Archive for the 'Beyond Bounds' Category

Dec 09 2013

Snowy Owl Respect

If you read PABIRDS you’ve seen this discussion and perhaps the video, but it’s well worth passing along.

This winter has quickly shaped up to be an “invasion” year for snowy owls. These big, beautiful birds are popping up in open spaces, on buildings and at shorelines across the northern United States.  On the PABIRDS listserv alone, at least 33 snowies have been reported in Pennsylvania since December 1 — about half of them at Presque Isle State Park.

Snowy owls “invade” in the winter when they’ve had a hugely successful breeding season up north because of super-abundant lemmings last summer.  Most of the visiting birds are young owls on their first trip away from home. They’ve come south to eat our abundant food and rest between meals.  Studies have shown this is a good move on their part.  Scott Wiedensaul points out that the vast majority eat well and return to the Arctic in spring.  Of those that die, the leading cause of death is trauma, not starvation.

But they shouldn’t be harassed. Last Saturday there were seven snowy owls at Presque Isle as well as birders, photographers and owl enthusiasts.  Most people kept a respectful distance but two photographers approached the owls and flushed them repeatedly even though observers warned them not to. This prompted Jerry McWilliams to write:

“Just a reminder to birders and photographers who are interested in observing or photographing the Snowy Owls. You should resist the urge, as we have all experienced, to try and approach too closely. The owl that visited my waterbird count this morning was very alert and did not remain in one spot for long. Between the Coyotes and enthusiastic humans, it is a challenge for these northern invaders to have a chance to rest and find a meal. Please come and enjoy them, but keep your distance and respect their needs.”

The disrespect is not limited to Pennsylvania.  A similar discussion occurred on NJBIRDS about incidents in New Jersey.

Presque Isle Audubon and the state park are doing something about it.   Presque Isle Audubon is organizing volunteers to alert visiting photographers and birders about owl etiquette as they enter the Gull Point Trail.  State Park rangers (DCNR) will also be monitoring the situation.

If you see people harassing wildlife, speak up or report them to park rangers.  If you would like to volunteer at the Gull Point Trail, click here for Presque Isle Audubon contact information.

A gentle reminder to respect the owls will go a long way.

 

(video by Cornell Lab of Ornithology, first published in 2010)

p.s. Click here to read an excellent explanation of wild bird reactions to humans — with a special emphasis on raptors and owls — by Julia Ecklar of the National Aviary.

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Dec 06 2013

Bird Equivalents

Tufted titmouse, Great tit (photos from Wikimedia Commons)

Here’s an interesting thought: Around the world there are birds with similar habitat and food requirements that are ecological equivalents to each other.  Though they live on different continents they occupy similar niches.  Sometimes they even look alike.

I was intrigued by this when I found a graphic on page 630 of Ornithology by Frank B. Gill showing three sets of equivalent birds from North America and Europe.  Here they are:

Set #1.  The tufted titmouse in North America (at left above) is an ecological equivalent to the great tit in Europe (at right).

All About Birds says the tufted titmouse prefers “eastern woodlands below 2,000 feet elevation, including deciduous and evergreen forests. Tufted titmice are also common visitors at feeders and can be found in backyards, parks, and orchards.”

Europe’s great tit prefers similar habitat.  I wish our titmouse was as colorful.

 

Set #2.  Our black-capped chickadee (at left below) is equivalent to Europe’s willow tit (at right).

Again according to All About Birds, “Black-capped chickadees may be found in any habitat that has trees or woody shrubs, from forests and woodlots to residential neighborhoods and parks, and sometimes weedy fields and cattail marshes. They frequently nest in birch or alder trees.”

In Europe, look for the willow tit in these habitats.

Black-capped chickadee, Willow tit (photos from Wikimedia Commons)

 

Set #3.  The chestnut-backed chickadee of the Pacific Northwest (at left below) is equivalent to the coal tit in Europe (at right).

All About Birds says, “Chestnut-backed chickadees are found in dense coniferous and mixed coniferous forests of the Pacific Coast. You can also find them in shrubs, trees, and parks of cities, towns, and suburbs.”

The coal tit has similar habitat requirements in Europe and fills a wider niche in Ireland where competing marsh, willow and crested tits aren’t present.

Chestnut-backed chickadee, Coal tit (photos from Wikimedia Commons)

 

There are many more ecologically equivalent species.  GrrlScientsist shows us Kenya’s ecological equivalent of the red-tailed hawk at this link.

Can you think of other bird equivalents?

 

(photos from Wikimedia Commons. Click on these links to see the originals: tufted titmouse, great tit, black-capped chickadee, willow tit, chestnut-backed chickadee, coal tit.
Today’s Tenth Page is inspired by page 630 of Ornithology by Frank B. Gill.
)

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Dec 04 2013

In A Shrinking Bubble

Ethiopian bush crow (photo from Wikimedia Commons)

As things stand now this intelligent, resourceful, omnivorous bird may go extinct in the 21st century.  Why?  Because he lives in a shrinking bubble.

For a long time scientists could not figure out why the Ethiopian bush-crow (Zavattariornis stresemanni) lived in only one 6,000 square mile area of southern Ethiopia.   He’s really smart, eats anything, and nests cooperatively but the bush-crow does not expand his range even though the habitat bordering his domain appears to be exactly the same.

His size and threatened lifestyle resemble that of the Florida scrub-jay whose range was 7,000 square miles but an area of suitable habitat much smaller.  Scientists approached the bush-crow with the same tools they used on the scrub-jay and came up empty.  The bush-crow’s bordering habitat was the same.  Why didn’t the bush-crow use it?

Then in 2012 a team headed by Dr Paul Donald of the RSPB figured out that the Ethiopian bush-crow lives in a cool, dry climate bubble where the average temperature is less than 20oC (68oF).  Outside his range it’s hotter and he won’t go there.  Terrain and elevation created his zone but climate change is raising the temperature and the bush-crow’s bubble is shrinking.

If his problem was caused by loss of habitat, as it is for the Florida scrub-jay, laws and habitat restoration could increase the bush-crow’s available land but climate change is a much thornier problem requiring international political will.  This bird is endangered.

Right now there are about 9,000 breeding pairs of Ethiopian bush-crows on earth.  But for how long?

Click here to read about the Ethiopian bush-crow’s climate preference.  Click here for his range map.

 

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

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Dec 01 2013

Pharoah’s Chicken

Pharoah's Chicken, Egyptian vulture (photo from Wikimedia Commons)

During this turkey weekend I found a bird called Pharoah’s Chicken, though he isn’t a chicken at all.

This large bird of prey is an Egyptian vulture (Neophron percnopterus) whose nickname refers to his use as a symbol of Egyptian royalty.

He lives in Europe, Asia and Africa but he no longer lives well.  Sadly he’s endangered, having declined by 50% in Europe in only 20 years (1980-2001) and drastically in India where there’s a vulture crisis caused by livestock antibiotics that are poisonous to the vultures.

This bird posed nicely for a photograph in a zoo in Spain.

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

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Nov 24 2013

The Falcon That Laughs

Laughing Falcon (photo by Charlie Hickey)

Snakes seem to be a subtext on my blog lately.  Snakes caused the extirpation of the Guam rail, they’re one of many foods eaten by secretary birds, and now I’ve learned there’s a falcon in Central and South America that eats poisonous snakes and laughs.

The laughing falcon (Herpetotheres cachinnans) is named for his two most obvious traits.  Herpetotheres roughly means to “mow down snakes,” cachinnans means to “laugh immoderately.”

He captures snakes by watching from a perch, then pouncing to break their necks or behead them.  And he really does laugh.  Listen to this recording of a pair “singing” a duet.

Laughing falcons are about the size of peregrines and are often pictured with their head feathers raised, a pose that makes them resemble ospreys not falcons.  When they lower their head feathers, as in this photo on Wikimedia Commons, you can see their falcon family resemblance.

I first heard of this species when Charlie Hickey posted photos from his trip this month to Puntarenas, Costa Rica.  (Click here for Charlie’s photos.)  I wonder if it was hard to find this bird in Costa Rica.  According to BirdLife International the laughing falcon has declined drastically in some locations but has such a wide range that it has not yet been listed as “vulnerable.”

 

(photo by Charlie Hickey)

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Nov 19 2013

An Eagle Like A Crane

In Africa there’s a bird of prey with legs so long he looks like a crane.

Though the secretary bird (Sagittarius serpentarius) can fly he prefers to walk as he browses for food in the underbrush.  His legs are so long he has to crouch to get his beak to the ground.

A scorpion is a snack, a mongoose is a meal.  Secretary birds even eat poisonous snakes, adders and cobras, which they stun and kill by stomping with their feet.

Perhaps that’s why these birds are so tall.  Their bodies are out of reach of their dangerous prey.

I love to watch them walk:  crane-like eagles with black knee-pants.

 

(video from WildlifeVideoChannel on YouTube)

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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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