Using isotope fingerprints in feathers, researchers have pinpointed the northern breeding grounds of a small, colourful songbird.
Myrtle warblers breed across much of Canada and the eastern United States, but winter in two distinct groups—one along the Atlantic and Gulf coasts, another along the US Pacific Coast. They are also one of the few breeds of eastern warbler that have been able to extend their range into the far northwest of the continent.
“The Pacific Coast warblers migrate through the Vancouver area, but it’s been a bit of a mystery exactly where they breed over the summer,” says David Toews, who began the research while a graduate student at the University of British Columbia (UBC).
So Toews, UBC undergraduate student Julian Heavyside, and UBC professor Darren Irwin used isotope signatures to pinpoint where the myrtle warblers breed.
‘We were able to match stable hydrogen isotopes in feathers collected in Vancouver to latitudinal isotope records in rainwater, to determine where the feathers were actually grown,” says Toews, who conducted the analysis as a postdoctoral researcher at Cornell University.
It turns out the warblers that summer on the Pacific Coast breed in Alaska and Yukon, suggesting this form of the eastern warbler spends its entire lifecycle—wintering, migrating and breeding—near the western edge of the continent.
The observatory was started in 2010 by WildResearch, a non-profit dedicated to conservation science and outreach. The observatory allows researchers to monitor how birds use Iona Beach Regional Park, estimate population trends, and create training and
These high latitude warblers also have longer wings and tails, likely adaptations for their longer migration. The evolution of the shorter migration route to wintering sites on the Pacific Coast may have facilitated the breeding expansion of myrtle warbles into northwestern North America.
“Migration has been shown to be genetically based in many species of songbirds such as warblers,” says Irwin. “An intriguing possibility is that the genes for the western migratory route were introduced to the myrtle warblers through interbreeding with a related western group, the Audubon’s warblers.”
The feathers were collected by Heavyside and volunteers at the Iona Island Bird Observatory in Iona Beach Regional Park, Vancouver, with permission from Metro Vancouver Regional Parks.
“UBC has fantastic research opportunities for undergraduate students, and I really enjoyed the chance to contribute to this project,” says Heavyside.
“I’ve volunteered at the IIBO station for several years and it was exciting to see a collaboration form between UBC and WildResearch. Holding a bird in the hand will never get old, and it’s amazing what we can learn from a single feather.”
(Science Daily 19 July 2017)
Roads can be dangerous to wildlife. Animals making the perilous journey against the traffic run the risk of meeting an untimely death. Until recently, it was widely believed, unlike other animals, birds were largely unaffected by the presence of roads and traffic, simply because they could fly.
A new study, published in the open-access journal, Frontiers in Ecology and Evolution, reveals this is not the case. Birds can find roads challenging too – they are less likely to be found next to roads and are hesitant to cross them.
“We observed fewer bird species and individuals of each species near to roads. In addition, they were less likely to cross wide roads,” says Christopher Johnson, who completed this research as part of his graduate studies at the Griffith University, Brisbane, Australia. “We found the smaller-bodied, forest-dependent species were the most affected, avoiding all but the narrowest of roads.
A keen bird-watcher, Mr. Johnson spent many hours carefully recording birds seen next to and crossing roads of different widths around the southern suburbs of Brisbane, Australia. He made sure that the vegetation on either side of the road of his recording sites were the same, as it was more likely that bird crossings occurred between similar habitats. These results were compared to the number of birds seen and heard in the vegetation 100m in from the roadside, to see if the species and numbers of individuals differed.
“For this study, we decided to try something new, by looking at the influence of different road widths (two, four and six-lanes) on bird crossings. In addition, we analyzed the road-crossing ability of birds of different body sizes and whether the type of bird, for example, small forest dependent, large forest dependent, honeyeater or urban tolerant species, had an effect,” explains Mr. Johnson.
The results were quite clear. The widest roads – six-lane carriageways – had fewer bird species and individuals of each species crossing them than the narrower two- and four-lane carriageways. When they looked at the different body sizes and bird types, it was the smaller forest-dependent species that showed the biggest difference.
The authors have suggested several reasons for these findings, such as birds choosing not to come out into the open for fear of predation and the creation of territorial boundaries, as breaks in vegetation can be used by birds to mark the edge of their territory. In addition, many highly aggressive, territorial bird species were seen to be taking advantage of the space near the roads, which would put off other birds crossing.
The findings of this study raises concerns, because bird species play an important role in the health of our natural environment.
Professor Darryl Jones, co-author of the study and Deputy Director of Environmental Futures Research Institute and the School of Environment at the Griffith University explains. “Birds perform a range of services that are of huge benefit to humans, from controlling pests such as mosquitoes and flies to the pollination and seed dispersal of many plants, including those of economic and medicinal value. By restricting bird movements through transportation networks, we are limiting their ability to perform these services and, ultimately, undermining the benefits we gain.”
The authors of the study strongly advise that measures are put in place to connect fragments of forest across roads, allowing wildlife to move freely.
“People use the road transport system to get from point a to b. Unfortunately, this has a negative impact on wildlife movement, particularly within urban environments,” says Daryl Evans, who also collaborated on this the research and is based at the Griffith University. “There are wildlife-friendly solutions to many of these issues, such as specially-designed overpasses, fauna underpasses and fencing so animals can avoid accessing the road, all of which need to be incorporated into the design of our road systems.”
“Further studies should look at the impacts of man-made breaks in vegetation, such as forest tracks and park walkways on bird movements,” adds Professor Jones. “We are currently using our data to identify the ‘at risk’ bird species within suburban areas, to assist with conservation management.”
(Toke F. Nyborg 26 June 2017)
Intens træfældning i Bialowieza-skoven i Polen er ved at tilintetgøre Europas bedst bevarede og sidste stykke urskov
Under trækronernes beskyttende baldakin i Bialowieza-skoven i Polen finder man det bedst bevarede skov-økosystem og sidste stykke løvfældende urskov i hele Europa.
Skoven er udpeget som UNESCO verdensarv og Natura 2000 område.
Nu er intens afskovning ved at tilintetgøre Europas ‘Yellowstone’. Det beretter Jaroslaw Krogulec, leder af BirdLife Polens naturfaglige afdeling:
”Så langt øjet rækker har træfældning efterladt et spor af ødelæggelse. Bialowieza-skoven er et paradis for biodiversitet uden sidestykke på dette kontinent, som byder på et rigt dyre- og planteliv blandt andet Europas største bestand af bisoner”.
Intet undslipper skovarbejdernes motorsave
Godt en tredjedel af Bialowieza-skoven er under officiel beskyttelse som nationalpark, mens de resterende to tredjedele er underlagt skovforvaltning og i stigende grad dårlig forvaltning. I store områder er det kun stubbene efter 150 år gamle træer, som vidner om skovens majestætisk fortid.
BirdLife Polen gør hvad de kan, for at stoppe, hvad de kalder ”statsstøttet hærværk”:
”I løbet af de seneste uger vi (red. BirdLife Polen) sammen med andre miljøorganisationer holdt UNESCO underrettet om ødelæggelserne, og opfordrer indtrængende EU-Kommissionen til at skride ind overfor den polske regerings overtrædelse af habitatdirektiverne,” forklarer Jaroslaw Krogulec.
DOF til Polens premierminister
Sammen med andre BidLife-organisationer støtter DOF de polske organisationers kamp for bevarelse af Europas sidste urskov, og har blandt skrevet direkte til den polske premierminister, Beata Szydlo, med en kraftig opfordring til at stoppe den ødelæggende skovhugst og respektere EU’s naturbeskyttelsesdirektiver.
(Anne Chaon 13 June 2017)
A rare Afghan marsh that was once a royal hunting ground is set to come under the official protection of the UN environment agency, with the aim of saving hundreds of migratory bird species.
On the long, arid journey to the Caucasus and Siberia, across the Hindu Kush massif, the Kol-e-Hashmat Khan wetlands outside Kabul provide sanctuary for the thousands of storks, egrets, pelicans and flamingos that head north every spring from southern India.
But after 40 years of conflict and neglect, their habitat is being threatened by the growth in new homes, irrigation systems, rubbish and global warming which is gradually changing the local environment.
Now the UN has designated the wetlands a conservation site, the Afghan government said on Sunday, as it also looks to help preserve the water supply of the capital.
“There are probably more than 300 or 400 species that pass through, though without an accurate count it is hard to be sure,” says Andrew Scanlon, head of the United Nations Environment Programme (UNEP) in Afghanistan.
They are migratory birds and “tourists” who stay for a very short period of time to find food, he adds.
At daybreak, the marsh comes alive with the morning chatter of the birds hungry for breakfast.
Binoculars in hand, Scanlon stands atop a tower that dominates the landscape.
In the distance is the silhouette of Bala Hissar, an ancient fortress that defended the city for centuries. Opposite, mud houses and sturdier dwellings made from bricks seem to spring up at random, hurrily erected during wars for tides of refugees and displaced people.
It was once a favoured place for royals to go hunting, though Scanlon stresses any activity would have been carried out “in a sustainable way”.
But with the invasion of the Soviet army in 1979 and the succession of conflicts afterwards, including the civil war in the early 1990s, Afghans were preoccupied by their own survival and the environment suffered.
War saw the marshes more or less abandoned until 2005, Scanlon explains.
(Oddvar Heggøy 31 may 2017)
To hekkesesonger på rad med et nedslående antall syngende åkerrikser i Norge kan i 2017 følges av en tredje. Forhåpentligvis går det ikke slik. En av våre aller sjeldneste hekkefugler har møtt mer motgang enn de fleste andre. Kanskje kan nettopp du bidra til å gi den litt etterlengtet hjelp?
Går vi 150 år tilbake i tid fantes trolig titusenvis av åkerrikser i Norge. I dag er arten er en av våre aller sjeldneste hekkefugler. Som en av seks fuglearter i Norge er den kategorisert som kritisk truet (CR) på den norske rødlista, og har dermed en svært stor risiko for å dø ut hos oss. Hvordan har den så kommet i denne situasjonen?
Industrijordbruk og åkerrikse går ikke hånd i hånd
Moderne intensivjordbruk og en solid hekkebestand av åkerrikse går dessverre ikke hånd i hånd. Den sky men høylytte fuglens forkjærlighet for åpne landskap med høyt gress ble også dens svøpe over store deler av Vest- og Nord-Europa på slutten av 1800- og starten av 1900-tallet, da slåmaskinen for alvor gjorde sitt inntog i det alminnelige jordbruket. Åkerriksa legger nemlig reiret sitt på bakken, og da helst i gress som er høyt nok til å gi den skjul i det åpne landskapet som den foretrekker i sine hekkeområder. I løpet av det siste århundret har dette stadig oftere vært snakk om intensivt drevet kulturmark. Dermed havner fort både egg og unger i slåmaskina. Fra å være en folkekjær lyd gjenkjent av de fleste, forsvant åkerriksas kreksing fullstendig fra det meste av vårt langstrakte land fram mot midten av 1900-tallet, da bestanden sannsynligvis nådde et historisk lavmål.
Tilførsel fra øst?
Helt siden 1995 har NOF fulgt utviklingen i den norske åkerriksebestanden gjennom årlige tellinger. Fra bunnivået på midten av 1990-tallet økte antallet syngende åkerrikser ganske markant fram mot slutten av tiåret og utover 2000-tallet. I flere hekkesesonger ble mellom 150 og 250 syngende individer påvist, fra rundt 50 individer i året på midten av 1990-tallet. Tilsvarende økninger i forekomstene ble påvist i flere av våre naboland, og skyldtes etter alt å dømme innvandring fra en økende østeuropeisk hekkebestand. Man regner denne økningen som et resultat av nedleggelsen av de store kollektivjordbrukene etter Sovjetunionens fall i 1992, og påfølgende brakklegging av dyrka mark eller omlegging mer ekstensiv drift. Dette var til stor fordel for åkerriksa. Man har hele tiden regnet med at den positive utviklingen i øst vil være av forbigående art, etter hvert som de brakklagte områdene gror til med busker og trær, eller dyrkes opp igjen for mer intensiv drift. De siste to årene har antallet syngende åkerrikser påvist i Norge vært temmelig lavt, med rundt 100 syngende individer påvist. Kan dette være starten på nok en nedgang for arten? Skulle det være tilfellet begynner det virkelig å haste om man skal bevare arten som norsk hekkefugl.
Hjelp NOF med å redde åkerriksa!
For å sikre åkerriksa en framtid i Norge er vi nødt til å reetablere en selvrekrutterende hekkebestand hos oss som i minst mulig grad er avhengig av innvandring utenfra for å opprettholdes. Derfor må vi forsøke å verne om artens hekkeområder.
(AOS 31 may 2017; Photo: Stephanie Eyes)
Fire is a crucial part of the forest ecosystem on which threatened Spotted Owls rely, but climate change and decades of fire suppression are changing the dynamics of these forests. A new study from The Condor: Ornithological Applications examines California Spotted Owl habitat use in Yosemite National Park and shows that while owls avoid the badly burned areas left behind by massive stand-replacing fires, they benefit from habitat that includes a mosaic of burned patches of different sizes and degrees of severity.
The National Park Service’s Stephanie Eyes (formerly of Humboldt State University) and her colleagues wanted to know how Spotted Owl foraging patterns are influenced by fire severity and fire-created edges, with the goal of informing future fuels reduction efforts and prescribed burning programs. They used radio-transmitters to track movements of 13 owls on eight territories in Yosemite National Park between 2010 and 2012 and found that overall, owls foraged near their roosts and along the edges of patches of burned forest, preferring these edge habitats. Owls selected larger burned patches than the average available size but avoided the interiors of severely burned patches.
“Maintaining a complex mosaic of forest patches with smaller patches of high severity fire can help sustain California Spotted Owls in the greater landscape,” says Eyes. “What’s unique about our study is that we investigated fires that burned within the natural range of variation, so it paints a picture of how owls used a burned landscape before the onset of today’s large stand-replacing fires.” Despite the owls’ preference for edges, there may be a threshold over which edges have a negative effect on habitat quality, and more research is needed to find the right balance between beneficial edge habitat and potentially harmful habitat fragmentation.
“This paper provides new radio telemetry data on how owls use home ranges that have had recent wildfires,” according to the University of Minnesota’s R.J. Gutiérrez, an expert on Spotted Owl habitat use. “Eyes and her colleagues provide a new piece of the puzzle about how owls respond, and they show that this response can be complex. More importantly, because their work occurred within a national park, it will serve as a ‘natural control’ that can be compared with other owl–fire studies occurring on managed forests.”