White-crowned Sparrow Males Unruffled by Younger Rivals

March 13, 2012 by  
Filed under News

In the territorial world of nature, it’s not uncommon for older males to give way to the younger generation, albeit with a fight. Researchers have recently discovered that this is not necessarily the case with mature white-crowned sparrow males. In fact older males don’t even bother to get involved in any altercation, verbal or physical, and this is seen as evidence that they don’t view younger males as a threat.

In the study, which was carried out by Angelika Poesel and Douglas Nelson of the Ohio State University and funded by the National Science Foundation, it was noted that the older male would, however, become agitated and aggressive upon hearing a rival bird of the same age in his territory. It appears that the males of this species assess the fighting ability of their opponents based on age, and younger males simply don’t scare them.

The study observed a migratory population of white-crowned sparrows nesting in Bandon, Oregon, from 2008 to 2011. While plumage is an important indicator of maturity, the results of the study reveal that some birds use each other’s songs to determine age and threat level. As is the case with many bird species, male white-crowned sparrows use their songs to establish nesting territory and court a potential mate. Should a male sing in another’s territory, he can expect to be attacked and driven off if perceived to be a threat. With this particular bird species, second-year males do have plumage differences, but they also sing two or more versions of their species unique song before they choose one, and abandon the rest. This multiple version singing indicates to more mature males that the bird singing in his territory is a second-year male, and not a threat worth getting ruffled feathers about.

The research was carried out by playing various songs through loudspeakers within the established territories of mature males, and careful observation of the birds’ behavior. It was noted that second-year males that have established territory, did not tolerate other second-year males invading their space. It is thought that female birds are naturally more attracted to mature birds than to younger ones, and the older birds know this. Also, younger birds are disinclined to push their luck with a mature male which is likely to be stronger and more experienced.

Lead author of the study, Angelika Poesel, is curator of the Borrer Laboratory of Bioacoustics. Douglas Nelson is associate professor of evolution, ecology and organismal biology, and director of the University’s Borrer Laboratory.

Interesting RSPB Survey Results

August 23, 2011 by  
Filed under News

The RSPB’s wildlife survey would not be possible if not for the loyal participation of the public, who assist in the Make Your Nature Count project. The survey began on the 4th of June and ran to the 12th of June, involving over fifty thousand gardens. Due to the assistance of the participants, the RSPB Make Your Nature Count project could collect the necessary information to compile a report on a variety of bird species to determine how successful the breeding season was. The feedback was extremely positive.

Once all the data was received, it showed that there was an increase in the breeding of robins, and that there was a ten percent increase in song thrushes in gardens across the United Kingdom. The organizer of the RSPB Make Your Nature Count, Richard Bashford, commented that it was very exciting to see the increase of song thrushes, blackbirds and robins, as it means that weather conditions were ideal during the breeding season. Since 2010, blackbirds had increased by fifteen percent. Bashford said that even though the numbers of the song thrushes had increased, it is important to remember that they did go through a period of decline and are slowly beginning to recover and have a far way to go before their numbers are satisfying, even though there are not any guarantees that the same favorable outcome will appear next year. House sparrows also seemed to increase by approximately twenty percent, but are still to be watched carefully. Thirty percent increases were recorded for chaffinches and blue tits.

The survey was performed in rural areas, urban and suburban areas and it was also the first time the public participants were asked to be on the lookout for grass snakes and bats. Almost one in fifty of the participating members reported grass snakes and they are more likely to be found in rural areas. Thirty-three percent of the participants also reported bats. As an added request they were also asked to take note of toads and frogs, as there had been a decline in their numbers over the last two years. The wildlife in any garden impacts the environment, and through the voluntary services of the public the RSPB is able to conduct their surveys and compile their reports to keep constant records on the various species.

Bills Regulate Body Temperature

July 26, 2011 by  
Filed under Features

On 20 July 2011 the research done by a team of scientists from the well-known Smithsonian Migratory Bird Center was published in the Ecography journal, and has revealed more insight into the use of bird’s bills. Working at the Conservation Biology Institute of the Smithsonian Center, the team focused their attention on five different sparrow species that prefer the marshes of various regions, and discovered that they use their bills for more than just eating food and foraging. It was shown that not only are their bills adapted to their diets, but they can also assist birds to regulate body heat.

There were ten sparrow species and their subspecies that the team found to enjoy the salt marshes that are located along the North American Gulf Coasts, and they looked at more than one thousand three hundred individual birds. When measuring the individual birds and looking at their bills, along with the temperatures where they reside, it has been recorded that the size of their bills were determined by this feature as well, as their bills assisted them to regulate their body heat during the soaring temperatures of the summer. The higher the average summer temperature of a specific region, the bigger the bills were on the birds. To release their body heat, it was determined that the birds are able to transfer blood into the tissue that is found in their bills and from there the heat is expelled into the air. Therefore the bigger the bill on the bird, the more heat is able to be released into the air.

This was confirmed by comparing the birds in the different areas, as the birds living in the cooler marsh areas have smaller bills than those living in higher temperatures. Leader of the research team and director of the Smithsonian Migratory Bird Center, Russ Greenberg, commented that is has been known that in animals, such as rabbits and seals, blood is able to be increased to the extremities of animals that are not well insulated, but now it is known that birds are able to cool down their body temperature through their bills, as well as retain their body moisture, which they so desperately need in such high temperatures. The team is now continuing their research with Brock University physiologists, trying to form a more detailed database by using thermal imaging.

Attracting Birds: Seed Preferences

July 6, 2010 by  
Filed under Birding Tips

There is no better way to decorate your garden than with a collection of wild birds that bring color and song to the trees and landscaped areas. Luring a variety of birds to a garden is not always as easy as it may sound. Most birds know exactly what they like and will travel to an area where they know they can eat their preferred seed or form of food. Fortunately, if you know what birds you want to attract, you can purchase the seeds and items that draw these species into your garden.

It is important to fill a variety of bird feeders and place them in different locations throughout the garden. This way birds will not be fighting to get to the food and a greater number of birds will frequent the feeders. Putting out their favorite foods is the best way to ensure that they will continue to return, and in winter bird feeders assist a great number of birds to survive the cold weather. Wild birds will not usually eat artificial pellets or processed seeds as they are not accustomed to them, so natural seeds are the key.

Sunflower seeds are generally a safe bet, as a wide variety of birds will eat them, such as chickadees, nuthatches, finches, cardinals, grosbeaks, sparrows, blackbirds, jays, woodpeckers and titmice. All these birds, with the exception of the sparrows, blackbirds, jays and woodpeckers, will also eat Safflower seeds. When trying to lure ducks, geese, mourning doves and quails, cracked corn will do the trick; and woodpeckers, titmice and chickadees are also known to eat unsalted peanuts. Nyjer (or Thistle) will attract redpolls, doves and pine siskins; while orioles, thrushes and hummingbirds prefer nectar. Fruit is another option to use in combination with seeds as mockingbirds, bluebirds, thrushes, cedar waxwings and orioles will enjoy the treat. The preferred food for juncos and towhees is millet. Setting out a mixture of seeds, fruits and nectar will have any garden filled with birds in no time, allowing home owners to enjoy the beauty of these winged creatures and relax to the melodies of their cheerful songs.

Shifting Migrations Might Indicate Global Warming

February 19, 2009 by  
Filed under Features

Each year thousands of citizens in the US get involved with the annual Christmas bird count. They are not professional birders, but their counts do help biologists and other researchers to get a better idea of the grand scale of things. Over time this count has revealed that almost 60 percent of migratory birds are spending their winters further north than they did forty years ago.

According to studies, the American Robin and White-throated Sparrow are just two of the 305 bird species examined which showed a dramatic northward shift in their annual migratory patterns. While this does not prove global warming in itself, it is consistent with the sort of behavior you’d expect to take place in direct reaction to a steadily warming climate. The concern is not so much for the birds themselves, but for other non-migratory bird species and animals that are left behind to suffer through the heat. Kenn Kaufman, field editor for Audubon Magazine, stressed the interdependence of everything in an ecosystem when he said about the trend: “Everything is connected. Birds are not isolated; it’s an ecosystem. It’s a system and something that happens in one area is going to affect everything else.”

While bird ranges can change for a number of different reasons, such as urban sprawl, supplemented diets and deforestation, researchers have noted that the most likely explanation for why so many different migratory birds over such a broad area are choosing to winter further north is most likely global warming. The shift is not just affecting one or two species from one or two areas – its affecting a large number of species from a large number of areas. The phenomenon is simply too widespread to be attributed entirely to only one localized cause.

So where does the report released by the National Audubon Society leave bird lovers? It refreshes in our minds the need to not contribute to the many factors causing global warming. Not only can we change our own lifestyles and encourage others to do likewise, but if we live in an area where there are non-migratory birds, we can try to be aware of their needs, providing them with food, water and shelter so that they can survive the conditions as best as possible.

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