![]() ![]() We discuss possible explanations why sparrow populations may not differ in competitiveness despite the smaller body mass of urban birds. Thus our results did not support the hypothesis that urbanization shifts population structure towards an over-abundance of weak competitors in house sparrows. Moreover, the variance in competitive abilities also did not differ between birds from more and less urbanized habitats. We found that sparrows exhibited consistent individual differences in competitiveness, but these differences were not related either to the degree of urbanization of their original habitats or to their body mass. Here we compared several aspects of their competitiveness (fighting, scrambling and searching for food) in captive mixed flocks of urban and rural birds. We previously showed that wild urban sparrows are smaller and leaner than rural conspecifics, and this difference persists for months under identical captive conditions. To evaluate this hypothesis, we tested whether competitive performance differs between differently urbanized populations of house sparrows Passer domesticus. Existing theory of this topic suggests that the cities' more constant food supplies and lower predation pressure lead to a high proportion of weak competitors in urban populations. How urbanization affects animal populations is in the focus of current ecological research. Our findings indicate that the significance of kin selection may be restricted in some social systems such as winter aggregations of birds. due to competition among relatives as predicted by a recent refinement of kin-selection theory. These results suggest that the pay-offs of reduced aggression towards kin may be low in non-breeding flocks of sparrows, e.g. Fighting success was also unrelated to kinship and the presence of relatives in the flock did not influence the birds’ dominance rank. We found that sparrows did not reduce their aggression towards kin, as neither the frequency nor the intensity of fights differed between close kin and unrelated flock-mates. To test this hypothesis, we investigated whether relatedness affects aggressive behavior during social activities in captive house sparrow (Passer domesticus) flocks. Sign up here to receive the RCC E-News and other RCC newsletters, information and alerts.Kin-selection theory predicts that relatedness may reduce the level of aggression among competing group members, leading to indirect fitness benefits for kin-favoring individuals. The Rachel Carson Council depends on tax-deductible gifts from concerned individuals like you. He is also the owner/art director of New Age Graphics, a full-service graphic design firm in Wheaton, MD. Ross also serves as a guide at the Patuxent National Wildlife Refuge, a frequent birding spot for Rachel Carson who first learned about the health effects of DDT at the laboratory there. ![]() ![]() Ross is a life-long birder and photographer who is the editor of the Friends of Patuxent National Wildlife Refuge newsletter. Ross Feldner is the lead, with Bob Musil, of the RCC Bird Watch and Wonder Program. Wrens: herd, chime The next time you’re at the beach impress your friends and say “will you look at that squabble of gulls!” Swans: wedge, ballet, lamentation, whiteness, regatta Watch this amazing murmuration of starlings in the United Kingdom! Other birds, such as dunlins, may synchronize a subtle tilt to their bodies while in a flight flock as a way to camouflage their plumage to confuse predators. This flock behavior is meant to quickly deter their predator, the fast and furious falcon. Birds drafting off of each other’s flapping wings can make the journey easier and less exhausting.Ĭertain birds, such as starlings, for example, form acrobatic flocks that can turn on a dime to create shapes and undulating feats in the air. Flocks of birds that fly in “V” formations may be doing so to conserve energy. Flocking can increase the possibility of finding food and protecting each other from trouble and predators. Most experts believe flocks increase the odds of survival and safety. Many make perfect sense, but some are real head scratchers.īirds form clusters of organized groups, called flight flocks, for a reason. Ever wonder what a group of turkeys is called, or maybe a flock of gulls? Most of us have heard the term a gaggle of geese but what about a group of cardinals? Here’s a fun listing of names for various groups of birds. ![]()
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![]() data? Seriously? ) No other distro ever had /data. Yeah, that's probably a good idea anyway, and it would fix this issue. Ideally we should remember somewhere version number, or at least check if karts and tracks directories exist. We sould detect if this is our data directory. I would hope that it would define SUPERTUXKART_DATADIR to the correct value, though. I'm not familiar with the STK codebase, so I must be missing something here - maybe cmake defines SUPERTUXKART_DATADIR by default and uses an incorrect value?Įdit: I just took a look at CMakeLists.txt and saw that it always defines SUPERTUXKART_DATADIR when building on Macs. The only time I can see #2074 being a problem is if SUPERTUXKART_DATADIR was defined to the wrong directory when building 0.9-rc1. Wouldn't you define the preprocessor option SUPERTUXKART_DATADIR to the correct directory ( /home/Games/Supetuxkart-0.9-rc1) or just leave it undefined when building 0.9-rc1? If you defined it to the correct directory, things would work (because the correct path would take precedence), and if you left it undefined, STK would behave as it does now (because that section would be compiled out). ![]() If you will prioritize SUPERTUXKART_DATADIR, then 0.9-rc1 version will find 0.8.1 data directory in /usr/local/share/supertuxkart and it will crash. Thank you both for your responsiveness and helpfulness. Temporary workaroundįor the time being, I can manually specify the correct data directory with supertuxkart -root=/usr/share/supertuxkart/data. ![]() Note that even if the Arch Linux package was built with SUPERTUXKART_DATADIR defined to the correct directory, STK would still check for the problematic path. /data exists (in this case /data), it must contain the STK data files. The problem is that STK erroneously assumes that if a directory. Looking at the source, it appears that the bug was introduced in b9b2f96. : Directory 'textures' not found, aborting. : Directory 'skins' not found, aborting. : Directory 'shaders' not found, aborting. : Directory 'tracks' not found, aborting. : Directory 'music' not found, aborting. : Directory 'models' not found, aborting. : Directory 'library' not found, aborting. : Directory 'grandprix' not found, aborting. : Directory 'fonts' not found, aborting. : Directory 'challenges' not found, aborting. : User-defined grand prix will be stored in '/home/jim/.local/share/supertuxkart/grandprix/'. : Screenshots will be stored in '/home/jim/.cache/supertuxkart/screenshots/'. : Addons files will be stored in '/home/jim/.local/share/supertuxkart/addons/'. ![]() : User directory is '/home/jim/.config/supertuxkart/0.8.2/'. : Data files will be fetched from: '././data/' Main: Error messages and other text output will be logged to /home/jim/.config/supertuxkart/0.8.2/stdout.log. ![]() |