linda040899
07-16-2005, 06:10 PM
Found this in my inbox and thought I would share it with everyone. It's cross-posted with permission.
Subject: Big-brained birds less likely to migrate
29 June 2005
Big-brained birds less likely to migrate
Michael Hopkin
Clever species stay put for winter, while others flee.
It takes brains to make it through the winter, at least
if you're a bird. A new survey suggests that bird species
that have evolved to fly south for the coldest months
tend to be those that weren't smart enough to survive if
they stayed put.
The study shows that migratory birds, which leave
temperate regions in search of warmer climes when
temperatures start to dip, have smaller brains than those
who stay behind. Non-migrating species also show more
creativity when it comes to finding a meal in the frugal
winter months.
Daniel Sol of the Independent University of Barcelona in
Spain and his colleagues used previous observations of
134 bird species in Europe, Scandinavia and western
Russia. They collected data on brain size, and also
counted the number of times researchers had spotted the
birds adopting a novel feeding technique.
Not-so-fussy eaters
Species that remain resident during the winter have
adopted more feeding innovations, the team reports in a
paper published online by Proceedings of the Royal
Society [1]. The blackbird, Turdus merula, for example,
has been seen using twigs to clear snow away while
foraging. And the bullfinch, Pyrrhula pyrrhula, has been
spotted tearing flesh from chicken and duck carcasses to
get a meal.
On average, non-migratory birds have been spotted using
four novel feeding styles per species, compared with
around three for short-distance migrants, and just over
one for species that commute beyond the Sahara Desert to
the south.
"Species with greater foraging flexibility seem to be
able to cope with seasonal environments better, while
less flexible species are forced to become migratory,"
say Sol and his team.
Bird brains
A similar pattern was seen in brain size, with the
resident species tending to have more upstairs than
short-distance migrants, who in turn had larger brains
than the long-distance fliers.
Brain tissue requires a lot of energy, the researchers
say. So migratory birds, which expend a large chunk of
their energy commuting, may benefit from having smaller
brains to maintain. But, the team argues, small brains
probably forced the birds to adopt a migratory lifestyle
in the first place, because they were not smart enough to
cope with winter.
Their lack of inventiveness may mean that migratory
species will have more trouble adapting to future changes
in environmental conditions, Sol and his colleagues add.
With climate change and human intervention changing the
landscape, these birds may be at greater risk of
extinction than those that stay put.
References
[1] Sol D., Lefebvre L. & Rodriguez-Teijeiro J. D. Proc,
R. Soc. B, doi:10.1098/rspb.2005.3099 (2005).
Story from news@nature.com:
http://news.nature.com//news/2005/050627/050627-8.html
Subject: Big-brained birds less likely to migrate
29 June 2005
Big-brained birds less likely to migrate
Michael Hopkin
Clever species stay put for winter, while others flee.
It takes brains to make it through the winter, at least
if you're a bird. A new survey suggests that bird species
that have evolved to fly south for the coldest months
tend to be those that weren't smart enough to survive if
they stayed put.
The study shows that migratory birds, which leave
temperate regions in search of warmer climes when
temperatures start to dip, have smaller brains than those
who stay behind. Non-migrating species also show more
creativity when it comes to finding a meal in the frugal
winter months.
Daniel Sol of the Independent University of Barcelona in
Spain and his colleagues used previous observations of
134 bird species in Europe, Scandinavia and western
Russia. They collected data on brain size, and also
counted the number of times researchers had spotted the
birds adopting a novel feeding technique.
Not-so-fussy eaters
Species that remain resident during the winter have
adopted more feeding innovations, the team reports in a
paper published online by Proceedings of the Royal
Society [1]. The blackbird, Turdus merula, for example,
has been seen using twigs to clear snow away while
foraging. And the bullfinch, Pyrrhula pyrrhula, has been
spotted tearing flesh from chicken and duck carcasses to
get a meal.
On average, non-migratory birds have been spotted using
four novel feeding styles per species, compared with
around three for short-distance migrants, and just over
one for species that commute beyond the Sahara Desert to
the south.
"Species with greater foraging flexibility seem to be
able to cope with seasonal environments better, while
less flexible species are forced to become migratory,"
say Sol and his team.
Bird brains
A similar pattern was seen in brain size, with the
resident species tending to have more upstairs than
short-distance migrants, who in turn had larger brains
than the long-distance fliers.
Brain tissue requires a lot of energy, the researchers
say. So migratory birds, which expend a large chunk of
their energy commuting, may benefit from having smaller
brains to maintain. But, the team argues, small brains
probably forced the birds to adopt a migratory lifestyle
in the first place, because they were not smart enough to
cope with winter.
Their lack of inventiveness may mean that migratory
species will have more trouble adapting to future changes
in environmental conditions, Sol and his colleagues add.
With climate change and human intervention changing the
landscape, these birds may be at greater risk of
extinction than those that stay put.
References
[1] Sol D., Lefebvre L. & Rodriguez-Teijeiro J. D. Proc,
R. Soc. B, doi:10.1098/rspb.2005.3099 (2005).
Story from news@nature.com:
http://news.nature.com//news/2005/050627/050627-8.html