Archive for the ‘Avian Reproduction’ Category

Singing Sparrows

June 6, 2014

Chipping_Sparrow

From The New York Times we learn that chipping sparrows love their neighbors, but only if they are weaklings. Male intruders can invade and take over another bird’s territory and strong invaders are usually the winners. Male chipping sparrows will form a neighborhood coalition to defend their territories, but apparently only if the intruder is weaker.  And how do they know this?  By the intruder’s song.  If the intruding sparrow’s trill is weaker, i.e. slower, then that bird is less aggressive.  A faster trill indicates a strong invader.

Stick to those music lessons, little chippers!

Click here to read the New York Times article.

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In a Bird’s Nest, an Animal Behavior Puzzle

December 11, 2013

From The New York Times

Sometimes the scientists who study animal behavior solve puzzles and other times they uncover new ones. The war between mockingbirds and cowbirds is a case in point.

Cowbirds are brood parasites, meaning they lay their eggs in the nests of other bird species, thus unloading the messy and demanding business of chick-rearing. They also peck holes in the eggs of the host birds, destroying as many as they can.

Mockingbirds are a favorite target of this plan, and it seems to make perfect sense for them to viciously attack cowbirds when they catch them in the nest.

But when Ros Gloag, then a doctoral student at Oxford, and her colleagues in Argentina looked closely at the war between chalk-browed mockingbirds and shiny cowbirds, they found something unexpected, as they reported in the November issue of Animal Behaviour.

They stationed small video cameras near the nests of 40 pairs of chalk-browed mockingbirds. Over two breeding seasons they recorded more than 200 attacks on intruding cowbirds.

They were surprised to find that these attacks, which their videos show to be quite vicious, did not stop the cowbirds from laying eggs. The cowbirds would hunker down and let the much large mockingbirds deliver hammer blows to the head, but in matter of seconds they would lay an egg and flee.

How could such a failed strategy persist in evolution?

The answer, according to Dr. Gloag, now a postdoctoral researcher at Australian National University, was that the attacks did prevent the cowbirds from carrying out the second prong of their plan, destroying the mockingbird eggs already in the nest.

So the mockingbirds managed to save some of their offspring. They still end up raising unwanted baby cowbird guests. But, said Dr. Gloag, once the eggs hatch, the larger mockingbird chicks compete very well with the smaller cowbirds.

PERMALINK + VIDEO: The New York Times

10 Ways to Help Migratory Birds

December 2, 2013

From the National Wildlife Federation

ImageFrom the American Bird Conservancy: top 10 things you can do in your home or yard to help declining migratory birds

The American Bird Conservancy (ABC) often gets asked how people can help birds during this time of year. Toward that end, ABC has identified the top ten things people can do to aid or protect migratory birds in their homes and yards.

1.  Keep your cat indoors—this is best for your cat as well as the birds, as indoor cats live an average of three to seven times longer. Even well fed cats kill birds, and bells on cats don’t effectively warn birds of cat strikes. For more information, go to http://www.abcbirds.org/cats.

2.  Prevent birds from hitting your windows by using a variety of treatments to the glass on your home—check out ABC’s tips at http://www.abcbirds.org/abcprograms/policy/collisions/glass.html

3.  Eliminate pesticides from your yard—even those pesticides that are not directly toxic to birds can pollute waterways and reduce insects that birds rely on for food.

4.  Create backyard habitat—if you have a larger yard, create a diverse landscape by planting native grasses, flowers, and shrubs that attract native birds. You will be rewarded by their beauty and song, and will have fewer insect pests as a result.

5.  Donate old birdwatching equipment such as binoculars or spotting scopes to local birdwatching groups—they can get them to schools or biologists in other countries who may not have the resources they need.

6.  Reduce your carbon footprint—use a hand-pushed or electric lawnmower, carpool, use low energy bulbs and Energy Star appliances. Contact your energy supplier and ask them about purchasing your energy from renewable sources.

7.  Buy organic food and drink shade-grown coffee—increasing the market for produce grown without the use of pesticides, which can be toxic to birds and other animals, will reduce the use of these hazardous chemicals in the U.S. and overseas. Shade coffee plantations maintain large trees that provide essential habitat for wintering songbirds.

8.  Keep feeders and bird baths clean to avoid disease and prevent mosquitoes from breeding.

9.  Support bird friendly legislation both locally and in the U.S. Congress.

10.  Join a bird conservation group—learn more about birds and support important conservation work.

According to ABC, birds need our help now more than ever.  In addition to the ongoing threat of loss of habitat that is becoming magnified by global warming, millions of birds are directly killed due to a number of different human-related causes.
Scientists estimate that 300 million to 1 billion birds die each year from collisions with buildings. Up to 50 million die from encounters with communication towers.  At least 11 million die from car strikes.  Another 1 million may die each day from attacks by cats left outdoors.

Some of these deaths occur year-round but many occur during the peak spring and fall migrations. Some studies suggest that perhaps as many as half of all migrating birds do not make it back to spring and summer grounds, succumbing to various threats on either end of the journey.

“Protecting and helping birds is not only the right thing to do, it is also good for the economy and the future of our environment. Birds are invaluable as controllers of insect pests and as pollinators of crops, and also generate tremendous economic revenues through the pastimes of bird feeding and birdwatching,” says ABC President George Fenwick.

A recent federal government study reports that over 20 percent of the U.S. population – 48 million people – participates in birdwatching.  Of that total, about 42 percent (20 million people) actually travel to see birds. Birders spend about $36 billion annually in pursuit of their pastime.  The top five birdwatching states by percentage of total population are: Montana (40%); Maine (39%); Vermont (38%); Minnesota (33%); and Iowa (33%).

Photo of Scarlet Tanager by Brian Tang

PERMALINK: National Wildlife Federation

Brazilian Logger Turned Birder Aims to Turn His Community into Bird Sanctuary

December 2, 2013

From SustainableTrip.org

sustainableTripIn the heart of the Brazilian Amazon is the Rio Negro Sustainable Development Reserve, an area that is rich in biodiversity and home to several small communities that depend on natural resources for a living. Pousada Garrido is the only hotel in the Tumbira region, and it is owned by a former logger and community leader named Roberto Mendonça.

Pousada Garrido has become a source of income for Mendonça as well as several other local families who offer tourism services to visitors. The inn also uses solar energy (as does the entire community), recycles, supports local artisans with reusable materials, and purchases foods from local producers. This year, Pousada Garrido earned Rainforest Alliance verification for sustainable tourism.
Tourists are drawn to Tumbira for the richness and exuberance of its forests, including the many bird species that abound there.

Mendonça partnered with a local tour guide named Cleudilon, whose nickname is Passarinho, or “little bird” in Portuguese, because he can perfectly imitate 32 types of birds! (Scroll down to see an awesome video of Cleudilon calling to birds in the forest.) The two recently undertook a project to make the inn into a perfect site for bird watching. And you can help make it happen! Visit the community’s crowdfunding page, to help them turn Tumbira into a community-based ecotourism center.

Paula Arantes of Garupa, the NGO helping Mendonça and Cleudilon raise money for the project, tells us more about the initiative.

Question: What is the plan for the money you hope to raise?
Paula Arantes: Roberto and Cleudilon want to turn their community into a birding and community tourism center. To get started, they intend to adapt the infrastructure of Pousada Garrido to sustainably accommodate more guests and provide what is needed for birding. They also want to publish a guide to the local birdlife as a reference for tourists and an educational resource for the children of the community.

Q: Why are Tumbira and Pousada Garrido such special places for bird watching?
Arantes: Though you can see birds everywhere in Amazon, Tumbira is special because its pathways make it easy to see many varieties of birds, and the area is easily accessible by land or by boat. Furthermore, Cleudilon’s incredible talent for imitating birds and really enhances the birding experience.

Q: What do you need to carry out the project?
Arantes: Investments need to be made to expand the inn without negatively impacting the environment. More equipment is also needed for bird watching, and Cleudilon needs resources to develop the bird guide. The goal is to raise around US$8,800 (20,000 Brazilian reales) to help cover building materials, labor, the development of the guide, and more.

Q: What progress has been made so far?
Arantes: Thanks to the Rainforest Alliance verification process, we’ve identified the appropriate areas for making investments and improvements in a sustainable way.

Q: How does this project benefit the community?
Arantes: More tourists means more sustainable income for the residents! Supporting community-based tourism is one of the best ways for travelers to ensure that their vacation is sustainable.

Q: How can people help?
Arantes: On the project page on the Garupa website, you can find more details about the initiative and make an online donation to co-finance this effort. Donors receive tokens of appreciation, such as photographs, the bird guide, and even stays at the inn, depending on the amount contributed. Donating any amount, no matter how small, and sharing our project with your friends and family is the best way to make Roberto’s dream a reality!

PERMALINK: sustainabletrip.org

An Earlier Exodus Amid Climate Change

December 2, 2013

From The New York Times

godwit-NYTimesBirds are migrating earlier and earlier each year, and scientists have long suspected that climate change is responsible. A new study by researchers at the University of East Anglia in England shows that individual birds migrate like clockwork, but nesting and hatching are happening earlier as a result of warmer temperatures, and this appears to be linked to the advancing of overall migration patterns.

PERMALINK: The New York Times

Negative Effects of Road Noises on Migratory Birds

December 2, 2013

From Science Daily

A first-of-its-kind study by Boise State University researchers shows that the negative effects of roads on wildlife are largely because of traffic noise.

Biologists have known that bird populations decline near roads. But pinpointing noise as a cause has been a problem because past studies of the effects of road noise on wildlife were conducted in the presence of the other confounding effects of roads. These include visual disturbances, collisions and chemical pollution, among others.

“We present the first study to experimentally apply traffic noise to a roadless area at a landscape scale, thus avoiding the other confounding aspects of roads present in past studies,” said Christopher J. W. McClure, post-doctoral research associate in the Department of Biological Sciences.

“Understanding the effects of road noise can help wildlife managers in the selection, conservation and management of habitat for birds,” said Jesse R. Barber, assistant professor of biological sciences and one of McClure’s fellow researchers.

Beside McClure and Barber, researchers in the study include Heidi E. Ware, graduate student; Jay Carlisle, assistant research professor and research director of the Idaho Bird Observatory; and Gregory Kaltenecker, executive director of the Idaho Bird Observatory.

Researchers created a phantom road on a ridge southeast from Lucky Peak, near the Idaho Bird Observatory’s field site. Putting speakers in trees, they played roadway sounds at intervals, alternating four days of noise on with four days off during the autumn migratory period. The researchers conducted daily bird surveys along their phantom road and at a nearby control site.

“We documented more than a one-quarter decline in bird abundance and almost complete avoidance by some species between noise-on and noise-off periods along the phantom road,” Barber said. “There were no such effects at control sites. This suggests that traffic noise is a major driver of the effects of roads on populations of animals.”

PERMALINK: Science Daily

Valentine’s Day and Sex

February 14, 2011

Valentine's Hors d'oeuvre

For Valentine’s Day the folks at Enature have contributed a mating game for we humans to discover which members of the other species our romantic behavior most closely emulates. Play their Mating Game and discover for yourself. However, even if you turn out not to resemble a bird romantically, be sure to click on the bird species descriptions. There you will learn, for instance , that the male Greater Roadrunner dangles a tasty food morsel – a mouse, say – in front of his intended but won’t let her have it until after they’ve mated. Or that Sandhill Cranes, which mate for life, go through elaborate courtship rituals when young. They dance, display, hop, flap, and strut. But after many years together, they simply jump up and down a couple of times before mating.

Wild Swans

February 20, 2009

swan_flying1

Writing adequately about swans and their place in mythology and literature would take a very long time indeed.  We started the process early in the history of this blog when we began our series about bird sex.  (Part I, Part II, Part III)

cygnus

Today, while waiting for the end of winter, that season during which the constellation Cygnus the Swan is not flying up the Milky Way high overhead, we turn to Edna St. Vincent Millay’s poem of a woman inspired by wild swans to open her heart to all the myriad joys of life.

Wild Swans

I looked in my heart while the wild swans went over.
And what did I see I had not seen before?
Only a question less or a question more:
Nothing to match the flight of wild birds flying.
Tiresome heart, forever living and dying,
House without air, I leave you and lock your door.
Wild swans, come over the town, come over
The town again, trailing your legs and crying!

Edna St. Vincent Millay

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Photo Credit: Ginger Holser, WDFW photos.

Turkeys

November 25, 2008
Wild Turkey

Wild Turkey

Benjamin Franklin famously believed that the national bird of the United States should be the wild turkey.  Of course, he also thought the rattlesnake would be a good symbol for the new country; because this is a bird blog, we’ll let that go.

In a letter to his daughter Franklin wrote about the bald eagle,

He is a Bird of bad moral Character. He does not get his Living honestly. You may have seen him perched on some dead Tree near the River, where, too lazy to fish for himself, he watches the Labour of the Fishing Hawk; and when that diligent Bird has at length taken a Fish, and is bearing it to his Nest for the Support of his Mate and young Ones, the Bald Eagle pursues him and takes it from him.

On the other hand, Franklin asserted,

For the Truth the Turkey is in Comparison a much more respectable Bird, and withal a true original Native of America . . . He is besides, though a little vain & silly, a Bird of Courage, and would not hesitate to attack a Grenadier of the British Guards who should presume to invade his Farm Yard with a red Coat on.

Franklin was right about the turkey being a native of North America.  It has been here a long time. Because of its large size and historical use as human food, the turkey has a good fossil record.  Fossils have been found as far back as the Miocene and the Pleistocene in North America. Archeology established long ago that many subsistence cultures ate them.

Female Wild Turkey with chicks

Female Wild Turkey with chicks

Hunting them must have been a challenge to those early hunters. Franklin aside, the birds are extremely wary; no wild turkey would have attacked a British Grenadier.  But it would have seen and heard that Red Coat coming from miles away and fled.  Wild turkeys possess keen eyesight and exquisite hearing which makes them hunting challenges even for their primary modern predator, humans.  Males prefer running away; females, flying.  Both can fly and at speeds up to 50mph.

That turkey in your kitchen for this Thanksgiving is a pale imitation of the real thing.  Because of the popularity of white meat — white because it is different muscle with less ability to store oxygen than dark muscle — your turkey was bred for a large breast.  In fact, domesticated turkeys raised for food have such large breasts they are incapable of mounting females for the cloacal kiss.  Instead the males are artificially manipulated and then milked for their semen which is then injected into the females to fertilize their eggs. Confined to quarters, these domesticated turkeys are tricked by artificial light into breeding year round so that the supply, especially now, is adequate.  Far too heavy for flight, it could never have escaped a British soldier.

But even though that Broad-breasted White Turkey you cut into this Thanksgiving is not the same as his wild, shrewd cousin, you partake of a North American tradition far older than Thanksgiving.

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If you need any help carving a turkey, here is a video of a pretty good way to do it.

Displayers of the Purple Sage

October 6, 2008

The governor of Wyoming, unlike the federal government, is worried about the Greater Sage-grouse.  The mad dash to sell and lease the West to the oil and gas companies, frenetic for the last seven years, has reached an even more frenzied state as the Bush Administration winds down.

Lewis and Clark wrote about the Sage-grouse in 1805, back when it was abundant on western prairies.  That was before conversion of the prairie to agricultural uses and mineral extraction.  Millions of acres were stripped in order to grow wheat and potatoes. Millions more were stripped to make the land safe for cattle.  Sagebrush, almost as nutritious as alfalfa, contains toxins which kill bacteria in the stomachs of cows which can result in death. Cattle, unlike Pronghorn Antelope, did not co-evolve with sagebrush.  Antelope thrive on it.  Their ancestral range shrunk along with that of the Sage grouse and Native Americans who used sagebrush to stop internal bleeding and to rid themselves of internal parasites.

Cities required yet more sagebrush land.  As a result of all this human activity, sagebrush is dying and so is the Sage-grouse.  We’ve denuded an area the size of Europe of its natural cover.  If he were writing today Zane Grey would name his most famous novel, Riders of the Long Gone Sage.  What little sagebrush habitat is left overlies deposits of natural gas and oil.  Exploration, drilling and extraction disrupt the habitat and its occupants even more.

Sagebrush

Sagebrush

The Greater Sage-grouse is the largest North American grouse and is famous for the mating displays of the males.  When the spring mating season comes, their esophagi enlarge as much as 50 times, apparently the result of large doses of testosterone.  They expand and collapse their esophagi pouches making noise to attract females.  The males gather on breeding grounds known as leks to strut their stuff as you can see in this video.

The females wander through the leks and select males.  Actually they select very few males.  In one study two males copulated with 76% of the available females.  Because mating, a cloacal kiss, takes only few seconds, males may mate as many as 20 times a morning. One male was caught by a scientist copulating 169 times in one season.  Less successful males hang around, apparently hoping that the successful males will tire, leading other females to select them.  (“The spillover effect,” according to one scientist.)

Mostly this activity occurs around sunrise during springtime.  Golden Eagles learned about this.  Now they wait, up in the eastern sky for the strutting to begin then swoop down out of the sun attempting to grab a bird. The most successful males are in the most danger because they keep strutting after the other males and females have gone to ground.  A little testosterone is a good thing; a lot of it can get you in trouble.

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The film and the photos, except for the last one, come from Dr. Gail Patricelli of UC Davis.  You can read more about Greater Sage-grouse at this Audubon site.  If you want to weigh in on habitat protection the Audubon Society has a form letter you can send to the BLM, although it is always better to write your own.


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