses are one of the most threatened groups of birds in the world, with 15 of 22 species currently at risk of extinction. One of the major causes of their decline is being caught accidentally as bycatch on baited longline hooks or struck by trawl cables and dragged under the water.

Horrifyingly it’s estimated that around 100,000 albatross die every year in longline and trawl fisheries around the globe. For birds that are long-lived yet slow to breed, these deaths have lead to huge population declines with some colonies having halved in size since the 1990’s.

To combat these needless deaths the Albatross Task Force was set up in 2006 to find solutions to this problem, and work with fisheries and governments to save the albatross. Over the last 12 months the team has made good progress towards saving vulnerable seabirds in some of the world’s most deadly fisheries, the details of which are in our new report.

8/10 of our high priority fisheries now have regulations in place to protect seabirds, following an announcement from Argentina that seabird regulations are to be introduced by May 2018 that will require trawlers to use bird-scaring lines.

The benefit for seabirds in Argentina will be huge, as the main trawl fleet is responsible for the death of 13,500 black-browed albatross per year, an impact we expect to reduce by over 85% based on our experimental results.

Across the Atlantic in Namibia, since seabird regulations came into force there, 100% of trawl and demersal longline vessels have now been provisioned with bird-scaring lines, constructed through our collaboration with a local women’s group, Meme Itumbapo.

By next year we hope to show that Namibia has achieved significant bycatch reductions similar to South Africa where we documented a 99% reduction in albatross deaths in the trawl fishery following the introduction of bird-scaring lines. This will be a major win for albatross, as our estimates for the two Namibian fleets suggest in excess of 25,000 seabirds were previously killed annually.

Our work in small scale fisheries has also leapt forward over the last 12 months; in Chile we have shown that modifications to purse-seine net design has the potential to reduce shearwater bycatch massively, and in Peru trials of net lights have virtually eliminated bycatch of not just seabirds, but also turtles and marine mammals.

This is all hugely exciting as no mitigation measures previously existed for these types of fisheries.

All of these successes have only been possible due to the collaborative efforts between our in country partners, the RSPB and BirdLife International, plus generous funding from RSPB membership, external sponsors and many kind individual donations.

We are extremely thankful for the continued support we receive, without which we wouldn’t be able to keep up the fight to save the albatross.

Högsta hönset – en personlighetsfråga?

gammalsvensk_dvärghöna.jpg

(Marie Mattsson 11 juni 2017; Foto Anna Favati)

Länge har det funnits evolutionära modeller som bygger på att djur är optimalt anpassade som konsekvens av det naturliga urvalet. Men djurindivider kan ha olika personligheter och därmed kan deras beteende ibland te sig icke-optimalt. I flera svenska studier har forskare försökt reda ut hur och varför djur har personlighet med hjälp av gammalsvenska dvärghöns.

Forskning kring att djur har personlighet är något relativt nytt. Med personlighet hos djur menar man att individer beter sig olika varandra, men relativt lika sig själva över tid och i olika situationer. Trots tidiga observationer av att individer kan skilja sig åt i beteenden, började personlighetsforskning hos djur först i början på 2000-talet.

Hur ser då personlighet hos ett djur ut? Hanne Løvlie är etolog vid Linköpings universitet och har forskat mycket på höns och dess vilda anfader djungelhönset.

– Att djur har olika personlighet är något som ifrågasätter idén att djurs beteenden är optimala då det kan leda till att till exempel en tuff individ är tuff också när det kan vara farligt, och en feg individ kan vara feg när det istället kanske kan löna sig att vara tuffare, berättar Hanne Løvlie.

Olika personlighetstyper kan ha olika överlevnadsstrategier

Precis som hos människan utvecklas djurens personlighet genom både arv och miljö. De flesta djur lär sig hur de ska reagera på olika saker, men de har inte obegränsat med energi, tid och kapacitet, och måste därför göra avvägningar. För ett djur kan responsen inför en situation vara en fråga om liv eller död.

–  Personligheter kan även hittas hos ryggradslösa djur. En av de allra första studierna av djurs personlighet gjordes faktiskt på spindlar. Där kunde man se att beteenderesponserna skilde sig mellan olika individer, vissa var onödigt aggressiva när aggression inte behövdes. Responser behöver inte vara antingen eller, det kan finnas flera steg på skalan mellantvå extrema sätt att reagera, säger Hanne Løvlie.

Variation i personligheter kan vara olika strategier som påverkar till exempel överlevnad. Det har gjorts studier med bland annat talgoxe där man sett att vissa personligheter överlever bra under vissa förhållanden, medan andra personligheter fungerar bättre i andra situationer. Ett utforskande och risktagande karaktärsdrag hos en hane kommer exempelvis till nytta efter en vinter med gott om mat då det sedan blir hård konkurrens om häckningsrevir, medan en mer passiv hane sparar energi och kan ha en större chans att överleva under vintrar då det istället är ont om mat.

Höns är bra forskningsobjekt

Tillsammans har Anna Favati, doktorand i etologi vid Stockholms universitet, och Hanne Løvlie har gjort flera studier på hönsrasen gammalsvensk dvärghöna, en nära släkting till röd djungelhöna som är ursprunget till de flesta tamhönsarter. Dvärghöns lämpar sig bra för den här sortens forskning eftersom de inte är så hårt avlade utan beter sig som den ursprungliga hönset.

–  Hönsen i studierna är tama vilket gör dem lätta att observera, samtidigt som de ger relevant information eftersom de är nära ursprunget i sitt beteende, berättar Anna Favati.

Höns är en grupplevande art, som under naturliga omständigheter lever i grupper med ett par tuppar och något fler hönor. De bildar inte par, utan båda könen har många sexuella partners, och för tupparnas del leder det till hög konkurrens om hönorna. Både tuppar och hönor bildar tydliga dominanshierarkier. Det är som en trappstege där de högst upp har främst tillgång till resurser som exempelvis mat eller, i hanarnas fall parningar. När den sociala ordningen väl är upprättad behöver tupparna oftast inte slåss mer, utan hackordningen blir stabil och leder till att det är få onödiga slagsmål och konflikter.

Vad kom först; hönan eller ägget?

Man vet att det finns ett samband mellan dvärghönsens personlighet och rang, men hur kommer det sig? I en av studierna så tittade man på om det finns ett samband mellan hierarki och personlighet hos höns. Individer beter sig olika beroende på var de befinner sig i rangordningen, men har en viss individ större chans att stå högt i rang på grund av sin personlighet eller har den fått personligheten tack vare sin position i hierarkin? För att undersöka kopplingen mellan personlighet och rang började forskarna med att kategorisera tupparnas personlighet genom att titta på hur de reagerar i olika situationer.

Läs mer

 

Gribbene spøger i det danske luftrum

Gaasegrib.jpg

(Jan Skriver 21 juni 2017)

Den seneste måned er der set tre gribbearter i Danmark. Og tiden nærmer sig årsdagen for historiens største forekomst af gribbe i det danske landskab, da 34 gåsegribbe fløj Jylland tyndt på fire dage. Mange ornitologer har gribbe i tankerne, når de på dage med god termik spejder efter store vingefang i gribbemåneden over dem alle

Det er slet ikke umuligt, at flokke af gåsegribbe kan blive et hyppigere indslag, ja måske ligefrem til årlige gæster i den danske natur.

Bestanden af gåsegribbe er vokset markant til skønsmæssigt måske flere end 17.500 ynglepar i Spanien, hvor der i 1980’erne kun var et par tusinde gribbe.

Spanien er Europas gribbeland nummer et, og unge gribbe fra Den Iberiske Halvø tager efter de senere årtiers fremgang i stigende grad på strejftog nordpå, mens de store ådselædende fugle spejder efter døde dyr i terrænet.

I slutningen af maj blev der set 94 gåsegribbe i den sydvestlige del af Tyskland. Kort forinden var flokken observeret i Belgien.

”Der er ikke mange hundrede kilometer fra Nederlandene eller Tyskland til Danmark for en flok gribbe, der i løbet af en dag kan tilbagelægge virkelig store afstande på brede vinger uden at bruge nævneværdig energi. En god vind fra sydlige retninger, som kan bære gribbene mod nord, og vi har en situation som i de magiske dage i 2016, da 34 gåsegribbe nåede til egnen omkring Aalborg og fra 24. juni og fire dage frem blev observeret mange steder i Nord- og Midtjylland”, siger ornitologen Henrik Haaning Nielsen, der er redaktør af Dansk Ornitologisk Forenings internetmagasin Pandion.

”Noget tyder på, at ustadigt vejr, hvor en front fra sydlige retninger, gerne med lummer og trykkende tordenluft, kan bringe gribbe fra Sydeuropa til vores breddegrader. Termiktrækkerne bevæger sig bogstaveligt talt foran fronten. Det er ustadigt sommervejr mere end stabilt højtryksvejr, som kan øge chancen for, at Danmark får gribbebesøg”, siger Henrik Haaning Nielsen.

Gribbebesøg fra Alpelandet

Gribbesæsonen i Danmark anno 2017 begyndte i år 20. maj, da en lammegrib blev set først ved Hyllekrog senere på Møn. Dagen efter blev gribben observeret over Feddet ved Præstø, hvor den kæmpemæssige fugl, der i silhuet kan minde om en falk af gigantiske dimensioner, fløj nordpå.

Lammegribben er en af Europas mest sjældne rovfugle, men et udsætningsprojekt i Alperne har hjulpet bestanden til fremgang. Projektet, der begyndte i 1986, har resulteret i en ynglebestand i Alperne, der i disse år nærmer sig 50 par.

Lammegribben er kendt for at opholde sig i store højder. Den kan have sine ynglepladser i op imod 2.000 meters højde.

Den voksende bestand af lammegribbe giver flere fund af strejfende unge fugle til landene nord for Alperne. For eksempel har også Norge haft besøg af en lammegrib. Ligesom det er tilfældet med gåsegribben, er det overvejende sandsynligt, at Danmark vil få besøg af lammegribben med jævne mellemrum som et resultat af flere ynglepar i Alperne.

”Unge lammegribbe er kendt for at strejfe over store afstande, så selv om arten er stærkt knyttet til bjergrige områder, kan vi forvente i hyppigere grad også at se den i lavlande som Danmark”, siger Henrik Haaning Nielsen.

Läs mer