Mostrando entradas con la etiqueta Fotos. Mostrar todas las entradas
Mostrando entradas con la etiqueta Fotos. Mostrar todas las entradas

martes, 11 de noviembre de 2014

Rosetta. Top 10 at 10Km

ESA’s comet-chasing Rosetta mission spent much of the second half of October orbiting Comet 67P/Churyumov–Gerasimenko at less than 10 km from its surface. This selection of previously unpublished ‘beauty shots’, taken by Rosetta’s navigation camera, presents the varied and dramatic terrain of this mysterious world from this close orbit phase of the mission.

Some light contrast enhancements have been made to emphasise certain features and to bring out features in the shadowed areas. In reality, the comet is extremely dark ­– blacker than coal. The images, taken in black-and-white, are grey-scaled according to the relative brightness of the features observed, which depends on local illumination conditions, surface characteristics and composition of the given area. Some slight vignetting can also be seen in the corners of some images.


Title NAVCAM top 10 at 10 km – 1
Released 11/11/2014 8:00 am
Copyright ESA/Rosetta/NAVCAM – CC BY-SA IGO 3.0

Description
This image showcases one of the many pits seen on the surface of 67P/Churyumov–Gerasimenko. Pits like these are thought to be where gas vents into space from the porous subsurface, carrying with it dusty grains of comet material. Scientists are keen to learn the role of this pit – and others – in the development of the comet’s activity, as it gets ever closer to the Sun.

This single-frame NAVCAM image measures 1024 x 1024 pixels. It was captured from a distance of 9.9 km from the centre of the comet (about 7.7 km from the surface) at 02:22 GMT on 15 October 2014. At this distance, the image resolution is 84.6 cm/pixel and the size of the image is 866 x 866 m.

This work is licenced under the Creative Commons Attribution-ShareAlike 3.0 IGO (CC BY-SA 3.0 IGO) licence. The user is allowed to reproduce, distribute, adapt, translate and publicly perform this publication, without explicit permission, provided that the content is accompanied by an acknowledgement that the source is credited as 'European Space Agency - ESA', a direct link to the licence text is provided and that it is clearly indicated if changes were made to the original content. Adaptation/translation/derivatives must be distributed under the same licence terms as this publication. To view a copy of this license, please visit http://creativecommons.org/licenses/by-sa/3.0/igo/
Id 326679


DETAILS
Title NAVCAM top 10 at 10 km – 2
Released 11/11/2014 8:00 am
Copyright ESA/Rosetta/NAVCAM – CC BY-SA IGO 3.0

viernes, 31 de enero de 2014

18 strange and beautiful hummingbird species

All photos: David Hemmings

Birds, bats, bees and other insects are all important pollinators, but hummingbirds seem to do the job with the most flare. They have that vibrant coloration, their rapier-like bills perfectly adapted to each species' flowery food source, their adorably tiny size, and of course their jaw-dropping flying abilities.

Wildlife photographer David Hemmings captures a diversity of species in his travels, but he is particularly good at capturing these tiny flying jewels, and has many incredibly beautiful species in his portfolio. For instance, there's the sword-billed hummingbird pictured above. This is the only species of bird with a beak longer than its body. And no wonder — wielding that beak can't be an easy task. The creature actually has to hold its bill pointed up in the air when perched to keep from tipping over. But the oddity also has a purpose. This hummingbird feeds on flowers with long corollas, so it has to reach deep to get to nectar. Even when you count that impressive beak, the hummingbird still averages less than 10 inches in length.

There are well more than 300 species of hummingbirds, 51 of which are considered threatened or endangered. There are so many, it's hard to pick favorites. But we gave it a try anyway. Here are 17 more examples of the diversity and wonder of hummingbirds:

Rufous breasted hummingbird: This species (pictured below) is a very picky eater. It will only eat from flowers that have a corolla (the whorl of petals that lead down into the nectaries) length and curvature exactly match that of its bill. Interestingly, the males and females have differently shaped bills, an evolutionary trait that researchers think cuts down on competition with each other for food sources.

Long-tailed sylph: The males of this species sport an amazingly long tail — so long that it hampers their flight and a male has to be a particularly strong and skilled flier to survive to breeding age. Females choose to mate with males with the longest tail feathers, since the length proves the male's level of strength and fitness.

Rufous-crested coquette: Coquettes are some of the smallest species of hummingbird, and the rufous-crested coquette measures only a little more than 2.5 inches in length and weight just under 3 grams. Now that's a featherweight!


Ruby topaz hummingbird: This species may look small and dainty but don't let their size fool you. Males will perch in conspicuous places, and aggressively defend their territories from competitors.


Anna's hummingbird: Those of us living along the western coast of North America will likely recognize the species below. This is the most common hummingbird along the Pacific Coast. And they have a fascinating courtship dance. Males will fly up to 130 feet in the sky and swoop down to Earth with alarming speed, making a chirp sound with their tail feathers before swooping back up to the sky again. You can see a video of the behavior here.

Booted racket-tail hummingbird: The male of this species has a pair of impressive tail feathers. The feathers extend well past his body and end in two iridescent racket-like flares. Many native flowering plants rely on this hummingbird species for pollination, since they can reach into the long tubular flowers that exclude bees or butterflies from access.
Many native and cultivated plants on whose flowers these birds feed heavily rely on them for pollination. The mostly tubular-shaped flowers actually exclude most bees and butterflies from feeding on them and, subsequently, from pollinating the plants. -
See more at: http://www.avianweb.com/bootedrackettailhummingbirds.html#sthash.ecnYxNE...

Many native and cultivated plants on whose flowers these birds feed heavily rely on them for pollination. The mostly tubular-shaped flowers actually exclude most bees and butterflies from feeding on them and, subsequently, from pollinating the plants. -
See more at: http://www.avianweb.com/bootedrackettailhummingbirds.html#sthash.ecnYxNE...

Many native and cultivated plants on whose flowers these birds feed heavily rely on them for pollination. The mostly tubular-shaped flowers actually exclude most bees and butterflies from feeding on them and, subsequently, from pollinating the plants. -
See more at: http://www.avianweb.com/bootedrackettailhummingbirds.html#sthash.ecnYxNE...


Cinnamon hummingbird: This long-winged lovely gets its name from its light brown coloring on the underside of its body. Found in western Mexico down to northwestern Costa Rica, they thrive in dry forests, and are sometimes spotted as far north as Texas and the southwest U.S.

Green hermit hummingbird: This is one of the larger hummingbird species, measuring about 5.3 inches in body length. In this species, the males have shorter tails than the females, but they still proudly wiggle these white-tipped feathers during competitive displays with other males as they vie for female mates.

Rufous-tailed hummingbird: This is a common bird of riverbanks and woodlands, living everywhere from open country to the edges of forests, and even coffee plantations (yes, your morning coffee might have been pollinated by a rufous-tailed hummingbird!). Not only your coffee, but perhaps also the banana you're snacking on, since they also love visiting the flowers of banana trees. Highly aggressive about defending their feeding territory, they're usually the top hummingbird in an area.

Brown violetear hummingbird: Don't let the relatively drab coloring of this species fool you. They do sport some wonderfully colored iridescent feathers under their throats and of course, they have that speck of violet over their ears, hence their name. They can flare these purple feathers out in a beautiful display. They can be found in the canopy of rain forests, in tall second growth forests, and they also visit coffee plantations like the rufous-tailed hummingbird. Plantations that use shade growing methods help birds (and other native pollinators) thrive by providing both a food source and the shrubby habitat needed for shelter and breeding.

Green crowned brilliant hummingbird: This emerald bird is one of the larger hummingbird species and is found in highlands from Costa Rica to western Ecuador. Instead of hovering at flowers like most hummingbird species, the green crowned brilliant hummingbird actually perches while feeding.


Chestnut-breasted coronet: This hummingbird is admired for the striking contrast between its rufous-colored underbody and its bright green head and back. It also has a characteristic trait of holding its wings upright over its back for a few moments after landing on a new perch. It can be found on the eastern slopes of the Andes mountain range.
The Chestnut-breasted Coronet (Boissonneaua matthewsii) is a South American hummingbird that occurs naturally in the humid montane Andean forests in extreme southeastern Colombia, Ecuador and Peru (on the western slope south to Cajamarca, on eastern slope south to Cuzco. - See more at: http://www.avianweb.com/chestnutbreastedcoronethummingbirds.html#sthash....



Snow capped hummingbird: We'll give you one guess as to how this species got its name. Despite its stand-out markings, it is a very difficult hummingbird species to find as they are extremely localized and do not visit feeders. Plus, they are only 2.5 inches long and weigh less than a penny — so looking for them is like looking for a moving flower among other flowers!

Snowcaps occur naturally in Honduras, Nicaragua, Costa Rica, as well as central and western Panama; but they are extremely localized and difficult to find.
They inhabit the Central American cloud forests; where they feed in humid montane evergreen forests. They are typically found high up in the canopy and along the edges of wet forest, as well as adjacent woodland.
The highest concentration occurs on the Caribbean mountain slopes, where they breed at heights of ~1,000 - 2,600 ft (300–800 m). After the breeding season, most will move down to the adjacent lowlands. However, some may move up to higher elevations to about 4,500 ft (1,400 m).
- See more at: http://www.avianweb.com/snowcaphummingbirds.html#sthash.VvdMSVR4.dpuf

Ecuadorian hillstar: This species's name is apt, given that they live at high altitudes in the Andes, feeding along the slopes right up to the snowline. Because they live in such cold areas year-round, they save energy by taking shelter in protected roosts and going into torpor (lowered metabolic rate, heart rate, oxygen intake and body temperature) at night.


White-necked Jacobin hummingbird: It's hard to miss this species of hummingbird, with the bright white belly and tail of the males, and of course that dark blue head. Like many hummingbird species, the Jacobin feeds not only on nectar but also gets protein from small insects, which it catches by "hawking" or snatching in mid-air.

Velvet purple coronet: This incredibly beautiful bird may appear all black at first, but just wait until the light catches those iridescent feathers and you'll see flashes of vivid purple, blue and green. The underparts of its wings are also a contrasting chestnut color. No wonder it is called a flying jewel!

Green-throated mango hummingbird: This species loves mangrove and swamp forests, and can be found along a narrow strip of the Atlantic Coast along the north and south of the Amazon river outlet. Though not much is known about this species, it is known that the population occurring in Trinidad is now rare due to the loss of its preferred swamp and mangrove habitat.


ORIGINAL: Mother Nature Network
By Jaymi Heimbuch
Jan 14, 2014