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|Great Tits - Parus major|
|Tweet Topic Started: Jan 8 2012, 10:19 PM (979 Views)|
|Taipan||Jan 8 2012, 10:19 PM Post #1|
Great Tit - Parus major
Order : Passeriformes
Family : Paridae
Size : 14 cm
Wingspan : 23 à 26 cm
Weight : 16 à 21 g
Physical description :
Great Tit has yellow underparts with central black stripe from chin to belly. Males have bold black stripe. On the upperparts, back is greenish. Wings are greyish-blue with white wing bars. Tail is blue-grey with white outer feathers.
Head is glossy blue-black with white cheeks. Eyes are black. Short bill is blackish. Legs and feet are pale blue-grey.
Both sexes are similar, but female has narrower black stripe on underparts than male.
Juvenile is duller, with dark brownish head, yellowish cheeks, and dark brownish ventral stripe.
Great Tit has several calls, and all are loud and ringing, including 'chick-pee-chick-pee...', an alarm call 'tink-tink-tink', also a 'zik-zik-doo-doo', and a harsh scolding 'tchairrr' often repeated.
The usual and best known song is a loud and ringing 'teechu-teechu-teechu-teechu...'. Some mimicry adds variation to a wide repertoire.
Great Tit lives in deciduous and mixed woodlands and thickets, gardens, hedgerows, parks, orchards and close to human habitations.
GEOGRAPHIC RANGE: Great Tit is widespread throughout Eurasia, from Great Britain to Japan, and also in North Africa.
Because its large size, Great Tit tends to feed on the ground more than other smaller tits. During summers, Great Tit gleans invertebrates from leaves and bark crevices, and frequents bird-feeders in winter.
Great Tit is gregarious, living and feeding in groups with other tits, outside breeding season. It moves easily on the ground, hopping among grasses.
It is very aggressive, and may attack other nests, to capture chicks. They roost in flocks, in hollows, holes in trees or walls.
Courtship displays are not very elaborated. Male erects its crest feathers, and sticks out its breast, fluffing its feathers, in order to display the wide black stripe and throat.
Great Tit has an undulating flight. It performs short flights from tree to tree, with rapid wing beats. It may hover to catch insects in midair.
Great Tit nests in hollows in trees, holes, crevices in walls, burrows, holes in rocks, but also in nest-boxes, letter-boxes and pipes.
Female builds the nest adding a lot of materials such as moss, wool, hair and feathers. It is situated from very low level to 6 metres above the ground.
Female lays 6 to 8 white eggs, sparsely spotted with reddish. Incubation lasts about 13 to 16 days by female. Male feeds her at nest.
Altricial chicks are covered with sparse long grey down on head and back. They are fed by both parents, mainly with caterpillars. They grow slowly, opening their eyes only at about 8 to 9 days after hatching. Young fledge at about 18 to 24 days of age. Both parents feed them for 15 to 25 days more after fledging.
This species produces two broods per season.
Food habits : Great Tit feeds on invertebrates in spring and summer, and also on seeds and fruit in autumn and winter. They frequent bird-feeders in winter.
Protection / threats : Populations of Great Tits have increased since 1960, and they are not threatened at present. They are common and widespread in their range.
Longevity : 15 years
Edited by Taipan, Sep 21 2013, 02:54 PM.
|Taipan||Jan 11 2012, 04:43 PM Post #2|
Great Tit Birds Shift Mating Schedules Due to Warming
Matt Kaplan in London
for National Geographic News
May 8, 2008
Birds called great tits are adapting to global warming by altering their behavior in England, a decades-long study has found.
The common birds are found in gardens throughout most of Europe. They have a specific mating schedule linked both to warm temperatures and to the presence of caterpillars, which great tits feed to their young.
Researchers monitored a population of the birds in Wytham, near Oxford, for 47 years, looking carefully at when eggs were laid, which chicks survived, and what the conditions were at the time.
"We wanted to know how well great tits in Wytham could adjust their timing of breeding to the timing of food abundance … and how efficient this adjustment was for population adaptation to the increase in spring temperature," said lead study author Anne Charmantier of the University of Oxford.
The study appears in tomorrow's issue of the journal Science.
Because great tits rely on recurring annual conditions to rear their young, scientists had assumed that the birds instinctively lay their eggs at the same time every year—just before caterpillars become abundant.
Birds that laid eggs on their typical schedule would have a difficult time raising their young as warm temperatures—and caterpillars—arrived earlier, the researchers hypothesized.
Caterpillars would not be as plentiful when the eggs finally hatched a few weeks later.
Such a situation theoretically would lead to a steady decline in birds that stick to the old schedule, because their chick-rearing record would be poor, and would drive the population to have more birds that lay their eggs sooner—a classic case of natural selection.
Charmantier and her colleagues found that the Wytham population moved its egg-laying schedule forward 14 days to synchronize with the earlier caterpillar activity—without a lot of chick deaths.
The fact that few dead chicks were found meant that the tits were not making the mistake of laying on the old schedule as temperatures changed, the researchers say.
In other words, rather than being picked off by natural selection, the birds were surviving by shifting their behavior—adjusting their breeding schedule each year to coincide with caterpillar abundance, the scientists say.
Dan Nussey, an evolutionary biologist at the University of Edinburgh, Scotland, was not involved with the study.
"What is really striking here is the difference between this population and a population of great tits living in Holland, where springs are warming but the average bird breeding times are just not changing fast enough to keep up," he said.
"Same species, similar habitat, and yet quite a different picture. This study suggests that we cannot generalize about the effects of global warming."
Marcel Visser, an evolutionary ecologist at the Netherlands Institute of Ecology, was also not involved with the study. But he has a different opinion about why the two populations are responding to climate change differently.
In the United Kingdom, springs are getting warmer earlier. In the Netherlands, though, it's the late part of spring—after the birds have laid eggs—that is increasing in temperature.
"This is a big difference," he said. "In the U.K. the birds lay eggs as the weather warms and have caterpillars available to feed their young.
"In the Netherlands the birds lay their eggs when the weather is the same as it always was, but because the temperatures in late spring are much warmer, the [temperatures] accelerate insect development, and caterpillars are not available when it is time to feed the young," he added.
"The U.K. birds are just lucky that the old rule of laying eggs when temperatures get warmer still works for them. What is being observed in this new study is probably an exceptional situation."
As spring arrives earlier in England, great tits, such as the one in this undated photo, are moving up their mating schedules to coincide with an earlier emergence of caterpillars, a new study says.
|Taipan||Jan 11 2012, 04:43 PM Post #3|
Great tits acquire taste for bats
By Richard Black
Environment correspondent, BBC News website
Page last updated at 10:11 GMT, Wednesday, 9 September 2009 11:11 UK
A Hungarian cave has turned out to be a larder of highly unusual food for great tits: hibernating pipistrelle bats.
Over two winters, researchers found the birds were systematically hunting bats by sight and sound as they hibernated through the cold months.
Writing in the journal Biology Letters, the scientists say this is the first proof of bat-hunting in songbirds.
Great tits usually dine on smaller prey such as insects and seeds, with bat-eating probably very rare.
The researchers found the birds preferred other food when they could get it.
"It doesn't look like this is an overwhelming thing that threatens the bat population," said Bjorn Siemers from the Max-Planck-Institute for Ornithology in Seewiesen, Germany, one of the research team.
"So then the question to ask is 'how do they invent it?', and so far we can only speculate - it could be a kind of cultural learning," he told BBC News.
In previous decades, researchers have reported finding dead or injured bats outside caves in Sweden and Poland.
In one case, the bat was being eaten by a great tit, in others they bore wounds that could have been inflicted by a tit's beak; but there was no proof that the birds had hunted or killed them.
If they did, said Dr Siemers, it raised the possibility that the habit or skill of bat-hunting was carried along migration routes.
During two field seasons in the Bukk Mountains of northeastern Hungary, the researchers documented 16 cases of great tits (Parus major) hunting, killing and eating a hibernating bat in the one cave.
Pipistrelle bats (Pipistrellus pipistrellus) are about one-quarter of a great tit's size.
The birds would fly close to the cave walls, landing frequently and often disappearing into crevices. They would either eat the bats there and then or carry them away for feeding.
After feeding: remains of the bat
When their hibernation is disturbed, the bats squeak in the audible range for humans and great tits.
The researchers speculated that the birds may have learned to listen for these squeaks - and when they recorded some and played them back, the birds responded with interest about 80% of the time.
However, the team believes the birds can only bat-hunt when they can see their prey, as they can in this wide-mouthed cave where lots of light penetrates - again suggesting it would be a rarely-found behaviour.
In a later experiment, the scientists provided other food - sunflower seeds and bits of bacon - and found that the birds preferred to eat those, leaving the bats largely untouched. This raises the suggestion, said Dr Siemers, that bats are a food of last resort in a harsh winter.
Graham Madge, a spokesman on conservation issues for the UK's Royal Society for the Protection of Birds (RSPB), said it was new to him.
"Normally, great tits are feeding on things like insects, beetles, spiders, seeds and maybe fruit in winter - there's no indication they'd be able to predate something like a bat. It's incredible behaviour."
He noted that in the UK, a close relative, the blue tit, has also been quick to take advantage of novel foods.
"There was this phenomenon where blue tits learned how to open the foil tops of milk bottles, and quickly this behaviour spread through the population; so they're quick learners," he said.
|Taipan||Jan 11 2012, 04:44 PM Post #4|
Brightly coloured male great tits may have a reproductive advantage over "paler males", say scientists. Fabrice Helfenstein from the University of Bern in Switzerland, and his colleagues, discovered that sperm of the more brightly coloured birds was less vulnerable to damage by free radicals.
|Taipan||Sep 21 2013, 03:03 PM Post #5|
Shy Great Tit Birds Flock Together
A new study finds that personality influences social behavior in birds.
Great tits, like the birds above, have been the subject of decades-long population studies.
Rachel Hartigan Shea
Published September 20, 2013
It really is true: Birds of a feather do flock together.
Shy male birds prefer the company of fellow introverts, according to a study published this week in Ecology Letters.
Researchers associated with the Edward Grey Institute of Field Ornithology at the University of Oxford in England studied great tits (Parus major) in Wytham Woods, near Oxford, to determine how personality affects social behavior.
Previous research found evidence that birds with larger social networks can find more food, with the advantage going to individuals more apt to mingle.
The intersection of personality and social behavior is a new and growing area of study in biology and behavioral ecology, says study co-author Julie Morand-Ferron. "If you take the simple definition of personality as behaving consistently over time, then you can find personality traits in vertebrates and insects and all sorts of animals."
For the purposes of this study, shy or "reactive" birds are slower to explore and less likely to take risks. Bold or "proactive" birds prefer high risks and high rewards.
But researchers first needed to determine which great tits were shy, and which were bold explorers.
So they captured 221 great tits from the wild and released them one by one into a room containing five artificial trees. The scientists then recorded their movements.
"The very shy birds basically don't move that much," says Morand-Ferron. "They seem to be very careful. They hop from tree to tree, or they fly a bit."
Bolder birds, on the other hand, "have a very high activity rate. They land on the ground. They fly quickly."
With the personalities of the 221 captured birds established, the researchers released them back into the wild, where they tracked the birds' movements.
The great tits of Wytham Woods have been studied for more than six decades, and most of them wear plastic rings containing transponders around their legs. Sensors on the 65 feeding stations dotting the forest pick up the transponder signals whenever the birds come close enough.
Over the winter months, when great tits congregate in loose flocks, the researchers monitored where the tested birds were feeding and who they were hanging out with.
They discovered that male birds who exhibited shy behavior in captivity tended to stay in flocks with their shy friends in the wild for longer periods of time, while the bolder birds flitted from flock to flock.
In a previous paper, Morand-Ferron and her colleagues determined that birds with larger social networks—like those bold birds—find out about hidden sources of food quickly because they have access to more information.
But they're not sure yet what evolutionary advantage shy males might gain from sticking together. In the paper, the authors hypothesize that the shy males are trying to avoid the more aggressive bold males, but Morand-Ferron emphasizes that this is a question for further study.
No word yet on whether a bird in the hand has been proved to be worth two in the bush.
Individual personalities predict social behaviour in wild networks of great tits (Parus major)
L. M. Aplin1,2,*, D. R. Farine1, J. Morand-Ferron1,3, E. F. Cole1, A. Cockburn2, B. C. Sheldon1
Article first published online: 17 SEP 2013 DOI: 10.1111/ele.12181
Social environments have an important effect on a range of ecological processes, and form a crucial component of selection. However, little is known of the link between personality, social behaviour and population structure. We combine a well-understood personality trait with large-scale social networks in wild songbirds, and show that personality underpins multiple aspects of social organisation. First, we demonstrate a relationship between network centrality and personality with ‘proactive’ (fast-exploring) individuals associating weakly with greater numbers of conspecifics and moving between flocks. Second, temporal stability of associations relates to personality: ‘reactive’ (slow-exploring) birds form synergistically stable relationships. Finally, we show that personality influences social structure, with males non-randomly distributed across groups. These results provide strong evidence that songbirds follow alternative social strategies related to personality. This has implications not only for the causes of social network structure but also for the strength and direction of selection on personality in natural populations.
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