Archive for the 'Beyond Bounds' Category

Nov 06 2013

Magic Eyes

Published by under Beyond Bounds,Mammals

When lights shine on an animal’s eyes at night, what color is reflected back at you?

For cats it’s green.  For possums it’s red.  For arctic reindeer it depends on the time of year!

The tapetum lucidum in reindeer’s eyes changes color to cope with the bright light of summer and low light of winter.  In summer their eyes reflect gold, in winter they look blue.

This cool effect was discovered by a team from University College London and University of Tromsø, Norway thanks to funding from BBSRC (Biotechnology and Biological Sciences Research Council).

Watch the video above and read more about the study here at Phys.org.

 

(video from BBSRC via phys.org)

 

p.s. Reindeer have two other amazing traits: (1) They can see ultraviolet light and (2) They have no circadian rhythm.

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Oct 18 2013

The Virtuoso

Published by under Beyond Bounds

The weather changed and it feels like fall today in Pittsburgh.  The warblers have left, the sparrows are migrating, and none of the birds are singing.

On the other side of the world it’s spring and time to sing.

In the video above a male Australian magpie sings his very best imitations, a quiet serenade in a back garden.

Can you recognize the sounds he’s imitating?  Listen for dog barks and budgie sounds.

Quite a virtuoso.

(video by candykim22 from YouTube)

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Oct 17 2013

Catch-22 For Cape Vultures

Cape vulture in flight (photo from Wikimedia Commons)

Birds love to perch on wires and power poles, the bigger the bird the bigger the wire.  Unfortunately this affinity poses a threat to very large birds because their long wings can touch two wires at the same time and electrocute them.  Vultures are especially vulnerable because they roost in large gregarious groups.  If they jostle their buddies too much … ooops!

Cape vultures (Gyps coprotheres) of southern Africa, like most Gyps species, are declining.  They are listed as threatened because of decreased carrion for their chicks, poisoning from medication in livestock carcasses, electrocution and collision with wires, and exploitation for traditional medicine/religion.

Cape vultures live a long time and reproduce slowly so significant losses of any kind pose a problem.  There are protected areas in southern Africa where the vultures aren’t exposed to so many threats but there is also a growing power grid.

W. Louis Phipps and his team decided to find out how cape vultures used the power grid so they affixed GPS trackers on nine cape vultures — five adults and four immatures — to see where they would go.  The results were somewhat surprising.

The cape vultures’ home range is larger than expected; some traveled more than 600 miles one way.  Given the opportunity to travel the power corridors, that’s what they did.  Cape vultures are cliff birds so the power towers gave them high perches and clear sight lines in formerly useless habitat.  The study also found that the vultures fed more often on private farmland than in protected areas.  (The vultures would say, “Well, that’s where the food was.”)

It’s the classic Catch-22.  The power corridors have expanded the cape vultures’ range but the wires sometimes kill them.  In a declining population it makes a difference.

For more information read the full study here at PLOS One.

(photo from Wikimedia Commons. Click on the image to see the original)

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Sep 13 2013

Red Legs

Black guillemot in breeding plumage at Metinic Island, Maine (photo from Wikimedia Commons)

About the size of a pigeon, this northern alcid comes south to Maine for the winter.

I’ve seen black guillemots fishing close to rocky shores.  Some are still in their black-and-white breeding plumage (above). Most have changed to mottled white for winter.

Black guillemot in winter plumage (photo from Wikimedia Commons)

In either case they have bright red legs that match the insides of their mouths.

I can see their red legs through the water.

(photos from Wikimedia Commons. Click on the image to see the original)

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Aug 02 2013

8 Minutes at the Yukon Delta

Published by under Beyond Bounds

Early this month Cornell Lab of Ornithology featured this gorgeous video in their eNewsletter.

The Yukon Delta National Wildlife Refuge is the breeding ground for birds from every continent on earth and the only place where four threatened/endangered species breed.

Learn about the delta and see its beautiful birds in just eight minutes.

(video by Cornell Lab of Ornithology)

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Jul 24 2013

Has Used A Motorcyle

Aplomado falcon (photo from Shutterstock.com)

Some raptors have special techniques for finding food.  This one has used trains and motorcycles.

Aplomado falcons (Falco femoralis) are native to grassland and marshland from Mexico to South America where they eat birds, insects and small vertebrates.  Sometimes they hunt while soaring or from a perch but when hunting birds they prefer to fly fast through thickets to flush them from cover. This technique is similar to a Coopers hawk.

Mated pairs like to hunt cooperatively.  The male makes a distinctive “chip” sound to call his mate to a hunt.  Sometimes the female will even come off the nest to participate.  The male corners the prey by hovering above the thicket.  The female flies through and flushes it.

When his mate can’t come out to hunt, what’s a guy to do?  Borrow a motorcycle.

Aplomados have figured out that our large, loud vehicles scare small birds into flight.  According to Birds of North America online, one researcher reported an aplomado following a motorcycle to pick off small birds flushed from the side of the road.  Another reported a falcon flying with a train and switching sides to check out the ditches.

These falcons were extirpated from the U.S. in the 1950′s and only recently made a comeback in New Mexico and south Texas, partly on their own and partly thanks to reintroduction programs.

When I travel southwest to find an aplomado I wonder … will it help to watch for motorcycles?

 

(photo from Shutterstock.com)

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Jul 20 2013

Mr. Gorgeous

Indigo Bunting, male (photo by Shawn Collins)

Beautiful and blue, a male indigo bunting poses for a photograph.

Gorgeous!

 

(photo by Shawn Collins)

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Jul 16 2013

Arctic Summer Bird Activities

Red phalarope, Barrow, Alaska (photo from Wikimedia Commons)

Though the solstice was more than three weeks ago the sun still hasn’t set in the Arctic.  Some arctic animals have no circadian rhythm because there’s no light/dark cycle.  What do the birds do?

The Max Planck Institute of Ornithology studied four species that nest near Barrow, Alaska.  What they found is that some stayed on a 24-hour clock while others had no daily pattern.  Their circadian rhythms varied based on lifestyle, sex and breeding stage.  Here are the four they studied:

  • Semi-palmated sandpipers are totally monogamous and share incubation and child rearing.
  • Pectoral sandpiper males have multiple wives. Only the females incubate and take care of the kids.
  • Red phalaropes reverse these roles.  The females have multiple husbands.  Only males incubate and raise the kids.
  • Lapland longspurs are monogamous with the occasional male having multiple mates.  Both parents take care of the kids but only the female incubates.

During the courtship period the shorebirds showed no daily pattern while the lapland longspurs simplified their lives by never giving up their 24-hour clock.

Incubation changed the shorebirds’ clocks.  In summertime the ground temperature in Barrow varies daily from near freezing (11:00pm to 7:00am) to 60 degrees F (noon to 6:00pm).  As soon as incubation began the incubating parents — pectoral sandpiper females and red phalarope males — began to follow a daily clock so they’d be on the nest when it’s cold.

The exception were the semi-palmated sandpipers.  Because they completely share parental duties they threw out the clock when incubation began and synched as couples.  “Who cares what time it is.  We have each other.”

Meanwhile the pectoral sandpiper males and red phalarope females never stopped courting so they never developed a daily rhythm.

In the end the study shows that arctic-nesting birds are very flexible.  They can be active regardless of time of day, then alter their circadian clocks when their needs change.

Those needs will change soon.  The sun will set for the first time on August 1 and the birds will prepare to leave.  For some shorebirds, migration has already begun.

For more information read a summary of the study in Science Now or the entire study at the Proceedings of the Royal Society.

 

(photo of a female red phalarope in Barrow, Alaska from Wikimedia Commons. Click on the image to see the original)

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Jul 10 2013

Falcon From Down Under

Brown Falcon, Australia (photo from Wikimedia Commons)

Browsing through photos on Wikimedia Commons, this portrait of a falcon caught my eye.  He’s one of six species of falcons found in Australia, new to me because he doesn’t occur in North America.  The only falcon we all have in common is the peregrine.

The brown falcon (Falco berigora) is slightly smaller than a peregrine and has a different lifestyle.  Rather than capture prey in the air he uses a perch-and-pounce method to capture small mammals, lizards and snakes, small birds, and insects.  This is similar to the red-tailed hawk’s hunting technique.

Brown falcons don’t need to fly fast.  Their wing beats are slow and they glide in a shallow V the way northern harriers do.

Though they share characteristics with hawks, Perth Raptor Care says they have a lot of personality.  Click here for a video at Arkive.org that gives you a window on the lives of brown falcons: contending with crows, sharing with a mate, feeding the “kids.”

I love their brown pantaloons.

(photo from Wikimedia Commons. Click on the image to see the original)

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Jul 08 2013

African Starlings Invent New Colors

Greater blue-eared glossy-starling in South Africa (photo by Dick Daniels on Wikimedia Commons)

African starlings evolve color faster than any other bird — 10 times faster than their ancestors and modern relatives according to a new study from the University of Akron.

Like other Sturnidae these birds had iridescent qualities, but after they made it to sub-Saharan Africa 17 million years ago their colors went wild.   The cells that give their feathers iridescence are called melanosomes.  Instead of the usual simple rod-like forms, glossy starlings (Lamprotornis) developed hollow rods, solid flattened rods, and hollow flattened rods.  Though these divergent melanosomes are sometimes found in other birds, glossy starlings can have all the variations in one species.  This produced an explosion of new colors.

At the University of Akron Rafael Maia studied microscopic feather structures and used spectral color analysis and evolutionary modelling to figure out how these starlings evolved four types of melanosomes and 19+ species.   It happened very fast.

Their social structure helped.  For glossy starlings, color confers high rank in both sexes so the most colorful birds are the most successful breeders.  Intense social pressure selected for better and better colors.

The results are gorgeous.  Above, a greater blue-eared starling (Lamprotornis chalybaeus) shows off his teal and blue back. Below, a lesser blue-eared starling (Lamprotornis chloropterus) displays five colors even though he’s molting.

Lesser blue-eared starling (photo by Sumeet Moghe via Wikimedia Commons)

 

Read more about the study here in Science Daily.

 

(photos of a greater blue-eared and lesser blue-eared starling from Wikimedia Commons. Click on the images to see the originals)

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