Ornitologiarekin, Euskal Herriko naturarekin zein kontserbazioarekin zerikusia duten kontuak, beste iturrietakoak. Itsas Enara Ornitologia Elkarteak bilduak eta kudeatuak.
Asuntos sobre ornitología, naturaleza en Euskal Herria y conservación, procedentes de terceros. Recopilados y gestionados por Itsas Enara Ornitologia Elkartea
ScienceDaily (Nov. 26, 2012) —
Despite -- or perhaps because of -- their large size, swans seem
particularly prone to injury. Known problems include collisions with
cars, lead poisoning due to gunshot wounds or ingested foreign bodies
and injuries from fishing hooks. Injuries to the birds' hips, however,
are believed to be uncommon. Michaela Gumpenberger and Alexandra Scope
of the University of Veterinary Medicine, Vienna now present evidence to
suggest that such injuries are more frequent than suspected but are
under-recorded because of difficulties in diagnosis. They show that
computerized tomography is far better suited to examine the hip joint
than classical radiographic methods.
CT image of a
swan's hip: the hip joint on the right is intact, the one on the left is
dislocated. (Credit: Vetmeduni Vienna/Diagnostic Imaging)
Their results are published in the journal Avian Pathology.
Diagnosing an injury in a swan is a far from easy undertaking. Not
only are swans large, frequently weighing over 10 kg, but they are
generally not happy at being handled and thus many of them can only be
examined after sedation, which naturally represents a risk. The hip
joints of many species of bird are known to be vulnerable to injury but
swans are believed to suffer broken hips only rarely. The traditional
way of examining the birds' hips relies on radiography but Gumpenberger
and Scope now show that computerized tomography (CT) gives more reliable
findings.
The researchers examined the hip joints of five swans that had been
brought to the Clinic for Avian, Reptile and Fish Medicine of the
University of Veterinary Medicine, Vienna because they were unable to
stand. Radiographs were taken of three of the birds, while all of them
were subjected to CT scans. The results were highly illuminating.
Radiography gave indications that one of the swans might have problems
with its hip joint but the diagnosis was not conclusive and the other
two swans examined seemed to have intact joints. In contrast, CT showed
correctly that all five swans had lesions of the hip.
Computerized tomography is thus much better able to identify problems
with the hip joint than classical radiographic methods. In addition, it
is often less stressful for the animals: imaging can be performed
without the need for narcosis by simply placing the bird in a darkened
cardboard box and allowing it to sit comfortably, whereas radiography of
many species requires their sedation.
It seems, then, that hip problems in swans are more common than
previously believed. It is likely that the majority of injuries of this
kind arise when the birds attempt to land on hard surfaces, when the
landing forces are transmitted through their legs to their hips. Of
course, such emergency landings may simply be the result of air
turbulence but Gumpenberger notes that "many injured swans are found
near roads or railway lines, so it is possible that they misinterpret
shiny rails or even concrete road surfaces as being water and thus try
to land."
Story Source:
The above story is reprinted from materials provided by University of Veterinary Medicine -- Vienna. Note: Materials may be edited for content and length. For further information, please contact the source cited above.
Journal Reference:
Michaela Gumpenberger, Alexandra Scope. Computed tomography of coxofemoral injury in five mute swans (Cygnus olor). Avian Pathology, 2012; 41 (5): 465 DOI: 10.1080/03079457.2012.712205
Codorniz china (Coturnix chinensus). Macho y hembra. Tomada de Avikultura.
La codorniz china (Coturnix chinensis) es una galliforme
común en el sur de Asia, islas de la Sonda y Australia. Por la facilidad
para su crianza y su evidente atractivo es relativamente habitual como
ave ornamental. El caso es que un macho de esta especie ha aparecido
atropellado el 12 de julio de 2012 en la autovía A-5, a la altura del
Parque Natural de Cornalvo (Badajoz). El autor de la observación es
Jesús Manuel Crespo, quien envió algunas fotos al Comité de Rarezas de
SEO/BirdLife. Como no se trata de una rareza y su llegada natural queda
completamente descartada, la descripción fue derivada al Grupo de Aves
Exóticas (GAE), a través del cual nos hemos enterado. Lo más seguro es
que se trate de un escape, aunque por la fecha pudiera ser una suelta
para caza.
Codorniz china (Coturnix chinensus). Macho atropellado en Cornalvo, Badajoz (Jesús María Crespo)
Lamentablemente, esta observación muestra los riesgos derivados de la
introducción de especies exóticas. Una de las mayores causas de
extinción en tiempos recientes. Quizás la codorniz china no esté entre
las más peligrosas, aspecto que sí podría cumplir su pariente la codorniz japonesa (Coturnix japónica). Otra especie propia del este de Asia muy parecida a nuestra codorniz común (Coturnix coturnix)
y durante mucho tiempo consideraba una simple subespecie de esta. De
hecho, en cautividad hibridan con facilidad, siendo los híbridos
resultantes difíciles de identificar (el canto es algo diferente) y
debiendo acudir a pruebas genéticas.
La caza de la codorniz es habitual en Extremadura, pero es totalmente desconocido el alcance de la introducción de la codorniz japonesa y sus híbridos. Sin embargo, los estudios del equipo de Manuel Puigcerver entre 1999 y 2005 detectan un 4’4% de híbridos en las codornices analizadas en Cataluña (si se consideran los ejemplares dudosos, el porcentaje sube al 15%).
Codorniz japonesa (Coturnix japonica). Tomada de aquí.
La suelta de codorniz japonesa para su caza es una práctica reciente,
pues los citados autores, que empezaron sus estudios en 1983, no
detectaron híbridos hasta 1990. En la actualidad todas las codornices de
granja son japonesas (ninguna granja cría codorniz común), siendo estas
las liberadas, bien puras bien como híbridos. En algunos sitios
empiezan a ser mayoría, así se citan casos en Francia donde el 75% de las codornices cazadas son japonesas.
Las sueltas en Cataluña también van en aumento y las cifras oficiales
hablan de 2.430 codornices japonesas liberadas en 1991 y 153.600 en
2003, 60 veces más. En 17 años ¡¡suman más de un millón¡¡ Para comparar,
la población reproductora de codorniz común en Extremadura se estima en tan sólo 15.600 aves (Carrascal y Palomino, 2008); aunque en verano llegan aves migratorias de otros puntos.
En Extremadura se realizan sueltas de codornices de granja (ver aquí y aquí), durante todo el año, incluido el invierno. Por tanto la presencia de codorniz japonesa es segura,
aunque no haya registros confirmados y de momento no figure en ningún
listado. En otras partes tampoco se conoce la proporción de híbridos
naturales, si es que existen. A pesar de las sueltas masivas que se
realizan en España, Francia e Italia, parece que la mayoría de las
codornices japonesas mueren, bien cazadas, bien poco después de la
suelta. Ningún estudio muestra que haya una tendencia al aumento en la
proporción de híbridos. Dado que la práctica habitual es soltarlas en la
media veda a final del verano y como las aves de granja han perdido el
instinto migratorio, no suelen sobrevivir al invierno. Pero por otro
lado, también se está ha detectando mayor invernada y menor tendencia a
la migración en las codornices ibéricas. Quizás los híbridos sean los
responsables... pero está pendiente de demostrar.
Fuentes:
- Puigcerver, M., Vinyoles, D. & Rodríguez-Teijeiro, J. D. 2007.
Does restocking with Japanese quail or hybrids affect native population
of common quail Cotunix coturnix? Biological Conservation 136:628-635.
- Rodríguez-Teijeiro, J. D. & Puigcerver, M. 2006. Estudio del grado
de hibridación etre la codorniz común y la codorniz japonesa en
Cataluña. Informe. Universitat de Barcelona y Generalitat de Catalunya.
- Carrascal, L. M. & Palomino, D. 2008. Las aves comunes reproductoras en España. Población en 2004-2006. SEO/BirdLife. Madrid.
ScienceDaily (Nov. 21, 2012) — A new study looking at the structure of feathers in bird-like dinosaurs has shed light on one of nature's most remarkable inventions -- how flight might have evolved.
Academics at the Universities of Bristol, Yale and Calgary have shown that prehistoric birds had a much more primitive version of the wings we see today, with rigid layers of feathers acting as simple airfoils for gliding.
Close examination of the earliest theropod dinosaurs suggests that feathers were initially developed for insulation, arranged in multiple layers to preserve heat, before their shape evolved for display and camouflage.
An artist’s impression of what the Archaeopteryx lithographica would have looked like in flight. (Credit: Image by artist Carl Buel)
As evolution changed the configuration of the feathers, their important role in the aerodynamics and mechanics of flight became more apparent. Natural selection over millions of years ultimately modified dinosaurs' forelimbs into highly-efficient, feathered wings that could rapidly change its span, shape and area -- a key innovation that allowed dinosaurs to rule the skies.
This basic wing configuration has remained more or less the same for the past 130 million years, with bird wings having a layer of long, asymmetrical flight feathers with short covert feathers on top. They are able to separate and rotate these flight feathers to gain height, change direction and even hover.
This formation allows birds to move in such a way as to produce both lift and thrust simultaneously -- a capability that man, with the help of technology, is still trying to successfully imitate.
The research, published November 21 in Current Biology,looked at the dinosaur Anchiornis huxleyi and the Jurassic birdArchaeopteryx lithographica. The latter is 155 million years old and widely considered to be the earliest known bird, presenting a combination of dinosaur and bird characteristics.
Their wings differed from modern day birds in being composed of multiple layers of long feathers, appearing to represent early experiments in the evolution of the wing. Although individual feathers were relatively weak due to slender feather shafts, the layering of these wing feathers is likely to have produced a strong airfoil.
The inability to separate feathers suggests that taking off and flying at low speeds may have been limited, meaning that wings were primarily used in high-speed gliding or flapping flight.
Dr Jakob Vinther, from the University of Bristol's Schools of Biological and Earth Sciences, said: "We are starting to get an intricate picture of how feathers and birds evolved from within the dinosaurs. We now seem to see that feathers evolved initially for insulation. Later in evolution, more complex vaned or pinnate feathers evolved for display.
"These display feathers turned out to be excellent membranes that could have been utilised for aerial locomotion, which only very late in bird evolution became what we consider flapping flight. This new research is shedding light not just on how birds came to fly, but more specifically on how feathers came to be the way they are today -- one of the most amazing and highly specialised structures in nature."
Dr Nicholas Longrich of Yale University added: "By studying fossils carefully, we are now able to start piecing together how the wing evolved. Before, it seemed that we had more or less modern wings from the Jurassic onwards. Now it's clear that early birds were more primitive and represented transitional forms linking birds to dinosaurs. We can see the wing slowly becoming more advanced as we move from Anchiornis, toArchaeopteryx, to later birds."
Note: Materials may be edited for content and length. For further information, please contact the source cited above.
Journal Reference:
Nicholas R. Longrich, Jakob Vinther, Qingjin Meng, Quangguo Li, Anthony P. Russell. Primitive Wing Feather Arrangement in Archaeopteryx lithographica and Anchiornis huxleyi. Current Biology, 21 November 2012 DOI: 10.1016/j.cub.2012.09.052
ScienceDaily (Nov. 21, 2012) — For the first time, researchers tracking the behavior of emperor penguins near the sea have identified the importance of sea ice for the penguins' feeding habits. The research, published November 21 in the open access journal PLOS ONE by Shinichi Watanabe from Fukuyama University, Japan and colleagues, Japan describes emperor penguin foraging behavior through the birds' chick-rearing season.
Unlike other species like Adelie penguins, emperor penguins spent much more time diving for food, and only used about 30% of their time at sea to take short breaks to rest on sea ice. The birds did not travel for long distances on the ice, or use it for other activities. The study also suggests that these short rest periods on sea ice may help the penguins avoid predators such as leopard seals.
Emperor penguins near the sea. (Credit: Katsufumi Sato (Atmosphere and Ocean Research Institute, The University of Tokyo))
Though sea ice conditions are known to affect penguin populations, the relationship between ice levels and penguins' foraging has been unclear because of the difficulties of tracking the birds at sea. Watanabe says, "The monitoring technique developed in this study will help to understand the relationship."
Note: Materials may be edited for content and length. For further information, please contact the source cited above.
Journal Reference:
Shinichi Watanabe, Katsufumi Sato, Paul J. Ponganis.Activity Time Budget during Foraging Trips of Emperor Penguins. PLoS ONE, 2012; 7 (11): e50357 DOI:10.1371/journal.pone.0050357
ScienceDaily (Nov. 20, 2012) — Do birds change their tune in response to urban noise? It depends on the bird species, according to Dr. Alejandro Ariel Ríos-Chelén from the Universidad Nacional Autónoma de México and colleagues. Their work shows that while some birds do adapt their songs in noisy conditions by means of frequency changes, others like the vermilion flycatchers adapt their song by means of changes in song lengths.
The work is published online in Springer's journal, Behavioral Ecology and Sociobiology.
Birds use their songs during social interactions to attract females and repel intruders. Factors affecting acoustic communication, such as urban noise, may therefore impair breeding success. Research to date has shown that several songbird (or oscine) species like robins, nightingales and blackbirds, adapt their song in response to noise. This is done in order to improve acoustic communication in noisy conditions. However, little work has been done on the more tropical sister group of the oscines, the sub-oscines, which includes the vermilion flycatcher.
Rios-Chelén and team investigated whether male vermilion flycatchers adapted their song under noisy conditions in the same way as their less tropical sister group. They recorded the songs of 29 territorial vermilion flycatcher males in different parks and urban areas of Mexico City. They registered noise levels at different moments of both the pre-dawn and dawn chorus, measured song length, and counted the total number of elements in the birds' song to assess song versatility.
They found that males occupying territories with relatively high noise levels produced longer songs, whereas males in quieter places sang both long and short songs. Males also showed song plasticity as they sang less versatile songs later in the morning when noise level was higher, but time of day seemed to play a more important role in driving this shift than did noise levels.
The authors conclude, "While these results show that time of day has an effect on individual song versatility, we cannot discard an influence of noise... this study supports the idea that sub-oscine adaptation to noise is different in degree and mode to that taking place among oscines, suggesting heterogeneity in the capacity of bird species to colonize and survive in the urban environment."
ScienceDaily (Nov. 19, 2012) —
Owls have the uncanny ability to fly silently, relying on specialized
plumage to reduce noise so they can hunt in acoustic stealth.
Researchers from the University of Cambridge, England, are studying the
owl's wing structure to better understand how it mitigates noise so they
can apply that information to the design of conventional aircraft.
They present their findings at the American Physical Society's (APS)
Division of Fluid Dynamics meeting, held Nov. 18 -- 20, in San Diego,
Calif.
"Many owl species have developed specialized plumage to effectively
eliminate the aerodynamic noise from their wings, which allows them to
hunt and capture their prey using their ears alone," said Justin
Jaworski with the department of applied mathematics and theoretical
physics at the University of Cambridge. "No one knows exactly how owls
achieve this acoustic stealth, and the reasons for this feat are largely
speculative based on comparisons of owl feathers and physiology to
other not-so-quiet birds such as pigeons."
All wings, either natural or engineered, create turbulent eddies as
they cut through the air. When these eddies hit the trailing edge of the
wing, they are amplified and scattered as sound. Conventional aircraft,
which have hard trailing edges, are particularly noisy in this regard.
Owls, however, possess no fewer than three distinct physical
attributes that are thought to contribute to their silent flight
capability: a comb of stiff feathers along the leading edge of the wing;
a soft downy material on top of the wing; and a flexible fringe at the
trailing edge of the wing. At present it is not known whether it is a
single attribute or the combination of attributes that are the root
cause of the noise reduction.
The researchers attempted to unravel this mystery by developing a
theoretical basis for the owl's ability to mitigate sound from the
trailing edge of its wing, which is typically an airfoil's dominant
noise source. Earlier owl noise experiments suggest that their wing
noise is much less dependent on air speed and that there is a large
reduction of high frequency noise across a range where human ears are
most sensitive.
Using mathematical models, the researchers demonstrated that elastic
and porous properties of a trailing edge could be tuned so that
aerodynamic noise would depend on the flight speed as if there were no
edge at all. "This implied that the dominant noise source for
conventional wings could be eliminated," said Nigel Peake also of the
University of Cambridge. "The noise signature from the wing could then
be dictated by otherwise minor noise mechanisms such as the roughness of
the wing surface."
CASTILLA LA MANCHA | 15.11.2012 | 11:28CIENCIA CONSERVACIÓN
Cuestionan efectividad de la reintroducción de especies
Toledo,
15 nov (EFEverde).- La Universidad de Castilla-La Mancha (UCLM) ha
participado en un estudio en el que se cuestiona la efectividad de los
proyectos actuales de reintroducción de animales como herramienta para
la conservación de especies, ya que los actuales proyectos de no cumplen
con los criterios básicos.
La Universidad de Castilla-La Mancha
(UCLM) ha participado en un estudio en el que se cuestiona la
efectividad de los proyectos actuales de reintroducción de animales como
herramienta para la conservación de especies, ya que los actuales
proyectos de no cumplen con los criterios básicos. En la foto de
archivo, distribuida por la Fundación Migres de polluelos de águila
pescadora para reintroducir en Cádiz y Huelva. EFE/Javi Elorriaga
En un comunicado, la profesora de la Facultad de Ciencias Ambientales y Bioquímica de la UCLM
Graciela Gómez Nicola ha explicado que "la mayoría de las
reintroducciones realizadas en España no cumple con los criterios
básicos relativos tanto a su necesidad como a sus posibilidades de
éxito".
Esta es una de las conclusiones del trabajo desarrollado
con científicos de la Universidad Miguel Hernández, del Museo Nacional
de Ciencias Naturales (CSIC), de la Estación Biológica de Doñana (CSIC) y
de la Arizona State University (Estados Unidos), en el que se han
revisado 280 proyectos de reintroducción de especies a nivel mundial y
107 en España.
Sin embargo, la profesora ha indicado que este no
es un problema exclusivo de España, ya que se han obtenido resultados
similares a escala mundial, mediante la evaluación de resultados
publicados en revistas científicas de conservación. "Difícilmente justificables"
Dado
que la mayor parte de los proyectos son "difícilmente justificables"
desde un punto de vista de conservación o no han sido adecuadamente
diseñados para evitar posibles consecuencias negativas o aumentar su
probabilidad de éxito, el equipo científico propone desarrollar un
sistema jerárquico de decisión para evaluar la necesidad, los riesgos y
el diseño técnico de un determinado proyecto de reintroducción.
Así,
los expertos se han mostrados convencidos de que "el uso de este
sistema podría mejorar la efectividad de las reintroducciones como
herramienta de conservación".
El trabajo, publicado en Estados
Unidos en el número de noviembre de la revista Frontiers in Ecology and
the Environment, verá la luz en España en una extensa versión en
castellano en la revista Quercus del mes de diciembre. EFEverde
ScienceDaily (June 18, 2012) — A new way of analyzing the social networks that link individual animals to each other has been tested on wild great tits by Oxford University researchers.
How animals associate in groups can have important consequences in terms of the health and survival of both individuals and whole populations; influencing factors such as the spread of disease and the ability to find food or mates.
But revealing the networks underlying animal societies is a challenge when a large amount of fieldwork data consists of a long stream of automated observations of the times and locations of individuals, leaving scientists to try and reconstruct the 'big picture' of how individuals are connected.
The new approach can automatically identify periods of intense social activity within a large number of observations -- in this example around one million observations of wild great tits (Parus major). This makes it possible to examine these periods in greater detail and calculate which individuals are real 'friends', rather than random passers-by, and even which are looking to pair up and mate.
A report of the research is published in this week's Journal of the Royal Society Interface.
'If you think of the data about you in Facebook it records things like who you are friends with, where you've been, and what you share with others,' said Ioannis Psorakis of Oxford University's Department of Engineering Science, who led the research. 'What we have shown is that we can analyse data about individual animals, in this case great tits, to construct a 'Facebook for animals' revealing who affiliates with who, who are members of the same group, and which birds are regularly going to the same gatherings or 'events.''
They team tested the new technique on data from two breeding seasons of wild great tits (August 2007-March 2008 and August 2008-March 2009). The data came from transponders attached to thousands of birds and sensors that logged when individuals appeared at any one of 67 bird feeders spread throughout Wytham Woods, Oxford.
The researchers found that their predictions from this data about which birds were 'friends' that regularly foraged for food together, as well as which birds were starting the process of pairing up or were already in a pair, matched visual observations made by zoologists.
'What we've shown is that our technique can extract information about the networks that bind individuals together by sampling and analysing their mobility patterns,' said Ioannis Psorakis. 'Our approach makes it possible to look at huge amounts of data without having to decide what time resolution is best to extract meaning -- the model evaluates this automatically. This is just the first example of how zoologists are beginning to use our method to explore social networks of animals in a 'big data' context.'
Early results from the work with great tits suggest that individual birds do not participate in flocks at random, but have a bias towards other members of the population they interact with. The majority of networks extracted using the approach are strongly clustered, and in such tight bird communities, individuals forage together and interact with their current or future mating partner.
This approach is being used not only in great tits, but also in a mix of wild-bird social networks, exploring the animal sociality at an inter-species level. Some of the most important future steps in this work are to combine the 'social' information available through this method, with other types of information: for example combining it with genetic data is enabling researchers to explore the genetic basis of sociality: do genetically similar individuals attract each other, or is it the other way round? Can we find specific areas of the genome that account for gregariousness?
The work could also help researchers understand how information spreads through animal populations. Tits are a famous exemplar of social learning: for instance, the habit of pecking open milk bottles on doorsteps to get access to cream spread rapidly through England in the mid 20th Century. The new approach is helping scientists to test how specific social structures help or hinder the spread of novel information from individual to individual.
The secret password Australian songbirds use to identify their offspring (and catch out copycat cuckoos)
Adelaide researchers found mother's pass on a single note to their offspring
The young birds have to include the password in their songs to be fed
By
Mark Prigg PUBLISHED:
17:04 GMT, 8 November 2012
|
UPDATED:
17:10 GMT, 8 November 2012
An Australian song bird uses secret passwords to prevent identity theft, scientists have learned.
When they are still in the egg, superb fairy wrens learn a unique single note sung by their mother.
Once hatched, they have to include the password within their begging calls in order to be fed.
Two Superb Fairy Wrens: researchers have found they pass on a secret password to their young in order to identify them
THE SUPERB FAIRY WREN
The
Superb Fairywren, also known as the Superb Blue-wren or colloquially as
the Blue Wren, is a passerine bird of the family Maluridae, common and
familiar across southeastern Australia.
Male Superb Fairy-wrens have been labelled as 'the least faithful birds in the world'. Females may be courted by up to 13 males in half an hour, and 76% of young are sired by males from outside the social group.
Researchers found that the begging calls of fairy wren chicks differed from one nest to another. Mother
wrens also taught their mates the password, as well as trusted helpers,
by singing a 'solicitation song' away from the nest.
The system is believed to have evolved to prevent identity theft by cuckoos.
Parasitic cuckoos typically lay an egg in another bird's nest which hatches early. The young cuckoo throws out the other eggs or chicks and takes over the nest, being fed and raised by the unsuspecting parents. In
the case of the superb fairy wren, an invading cuckoo that does not
produce the necessary password after hatching is likely to find itself
abandoned.
'Parents
and others attending the nestlings will only feed them if their begging
calls contain the learned password,' said study leader Dr Sonia
Kleindorfer, from the University of Adelaide in Australia.
Studies
showed that when clutches of eggs were swapped between nests, newly
hatched chicks produced begging calls that matched those of their foster
mothers. This was evidence that the passwords were learned.
A Male Superb Fairy-wren in Tasmania, Australia. The birds learn a secret note from their mother soon after they hatch
The researchers were able to
prevent attending parents feeding their young by playing the wrong
begging call from a loudspeaker under the nest.
Reporting
their findings in the journal Current Biology, they wrote: 'Playback
experiments showed that adults respond to the begging calls of offspring
hatched in their own nest and respond less to calls of other wren or
cuckoo nestlings.
'We
conclude that wrens use a parent-specific password learned
embryonically to shape call similarity with their own young and thereby
detect foreign cuckoo nestlings.'
ScienceDaily (Nov. 2, 2012) —
Young birds can get 'drunk' on fermented berries. But unsteadiness on
the feet, a tendency to fall over, and losing the ability to steer is
considerably more of a problem when life is normally spent in trees or
in the air.
The authors from the Animal Health and Veterinary Laboratories Agency
(AHVLA) reveal how they were called to a primary school in Cumbria last
summer after the bodies of 12 young blackbirds were found.
A further blackbird was discovered alive, but obviously "unwell." And two more dead birds were subsequently found.
Foul play was suspected, especially as some of the birds had clearly been injured. The police were called.
Post mortem exams were carried out on the dead birds, who were
otherwise in good physical condition. Tests to rule out lethal
infections, such as avian flu, came back negative. But berries were
found in all the birds' guts.
A few blackbirds had been spotted on rowan trees, beneath which
berries similar to those found inside the dead birds covered the ground.
Many of these berries looked as if they had been partially eaten.
Rowan berries are not normally considered poisonous to wild birds,
but the berries found inside the birds smelled as if they were
fermenting.
Three tissue samples from the dead birds were sent for toxicological
analysis, one of which revealed high levels of pure alcohol (ethanol).
Staff at the wildlife rescue centre to which the live bird was sent also
reported that it had been unsteady on its feet and appeared "drunk."
The bird had had to place its wings on the ground to steady itself,
and had leant against the walls of its enclosure to keep upright, they
said. After two days the bird fully recovered and was released back into
the wild.
The authors can't explain why only one of the samples revealed the
presence of ethanol, but suspect that all the dead birds had become
intoxicated on fermented berries, and that some of the injuries they had
sustained were the result of mid-air collisions.
The berries on the ground were damaged, so would have been vulnerable
to yeast infestation, which would have precipitated fermentation and
subsequent alcohol production, they explain.
The authors say that they can't prove that the birds died after
consuming too much alcohol, but they refer to a similar diagnosis made
in 1999 of redwings who had been feeding on holly berries.
Several of these birds were seen falling out of the holly tree onto
the concrete below. Laboratory analysis did not reveal any hazardous
chemicals, but holly berries were found in their crops and gizzards,
samples of which contained high levels of alcohol.
ScienceDaily (Nov. 5, 2012) — A
cockatoo from a species not known to use tools in the wild has been
observed spontaneously making and using tools for reaching food and
other objects.
A cockatoo
from a species not known to use tools in the wild has been observed
spontaneously making and using tools for reaching food and other
objects. (Credit: Image courtesy of University of Oxford)
A Goffin's cockatoo called 'Figaro', that has been reared in
captivity and lives near Vienna, used his powerful beak to cut long
splinters out of wooden beams in its aviary, or twigs out of a branch,
to reach and rake in objects out of its reach. Researchers from the
Universities of Oxford and Vienna filmed Figaro making and using these
tools.
How the bird discovered how to make and use tools is unclear but
shows how much we still don't understand about the evolution of
innovative behaviour and intelligence.
A report of the research is published this week in Current Biology and an accompanying video showing the behaviour is available here: http://www.zoo.ox.ac.uk/group/kacelnik/movie_figaro_for_media.mov
Dr Alice Auersperg of the University of Vienna, who led the study,
said: 'During our daily observation protocols, Figaro was playing with a
small stone. At some point he inserted the pebble through the cage
mesh, and it fell just outside his reach. After some unsuccessful
attempts to reach it with his claw, he fetched a small stick and started
fishing for his toy.
'To investigate this further we later placed a nut where the pebble
had been and started to film. To our astonishment he did not go on
searching for a stick but started biting a large splinter out of the
aviary beam. He cut it when it was just the appropriate size and shape
to serve as a raking tool to obtain the nut.
'It was already a surprise to see him use a tool, but we certainly
did not expect him to make one by himself. From that time on, Figaro was
successful on obtaining the nut every single time we placed it there,
nearly each time making new tools. On one attempt he used an
alternative solution, breaking a side arm off a branch and modifying
the leftover piece to the appropriate size for raking.'
Professor Alex Kacelnik of Oxford University, an author of the
study, said: 'Figaro shows us that, even when they are not habitual
tool-users, members of a species that are curious, good problem-solvers,
and large-brained, can sculpt tools out of a shapeless source material
to fulfil a novel need.
'Even though Figaro is still alone in the species and among parrots
in showing this capacity, his feat demonstrates that tool craftsmanship
can emerge from intelligence not-specialized for tool use. Importantly,
after making and using his first tool, Figaro seemed to know exactly
what to do, and showed no hesitation in later trials.'
Professor Kacelnik previously led studies in the natural tool-using
New Caledonian crows. One of them, named Betty, surprised scientists by
fashioning hooks out of wire to retrieve food that was out of reach.
These crows use and make tools in the wild, and live in groups that may
support culture, but there was no precedent for Betty's form of hook
making. Her case is still considered as a striking example of individual
creativity and innovation, and Figaro seems ready to join her.
Professor Kacelnik said: 'We confess to be still struggling to
identify the cognitive operations that make these deeds possible.
Figaro, and his predecessor Betty, may help us unlock many unknowns in
the evolution of intelligence.'
ScienceDaily (Nov. 7, 2012) —
Urban growth alters the behaviour of birds. Faced with the same threat,
city and country birds do not react in the same way despite being from
the same species. According to a new study, urban birds have changed
their anti-predator behaviour in new environments.
Blackbird in a city park. (Credit: J.D. Ibáñez-Álamo)
When a bird is faced with a predator, its only objective is to
escape. However, city birds do not react in the same way as their
countryside counterparts, despite being from the same species.
Urbanisation plays an influential role in their survival strategies.
To study this phenomenon, Juan Diego Ibáñez-Álamo, researcher at the
University of Granada (UGR) and Anders Pape Møller from Paris-Sud
University (France) analysed the escape techniques of 1,132 birds
belonging to 15 species in different rural and urban areas.
Published in the journal Animal Behaviour, the results show
that city birds have changed their behaviour to adapt to new threats
like cats (their main predator in the city) instead of their more
traditional enemies in the countryside, such as the sparrow hawk.
"When they are captured, city birds are less aggressive, they produce
alarm calls more frequently, they remain more paralysed when attacked
by their predator and they loose more feathers than their countryside
counterparts," as explained by Juan Diego Ibáñez-Álamo.
The surprising thing is that urbanisation is directly linked with
these differences, which become more acute the earlier the former has
taken place. This suggests that escape strategies evolve alongside the
expansion of cities; a concept that is on the increase worldwide. Adapt or die in the territory of man
Like the habitat of many animals and plants, the habitat of birds
changes and fragments. Discovering how they adapt to transformations in
their habitat is "crucial" for understanding how to lessen their
effects. "Predation change caused by city growth is serious," outlines
Ibáñez-Álamo.
As the scientist indicates, tactics against their hunters are
"crucial" so that birds can adapt to their new environment: "Birds
should modify their behaviour to be able to survive in cities because if
not, they will become extinct at the mercy of urban growth."
ScienceDaily (Nov. 7, 2012) — It
weighed about 155 pounds and had a 34-foot wingspan, close to the size
of an F-16 fighter jet. A five-foot-long skull looked down from a
standing height similar to that of a modern giraffe. By all measures,
the ancient pterosaur Quetzalcoatlus was a Texas-sized giant of the air and created a frightening shadow as it soared across the sky.
A fully
articulated skeleton of Quetzalcoatlus hangs in the Museum of Texas Tech
University. The animal stood as tall as a giraffe and needed a slope to
taxi into the air. (Credit: Texas Tech University)
It pushed the very boundaries of size to the brink, considered the
largest flying animal yet to be discovered. Any larger, and it would
have had to walk. But its bulk caused researchers to wonder how such a
heavy animal with relatively flimsy wings became airborne.
Sankar Chatterjee, Horn Professor of Geosciences and curator of
paleontology at the Museum of Texas Tech University, will describe the
flight dynamics of this animal on November 7 during the annual meeting
of the Geological Society of America in Charlotte, N.C.
Using a computer simulation, Chatterjee and his colleagues unraveled
the secrets of the flight for the massive pterosaur, discovered in the
Big Bend area of Texas, which has captured the imagination of
paleontologists and public so profoundly.
"This animal probably flew like an albatross or a frigate bird in
that it could soar and glide very well," Chatterjee said. "It spent most
of its time in the air. But when it comes to takeoff and landing,
they're so awkward that they had to run. If it were taking off from a
cliff, then it was OK. But if Quetzalcoatlus were on the ground, it
probably had to find a sloping area like a river bank, and then run
quickly on four feet, then two to pick up enough power to get into the
air. It needed an area to taxi."
Speculation exists on what this animal looked like, Chatterjee said. Some researchers suggested recently that Quetzalcoatlus
could have weighed up to 550 pounds and used forelimbs as a catapult in
the same manner of a common vampire bat to create a standing takeoff.
However, Chatterjee said that computer modeling proved what is
possible for a tiny, lightweight, 1-ounce bat appeared impossible for an
animal 10,000 times heavier.
Flight performance seems to degrade systematically with body size
because power decreases with body size, he said. Above a particular
size, the available power is insufficient and flapping flight is not
possible. The animal would not be able to maintain height when flying at
its maximum power speed and exert full power.
"Its enormous wings must have been difficult to manage," Chatterjee
said. "Each wing had at least a 16-foot span, so during its full
downstroke it would smash its wing resulting in crash landing. A
standing takeoff of flying of such a heavy animal violates the laws of
physics."
Like today's condors and other large birds, Quetzalcoatlus probably
relied on updraft to remain in the air, Chatterjee said. It was a superb
glider with a gliding angle close to two degrees and a cruising speed
of 36 miles per hour. Their bones were entirely hollow, filled with air,
lightweight and strong. This is how such a large animal could weigh so
little and still grow to its enormous size.
The animal had high-aspect-ratio wings like those of modern seabirds,
meaning the wings were long, narrow, flat and pointed. It soared in
open airspace by exploiting thermals or wind gradient above the ocean
surface. Trading for size, the wings were structurally weak for vigorous
flapping, causing the pterosaur difficulty during ground takeoff.
"Sooner or later the animal would come to the ground, especially
during foraging and nesting," Chatterjee said. "Like albatrosses and the
Great Kori bustards, which weigh 20 to 40 pounds, ground takeoff was
agonizing and embarrassing for Quetzalcoatlus. With a slight
headwind and as little as a 10-degree downhill slope, an adult would be
able to take off in a bipedal running start to pick up flying speed,
just like a hang glider pilot. Once it got off the ground, the giant
pterodactyl entered into thermal and soared like majestic masters of the
air."
ScienceDaily (Nov. 8, 2012) —
While about 2500 chicks of emperor penguins are raised this year at the
colony close to the French Dumont d'Urville Station, two new colonies
totalling 6000 chicks have just been observed about 250 km away, near
Mertz Glacier by the scientists Dr André Ancel and Dr Yvon Ancel, from
the Institut Pluridisciplinaire Hubert Curien in Strasbourg (CNRS and
Université de Strasbourg). Since a pair of emperor penguins may only
successfully raise one chick a year, the population of breeding emperor
penguins in this area of the Antarctic can therefore be estimated to
more than about 8500 pairs, about three fold that previously thought.
The two new colonies have been revealed on 1st and 2nd November,
during the late winter season trip of the MSS Astrolabe1 towards Dumont
d'Urville. They are located on the winter sea ice. This ice surrounds
the remains of the Mertz Glacier, from which a large ice wall, 80 km
long, 40 km wide and 300-400 m thick has separated. These may be two
sub-populations originating from the initial Mertz colony which,
following the Mertz Glacier break, are attempting to settle again on
favorable surroundings. One accounts for about 2000 chicks and the
second for about 4000 chicks.
Dr André Ancel had suspected the existence of an emperor penguin
colony near the Mertz Glacier since 1999, when with Dr Barbara Wienecke
(Australian Antarctic Division), they observed thousands of emperor
penguins going back and forth in the Mertz glacier area. Dr Peter
Fretwell and Dr Phil Trathan of the British Antarctic Survey localised
this colony in 2009 based on the images from space of emperor penguin
nitrogen dejections on the sea ice. However, the break of the Mertz
glacier in 2010 questioned the fate of this colony. New satellite images
obtained since then suggested that the birds might attempt breeding on
different sites. Over the last 13 years all French attempts to find the
birds had failed, due to the harsh winter conditions and the summer
disappearance of the sea ice where the Emperors breed.
This year, the human, logistic and environmental conditions finally
came together. The French Polar Institute (IPEV) then decided to modify
the Astrolabe's route to enable Dr André Ancel and Dr Yvon Le Maho to
find this population. A good climate window, the excellent knowledge of
the environment by the IPEV logistic teams, the expert navigational
skill of the Astrolabe crew in the ice and the essential helicopter
support in such areas, have allowed for the success of this detection.
The break of the Mertz Glacier had profoundly modified the environment
into a chaos of small icebergs and sea ice. The French scientists
discovered that the initial colony seen from space by their British
colleagues had been split over two sites. The first, whose localisation
had been recently indicated by the British, accounts for about 2000
chicks, whereas 4000 are being raised in the second. The second site was
discovered by chance, 15 km from the first, while conducting a
scientific helicopter survey.
ScienceDaily (Nov. 8, 2012) —
Scientists at the University of Liverpool have discovered that proposed
offshore renewable energy developments in the English Channel have the
potential to affect the foraging behaviour of northern gannets from
Alderney in the Channel Islands.
15 northern
gannets were tracked to find out about their feeding habits and routes
travelled. (Credit: Jill Pakenham of the British Trust for
Ornithology/courtesy of University of Liverpool)
The study by the University of Liverpool, the British Trust for Ornithology and Alderney Wildlife Trust, funded by the Alderney Commission for Renewable Energy,
used GPS technology to track 15 northern gannets breeding on Les Etacs
in North West Alderney to find out about their feeding habits and
whether the routes they travelled could be affected by proposed English
and French offshore energy developments. Not dependent on specific feeding sites
The study found that on the whole gannets flew in the same direction
and for the same distance but they vary significantly in the amount of
time they spend searching for food which suggests that individual
gannets do not depend on specific feeding sites.
Louise Soanes, from the School of Environmental Sciences,
said: “We found that the area where the gannets travelled for food
overlapped with nine sites earmarked for offshore marine energy
developments which suggests that the feeding habits of these birds could
be affected, as well as the potential for collision with wind turbine
developments.
Louise Soanes: “We found that the area where
the gannets travelled for food overlapped with nine sites earmarked for
offshore marine energy developments”
"These sites also fell across three different territorial waters --
in the UK, France and the Channel Islands -- which has implications for
international collaboration and cooperation. Importance of tracking technologies
"GPS technology is becoming cheaper, longer lasting, more accurate
and easier to use on a wide range of species. Our work highlighted the
important role tracking technologies can play in determining how sea
bird colonies would be affected by offshore developments and we
recommend that they become an integral part of the Environmental Impact
Assessment for marine renewable developments."
EU directives require that Europe must achieve 20% of its energy from
renewable sources by 2020 which has led to an increase in the number of
developments using offshore wind, tidal and wave technologies. Offshore
developments require an Environmental Impact Assessment which use
boat-based and aerial monitoring but do not routinely use tracking
technologies.
The gannets’ feeding sites fell across three different territorial waters
The preliminary findings from this study are being taken forward by
the University and its partners. The next phase of research, funded by a
NERC PhD studentship, will determine what exactly the gannets use these
areas for and how dependent the gannets are on these areas over the
next three years to better understand how the developments may impact
their populations.
(All photos by Jill Pakenham, of the British Trust for Ornithology)
Recent studies based on morphology, vocalizations and molecular phylogenetics suggest that Madeiran Storm Petrel represents a complex of species. Populations in the Azores which breed sympatrically but in different seasons differ from each other in morphology, have different calls, discriminate among these calls, and further differ in mitochondrial DNA (mtDNA) and microsatellite loci (Monteiro & Furness 1998, Bolton 2007, Friesen et al. 2007, Smith et al. 2007, Bolton et al. 2008, Robb et al. 2008). In addition, there are differences in ecology and moult (Monteiro & Furness 1998, Bolton et al. 2008). The concordance of these patterns of variation strongly indicates that these two populations have unique evolutionary histories, and are genetically and demographically distinct. The hot season breeding birds have recently been named O. monteiroi (Bolton et al. 2008). Storm petrels breeding on the Cape Verde Islands have very different calls from those in the Azores, and are highly divergent in mtDNA (more so than the sympatric O. monteiroi and O. castro, or indeed any other population in this complex). The evidence indicates that there are at least three population lineages in the Western Palearctic which are best treated as species.
Cape Verde Storm Petrel Oceanodroma jabejabe (monotypic) (endemic to the Cape Verde Islands)
Madeiran Storm Petrel Oceanodroma castro (monotypic) (hot-season breeders in Madeira and the Selvagens; also provisionally includes cool-season breeders in the Azores, Madeira, the Selvagens, and islands off Portugal)
Monteiro’s Storm Petrel Oceanodroma monteiroi (monotypic) (hot-season breeders in the Azores)
Birds breeding in the cool season in Madeira and the Selvagens (and also in the cool season in the Azores and islands off Portugal) are sympatric with hot-season breeders in Madeira (Nunes 2000) and the Selvagens (Faria 1998), but differ from these in vocalizations (Robb et al. 2008) and morphology (Faria 1998, Nunes 2000). However, DNA differences are less clear than those among Azorean populations (Friesen et al. 2007, Smith et al. 2007). As a consequence, although potentially a fourth species, this unnamed taxon is provisionally included in O. castro pending further study and taxonomic description.
Studies of vocalizations and phylogeography suggest that there are multiple lineages outside the Western Palearctic which should also be treated as species (Bolton 2007, Friesen et al. 2007, Smith et al. 2007).
There is a single British record of ‘Madeiran Storm Petrel’ sensu lato (off Isles of Scilly, 28 July 2007; British Ornithologists’ Union (BOU) 2012).
George Sangster (Department of Vertebrate Zoology, Swedish Museum of Natural History, Stockholm, Sweden) and colleagues writing in the journal Ibis have reviewed the taxonomy of the three Calonectris shearwater taxa of the Mediterranean and North Atlantic and consider that Scopoli's or Mediterranean Shearwater C. diomedea that breeds within the Mediterranean is a monotypic species, separable from Cory's Shearwater C. borealis
of the Macaronesian Islands in the North Atlantic. Hitherto these two
taxa have been usually separated only at the subspecific level. The
third taxon (now generally recognized as a full species) is the Cape
Verde Shearwater C. edwardsiiof the Cape Verde Islands.
Abbreviated extracts from their paper follow:
"Phylogenetic analyses of mitochondrial DNA sequences indicate that
the three subspecies of Cory's Shearwater form reciprocally monophyletic
groups and suggest that C. d. diomedea and C. d. edwardsii are more closely related to each other than either is to C. d. borealis. C. d. borealis and C. d. diomedea
differ in mean size and in the typical extent of white on the inner
webs of the primaries. The three taxa further differ in vocalizations.
Playback studies have documented differential responses to recordings
of C. d. borealis and C. d. diomedea. There are several reports of C. d. borealis within breeding colonies of C. d. diomedea
but most of these involved non-breeding individuals or birds of unknown
breeding status. Despite intensive monitoring of Atlantic and
Mediterranean breeding colonies, reports of interbreeding by C. d. borealis and C. d. diomedea
are limited. [T]he breeding grounds of these two forms are not fully
allopatric and ... some mechanisms of reproductive isolation are likely
to be involved in maintaining their differences. C. d. borealis and C. d. diomedea
breeding in sympatry in the Chafarinas Islands differ in their feeding
ecology and foraging areas during both chick-rearing and wintering
periods. The Cory's Shearwater complex is best treated as three full
species. [These are] Cory's Shearwater Calonectris borealis, Scopoli's Shearwater Calonectris diomedea, Cape Verde Shearwater Calonectris edwardsii."
A Cory's/Scopoli's Shearwater off South Africa. Photograph by John Graham
Reference:
Sangster, G., Collinson, J.M., Crochet, P.A., Knox, A.G., Parkin,
D.T. & Votier S.C. 2012. Taxonomic recommendations for British
birds: eighth report. Ibis 154: 874-883. John Cooper, ACAP Information officer, 3 November 2012
ScienceDaily (Oct. 31, 2012) — A Yale-led scientific team has produced the most comprehensive family tree for birds to date, connecting all living bird species -- nearly 10,000 in total -- and revealing surprising new details about their evolutionary history and its geographic context.
Analysis of the family tree shows when and where birds diversified — and that birds’ diversification rate has increased over the last 50 million years, challenging the conventional wisdom of biodiversity experts. (Credit: Image courtesy of Yale University)
Analysis of the family tree shows when and where birds diversified -- and that birds' diversification rate has increased over the last 50 million years, challenging the conventional wisdom of biodiversity experts.
"It's the first time that we have -- for such a large group of species and with such a high degree of confidence -- the full global picture of diversification in time and space," said biologist Walter Jetz of Yale, lead author of the team's research paper, published Oct. 31 online in the journal Nature.
He continued: "The research highlights how heterogeneously fast diversifying species groups are distributed throughout the family tree and over geographic space. Many parts of the globe have seen a variety of species groups diversify rapidly and recently. All this leads to a diversification rate in birds that has been increasing over the past 50 million years."
The researchers relied heavily on fossil and DNA data, combining them with geographical information to produce the exhaustive family tree, which includes 9,993 species known to be alive now.
"The current zeitgeist in biodiversity science is that the world can fill up quickly," says biologist and co-author Arne Mooers of Simon Fraser University in Canada. "A new distinctive group, like bumblebees or tunafish, first evolves, and, if conditions are right, it quickly radiates to produce a large number of species. These species fill up all the available niches, and then there is nowhere to go. Extinction catches up, and things begin to slow down or stall. For birds the pattern is the opposite: Speciation is actually speeding up, not slowing down."
The researchers attribute the growing rate of avian diversity to an abundance of group-specific adaptations. They hypothesize that the evolution of physical or behavioral innovations in certain groups, combined with the opening of new habitats, has enabled repeated bursts of diversification. Another likely factor has been birds' exceptional mobility, researchers said, which time and again has allowed them to colonize new regions and exploit novel ecological opportunities.
In their analysis, the researchers also expose significant geographic differences in diversification rates. They are higher in the Western Hemisphere than in the Eastern, and higher on islands than mainlands. But surprisingly, they said, there is little difference in rates between the tropics and high latitudes. Regions of especially intense recent diversification include northern North American and Eurasia and southern South America.
"This was one of the big surprises," Jetz said. "For a long time biologists have thought that the vast diversity of tropical species must at least partly be due to greater rates of net species production there. For birds we find no support for this, and groups with fast and slow diversification appear to occur there as much as in the high latitudes. Instead, the answer may lie in the tropics' older age, leading to a greater accumulation of species over time. Global phylogenies like ours will allow further tests of this and other basic hypotheses about life on Earth."
Other authors are G.H. Thomas of the University of Bristol in the United Kingdom; J.B. Joy of Simon Fraser University in Canada; and K. Hartmann of the University of Tasmania in Australia.
The work was supported by the National Science Foundation, NASA, the Natural Environment Research Council (U.K), the Natural Sciences and Engineering Research Council of Canada, Simon Fraser University, and the Yale Institute of Biospheric Studies.
La Universidad de Castilla-La Mancha
(UCLM) ha participado en un estudio en el que se cuestiona la
efectividad de los proyectos actuales de reintroducción de animales como
herramienta para la conservación de especies, ya que los actuales
proyectos de no cumplen con los criterios básicos. En la foto de
archivo, distribuida por la Fundación Migres de polluelos de águila
pescadora para reintroducir en Cádiz y Huelva. EFE/Javi Elorriaga
