NEWS

Blog post in Oikos blog about the phylosophy behind the Oikos paper "Colony size and foraging range in seabirds" Selected by R Jovani
Study Projects How Climate Change Will Affect the Functions Birds in Ecosystems Worldwide SciTech Daily (Global Change Biology paper) Selected by JL Alcantara
Swift Incredible Journey Selected by R Jovani
Flowers make the menu for nearly all Galapagos birds Science News (Nature Communications paper) Selected by JL Alcantara
Habitat degradation and climate shifts impact survival of the white-collared manakin EurekAlert! (Oecologia paper) Selected by JL Alcantara
Birds flying in a V take turns in the top spot, study finds Los Angeles Times-Science (PNAS paper) Selected by JL Alcantara Play the caterpillar defense National geographic (American Naturalist paper) Selected by J Broggi
Darwin 2.0: Scientists shed new light on how species diverge Phys.org (Nature paper) Selected by JL Alcantara
Agriculture Is Reshaping the Avian Tree of Life American Scientist (Science paper) Selected by JL Alcantara Fatal Attraction of Short-Tailed Shearwaters to Artificial Lights Science daily ( PloS One paper) Selected by J Broggi
Winter bird feeders: Get ready for a busy season Science/AAAS (Global Change Biology paper) Selected by JL Alcantara
Dinosaur family tree gives fresh insight into rapid rise of birds Phys.org (Current Biology paper) Selected by JL Alcantara
Migrating birds sprint in spring, but take things easy in autumn ScienceDaily (Behavioral Ecology and Sociobiology paper) Selected by Jose L. Alcantara
Hummingbirds evolved a strange taste for sugar ScienceNews (Science paper) Selected by JL Alcantara
Group foraging in little penguins ScienceDaily ( PLoS ONE paper) Selected by R Jovani
Mixed Genes Mix Up the Migrations of Hybrid Birds ScienceNewsline (Ecology Letters paper) Selected by JL Alcantara
Dinosaurs 'shrank' regularly to become birds BBC (Science paper) Selected by JL Alcantara
Parrot Who Was Among Last of Its Kind, Said to Have Inspired ‘Rio,’ Dies National Geographic Society Selected by JL Alcantara
Researchers declassify dinosaurs as being the great-great-grandparents of birds Phys.org (Journal of Ornithology paper) Selected by JL Alcantara
Pristine fossil confirms Archaeopteryx as original bird United Press International (Nature paper) Selected by JL Alcantara
All gone: How erasing billions of birds shocked us Yahoo! News (PNAS paper) Selected by JL Alcantara
Plants hitch a lift on migrating birds BBC Nature (PeerJ paper) Selected by JL Alcantara
Mapping the evolution of a ring species Univ. British Columbbia (Nature paper) Selected by R Jovani
Closest Living Relative of Ancient Elephant Bird Is Tiny LiveScience (Science paper) Selected by JL Alcantara
Identifying evolutionary distinct birds WIRED (Current Biology paper) Selected by R Jovani
Ten Thousand Birds: Ornithology since Darwin Myriad Birds Selected by JL Alcantara
The 100 most distinct and rare birds BBC Nature (Current Biology paper) Selected by JL Alcantara
Hummingbird Evolution Soared After They Invaded South America 22 Million Years Ago ScienceNewsline (Current Biology paper) Selected by JL Alcantara
Bird’s Extinction Is Tied to the Arrival of Humans The New York Times (PNAS paper) Selected by JL Alcantara
A bird-like dinosaur called “Chicken from Hell” NPR news (PLOS One paper) Selected by JL Alcantara
Wintering irruptions of Snowy owls in North America and Europe (in Spanish) SEO/BirdLife blog Selected by R Jovani
Punk Amazon pheasant is a European emigrant NewScientists (Naturwissenschaften paper) Selected by JL Alcantara
Flights of Fancy in Avian Evolution American Scientist Selected by JL Alcantara Why do birds fly in a V? Endangered ibis reveals its amazing secret (VIDEO) Los Angeles Times (Nature letter) Selected by J Broggi
Sharp-toothed tigerfish jumps to eat a bird (VIDEO) (J Fish Biol paper) Nature News Selected by J Broggi
On the evolution of bird fingers. PHYS.ORG (J Exp Zool paper) Selected by R Jovani
Albatross colony shows benefits of same-sex pairing ABC Science (J Proceedings of the Royal Society B paper) Selected by JL Alcantara Swifts stay airborne for six months at a time New scientist(Nature communications paper) Selected by J Broggi
100 years ago bird lovers were encouraged to use the field glasses rather than the gun The Guardian Selected by R Jovani
Trees send distress signals that birds use to find insects Sinc(Ecol Lett paper) Selected by R Jovani
I’m singing in the rainforest Max-Planck-Gesellschaft (journal of interdisciplinary music studies paper) Selected by JL Alcantara
Fossil Poo Reveals Where Ancient Giant Bird Ate Discovery News (PNAS paper) Selected by JL Alcantara
Colonizing songbirds lost sense of syntax e! Science News (Current Biology paper) Selected by JL Alcantara
Songbirds may have 'borrowed' DNA to fuel migration Phys.org (Evolution paper) Selected by JL Alcantara
Collision Course ScienceNews (ScienceNews paper) Selected by JL Alcantara
Social learning of migratory performance PhysOrg (Science paper) Selected by R Jovani
Evolution of parasitic egg colouration: parasites also select. Not Exactly Rocket Science blog(Biol Lett paper) Selected by R Jovani
European birds adjust their flight initiation distance to road speed limits BBC News(Biol Lett paper) Selected by R Jovani
The secret of male beauty (in turkeys) UCL News (PLOS Genetics paper) Selected by JL Alcantara
Bird hunters 'emptying Afghan skies' BBC News Asia Selected by JL Alcantara
Secrets of the world’s toughest little bird Griffith U. News (Nature Communications paper) Selected by JL Alcantara Outdoor Cats: Single Greatest Source of Human-Caused Mortality for Birds and Mammals American Bird Conservancy (Nature communications paper) Selected by J Broggi
Hiding in plain sight: New species of bird discovered in capital city e! Science News (Forktail paper) Selected by JL Alcantara
Foraging space partitioning without territoriality in a seabird ScienceDaily (Science paper) Selected by R Jovani
Bird extinction leads to rapid evolution of seed size The Red Notebook (Science paper) Selected by R Jovani
Bird song changes in translocated birds ScienceDaily (J Appl Ecol paper) Selected by R Jovani
Why penguins lost their wings ABC Science (PNAS paper) Selected by JL Alcantara
Simulated patternity uncertainty: Males care about intruders but feed nestlings regardless of patternity uncertainty ScienceDaily (PLoS ONE paper) Selected by R Jovani
Seabird Bones Reveal Changes in Open-Ocean Food Chain Science Daily(PNAS paper) Selected by F Mateos-Gonzalez
New fossil brings new light on the evolution of hummingbirds and swifts Science NOW(Proc R Soc B paper) Selected by R Jovani
Testosterone vs. audience on the regulation of bird fights and social status ScienceDaily (Hormones and Behavior paper) Selected by R Jovani
Lead bullet fragments poison rare US condors BBC News Selected by JL Alcantara
Avoiding cuckoo parasitism by breeding indoors Live Science(Beh Ecol Sociobiol paper) Selected by R Jovani
Why I study duck genitalia... or... why basic science matters Slate Selected by R Jovani
A study about play in cranes BBC Nature(Ibis paper) Selected by R Jovani
Pretty great tits make better mothers Discover (Frontiers in Zoology paper) Selected by JL Alcantara
Humans wiped out Pacific island birds ABC Science (PNAS paper) Selected by JL Alcantara
The Rise and Fall of Four-Winged Birds Not Exactly Rocket Science (Science paper) Selected by R Jovani
Sex role reversal: Female shorebirds rule the roost BBC News (Nature Communications paper) Selected by JL Alcantara
Birds communicate their size through song ScienceDaily(PLoS ONE paper) Selected by R Jovani
How Birds of Different Feathers Flock Together ScienceDaily (Animal Behaviour paper) Selected by JL Alcantara
The Owl Comes Into Its Own The New York Times-Science Selected by JL Alcantara
On the evolution of UV vision in birds ScienceDaily(BMC Evol Biol paper) Selected by R Jovani
A great tit predating upon a common redpoll (video; Finnish) Ilta Sanomat Selected by R Jovani
Killing Barred Owls To Save the Spotted Owl CNN Selected by JL Alcantara
New dinosaur fossil challenges bird evolution theory e! Science News (Nature paper) Selected by JL Alcantara
Fractal geometry of a plumage pattern changes with physical condition in partridges ScienceNow(Proc R Soc B paper) Selected by I Galván
As Andean condors decline, tradition draws critics Reuters Selected by JL Alcantara





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Sunday 7 December 2008

La màgia del estols d’estornells

Veure volar un estol d’estornells (Sturnus vulgaris) ens hipnotitza com una llar de foc. L’estol es mou com un tot, com un sol individu; es contrau i s’expandeix, s’enlaira i es deixa caure sobre els plàtans del passeig. L’estol se’ns presenta davant dels ulls com quelcom més que una suma desordenada d’ocells: l’estol és un sistema dinàmic autoorganitzat amb propietats emergents que escapen al nostre enteniment.

Per això està la ciència, per explicar el truc de la màgia, i gaudir-ne amb uns ulls diferents. Ja fa temps que sabem que en un estol no hi ha cap líder que prengui decisions per la resta: un estol es un sistema descentralitzat on la pròpia interacció entre ocells veïns en governa la forma i el moviment (veure introducció divulgativa i rigorosa a Resnick 1994).

Investigadors italians han anat un pas més enllà. Van fer fotografies des de diferents angles a estols d’estornells per poder reconstruir la imatge 3D a l’ordenador. Així van poder estudiar com la posició relativa i orientació dels ocells s’afectava entre els ocells veïns dins de l’estol. El que van veure es que la interacció entre els ocells no està governada per la seva distancia sinó que la clau està en la posició topològica. És a dir, els ocells no interaccionaven amb tots els ocells que quedaven dins d’un radi de distancia, sinó que ho feien amb uns sis veïns, independentment de la densitat de l’estol (i per tant de la seva distancia). D’aquesta manera, els estols mantenen la seva forma compacta, independentment de la densitat. Així, els estornells evadeixen l’atac del falcó, deixant-lo hipnotitzat amb la seva màgia.

> M. Resnick (1994) [2001] Turtles, Termites, and Traffic Jams. Explorations in Massively Parallel Microworlds. [Tortugas, Termitas y Atascos de Tráfico. Exploraciones sobre Micromundos Masivamente Paralelos]. Gedisa. Barcelona. Spain.
> M. Ballerini, et al. (2008) Interaction ruling animal collective behavior depends on topological rather than metric distance: Evidence from a field study. PNAS 105: 1232-1237. (Open Access)
Photo by "He and Fi" (Flickr; Creative Commons)


-------------------------------------- ESPAÑOL -----------------------------------------

La magia de las bandadas de estorninos

Ver volar una bandada de estorninos (Sturnus vulgaris) nos hipnotiza como el fuego de una chimenea. El grupo se mueve como un todo, como un solo individuo; se contrae y se expande, se eleva y se deja caer sobre los plátanos del paseo. La bandada se presenta ante nuestros ojos como algo más que una suma desordenada de pájaros: el grupo, es un sistema dinámico autoorganizado con propiedades emergentes que escapan a nuestro entendimiento. Para eso está la ciencia, para explicar el truco de la magia, y disfrutar de ella con una mirada diferente.

Ya hace tiempo que sabemos que en estas bandadas no hay ningún líder que tome decisiones por el resto: el bando es un sistema descentralizado donde la propia interacción entre pájaros vecinos gobierna la forma y el movimiento (ver introducción divulgativa y rigurosa en Resnick 1994). Investigadores italianos han ido un paso más allá. Hicieron fotografías desde diferentes ángulos a grupos de estorninos para poder reconstruir una imagen de 3D en el ordenador. Así, pudieron estudiar cómo la posición relativa y la orientación de los pájaros tenía lugar entre los pájaros vecinos dentro del grupo.

Lo que vieron fue que la interacción entre los pájaros no está gobernada por la distancia que mantienen entre ellos sino que la clave está en la posición topológica. Es decir, los pájaros no interaccionaban con todos los pájaros que quedaban dentro de un radio de distancia, sino que lo hacían sólo con unos seis vecinos, independientemente de la densidad del grupo (y por lo tanto de su distancia). De esta manera, los grupos mantienen su forma compacta, independientemente de la densidad. Así, los estorninos evaden el ataque del halcón, dejándolo hipnotizado con su magia.

> M. Resnick (1994) [2001] Turtles, Termites, and Traffic Jams. Explorations in Massively Parallel Microworlds. [Tortugas, Termitas y Atascos de Tráfico. Exploraciones sobre Micromundos Masivamente Paralelos]. Gedisa. Barcelona. Spain.
> M. Ballerini, et al. (2008) Interaction ruling animal collective behavior depends on topological rather than metric distance: Evidence from a field study. PNAS 105: 1232-1237. (Open Access)
Foto de "He and Fi" (Flickr; Creative Commons)

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